Circuit Board and Process for Preparing the Same

Abstract

The present invention provides a process for preparing a pre-treated low Dk-type glass fabric for constituting a circuit board, comprising pre-treating low Dk-type glass fabric with a pre-treating varnish having a Dk close to the Dk of the used low Dk-type glass fabric at different temperatures and having a small Df. The present invention further provides a bonding sheet and a circuit board prepared thereby. The circuit boards prepared by the preparation process of the present invention have a Dk having small differences in warp and weft directions, and can effectively solve the problem of signal propagation delay. The circuit boards have a small Df, so as to have a small signal loss. Meanwhile, the cured, partially-cured or uncured dry glue obtained after drying the solvent of the pre-treating varnish has similar dielectric properties at different temperatures to the used low Dk-type glass fabric, so that the circuit boards have a very small signal propagation delay at different temperatures.

Claims

1. A process for preparing a pre-treated low Dk-type glass fabric for constituting a circuit board, comprising (1) preparing a pre-treating varnish, wherein the pre-treating varnish has a dielectric constant Dk having a difference of ±5% from that of the low Dk-type glass fabric to be used at different temperatures (from −55° C. to 85° C.), and has a dielectric loss Df of 0.007 or less (10 GHz) at different temperatures (from −55° C. to 85° C.); and (2) pre-impregnating the low Dk-type glass fabric in the pre-treating varnish obtained in step (1), then drying solvent to obtain a pre-treated low Dk-type glass fabric having a Dk of 5.0 or less (10 GHz).

2. The process according to claim 1, wherein the pre-treating varnish has a Df of 0.005 or less (10 GHz) at different temperatures (from −55° C. to 85° C.).

3. The process according to claim 1, wherein the pre-treating varnish is a varnish obtained by dissolving a resin composition in an organic solvent; wherein the resin composition comprises a resin, a suitable amount of a curing agent, a first component filler, and a second component filler, and the nonvolatile ingredients are based on parts by mass, wherein the resin and curing agent are in an amount of 40 parts by mass; the first component filler and second component filler are in an amount of from 45 to 60 parts by mass.

4. The process according to claim 3, wherein the resin is one selected from the group consisting of polyphenyl ether resin having unsaturated double bonds, polybutadiene resin, polybutadiene copolymer resin, elastomer block copolymer, or a mixture of at least two selected therefrom.

5. The process according to claim 3, wherein the first component filler is one selected from the group consisting of titanium dioxide, calcium titanate, strontium titanate, or a mixture of at least two selected therefrom; the second component filler is one selected from the group consisting of alumina, magnesium oxide, magnesium titanate, or a mixture of at least two selected therefrom, wherein the first and second component fillers have a mass ratio of 1:(0.5-2.0).

6. The process according to claim 1, wherein the pre-treating varnish has a Dk which is ±0.1 (10 GHz) of that of the low Dk-type glass fabric.

7. The process according to of claim 1, wherein the low Dk-type glass fabric is NE glass fabric; the NE glass fabric has a resin content of from 20 wt. % to 50 wt. %.

8. A pre-treated low Dk-type glass fabric prepared according to the process of claim 1.

9. A bonding sheet prepared by mainly impregnating the pre-treated low Dk-type glass fabric according to claim 8 in a main resin varnish, and then drying solvent.

10. A circuit board prepared from the bonding sheet according to claim 9.

11. A laminate, characterized in respectively superimposing metal substrates at no, one or both sides of one or more sheets of the pre-treated low Dk-type glass fabric according to claim 8.

12. A laminate, characterized in respectively superimposing resin-covered copper foils at one or both sides of one or more sheets of the pre-treated low Dk-type glass fabric according to claim 8.

13. A laminate, characterized in respectively superimposing resin film layers at one or both sides of one or more sheets of the pre-treated low Dk-type glass fabric according to claim 8.

14. A printed circuit board prepared by the bonding sheet according to claim 9.

15. The process according to claim 4, wherein the polyphenyl ether resin having unsaturated double bonds is one selected from the group consisting of polyphenyl ether resin having two terminal modifying groups being acryloyl groups, polyphenyl ether resin having two terminal modifying groups being styryl groups and polyphenyl ether resin having two terminal modifying groups being vinyl groups, or a mixture of at least two selected therefrom.

16. The process according to claim 4, wherein the polybutadiene resin is one selected from the group consisting of 1,2-polybutadiene resin, polybutadiene resin modified with maleic anhydride, polybutadiene resin modified with acrylate, epoxy-modified polybutadiene resin, amino-modified polybutadiene resin, polybutadiene resin modified with terminal carboxyl group and polybutadiene resin modified with terminal hydroxyl group, or a mixture of at least two selected therefrom.

17. The process according to claim 4, wherein the polybutadiene copolymer resin is one selected from the group consisting of polybutadiene-styrene copolymer resin, polybutadiene-styrene-divinyl benzene-grafted copolymer resin, styrene-butadiene copolymer resin modified with maleic anhydride, and styrene-butadiene copolymer resin modified with acrylate, or a mixture of at least two selected therefrom.

18. The process according to claim 4, wherein the elastomer block copolymer is one selected from the group consisting of styrene-butadiene diblock copolymer, styrene-butadiene-styrene triblock copolymer, styrene-(ethylene-butylene)-styrene triblock copolymer, styrene-isoprene diblock copolymer, styrene-isoprene-styrene triblock copolymer, styrene-(ethylene-propylene)-styrene triblock copolymer, and styrene-(ethylene-butylene) diblock copolymer, or a mixture of at least two selected therefrom.

19. The process according to claim 3, wherein the curing agent is one selected from the group consisting of organic peroxide free radical initiator, carbon free radical initiator, or a mixture of at least two selected therefrom.

20. The process according to claim 3, wherein the organic solvent is one selected from the group consisting of aromatic hydrocarbon solvents such as toluene, xylol and mesitylene, or a mixture of at least two selected therefrom.

21. The process according to claim 7, wherein when the NE glass fabric has a mass area ratio of less than 30 g/m.sup.2, the pre-treated NE glass fabric has a resin content of from 25 wt. % to 50 wt. %; when the NE glass fabric has a mass area ratio of from 30 g/m.sup.2 to 100 g/m.sup.2, the pre-treated NE glass fabric has a resin content of from 20 wt. % to 45 wt. %; and when the NE glass fabric has a mass area ratio of from 100 g/m.sup.2 to 175 g/m.sup.2, the pre-treated NE glass fabric has a resin content of from 20 wt. % to 40 wt. %.

22. The bonding sheet according to claim 9, wherein the main resin varnish is a varnish obtained by dissolving a resin composition in an organic solvent.

23. The bonding sheet according to claim 22, wherein the resin composition comprises a resin, a filler and a curing agent.

24. The bonding sheet according to claim 23, wherein the resin is one selected from the group consisting of polyphenyl ether resin having unsaturated double bonds, polybutadiene resin, polybutadiene copolymer resin, elastomer block copolymer, dicyclopentadiene novolac epoxy resin and cyanate ester resin, or a mixture of at least two selected therefrom.

25. The bonding sheet according to claim 23, wherein the filler is one selected from the group consisting of silica, glass dust, aluminum nitride, boron nitride and aluminum hydroxide, or a mixture of at least two selected therefrom, wherein said silica comprises molten silica and crystalline silica.

26. The bonding sheet according to claim 23, wherein the curing agent is one selected from the group consisting of macromolecular anhydride curing agent, active ester, organic peroxide free radical initiator and carbon free radical initiator, or a mixture of at least two selected therefrom.

27. The bonding sheet according to claim 26, wherein the organic peroxide free radical initiator is one selected from the group consisting of dicumyl peroxide, 1,3-bi(tertiary-butyl-peroxy isopropyl)benzene, 2,5-di-t-butyl-peroxy-2,5-dimethylhexane, 2,5-di-t-butyl-peroxy-2,5-dimethyl-hexyne-3, di-t-butyl-peroxide, t-butyl cumyl peroxide, or a mixture of at least two selected therefrom.

28. The bonding sheet according to claim 26, wherein the carbon free radical initiator is one selected from the group consisting of 2,3-dimethyl-2,3-diphenylbutane, 2,3-dimethyl-2,3-di(4-methylphenyl)butane, 2,3-dimethyl-2,3-di(4-isopropyl-phenyl)butane, 3,4-dimethyl-3,4-diphenylhexane, or a mixture of at least two selected therefrom.

29. A printed circuit board prepared by the circuit board according to claim 10.

30. A printed circuit board prepared by the laminate according to claim 11.

Description

EMBODIMENTS

[0076] The present invention is detailedly stated as follows.

[0077] Dk of the present invention refers to the dielectric constant measured by the SPDR method at 10 GHz and a temperature of −55° C., −25° C., 0° C., 25° C., 50° C. and 85° C.

[0078] Df of the present invention refers to the dielectric loss measured by the SPDR method at 10 GHz and a temperature of −55° C., −25° C., 0° C., 25° C., 50° C. and 85° C.

[0079] The temperature coefficient of dielectric constant of the present invention refers to the relative average rate of change of the dielectric constant when the temperature increases by 1° C. within a certain temperature range, which is normally from −25 to +85° C., or from −55 to +125° C. The common unit thereof is 10.sup.−6/° C. or ppm/° C. The coefficient is an important electrical parameter of the materials, and can be based for classifying lots of ceramic dielectric materials, i.e. materials of positive, negative or zero temperature coefficient. The materials having different dielectric constant temperature coefficients may have different uses.

[0080] The glass fabrics of the present invention refer to the glass fabrics, including E-type glass fabrics, NE-type glass fabrics, S-type glass fabrics, D-type glass fabrics, L-type glass fabrics and the like, each of which have specification models of 7628, 2116, 1080, 106, 1037, 1078, 2112, 3313, 1500 and so on. Those skilled in the art will know that glass fabrics are mainly used as the reinforcing materials of circuit boards when applied in the circuit board field.

[0081] The low Dk-type glass fabrics of the present invention specifically refer to those having a Dk of 5.0 or less, preferably NE-type glass fabrics.

[0082] The resin composition of the present invention refers to a composition comprising resins and curing agents. For example, polybutadiene resin composition is a composition comprising polybutadiene resin and suitable curing agents. Those skilled in the art can choose suitable curing agents and amount thereof according to the resins used therein, and can also choose suitable organic solvents according to the resins and curing agents used therein.

[0083] The filler of the present invention refers to filling materials or fillers. Besides reducing the cost, to use fillers in the copper clad plate industry is to increase the performances of the copper clad plates, e.g. decrease of CTE, increase of flame retardancy, increases of thermal conductivity and mechanical properties of plates. With the development of filler technology, more new types of fillers are used in copper clad plates, e.g. functional fillers of the present invention for adjusting Dk of the pre-treating varnish.

[0084] The pre-treating varnish refers to a varnish obtained by dissolving the resin composition of the present invention in a suitable organic solvent. Preferably, the pre-treating varnish of the present invention refers to a dispersion system obtained by dissolving the resin composition of the present invention in a suitable organic solvent and then adding fillers. Those skilled in the art can adjust the amount of the fillers in the pre-treating varnish so as to make the pre-treating varnish have a suitable Dk. In the present invention, Dk of the pre-treating varnish is Dk of the cured, partially-cured or uncured dry glue in which the solvent is removed, which is merely relevant to the amounts of the resin composition and filler, rather than the amount of the solvent.

[0085] The impregnation of the present invention refers to the operations of impregnating the glass fabrics into a varnish and then drying solvent by using a gluing machine.

[0086] The pre-impregnation of the present invention refers to the operations of impregnating the glass fabrics into a prefabricated varnish and then drying solvent by using a gluing machine.

[0087] The main-impregnation of the present invention refers to the operations of impregnating the glass fabrics into a main varnish and then drying solvent by using a gluing machine.

[0088] The resin content of the present invention refers to the mass percent of the solid composition including the resin, besides the reinforcing material—glass fabrics, in the pre-treated low Dk-type glass fabric, bonding sheet and circuit board. For example, when the resin composition formula of the varnish comprises resins, curing agents and fillers, the resin content refers to the mass percent of the resins, curing agents and fillers. The resin content is a fixed term in the art. Those skilled in the art know that the resin content can be controlled by adjusting the processing parameters in combination of the solid content of the pre-treating varnish, such as intervals of clamp shafts of the gluing machine during the sizing, the sizing speed of the gluing machine and so on.

[0089] The pre-treatment of the current low Dk-type glass fabrics specifically includes pre-treating the low Dk-type glass fabrics with a pre-treating varnish having a Dk equivalent in the properties to the low Dk-type glass fabrics and good matching properties, filling the grids and intervals of the low Dk-type glass fabrics as the basic controlling object so as to make less Dk difference in the warp and weft directions, and forming the semi-product of the reinforcing materials for the main impregnation, i.e. the pre-treated low Dk-type glass fabrics.

[0090] The process of the present invention primarily comprises two steps detailedly and respectively as follows.

[0091] Step (1)

[0092] Preparing a pre-treating varnish, wherein the cured, partially-cured or uncured dry glue obtained by drying solvent of the pre-treating varnish has a Dk close to (having a difference of ±5%) that of the NE-type glass fabric to be used at different temperatures (from −55° C. to 85° C.); the dry glue has a Dk of 4.4-4.6 (10 GHz), and a Df of 0.007 or less (10 GHz), preferably a Df of 0.005 or less (10 GHz), more preferably a Df of 0.003 or less (10 GHz) at different temperatures (from −55° C. to 85° C.).

[0093] According to the present invention, the NE-type glass fabrics are electronic-grade glass fabrics, primarily comprising from 50 wt. % to 70 wt. % SiO.sub.2, from 0 wt. % to 10 wt. % CaO, from 10 wt. % to 15 wt. % Al.sub.2O.sub.3, from 15 wt. % to 20 wt. % B.sub.2O.sub.3, from 0 wt. % to 5 wt. % MgO, from 0.5 wt. % to 5 wt. % TiO.sub.2, from 0 wt. % to 1 wt. % Na.sub.2O and K.sub.2O.

[0094] By screening and studying relevant reinforcing materials, the inventor found that Dk and Df of the circuit boards may reach a lower level by using the NE-type electronic-grade glass fabrics as the reinforcing material as compared to other reinforcing materials. Dk and Df are important indexes of affecting the signal transmission rate and signal quality. As for the transmission rate, the lower the Dk value is, the faster the transmission rate of signals is. As for the signal integrity, the lower the Df value is, the less the signal loss during the transmission is. The NE-type glass fabrics have a Dk of from 4.4 to 4.6 (10 GHz) at different temperatures (from −55° C. to 85° C.) and a Df of 0.007 or less (10 GHz) at different temperatures (from −55° C. to 85° C.).

[0095] According to the present invention, the pre-treating varnish is a varnish obtained by dissolving a resin composition in an organic solvent.

[0096] The resin composition comprises a resin, a suitable amount of curing agent, a first component filler, and a second component filler, and the nonvolatile ingredients are based on parts by mass, wherein the resin and curing agent are in an amount of 40 parts by weight; the first component filler and second component filler are in an amount of from 45 to 60 parts by weight.

[0097] The resin is one selected from the group consisting of polyphenyl ether resin having unsaturated double bonds, polybutadiene resin, polybutadiene copolymer resin, elastomer block copolymer, or a mixture of at least two selected therefrom.

[0098] According to the present invention, the polyphenyl ether resin having unsaturated double bonds is one selected from the group consisting of polyphenyl ether resin having two terminal modifying groups being acryloyl groups, polyphenyl ether resin having two terminal modifying groups being styryl groups and polyphenyl ether resin having two terminal modifying groups being vinyl groups, or a mixture of at least two selected therefrom.

[0099] According to the present invention, the polybutadiene resin is one selected from the group consisting of 1,2-polybutadiene resin, polybutadiene resin modified with maleic anhydride, polybutadiene resin modified with acrylate, epoxy-modified polybutadiene resin, amino-modified polybutadiene resin, polybutadiene resin modified with terminal carboxyl group and polybutadiene resin modified with terminal hydroxyl group, or a mixture of at least two selected therefrom.

[0100] According to the present invention, the polybutadiene copolymer resin is one selected from the group consisting of polybutadiene-styrene copolymer resin, polybutadiene-styrene-divinyl benzene-grafted copolymer resin, styrene-butadiene copolymer resin modified with maleic anhydride, and styrene-butadiene copolymer resin modified with acrylate, or a mixture of at least two selected therefrom.

[0101] According to the present invention, the elastomer block copolymer is one selected from the group consisting of styrene-butadiene diblock copolymer, styrene-butadiene-styrene triblock copolymer, styrene-(ethylene-butylene)-styrene triblock copolymer, styrene-isoprene diblock copolymer, styrene-isoprene-styrene triblock copolymer, styrene-(ethylene-propylene)-styrene triblock copolymer, and styrene-(ethylene-butylene)diblock copolymer, or a mixture of at least two selected therefrom.

[0102] By studies, the inventor found that the aforesaid resin system having a low polarity can reduce the polarization, so as to finally achieve the object of decreasing Df.

[0103] According to the present invention, the first component filler is one selected from the group consisting of titanium dioxide, calcium titanate, strontium titanate, or a mixture of at least two selected therefrom, wherein said titanium dioxide comprises rutile and anatase titanium dioxides, preferably rutile titanium dioxide.

[0104] According to the present invention, the second component filler is one selected from the group consisting of alumina, magnesium oxide, magnesium titanate, or a mixture of at least two selected therefrom.

[0105] By studies, the inventor found that the temperature coefficient of dielectric constant of the first component filler is negative, and the temperature coefficient of dielectric constant of the second component filler is positive. By combining the two fillers together in a certain ratio, the Dk stability at different temperatures may be achieved.

[0106] Preferably, the first and second component fillers have a mass ratio of 1:(0.5-2.0), e.g. 1:0.5, 1:0.6, 1:0.8, 1:0.9, 1:1.2, 1:1.5, 1:1.7, 1:1.8 and 1:2.0.

[0107] By conducting a great deal of experimental researches on the amount ratio of the first and second component fillers, the inventor found that, for the temperature coefficient of dielectric constant after the first and second component fillers are mixed, the smaller is not the better. It is better that the temperature coefficient of dielectric constant of the resin composition as a whole consisting of the first component filler, the second component filler, resin and curing agent is close to that of the NE-type glass fabrics, which ensures that the Dk of the resin composition as a whole is close to that of the NE-type glass fabrics, and their variation tendencies or changes are also close at different temperatures, so as to solve the problem of signal propagation delay of circuit boards at different temperatures.

[0108] According to the present invention, the curing agent is one selected from the group consisting of organic peroxide free radical initiator and carbon free radical initiator, or a mixture of at least two selected therefrom.

[0109] According to the present invention, the organic peroxide free radical initiator is one selected from the group consisting of dicumyl peroxide, 1,3-bi(tertiary-butyl-peroxy isopropyl)benzene, 2,5-di-t-butyl-peroxy-2,5-dimethylhexane, 2,5-di-t-butyl-peroxy-2,5-dimethyl-hexyne-3, di-t-butyl-peroxide, of at least two, or a mixture of at least two selected therefrom.

[0110] According to the present invention, the carbon free radical initiator is one selected from the group consisting of 2,3-dimethyl-2,3-diphenylbutane, 2,3-dimethyl-2,3-di(4-methylphenyl)butane, 2,3-dimethyl-2,3-di(4-isopropyl-phenyl)butane, 3,4-dimethyl-3,4-diphenylhexane, or a mixture of at least two selected therefrom.

[0111] According to the present invention, the organic solvent is one selected from the group consisting of aromatic hydrocarbon solvents such as toluene, xylol and mesitylene, or a mixture of at least two selected therefrom.

[0112] Step (2)

[0113] Pre-impregnating the NE-type glass fabrics in the pre-treating varnish, then drying solvent to obtain a pre-treated NE-type glass fabrics.

[0114] According to the present invention, the main resin varnish is a varnish obtained by dissolving a resin composition in an organic solvent.

[0115] The resin composition comprises a resin, a filler and a curing agent.

[0116] According to the present invention, the resin is one selected from the group consisting of polyphenyl ether resin having unsaturated double bonds, polybutadiene resin, polybutadiene copolymer resin, elastomer block copolymer, dicyclopentadiene novolac epoxy resin and cyanate ester resin, or a mixture of at least two selected therefrom.

[0117] According to the present invention, the filler is one selected from the group consisting of silica, glass dust, aluminum nitride, boron nitride and aluminum hydroxide, or a mixture of at least two selected therefrom, wherein said silica comprises molten silica and crystalline silica, preferably molten silica.

[0118] According to the present invention, the curing agent is one selected from the group consisting of macromolecular anhydride curing agent, active ester, organic peroxide free radical initiator and carbon free radical initiator, or a mixture of at least two selected therefrom.

[0119] According to the present invention, the cured, partially-cured or uncured dry glue obtained by drying solvent of the pre-treating varnish has a Dk close to (having a difference of ±5%) that of the NE-type glass fabric at different temperatures (from −55° C. to 85° C.); the dry glue has a Dk of 4.4-4.6 (10 GHz), and a Df of 0.007 or less (10 GHz), preferably a Df of 0.005 or less (10 GHz), more preferably a Df of 0.003 or less (10 GHz) at different temperatures (from −55° C. to 85° C.). The less the Df of the dry glue is, the less the signal loss of circuit boards is.

[0120] According to the present invention, the pre-treating varnish is a varnish obtained by dissolving a resin composition in an organic solvent.

[0121] The resin composition comprises a resin, a first component filler, a second component filler, and a curing agent.

[0122] The resin is one selected from the group consisting of polyphenyl ether resin having unsaturated double bonds, polybutadiene resin, polybutadiene copolymer resin, elastomer block copolymer, or a mixture of at least two selected therefrom.

[0123] The first component filler is one selected from the group consisting of titanium dioxide, calcium titanate, strontium titanate, or a mixture of at least two selected therefrom, wherein said titanium dioxide comprises rutile and anatase titanium dioxides, preferably rutile titanium dioxide.

[0124] The second component filler is one selected from the group consisting of alumina, magnesium oxide, magnesium titanate, or a mixture of at least two selected therefrom.

[0125] The first and second component fillers have a mass ratio of 1:(0.5-2.0).

[0126] The curing agent is one selected from the group consisting of organic peroxide free radical initiator, carbon free radical initiator, or a mixture of at least two selected therefrom.

[0127] The organic solvent is one selected from the group consisting of aromatic hydrocarbon solvents such as toluene, xylol and mesitylene, or a mixture of at least two selected therefrom.

[0128] According to the present invention, the NE-type glass fabrics are electronic-grade glass fabrics, primarily comprising from 50 wt. % to 70 wt. % SiO.sub.2, from 0 wt. % to 10 wt. % CaO, from 10 wt. % to 15 wt. % Al.sub.2O.sub.3, from 15 wt. % to 20 wt. % B.sub.2O.sub.3, from 0 wt. % to 5 wt. % MgO, from 0.5 wt. % to 5 wt. % TiO.sub.2, from 0 wt. % to 1 wt. % Na.sub.2O and K.sub.2O.

[0129] According to the present invention, the NE-type glass fabrics are pre-treated, and the cured, partially-cured or uncured dry glue after drying solvent of the pre-treating varnish has a Dk of 4.4-4.6 (10 GHz).

[0130] According to the present invention, the NE-type glass fabrics have a resin content of from 20 wt. % to 50 wt. % after the pre-treatment.

[0131] If the resin content is too high, the pre-impregnating varnish will be dissolved and mixed with the main impregnating varnish after the main impregnation, which will affect the sizing amount of the main impregnation. The resin content is too low to fill out the pores of the glass fabric, so that the consistency of dielectric constants in warp- and weft-directions cannot be realized, so as to affect the signal transmission propagation delay.

[0132] According to the present invention, when the pre-treated NE glass fabric has a mass area ratio of less than 30 g/m.sup.2, the pre-treated NE glass fabric has a resin content of from 25 wt. % to 50 wt. %; when the pre-treated NE glass fabric has a mass area ratio of from 30 to 100 g/m.sup.2, the resin content of the pre-treated NE glass fabric from 20 wt. % to 45 wt. %; when the pre-treated NE glass fabric has a mass area ratio of from 100 g/m.sup.2 to 175 g/m.sup.2, the resin content of the pre-treated NE glass fabric from 20 wt. % to 40 wt. %.

[0133] The resin content of the pre-treated NE-type glass fabrics is selected according to the mass area ratio of the NE-type glass fabrics. If the resin content is too high, the pre-treating varnish will be dissolved and mixed with the main impregnating varnish after the main impregnation, so as to affect the sizing amount of the main impregnation. Meanwhile, since the Dk of general glass fabrics is far higher than that of the main impregnating varnish, the Dk of the prepared circuit boards after the main impregnation is too high, and the dielectric performances of circuit boards deteriorate. The resin content is too low to fill out the pores of the glass fabric, so that the microscopic consistency of dielectric constants in warp- and weft-directions cannot be realized, so as to affect the signal transmission propagation delay.

[0134] According to the present invention, the pre-treatment of the NE-type glass fabrics comprises drying the organic solvent in the resin varnish. During the drying, the pre-treating varnish on the NE-type glass fabrics may have or have no crosslinking reactions.

[0135] In one specific embodiment, the NE-type glass fabrics are pre-treated as follows.

[0136] Step 1: Seeking or testing the Dk value (10 GHz) of the NE-type glass fabrics according to the selected NE-type glass fabrics.

[0137] Step 2: Preparing a pre-treating varnish according to the Dk value (10 GHz) of the selected NE glass fabrics; the cured, partially-cured or uncured dry glue obtained by drying solvent of the pre-treating varnish has a Dk close to that of the NE-type glass fabric; the dry glue has a Dk of 4.4-4.6 (10 GHz), and a Df of 0.007 or less (10 GHz), preferably a Df of 0.005 or less (10 GHz), more preferably a Df of 0.003 or less (10 GHz).

[0138] Step 3: Adjusting according to the mass area ratio of the pre-treated NE glass fabric the processing parameters in combination of the solid content of the pre-treating varnish, such as intervals of clamp shafts of the gluing machine during the sizing, the sizing speed of the gluing machine and so on; when the pre-treated NE glass fabric has a mass area ratio of less than 30 g/m.sup.2, the pre-treated NE glass fabric has a resin content of from 25 wt. % to 50 wt. %; when the pre-treated NE glass fabric has a mass area ratio of from 30 to 100 g/m.sup.2, the resin content of the pre-treated NE glass fabric from 20 wt. % to 45 wt. %; when the pre-treated NE glass fabric has a mass area ratio of from 100 g/m.sup.2 to 175 g/m.sup.2, the resin content of the pre-treated NE glass fabric from 20 wt. % to 40 wt. %.

[0139] Step 4: Drying organic solvent in the pre-impregnated NE-type glass fabrics to obtain a specifically pre-treated NE-type glass fabrics.

[0140] The present invention further provides a bonding sheet comprising the aforesaid specifically pre-treated NE-type glass fabrics and the resin composition coated on the specifically pre-treated NE-type glass fabrics.

[0141] According to the present invention, the resin composition comprises a resin, a filler and a curing agent.

[0142] The resin is one selected from the group consisting of polyphenyl ether resin having unsaturated double bonds, polybutadiene resin, polybutadiene copolymer resin, elastomer block copolymer, dicyclopentadiene novolac epoxy resin and cyanate ester resin, or a mixture of at least two selected therefrom.

[0143] The filler is one selected from the group consisting of silica, glass dust, aluminum nitride, boron nitride and aluminum hydroxide, or a mixture of at least two selected therefrom, wherein said silica comprises molten silica and crystalline silica, preferably molten silica.

[0144] The curing agent is one selected from the group consisting of macromolecular anhydride curing agent, active ester, organic peroxide free radical initiator and carbon free radical initiator, or a mixture of at least two selected therefrom.

[0145] The resin composition of the present invention may be used together with various high polymers as long as they do not damage the intrinsic performances of the resin composition, specifically e.g. liquid crystal polymer, thermosetting resin, thermoplastic resin, different flame retardant compounds or additives which may be used alone or in combination.

[0146] In addition, the resin composition may comprise various additives, specifically e.g. antioxidant, heat stabilizer, antistatic agent, UV absorber, pigment, colorant, lubricant, coupling agent, flatting agent, viscosity modifier and the like.

[0147] The present invention further provides a circuit board of the bonding sheet of the present invention.

[0148] As the typical, but non-limitative examples, the process for preparing the circuit board may include the following steps.

[0149] Step 1: Preparing a pre-treating varnish. A pre-treating varnish was prepared according to the Dk of the used NE-type glass fabric, so as to make the Dk of the dry glue obtained after drying solvent of the varnish the same as or close to the Dk of the used NE-type glass fabric.

[0150] Step 2: Preparing a pre-treated NE-type glass fabric. A NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and solvent was dried to obtain a pre-treated NE-type glass fabric.

[0151] Step 3: Preparing a bonding sheet. A main resin varnish was prepared to mainly impregnate the aforesaid specially pre-treated NE-type glass fabric. After that, solvent was dried to obtain a bonding sheet.

[0152] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and metal foils were superimposed to both sides of the superimposed bonding sheets. The superimposed laminates were hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 100-400° C. and at a pressure of 10-65 Kgf/cm.sup.2 for 1-4 h.

EXAMPLES

[0153] In order to better state the present invention and better understand the technical solution of the present invention, the typical, but non-limitative examples of the present invention are stated as follows.

[0154] As for the above-prepared circuit board, the properties thereof, such as dielectric constant (Dk), dielectric loss (Df), signal propagation delay, board insertion loss and the like, are tested at different temperatures, and further stated and described in detail in the following examples, wherein the mass part of organic resins are based on the mass part of organic solids.

Example 1

[0155] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 1. The circuit board was prepared by the following steps.

[0156] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0157] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0158] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0159] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Example 2

[0160] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 1. The circuit board was prepared by the following steps.

[0161] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 35 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0162] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0163] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0164] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Example 3

[0165] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 1. The circuit board was prepared by the following steps.

[0166] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 20 parts by mass of a first component filler titanium dioxide and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0167] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0168] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0169] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 4

[0170] NE-type 3313 glass fabric (having a mass per unit area of 81.4 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 1. The circuit board was prepared by the following steps.

[0171] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 20 parts by mass of a first component filler titanium dioxide and 35 parts by mass of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0172] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 30 wt. %.

[0173] Step 3: Preparing a bonding sheet. Bisphenol-A cyanate ester resin and dicyclopentadiene novolac epoxy resin, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0174] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Example 5

[0175] NE-type 1078 glass fabric (having a mass per unit area of 47.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 1. The circuit board was prepared by the following steps.

[0176] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0177] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0178] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0179] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 6

[0180] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 1. The circuit board was prepared by the following steps.

[0181] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 35 parts by mass of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0182] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0183] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0184] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 7

[0185] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 2. The circuit board was prepared by the following steps.

[0186] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 20 parts by mass of a first component filler titanium dioxide and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0187] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0188] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0189] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 8

[0190] NE-type 3313 glass fabric (having a mass per unit area of 81.4 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 2. The circuit board was prepared by the following steps.

[0191] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 20 parts by mass of a first component filler calcium titanate and 35 parts by weight of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0192] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 30 wt. %.

[0193] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0194] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 9

[0195] NE-type 2116 glass fabric (having a mass per unit area of 103.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 2. The circuit board was prepared by the following steps.

[0196] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 30 parts by mass of a first component filler titanium dioxide and 15 parts by mass of the second component filler magnesium titanate were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0197] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 20 wt. %.

[0198] Step 3: Preparing a bonding sheet. Bisphenol-A cyanate ester resin and dicyclopentadiene novolac epoxy resin, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0199] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Example 10

[0200] NE-type 106 glass fabric (having a mass per unit area of 24.4 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 2. The circuit board was prepared by the following steps.

[0201] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 15 parts by mass of a first component filler strontium titanate and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0202] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 50 wt. %.

[0203] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0204] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 11

[0205] NE-type 1078 glass fabric (having a mass per unit area of 47.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 2. The circuit board was prepared by the following steps.

[0206] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0207] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0208] Step 3: One or more of the aforesaid pre-treated NE-type glass fabrics were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed pre-treated NE-type glass fabrics. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Example 12

[0209] NE-type 1078 glass fabric (having a mass per unit area of 47.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 2. The circuit board was prepared by the following steps.

[0210] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0211] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0212] Step 3: One or more of the aforesaid pre-treated NE-type glass fabrics were superimposed together, and a copper foil covered with resins was superimposed to each of both sides of the superimposed pre-treated NE-type glass fabrics. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Comparison Example 1

[0213] E-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 3. The circuit board was prepared by the following steps.

[0214] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 30 parts by weight of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0215] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0216] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0217] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Comparison Example 2

[0218] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; epoxy resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 3. The circuit board was prepared by the following steps.

[0219] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of bisphenol-A epoxy resin and bisphenol-A novolac resin, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 35 parts by mass of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0220] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0221] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0222] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Comparison Example 3

[0223] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 3. The circuit board was prepared by the following steps.

[0224] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 10 parts by mass of a first component filler calcium titanate and 20 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0225] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0226] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0227] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Comparison Example 4

[0228] NE-type 3313 glass fabric (having a mass per unit area of 81.4 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 3. The circuit board was prepared by the following steps.

[0229] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 50 parts by mass of a first component filler calcium titanate and 25 parts by mass of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0230] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 30 wt. %.

[0231] Step 3: Preparing a bonding sheet. Bisphenol-A cyanate ester resin and dicyclopentadiene novolac epoxy resin, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0232] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Comparison Example 5

[0233] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 3. The circuit board was prepared by the following steps.

[0234] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 40 parts by mass of a first component filler titanium dioxide and 5 parts by weight of a second component filler silicon dioxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0235] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0236] Step 3: Preparing a bonding sheet. Polyphenyl ether resin having two terminal modifying groups being acryloyl groups, a suitable amount of dicumyl peroxide, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0237] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Comparison Example 6

[0238] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 4. The circuit board was prepared by the following steps.

[0239] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 25 parts by mass of a first component filler titanium dioxide and 35 parts by weight of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0240] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0241] Step 3: Preparing a bonding sheet. Bisphenol-A epoxy resin and a suitable amount of bisphenol-A novolac resin, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0242] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Comparison Example 7

[0243] NE-type 1080 glass fabric (having a mass per unit area of 46.8 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 4. The circuit board was prepared by the following steps.

[0244] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 50 parts by mass of a first component filler calcium titanate and 10 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0245] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 45 wt. %.

[0246] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0247] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Comparison Example 8

[0248] NE-type 3313 glass fabric (having a mass per unit area of 81.4 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 4. The circuit board was prepared by the following steps.

[0249] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent, stirred for a certain time. Then 10 parts by mass of a first component filler calcium titanate and 50 parts by mass of a second component filler magnesium oxide were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0250] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 30 wt. %.

[0251] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0252] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

Comparison Example 9

[0253] NE-type 2116 glass fabric (having a mass per unit area of 103.8 g/m.sup.2) was used as a reinforcing material; polyphenyl ether resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 4. The circuit board was prepared by the following steps.

[0254] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of polyphenyl ether resin having two terminal modifying groups being acryloyl groups and dicumyl peroxide, as well as a suitable amount of a solvent, stirred for a certain time. Then 30 parts by mass of a first component filler titanium dioxide and 15 parts by mass of a second component filler magnesium titanate were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0255] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 15 wt. %.

[0256] Step 3: Preparing a bonding sheet. Bisphenol-A cyanate ester resin and dicyclopentadiene novolac epoxy resin, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheet.

[0257] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 200° C. and at a pressure of 35 Kgf/cm.sup.2 for 2 h.

Comparison Example 10

[0258] NE-type 106 glass fabric (having a mass per unit area of 24.4 g/m.sup.2) was used as a reinforcing material; polybutadiene resin was dissolved in a solvent, and a filler was added therein to obtain a pre-treating varnish. The varnish formulation and the physical property data of circuit board are shown in Table 4. The circuit board was prepared by the following steps.

[0259] Step 1: Preparing a pre-treating varnish. Into a suitable vessel were added 40 parts by mass of 1,2-polybutadiene resin and 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of solvent, stirred for a certain time. Then 15 parts by mass of a first component filler strontium titanate and 30 parts by mass of a second component filler alumina were added, sufficiently stirred, and emulsified and dispersed to form a pre-treating varnish.

[0260] Step 2: Preparing a pre-treated NE-type glass fabric. NE-type glass fabric was pre-impregnated with the aforesaid pre-treating varnish; and the solvent was dried to obtain a pre-treated NE-type glass fabric having a resin content of 60 wt. %.

[0261] Step 3: Preparing a bonding sheet. 1,2-polybutadiene resin, a suitable amount of 2,3-dimethyl-2,3-diphenylbutane, as well as a suitable amount of a solvent were used to prepare a main resin varnish. Then the main resin varnish was used to mainly impregnate the aforesaid pre-treated NE-type glass fabric. After that, the solvent was dried to obtain a bonding sheets.

[0262] Step 4: One or more of the aforesaid bonding sheets were superimposed together, and a copper foil was superimposed to each of both sides of the superimposed bonding sheets. The superimposed laminate was hot-pressed in a pressing machine to prepare a circuit board, wherein the curing was carried out at a temperature of 240° C. and at a pressure of 55 Kgf/cm.sup.2 for 3 h.

TABLE-US-00002 TABLE 1 Formulations in each example and the physical property data thereof Examples 1 2 3 4 5 6 Type of glass fabrics NE-type NE-type NE-type NE-type NE-type NE-type Model of glass fabrics 1080 1080 1080 3313 1078 1080 Pre-treating varnish Polyphenyl Polyphenyl Polyphenyl Polyphenyl polybutadiene polybutadiene resin system ether ether ether ether First component filler Titanium Titanium Calcium titanate Calcium Titanium dioxide Titanium dioxide dioxide dioxide titanate Second component filler Alumina Magnesium Alumina Magnesium Alumina Magnesium oxide oxide oxide Amount of the pre-treating 40 40 40 40 40 40 varnish resin Amount of first 25 25 20 20 25 25 component filler Amount of second 30 35 30 35 30 35 component filler Dk of the 85° C. 4.571 4.583 4.561 4.581 4.518 4.526 pre-treating 50° C. 4.545 4.564 4.542 4.565 4.497 4.517 varnish 25° C. 4.518 4.536 4.523 4.546 4.486 4.494  0° C. 4.491 4.517 4.504 4.514 4.465 4.475 −25° C.  4.482 4.495 4.476 4.493 4.451 4.451 −55° C.  4.456 4.472 4.468 4.472 4.432 4.449 Df of the 85° C. 0.00411 0.00404 0.00422 0.00431 0.00389 0.00417 pre-treating 50° C. 0.00395 0.00382 0.00404 0.00423 0.00367 0.00398 varnish 25° C. 0.00388 0.00375 0.00396 0.00414 0.00358 0.00375  0° C. 0.00369 0.00364 0.00377 0.00396 0.00336 0.00362 −25° C.  0.00347 0.00336 0.00351 0.00378 0.00314 0.00343 −55° C.  0.00335 0.00322 0.00332 0.00369 0.00305 0.00334 Resin content of the 45 wt. % 45 wt. % 45 wt. % 30 wt. % 45 wt. % 45 wt. % pre-treated glass fabrics Main impregnating Polyphenyl Polyphenyl Polybutadiene Cyanate Polyphenyl Polyphenyl resin system ether ether ether ether Dk (25° C.) of the main 2.565 2.565 2.354 3.089 2.565 2.564 impregnating varnish Df (25° C.) of the main 0.00224 0.00224 0.00186 0.00682 0.00224 0.00224 impregnating varnish Dk of the 85° C. 3.706 3.708 3.701 3.712 3.698 3.704 circuit board 50° C. 3.701 3.703 3.692 3.708 3.687 3.697 25° C. 3.688 3.683 3.682 3.693 3.678 3.686  0° C. 3.673 3.675 3.676 3.682 3.669 3.675 −25° C.  3.663 3.663 3.659 3.675 3.658 3.662 −55° C.  3.653 3.652 3.648 3.664 3.649 3.654 Df of the 85° C. 0.00403 0.00405 0.00401 0.00425 0.00402 0.00401 circuit board 50° C. 0.00387 0.00391 0.00388 0.00413 0.00385 0.00385 25° C. 0.00382 0.00388 0.00378 0.00398 0.00381 0.00381  0° C. 0.00371 0.00375 0.00368 0.00389 0.00372 0.00375 −25° C.  0.00357 0.00361 0.00359 0.00367 0.00355 0.00364 −55° C.  0.00335 0.00342 0.00338 0.00353 0.00334 0.00341 Warp-wise 85° C. 9 10 12 14 11 11 signal 50° C. 6 7 8 10 9 8 propagation 25° C. 4 6 5 7 5 4 delay/ps  0° C. 5 7 9 9 8 6 −25° C.  7 9 11 12 12 9 −55° C.  11 12 15 14 16 12 Weft-wise 85° C. 7 9 10 13 12 9 signal 50° C. 5 5 6 9 9 7 propagation 25° C. 1 3 2 4 2 2 delay/ps  0° C. 3 5 4 8 9 8 −25° C.  6 8 9 10 11 13 −55° C.  8 9 10 13 12 15 Insertion loss 85° C. −0.687 −0.691 −0.689 −0.698 −0.685 −0.681 of the board at 50° C. −0.669 −0.668 −0.653 −0.657 −0.652 −0.653 10 GHz/ 25° C. −0.636 −0.648 −0.641 −0.648 −0.635 −0.637 (dB/inch)  0° C. −0.598 −0.607 −0.603 −0.616 −0.593 −0.595 −25° C.  −0.565 −0.576 −0.571 −0.574 −0.562 −0.566 −55° C.  −0.547 −0.553 −0.549 −0.552 −0.543 −0.545

TABLE-US-00003 TABLE 2 Formulations in each example and the physical property data thereof Examples 7 8 9 10 11 12 Type of glass fabrics NE-type NE-type NE-type NE-type NE-type NE-type Model of glass fabrics 1080 3313 2116 106 1078 1078 Pre-treating varnish polybutadiene polybutadiene Polyphenyl polybutadiene polybutadiene polybutadiene resin system ether First component filler Calcium titanate Calcium titanate Titanium Strontium Titanium dioxide Titanium dioxide dioxide titanate Second component filler Alumina Magnesium oxide Magnesium Alumina Alumina Alumina titanate Amount of the pre-treating 40 40 40 40 40 40 varnish resin Amount of first 20 20 30 15 25 25 component filler Amount of second 30 35 15 30 30 30 component filler Dk of the 85° C. 4.562 4.574 4.583 4.581 4.518 4.518 pre-treating 50° C. 4.543 4.553 4.574 4.563 4.497 4.497 varnish 25° C. 4.521 4.531 4.567 4.551 4.486 4.486  0° C. 4.515 4.512 4.548 4.535 4.465 4.465 −25° C.  4.498 4.486 4.526 4.513 4.451 4.451 −55° C.  4.477 4.458 4.515 4.498 4.432 4.432 Df of the 85° C. 0.00412 0.00427 0.00611 0.00657 0.00389 0.00389 pre-treating 50° C. 0.00394 0.00409 0.00592 0.00646 0.00367 0.00367 varnish 25° C. 0.00386 0.00394 0.00585 0.00629 0.00358 0.00358  0° C. 0.00368 0.00375 0.00568 0.00598 0.00336 0.00336 −25° C.  0.00347 0.00352 0.00558 0.00575 0.00314 0.00314 −55° C.  0.00325 0.00348 0.00533 0.00557 0.00305 0.00305 Resin content of the 45 wt. % 30 wt. % 20 wt. % 50 wt. % 45 wt. % 45 wt. % pre-treated glass fabrics Main impregnating Polybutadiene Polybutadiene Cyanate Polybutadiene — — resin system Dk (25° C.) of the main 2.354 2.354 3.089 2.354 — — impregnating varnish Df (25° C.) of the main 0.00186 0.00186 0.00682 0.00186 — — impregnating varnish Dk of the 85° C. 3.702 3.696 3.876 3.795 4.512 4.510 circuit 50° C. 3.698 3.687 3.867 3.783 4.509 4.506 board 25° C. 3.689 3.676 3.853 3.772 4.505 4.502  0° C. 3.679 3.662 3.841 3.761 4.501 4.497 −25° C.  3.665 3.654 3.832 3.758 4.496 4.495 −55° C.  3.656 3.642 3.819 3.745 4.492 4.491 Df of the 85° C. 0.00403 0.00401 0.00502 0.00521 0.00368 0.00366 circuit 50° C. 0.00391 0.00386 0.00491 0.00509 0.00362 0.00365 board 25° C. 0.00383 0.00384 0.00481 0.00498 0.00365 0.00363  0° C. 0.00374 0.00372 0.00469 0.00479 0.00361 0.00360 −25° C.  0.00369 0.00361 0.00456 0.00487 0.00358 0.00358 −55° C.  0.00345 0.00338 0.00445 0.00475 0.00355 0.00356 Warp-wise 85° C. 10 12 16 14 11 10 signal 50° C. 7 8 12 11 7 8 propagation 25° C. 5 6 9 8 5 7 delay/ps  0° C. 8 9 11 10 8 9 −25° C.  10 11 13 13 11 12 −55° C.  13 15 17 18 13 15 Weft-wise 85° C. 11 12 15 13 11 12 signal 50° C. 7 8 11 9 7 8 propagation 25° C. 3 3 6 5 4 3 delay/ps  0° C. 6 6 8 7 6 7 −25° C.  9 10 11 10 9 10 −55° C.  14 12 13 12 10 11 Insertion 85° C. −0.698 −0.683 −0.887 −0.898 −0.678 −0.671 loss of the 50° C. −0.665 −0.651 −0.854 −0.856 −0.661 −0.658 board at 25° C. −0.642 −0.642 −0.842 −0.849 −0.638 −0.644 10 GHz/  0° C. −0.602 −0.593 −0.803 −0.816 −0.611 −0.615 (dB/inch) −25° C.  −0.573 −0.569 −0.776 −0.774 −0.567 −0.564 −55° C.  −0.556 −0.546 −0.748 −0.757 −0.554 −0.549

TABLE-US-00004 TABLE 3 Formulations in each Comparison example and the physical property data thereof Examples 1 2 3 4 5 Type of glass fabrics E-type NE-type NE-type NE-type NE-type Model of glass fabrics 1080 1080 1080 3313 1078 Pre-treating varnish Polyphenyl Epoxy Polyphenyl Polyphenyl Polybutadiene resin system ether ether ether First component filler Titanium Titanium Calcium titanate Calcium Titanium dioxide dioxide titanate dioxide Second component filler Alumina Magnesium Alumina Magnesium Titanium oxide oxide dioxide Amount of the pre-treating 40 40 40 40 40 varnish resin Amount of first 25 25 10 50 40 component filler Amount of second 30 35 20 25 5 component filler Dk of the 85° C. 4.571 4.682 3.721 5.723 4.972 pre-treating 50° C. 4.545 4.653 3.692 5.692 4.865 varnish 25° C. 4.518 4.624 3.664 5.654 4.552  0° C. 4.491 4.605 3.615 5.615 4.446 −25° C.  4.482 4.577 3.552 5.586 4.238 −55° C.  4.456 4.558 3.518 5.557 4.131 Df of the 85° C. 0.00411 0.00916 0.00512 0.00531 0.0045 pre-treating 50° C. 0.00395 0.00895 0.00481 0.00514 0.0042 varnish 25° C. 0.00388 0.00857 0.00453 0.00485 0.0038  0° C. 0.00369 0.00834 0.00415 0.00469 0.0035 −25° C.  0.00347 0.00793 0.00396 0.00438 0.0033 −55° C.  0.00335 0.00752 0.00387 0.00427 0.0031 Resin content of the 45 wt. % 45 wt. % 45 wt. % 30 wt. % 45 wt. % pre-treated glass fabrics Main impregnating Polyphenyl Polyphenyl Polybutadiene Cyanate Polyphenyl resin system ether ether ether Dk (25° C.) of the main 2.565 2.565 2.354 3.089 2.565 impregnating varnish Df (25° C.) of the main 0.00224 0.00224 0.00186 0.00682 0.00224 impregnating varnish Dk of the 85° C. 3.902 3.905 3.553 4.012 3.542 circuit board 50° C. 3.898 3.897 3.545 4.009 3.561 25° C. 3.888 3.885 3.531 3.995 3.592  0° C. 3.872 3.869 3.522 3.984 3.608 −25° C.  3.861 3.858 3.509 3.975 3.652 −55° C.  3.856 3.848 3.498 3.965 3.713 Df of the 85° C. 0.00704 0.00712 0.00382 0.00625 0.00454 circuit board 50° C. 0.00686 0.00698 0.00368 0.00615 0.00438 25° C. 0.00682 0.00687 0.00356 0.00598 0.00431  0° C. 0.00673 0.00675 0.00348 0.00588 0.00422 −25° C.  0.00656 0.00657 0.00337 0.00569 0.00409 −55° C.  0.00632 0.00635 0.00319 0.00557 0.00386 Warp-wise 85° C. 356 52 561 576 452 signal 50° C. 247 45 455 489 214 propagation 25° C. 135 23 364 421 16 delay/ps  0° C. 96 16 289 352 156 −25° C.  158 29 374 438 286 −55° C.  269 37 422 513 418 Weft-wise 85° C. 312 42 512 552 414 signal 50° C. 234 36 423 417 208 propagation 25° C. 121 19 315 386 12 delay/ps  0° C. 85 15 273 314 126 −25° C.  132 24 358 416 258 −55° C.  238 29 409 509 413 Insertion 85° C. −1.294 −1.361 −0.678 −0.954 −0.754 loss of the 50° C. −1.281 −1.343 −0.627 −0.912 −0.722 board at 25° C. −1.248 −1.315 −0.584 −0.905 −0.706 10 GHz/  0° C. −1.213 −1.278 −0.566 −0.872 −0.698 (dB/inch) −25° C.  −1.177 −1.239 −0.553 −0.838 −0.654 −55° C.  −1.159 −1.221 −0.525 −0.813 −0.627

TABLE-US-00005 TABLE 4 Formulations in each Comparison example and the physical property data thereof Examples 6 7 8 9 10 Type of glass fabrics NE-type NE-type NE-type NE-type NE-type Model of glass fabrics 1080 1080 3313 2116 106 Pre-treating varnish Polybutadiene Polybutadiene Polybutadiene Polyphenyl Polybutadiene resin system ether First component filler Titanium dioxide Calcium titanate Calcium titanate Titanium Strontium dioxide titanate Second component filler Magnesium oxide Alumina Magnesium Magnesium Alumina oxide titanate Amount of the pre-treating 40 40 40 40 40 varnish resin Amount of first 25 50 10 30 15 component filler Amount of second 35 10 50 15 30 component filler Dk of the 85° C. 4.526 4.973 4.969 4.583 4.581 pre-treating 50° C. 4.517 4.862 4.861 4.574 4.563 varnish 25° C. 4.494 4.554 4.552 4.567 4.551  0° C. 4.475 4.441 4.439 4.548 4.535 −25° C.  4.451 4.235 4.234 4.526 4.513 −55° C.  4.449 4.130 4.129 4.515 4.498 Df of the 85° C. 0.00417 0.0043 0.0041 0.00611 0.00657 pre-treating 50° C. 0.00398 0.0041 0.0039 0.00592 0.00646 varnish 25° C. 0.00375 0.0039 0.0038 0.00585 0.00629  0° C. 0.00362 0.0037 0.0037 0.00568 0.00598 −25° C.  0.00343 0.0036 0.0035 0.00558 0.00575 −55° C.  0.00334 0.0034 0.0034 0.00533 0.00557 Resin content of the 45 wt. % 45 wt. % 30 wt. % 15 wt. % 60 wt. % pre-treated glass fabrics Main impregnating Epoxy Polybutadiene Polybutadiene Cyanate Polybutadiene resin system Dk (25° C.) of the main 3.865 2.354 2.354 3.089 2.354 impregnating varnish Df (25° C.) of the main 0.01125 0.00186 0.00186 0.00682 0.00186 impregnating varnish Dk of the 85° C. 4.216 3.643 3.724 4.033 4.212 circuit 50° C. 4.218 3.662 3.718 4.026 4.208 board 25° C. 4.198 3.685 3.688 4.019 4.196  0° C. 4.185 3.698 3.671 4.008 4.181 −25° C.  4.174 3.712 3.652 3.999 4.175 −55° C.  4.162 3.726 3.641 3.991 4.157 Df of the 85° C. 0.00824 0.00405 0.00401 0.00772 0.00451 circuit 50° C. 0.00813 0.00397 0.00385 0.00766 0.00437 board 25° C. 0.00799 0.00392 0.00378 0.00749 0.00426  0° C. 0.00787 0.00385 0.00367 0.00738 0.00418 −25° C.  0.00768 0.00369 0.00358 0.00721 0.00407 −55° C.  0.00755 0.00361 0.00342 0.00708 0.00388 Warp-wise 85° C. 19 256 287 206 16 signal 50° C. 13 134 167 139 13 propagation 25° C. 9 11 15 67 10 delay/ps  0° C. 14 167 186 128 12 −25° C.  16 254 278 249 15 −55° C.  18 376 388 314 18 Weft-wise 85° C. 15 246 265 178 15 signal 50° C. 11 112 127 112 12 propagation 25° C. 7 9 12 56 8 delay/ps  0° C. 9 151 164 176 11 −25° C.  12 198 203 243 14 −55° C.  14 223 312 305 17 Insertion 85° C. −1.515 −0.708 −0.688 −1.392 −0.747 loss of the 50° C. −1.497 −0.675 −0.657 −1.374 −0.718 board at 25° C. −1.469 −0.651 −0.641 −1.345 −0.702 10 GHz/  0° C. −1.432 −0.613 −0.595 −1.308 −0.694 (dB/inch) −25° C.  −1.393 −0.582 −0.564 −1.267 −0.646 −55° C.  −1.375 −0.548 −0.545 −1.256 −0.622

[0263] The aforesaid properties are tested as follows.

[0264] (1) Dielectric properties Dk/Df: the dielectric constant Dk and dielectric loss Df of the boards were tested at 10 GHz and at −55° C., −25° C., 0° C., 25° C., 50° C. and 85° C. by means of SPDR.

[0265] (2) Signal propagation delay: the testing was made according to the method as stipulated under IPC TM-650 2.5.5.11; according to the directions of transmission lines on the circuit boards, the tested signal propagation delay was divided into warp-wise signal propagation delay and weft-wise signal propagation delay; the warp-wise signal propagation delay refers to the signal propagation delay tested when the transmission lines were wired in the warp-wise direction of the circuit boards; the weft-wise signal propagation delay refers to the signal propagation delay tested when the transmission lines were wired in the weft-wise direction of the circuit boards; the warp-wise signal propagation delay and weft-wise signal propagation delay of the boards were respectively tested at −55° C., −25° C., 0° C., 25° C., 50° C. and 85° C.

[0266] (3) Board insertion loss: the testing was made according to the method as stipulated under IPC TM-650 2.5.5.12A; the same copper foils were used for the circuit boards; the signal loss was represented with board insertion loss; board insertion loss was tested at −55° C., −25° C., 0° C., 25° C., 50° C. and 85° C. to compare the signal loss by using the insertion loss at 10 GHz.

[0267] (4) Resin content: tested according to the method as stipulated under IPC TM-650 2.3.16.1.

[0268] Analyses of physical property results:

[0269] In Comparison Example 1 as compared to Example 1, E-type glass fabric was used. The Dk of the pre-treating varnish was seriously lower than the Dk of the E-type glass fabric. The circuit board had a problem of signal propagation delay. Meanwhile, the circuit board had a higher Df, resulting in a higher board insertion loss.

[0270] In Comparison Example 2 as compared to Example 2, the pre-treating varnish resin was epoxy resin, and the Dk thereof was close to the Dk of the NE-type glass fabric. The circuit board had no obvious signal propagation delay problem. Meanwhile, the circuit board had a higher Df, resulting in a higher board insertion loss.

[0271] In Comparison Example 3 as compared to Example 3, the Dk of the pre-treating varnish was seriously lower than the Dk of the NE-type glass fabric. The circuit board had a problem of signal propagation delay. Meanwhile, the circuit board had a lower Df, so did the board insertion loss.

[0272] In Comparison Example 4 as compared to Example 4, the Dk of the pre-treating varnish was seriously higher than the Dk of the NE-type glass fabric. The circuit board had a problem of signal propagation delay. Meanwhile, the circuit board had a higher Df, resulting in a higher board insertion loss.

[0273] In Comparison Example 5 as compared to Example 5, the circuit boards had no signal propagation delay problem at 25° C. With the decrease or increase of temperature, the signal propagation delay problem in Comparison Example 5 became obvious increasingly, while there was no signal propagation delay problem in Example 5.

[0274] In Comparison Example 6 as compared to Example 6, the main impregnating resin was epoxy resin; the Dk of the pre-treating varnish was close to the Dk of the NE-type glass fabric. The circuit board had no obvious signal propagation delay problem. However, higher Df of the circuit board resulted in a higher board insertion loss.

[0275] In Comparison Example 7 as compared to Example 7, the amount of the first component filler is higher, and the amount of the second component filler is lower. At 25° C., the circuit boards had no signal propagation delay problem. With the decrease or increase of temperature, the signal propagation delay problem in Comparison Example 7 became obvious increasingly, while there was no signal propagation delay problem in Example 7.

[0276] In Comparison Example 8 as compared to Example 8, the amount of the first component filler is lower, and the amount of the second component filler is higher. At 25° C., the circuit boards had no signal propagation delay problem. With the decrease or increase of temperature, the signal propagation delay problem in Comparison Example 8 became obvious increasingly, while there was no signal propagation delay problem in Example 8.

[0277] In Comparison Example 9 as compared to Example 9, the resin content of the pre-treated glass fabric was too low to fill out the pores of the glass fabric; the circuit board had a problem of signal propagation delay; meanwhile, the circuit board had a higher Df, resulting in a higher board insertion loss.

[0278] In Comparison Example 10 as compared to Example 10, although the circuit board had no problem of signal propagation delay, and the board insertion loss was not very high, the resin content of the pre-treated glass fabric was too high; to reduce the glue amount resulted in a higher Dk of the circuit board.

[0279] As for Examples 11 and 12, since the pre-treated NE-type glass fabric was not mainly impregnated, and was directed pressed together with copper foils or copper foils covered with resin, the circuit boards had a higher Dk. However, the circuit boards had no problem of signal propagation delay, and there was a lower board insertion loss.

[0280] The aforesaid examples are only better examples of the present invention, and do not make any limits to the contents of the components of the present invention. Those skilled in the art shall know that they can make any corresponding amendments and deformations to the technical solution and concept according to the present invention. Any tiny amendment, equivalent change and modification according to the technical essence or ingredients or contents of the present invention all fall within the protection scope of the technical solution of the present invention.