Photo-curable and thermo-curable resin composition and dry film solder resist

Abstract

The present invention relates to a photo-curable and thermo-curable resin composition which can form a DFSR having micro unevenness on the surface without a separate treatment such as plasma treatment and the like and a DFSR. The photo-curable and thermo-curable resin composition includes an acid-modified oligomer having a carboxyl group (COOH) and a photo-curable unsaturated functional group; a polyimide-based resin; a photo-polymerizable monomer having two or more photo-curable unsaturated functional groups; a thermo-curable binder having a thermo-curable functional group; and a photoinitiator.

Claims

1. A photo-curable and thermo-curable resin composition, including: an acid-modified oligomer having carboxyl group (COOH) and photo-curable unsaturated functional group; a photo-polymerizable monomer having two or more photo-curable unsaturated functional groups; a polyamic acid having a weight average molecular weight of 10,000 to 100,000,, which has no photo-curable property, and is not miscible with the acid-modified oligomer and the photo-polymerizable monomer; a thermo-curable binder having thermo-curable functional group; and a photoinitiator, wherein the content of the polyamic acid is 1 to 30 weight % based on the total weight of the resin composition, and wherein a dry film solder resist formed from said resin composition has an average roughness (Rz) of 2 to 20 m of microunevenness.

2. The resin composition according to claim 1, wherein the photo-curable unsaturated functional group of the acid-modified oligomer is an acrylate group.

3. The resin composition according to claim 1, wherein the acid-modified oligomer includes a copolymer of a polymerizable monomer having carboxyl group and a monomer including acrylate-based compound.

4. The resin composition according to claim 1, wherein the content of the acid-modified oligomer is 15 to 75 weight % based on the total weight of the resin composition.

5. The resin composition according to claim 1, wherein the acid value of the acid-modified oligomer is 40 to 120 mgKOH/g.

6. The resin composition according to claim 1, wherein the photo-polymerizable monomer includes a multifunctional (meth)acrylate-based compound having two or more (meth)acryloyl groups in the molecule.

7. The resin composition according to claim 1, wherein the photo-polymerizable monomer includes one or more multifunctional (meth)acrylate-based compounds selected from the group consisting of a multifunctional acrylate-based compound having hydroxyl group; a water-soluble multifunctional acrylate-based compound; a multifunctional polyesteracrylate-based compound of a polyhydric alcohol; an acrylate-based compound of an ethyleneoxide adduct of multifunctional alcohol or polyphenol; an acrylate-based compound of an propyleneoxide adduct of multifunctional alcohol or polyphenol; a multifunctional or monofunctional polyurethaneacrylate-based compound; an epoxyacrylate-based compound; a caprolactone-modified acrylate-based compound; and a photosensitive (meth)acrylate-based compound.

8. The resin composition according to claim 1, wherein the content of the photo-polymerizable monomer is 5 to 30 weight % based on the total weight of the resin composition.

9. The resin composition according to claim 1, wherein the photoinitiator includes one or more compounds selected from the group consisting of a benzoin-based compound, an acetophenone-based compound, an anthraquinone-based compound, a thioxanthone compound, a ketal compound, a benzophenone-based compound, an -aminoacetophenone compound, an acylphosphineoxide compound, an oximeester compound, a biimidazole-based compound, and a triazine-based compound.

10. The resin composition according to claim 1, wherein the content of the photoinitiator is 0.5 to 20 weight % based on the total weight of the resin composition.

11. The resin composition according to claim 1, wherein the thermo-curable functional group is one or more group selected from the group consisting of an epoxy group, an oxetanyl group, a cyclic ether group, and a cyclic thioether group.

12. The resin composition according to claim 1, wherein the content of the thermo-curable binder corresponds to 0.8 to 2.0 equivalents per 1 equivalent of the carboxyl group of the acid-modified oligomer.

13. The resin composition according to claim 1, further including a solvent; and at least one component selected from the group consisting of a thermo-curable binder catalyst, a filler, a pigment, and an additive.

14. A dry film solder resist including a cured product of the resin composition according to claim 1, wherein the cured product includes: a cross-linked structure in which the carboxyl group of the acid-modified oligomer and the thermo-curable functional group are cross-linked; and a cross-linked structure in which the unsaturated functional groups of the acid-modified oligomer and the photo-polymerizable monomer are cross-linked each other.

15. A dry film solder resist including a cured product of the resin composition according to claim 1, further including a photoinitiator dispersed in the cured product.

16. A dry film solder resist including a cured product of the resin composition according to claim 1, which is for the preparation of a package substrate of a semiconductor device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic drawing showing the process of preparing the DFSR having micro unevenness by using the photo-curable and thermo-curable resin composition according to one embodiment of the invention.

(2) FIGS. 2 and 3 are FE-SEM photos showing the surface conditions of the DFSRs prepared in Examples 1 and 2.

(3) FIGS. 4, 5, and 6 are images of Examples 1, 2, and Comparative Example 1 obtained using OP.

DETAILED DESCRIPTION OF THE EMBODIMENT

(4) Hereinafter, the functions and effects of the present invention are explained in more detail by referring to specific examples of the present invention. However, the following examples are only for the understanding of the present invention and the scope of the present invention is not limited to or by them.

EXAMPLES

Example 1

(5) (1) Preparation of Polyimide-Based Resin

(6) In order to synthesize a polyimide-based resin, after dissolving ODA (4,4-diaminodiphenyl ether) as a polymerizing monomer in DMF, a solvent, to be 20 weight %, PMDA (pyromellitic dianhydride) was added therto with the mole ratio of 1:1 to ODA, and then the mixture was stirred for 24 hours in an ice bath condition and the PAA (polyamic acid) of which the weight average molecular weight was 31,500 was obtained.

(7) (2) Preparation of Dry Film Solder Resist

(8) A photo-curable and thermo-curable resin composition was obtained by mixing and stirring 11.5 weight % of the PAA (polyamic acid) type polyimide-based resin prepared above, 30 weight % of ZFR-1122 of Nipponkayaku Co., Ltd. as an acid-modified oligomer, 10 weight % of a multifunctional epoxy acrylate (DPEA-12 of Nipponkayaku Co., Ltd.) as a photo-polymerizable monomer, 3 weight % of Darocur TPO (Chiba Specialty Chemicals Co., Ltd.) as a photoinitiator, 16 weight % of YDCN-500-80P (Kukdo Chemical Co., Ltd.) as a thermo-curable binder, 1 weight % of 2-phenylimidazole as a thermo-curing catalyst, 15 weight % of B-30 (Sakai Chemical Co., Ltd.) as a filler, 0.5 weight % of BYK-333 of BYK-Chemie GmbH as an additive, and 13 weight % of DMF as a solvent, followed by dispersing the filler with a 3 roll mill device.

(9) A dry film composed of a carrier film, a photo-sensitive film, and a release film sequentially from the bottom was prepared by coating the prepared photo-sensitive resin composition on a carrier film (PET film), drying the same by passing through an oven of 75 C. for 8 minutes, and laminating a release film (PE film) thereon.

(10) (3) Preparation of Printed Circuit Board

(11) After peeling away the release film from the prepared dry film, the photo-sensitive film layer was vacuum-laminated with a vacuum laminator (MV LP-500 made by Meiki Seisakusho Co., Ltd.) on a board on which a circuit was formed, the film was exposed to the UV ray of 365 nm with 400 mJ/cm.sup.2, and the PET film was eliminated. A printed circuit board including a dry film solder resist (DFSR) was prepared by dipping the result product in 1% Na.sub.2CO.sub.3 alkaline solution of 31 C. being stirred for development, and heating and curing the same at 150 C. for 1 hour.

(12) Meanwhile, a copper clad laminate LG-T-500GA made by LG Chemical Co., Ltd. of which the thickness of the board was 0.1 mm and the thickness of copper foil was 12 m was used as the board on which a circuit was formed. At this time, the board was cut into 55 cm squares and micro unevenness was formed with chemical etching on the surface of copper foil of the same.

Example 2

(13) (1) Preparation of Polyimide-Based Resin

(14) In order to synthesize a polyimide-based resin, after dissolving ODA (4,4-diaminodiphenyl ether) as a polymerizing monomer in DMF as a solvent to be 20 weight %, ODPA (4,4-oxydiphthalic anhydride) was added therto with the mole ratio of 1:1 to ODA, and then the mixture was stirred for 24 hours in an ice bath condition and the PAA (polyamic acid) of which the weight average molecular weight was 33,000 was obtained.

(15) (2) Preparation of Dry Film Solder Resist

(16) A photo-curable and thermo-curable resin composition was obtained substantially according to the same method as in Example 1, except that the PAA (polyamic acid) type polyimide-based resin prepared above was used and 30 weight % of ZFR-1121 of Nipponkayaku Co., Ltd. was used as an acid-modified oligomer.

(17) A dry film composed of a carrier film, a photo-sensitive film, and a release film sequentially from the bottom was prepared by coating the prepared photo-sensitive resin composition on a carrier film (PET film), drying the same by passing through an oven of 75 C. for 8 minutes, and laminating a release film (PE film) thereon.

(18) (3) Preparation of Printed Circuit Board

(19) A printed circuit board including a DFSR was obtained substantially according to the same method as in Example 1, except that the dry film prepared above was used.

Comparative Examples

Comparative Example 1

(20) A printed circuit board including a DFSR was obtained substantially according to the same method as in Example 1, except that 41.5 weight % of ZFR-1122 was used as an acid-modified oligomer without using the polyimide-based resin of Example 1.

Experimental Examples

Property Evaluation of Protect Film for Printed Circuit Board

(21) Surface roughness, developing property, and heat-resistant reliability of the dry film solder resists for printed circuit board prepared in Examples 1 and 2, and Comparative Example 2 were measured according to the following methods.

Experimental Example 1

Surface Roughness

(22) Each DFSR obtained in Examples 1 and 2, and Comparative Example 2 was positioned on a copper clad laminate after peeling away the release films therefrom, and they were vacuum treated for 20 seconds and laminated with the temperature of 65 C. and the pressure of 0.7 Mpa for 40 seconds by using a vacuum laminator.

(23) And, after positioning a negative type quartz photo mask on the laminated DFSR, exposing the same to the UV ray (i band) of 400 mJ/cm.sup.2, and peeling away the PET carrier film therefrom, the laminate was developed in 1% Na.sub.2CO.sub.3 alkaline solution of 30 C., and then washed and dried.

(24) The surface condition of the dried sample was checked by FE-SEM (Hitachi S-4800), and the surface roughness values Rz and Ra of Example 1 and Comparative Example 1 were measured for comparing the difference of the surface roughness thereof by using an optical profiler (OP, nanoview of Nanosystem Co., Ltd.). The FE-SEM photos of the surface conditions of Examples 1 and 2 are annexed in FIGS. 2 and 3. The images of Examples 1 and 2 and Comparative Example 1 which were obtained by using the OP are annexed in FIGS. 4, 5, and 6, respectively. The Rz and Ra values of Examples 1 and 2 and Comparative Example 1 obtained by using the OP are listed in the following Table 1.

Experimental Example 2

Evaluation of Developing Property

(25) Each DFSR obtained in Examples 1 and 2, and Comparative Example 2 was positioned on a copper clad laminate after peeling away the release films therefrom, and they were vacuum treated for 20 seconds, and laminated with the temperature of 65 C. and the pressure of 0.7 Mpa for 40 seconds by using a vacuum laminator.

(26) And, after positioning a negative type quartz photo mask on the laminated DFSR, exposing the same to the UV ray (i band) of 400 mJ/cm.sup.2, and peeling away the PET carrier film therefrom, the laminate was developed in 1% Na.sub.2CO.sub.3 alkaline solution of 30 C., and then washed and dried.

(27) The evaluation standard and result of the developing property are listed in the following Table 2.

Experimental Example 3

Measuring Method of Heat-Resistant Reliability

(28) The protect film for printed circuit board was laminated on a copper clad laminate (CCL) and a photo-curing, a thermo-curing, and a post photo-curing processes were carried out to the film. And then, the film was cut into 150 mm130 mm. After setting the temperature of a lead bath (an electric furnace, which can be electrically heated and the temperature is controllable, including minimum 2.25 kg or more lead for test) to 288 C., the test specimen was floated on the lead bath, the film side up. It was examined whether the test specimen was exfoliated or deformed in external appearance.

(29) The evaluation standard and result of the heat-resistant reliability are listed in the following Table 2.

(30) TABLE-US-00001 TABLE 1 Rz Ra Example 1 6.01 m 335.98 m Example 2 5.12 m 317.70 m Comparative Example 1 0.94 m 48.52 m

(31) Referring to Table 1, it was recognized that micro unevenness having the average roughness (Rz) of about 6.01 m and the average roughness (Ra) of about 335.98 nm, and the average roughness (Rz) of about 5.12 m and the average roughness (Ra) of about 317.70 nm was formed on the surface of each DFSR of Examples 1 and 2 because they were formed from the resin compositions including the polyimide-based resin.

(32) On the contrary, it was recognized that the DFSR of Comparative Example 1 did not have such micro unevenness without a separate plasma treatment and just showed the average roughness (Rz) of about 0.94 m and the average roughness (Ra) of about 48.52 nm.

(33) TABLE-US-00002 TABLE 2 Results of Experimental Examples 2 and 3 heat-resistant reliability developing property Example 1 OK OK Example 2 OK OK Comparative OK OK Example 1 1. Evaluation standard of heat-resistant reliability (1) OK: 288 C., not bursting in the solder floating test (2) NG: 288 C., bursting in the solder floating test 2. Developing property Observing the Fe-SEM result, it is evaluated as OK when the hole formed by the mask size of 100 m has the size of 90 m or more.

(34) Referring to Table 2, it was recognized that the DFSRs of Examples had micro unevenness on the surface but the heat-resistant reliability and the developing property of the DFSRs of Examples were as good as the DFSR of Comparative Example not having micro unevenness. Therefore, the DFSR of Example can show good adhesive strength and good property as the DFSR at the same time.