Resin composition, metal foil provided with resin layer, metal clad laminate, and printed wiring board

Abstract

An object of the present invention is to provide a resin composition which enables formation of a resin layer having excellent electrical performance including high frequency performance and appropriate solubility with desmear solution required on a material used in manufacturing of a printed wiring board. To achieve the object, the resin composition used for constituting a resin layer on a metal layer surface of a laminate includes a polyphenylene ether compound and 10 parts by mass to 100 parts by mass of a styrene-butadiene block copolymer and 0.1 parts by mass to 100 parts by mass of a component promoting solubility with desmear solution against 100 parts by mass of the polyphenylene ether compound.

Claims

1. A resin composition used for constituting a resin layer of a laminate in which the resin layer is provided on a metal layer surface, the resin composition comprising a styrene-modified polyphenylene ether compound obtained from reacting a polyphenylene ether compound with chloromethyl styrene; 10 parts by mass to 100 parts by mass of a styrene-butadiene block copolymer; 0.1 parts by mass to 100 parts by mass of a component promoting solubility of the resin composition with a desmear solution, wherein the component is a polymer of diallyl phthalate; and 0.1 parts by mass to 30 parts by mass of a curl lessening component selected from the group consisting of 2,4-diphenyl-4-methyl-1-pentene, lauryl mercaptan, octyl mercaptan, 2-mercaptoethanol, octyl thioglycolate, and 3-mercaptopropionic acid, wherein parts by mass are per 100 parts by mass of the styrene-modified polyphenylene ether compound.

2. The resin composition according to claim 1, further comprising 50 parts by mass to 600 parts by mass of dielectric particles per 100 parts by mass of the resin composition excluding the dielectric particles.

3. The resin composition according to claim 2, wherein the dielectric particles are composed of a composite oxide having a perovskite structure.

4. A metal foil provided with a resin layer on at least one side of the metal foil, wherein the resin layer is formed with the resin composition according to claim 1.

5. The metal foil provided with a resin layer according to claim 4, wherein the resin layer is used as a dielectric layer.

6. A printed wiring board formed by using the metal foil according to claim 4.

7. A metal clad laminate comprising a resin layer formed by using the resin composition according to claim 1 and a metal layer.

8. A printed wiring board formed by using the metal clad laminate according to claim 7.

9. A resin composition used for constituting a resin layer of a laminate in which the resin layer is provided on a metal layer surface, the resin composition comprising a styrene-modified polyphenylene ether compound obtained from reacting a polyphenylene ether compound with chloromethyl styrene; 10 parts by mass to 100 parts by mass of a styrene-butadiene block copolymer; 0.1 parts by mass to 100 parts by mass of a component promoting solubility of the resin composition with a desmear solution, wherein the component is a polymer of diallyl phthalate; and 0.1 parts by mass to 30 parts by mass of 2,4-diphenyl-4-methyl-1-pentene as a curl lessening component, wherein parts by mass are per 100 parts by mass of the styrene-modified polyphenylene ether compound.

10. The resin composition according to claim 9, further comprising 50 parts by mass to 600 parts by mass of dielectric particles per 100 parts by mass of the resin composition excluding the dielectric particles.

11. The resin composition according to claim 10, wherein the dielectric particles are composed of a composite oxide having a perovskite structure.

Description

EXAMPLES

Example 1

Manufacturing of Metal Foil Provided with a Resin Layer

(1) In Example 1, a copper foil provided with a resin layer was manufactured in the following manner. First, 200 grams of polyphenylene ether resin (MX-90 manufactured by SABIC Japan) and 400 grams of toluene put into 1-liter capacity four-neck flask equipped with a stirrer, a temperature controller and a reflux tube were stirred to dissolve at 60° C. Then, 10 grams of chloromethyl styrene was put into the flask with stirring for dissolving, and the solution temperature was elevated to 80° C. Further, 24 grams of 50 mass % sodium hydroxide aqueous solution was dropped into the mixture while stirring continue for 3 hours at 80° C. Then, the content was neutralized with 1 N aqueous hydrochloric acid followed by adding methanol to the mixture for precipitation of a compound and filtration. After the filtrate was rinsed twice with methanol aqueous solution (methanol: distilled water=4:1), the solvent and water contained were dried to finish a polyphenylene ether compound.

(2) The polyphenylene ether compound obtained as above was then dissolved in toluene to prepare a 50 mass % polyphenylene ether compound solution. Further, a styrene-butadiene block copolymer (TR2003 manufactured by JSR Corporation) was dissolved in toluene to prepare a 30 mass % styrene-butadiene block copolymer solution. Further, as the component promoting solubility with desmear solution, a diallyl isophthalate oligomer (DAISO ISO DAP (registered trade mark) manufactured by Daiso Co., Ltd.) was dissolved in toluene to prepare a 30 mass % diallyl isophthalate oligomer solution. Then, respective solutions were mixed with each other to make a mass ratio among the polyphenylene ether compound, the styrene-butadiene block copolymer, the diallyl isophthalate oligomer, and 2,4-diphenyl-4-methyl-1-pentene (Curling Lessen Component: alpha-methyl styrene dimer manufactured by Wako Pure Chemical Industries, Ltd.) 50:30:10:10, and a resin solution (varnish) having a resin solid content of 40% was prepared.

(3) Into the resin solution prepared as described above, 233 parts by mass of barium titanate powder against 100 parts by mass of the whole amount of the resin composition in the resin solution was added and dispersed to obtain a resin solution applicable for formation of a resin layer (dielectric layer) in a semi-cured state including 70 mass % barium titanate powder. The barium titanate powder used has an average primary particle size of 0.25 micron-meters and a cumulative volume average particle size (D.sub.50) of 0.5 micron-meters.

(4) Then the resin solution was coated on the surface of a low-profile copper foil having a thickness of 35 micron-meters and a surface roughness (Rzjis) of 2.2 micron-meters by using a gravure coater to make thickness of the resin layer after drying 12 micron-meters. The obtained coated film was dried at 150° C. for 3 minutes to finish a copper foil provided with resin layer semi-cured the resin composition.

(5) <Manufacturing of Double-Side Metal Clad Laminate>

(6) The resin layers of the prepared two sheets of copper foils provided with resin layer faced with each other were laminated under hot pressing at 220° C. for 90 minutes and 30 kgf/cm.sup.2 to prepare a double-side metal clad laminate (double-side copper clad laminate).

Example 2

(7) A copper foil provided with resin layer and a double-side metal clad laminate were prepared in the same manner as in Example 1 except that respective solutions were mixed with each other to make a mass ratio among the polyphenylene ether compound, the styrene-butadiene block copolymer, the diallyl isophthalate oligomer, and 2,4-diphenyl-4-methyl-1-pentene in the resin solution 40:20:30:10.

Example 3

(8) A copper foil provided with resin layer and a double-side metal clad laminate were prepared in the same manner as in Example 1 except that the diallyl isophthalate oligomer as a component promoting solubility with desmear solution was replaced by a diallyl phthalate oligomer (DAISO DAP (registered trade mark) manufactured by Daiso Co., Ltd.).

Example 4

(9) A copper foil provided with resin layer and a double-side metal clad laminate were prepared in the same manner as in Example 1 except that the diallyl isophthalate oligomer as component promoting solubility with desmear solution was replaced by a tetraethylene glycol dimethacrylate (4G (polyethylene glycol dimethacrylate) manufactured by Shin-Nakamura Chemical Co., Ltd.).

Example 5

(10) A copper foil provided with resin layer and a double-side metal clad laminate were prepared in the same manner as in Example 1 except that the diallyl isophthalate oligomer as component promoting solubility with desmear solution was replaced by an unsaturated polyester resin (U-PICA 8523 manufactured by Japan U-PICA Co., Ltd.).

COMPARATIVE EXAMPLE

(11) Comparative Examples will be described.

Comparative Example 1

(12) A copper foil provided with resin layer and a double-side metal clad laminate were prepared in the same manner as in Example 1 except excluding a component promoting solubility with desmear solution and the other respective solutions were mixed with each other to make a mass ratio among the polyphenylene ether compound, the styrene-butadiene block copolymer and 2,4-diphenyl-4-methyl-1-pentene in the resin solution 55:35:10.

Comparative Example 2

(13) A copper foil provided with resin layer and a double-side metal clad laminate were manufactured in the same manner as in Example 1 except that respective solutions were mixed with each other to make a mass ratio among the polyphenylene ether compound, the styrene-butadiene block copolymer, the diallyl isophthalate oligomer and 2,4-diphenyl-4-methyl-1-pentene in the resin solution 30:20:40:10.

Comparative Example 3

(14) A copper foil provided with resin layer and a double-side metal clad laminate were prepared in the same manner as in Example 1 except that a bisphenol F-type epoxy resin (YDF-170 manufactured by Nippon Steel Chemical Co., Ltd.) which is used as a curing agent (cross-linking agent) for the polyphenylene ether compound was used instead of the component promoting solubility with desmear solution.

(15) Examination

(16) On the double-side metal clad laminates prepared in Examples 1 to 5 and Comparative Examples 1 to 3, (1) dielectric performance of the resin layer; and (2) solubility with a desmear solution were examined. The examination method and the examination results will be separately described later.

(17) 1. Examination Method

(18) (1) Examination on the Dielectric Performance of Resin Layer

(19) Examination on the dielectric performance of a resin layer was carried out as follows. The copper foils on both sides of the double-side metal clad laminates prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were removed by etching to prepare specimens for measurement of dielectric tangent. The dielectric tangents at 10 GHz of the specimens were measured by a network analyzer E8362B manufactured by Agilent Technologies. Results are shown in Table 1.

(20) (2) Examination on the Solubility with Desmear Solution

(21) Examination on the solubility with desmear solution was carried out as following. A laminate removed the copper foils on both sides of the double-side metal clad laminate manufactured in Examples 1 to 5 and Comparative Examples 1 to 3 by etching were prepared as specimens for examination of the solubility with desmear solution the same as the specimens for measurement of dielectric tangent. By using three specimens in respective examinations of the solubility with desmear solution, the weight of the respective specimen for examination of the solubility with desmear solution prepared was measured first. The specimens were then immersed into a swelling solution (manufactured by Rohm and Haas Electronic Materials K.K.) at 75° C. for 10 minutes followed by immersing into a potassium permanganate solution (manufactured by Rohm and Haas Electronic Materials K.K.) at 70° C. for 10 minutes. Then the specimens were immersed in a neutralizing solution (manufactured by Rohm and Haas Electronic Materials K.K.) at 40° C. for 3 minutes followed by rinsing with water. After the specimens were dried in the atmosphere, weight were measured. Based on the weight before and after immersion in the desmear solution (potassium permanganate solution) for 10 minutes, the amount dissolved in the desmear solution were determined. The dissolved amount was determined into the dissolution rate in desmear solution per minute. The results are shown in Table 1.

(22) 2. Examination Results

(23) (1) Dielectric Performance of Resin Layer

(24) According to Table 1, a dielectric tangent of the specimen in Comparative Example 3 is 0.0084, while a dielectric tangent of all the other specimens are 0.005 or less, i.e. dielectric tangent of the specimen in Comparative Example 3 is higher than that of the other specimens. The resin layer in Comparative Example 3 was prepared in the same manner as in Example 1 except for including a bisphenol F-type epoxy resin as cross-linking agent instead of the component promoting solubility with desmear solution. In contrast, a dielectric tangent of the resin layer in Comparative Example 1 formed of a resin solution excluding both component promoting solubility with desmear solution and bisphenol F-type epoxy resin is the lowest 0.0020. As is made apparent from the above, dielectric tangent of the resin layer formed of a resin solution excluding component promoting solubility with desmear solution is the lowest and high frequency performance is good. Further, it was confirmed that even the dielectric tangent of the resin layer formed by using the resin composition according to the present invention including the component promoting solubility with desmear solution in Examples are slightly higher than that in Comparative Example 1, but the resin layer is good in high frequency performance. In particular, as is apparent in Example 1 using diallyl isophthalate oligomer as component promoting solubility with desmear solution, the dielectric tangent equivalent to that of the resin layer in Comparative Example 1 excluding component promoting solubility with desmear solution can be achieved. In contrast, as is apparent in Comparative Example 3, the matter is confirmed that dielectric tangent increases and results poor high frequency performance if bisphenol F-type epoxy resin is included instead of the component promoting solubility with desmear solution. Note that the dielectric tangent tends to increase as the content of diallyl isophthalate oligomer in the resin composition increases as shown in Example 2 and Comparative Example 2.

(25) (2) Performance of Solubility with Desmear Solution

(26) According to Table 1, it was confirmed that a dissolution rate in desmear solution of the specimens in Comparative Example 1 excluding component promoting solubility with desmear solution is 0.00 mg/min, i.e. almost no solubility with desmear solution. So, if a resin layer is formed of a resin composition mainly composed of a polyphenylene ether compound and a styrene-butadiene block copolymer as in Comparative Example 1 and the resin layer is employed as a material used in manufacturing a multilayer printed wiring board having interlayer connections with “Through Holes”, smears may remain inside the “Through Holes” to possibly cause defective interlayer connections since the solubility with desmear solution is very low.

(27) In contrast, as a dissolution rate in desmear solution of the specimens in Examples 1 to 5 are 0.10 mg/min to 0.20 mgs/min, these specimens are confirmed to have an appropriate solubility with desmear solution. The matter is confirmed that application of the component promoting solubility with desmear solution according to the present invention together with the polyphenylene ether compound and the styrene-butadiene block copolymer can make the resin layer formed by using the resin composition soluble in desmear solution.

(28) Note that the dissolution rate in desmear solution tends to high as the content of component promoting solubility with desmear solution in the resin composition increases as shown in Example 2 and Comparative Example 2. If the resin composition includes a bisphenol F-type epoxy resin instead of the component promoting solubility with desmear solution as in Comparative Example 3, solubility with desmear solution is extremely high. The high solubility in desmear solution exceeding a certain limit as in Comparative Examples 2 and 3 is not preferable since sink of the resin due to the excess dissolution progress of resin layer around “Through Holes” may generate in desmear treatment and adhesion between the resin layer and the conductor layer may be made poor locally.

(29) The dielectric constants of the resin layer measured by a network analyzer E8362B manufactured by Agilent Technologies in the copper foil provided with resin layer prepared in Example 1 show relatively high values of 7.3/7.3/7.1 (1 GHz/3 GHz/10 GHz). In contrast, the dielectric constants of the resin layer measured on a copper foil provided with resin layer prepared in the same manner as in Example 1 except for excluding barium titanate powder are relatively low value of 2.5/2.5/2.5 (1 GHz/3 GHz/10 GHz). So, the matter is confirmed that as the resin composition according to the present invention is low in both dielectric constant and dielectric tangent, application of the resin composition according to the present invention enables formation of a resin layer excellent in high frequency performance. Further, the matter is also confirmed that the resin composition including dielectric particles enables formation of resin layer having a high dielectric constant. So, application of the resin composition according to the present invention enables formation of a resin layer having preferable electric performance required on a material used in manufacturing of a printed wiring board.

(30) TABLE-US-00001 TABLE 1 Com- Com- Com- Example Example Example Example Example parative parative parative 1 2 3 4 5 Example 1 Example 2 Example 3 Resin Polyphenylene ether 50 40 50 50 50 55 30 50 composition compound Styrene-butadiene 30 20 30 30 30 35 20 30 copolymer Diallyl isophthalate 10 30 — — — — 40 — oligomer Diallyl phthalate oligomer — — 10 — — — — — Tetraethylene glycol — — — 10 — — — — dimethacrylate Unsaturated polyester — — — — 10 — — — resin Bisphenol F-type epoxy — — — — — — — 10 resin 2,4-Diphenyl-4-methyl-l- 10 10 10 10 10 10 10 10 pentene Barium titanate powder 233 233 233 233 233 233 233 233 Examination Dielectric tangent Df (at 0.0022 0.0040 0.0030 0.0047 0.0026 0.0020 0.0041 0.0084 10 GHz) Dissolution rate in 0.12 0.17 0.10 0.20 0.20 0.00 0.28 0.43 desmear solution [mgs/min]

INDUSTRIAL APPLICABILITY

(31) Application of a resin composition including 10 parts by mass to 100 parts by mass of a styrene-butadiene block copolymer and 0.1 parts by mass to 100 parts by mass of a component promoting solubility with desmear solution against 100 parts by mass of a polyphenylene ether compound according to the present invention enables formation of a resin layer having excellent electrical performance including high frequency performance and so on and appropriate solubility with desmear solution required on a material used in manufacturing of a printed wiring board.