JPH04195050A - Photosensitive resin composition and photosensitive film using same - Google Patents

Abstract

PURPOSE:To improve plating resistance and flexibility of a hardened film by using a film-forming polymer containing carboxyl groups, a photopolymerization initiator, such as benzophenone, and a specified vinyl compound. CONSTITUTION:The composition to be used comprises the carboxy-containing film-forming polymer, such as an acrylate-acrylic acid copolymer, the photopolymerization initiator, such as benzophenone, and the vinyl compound represented by general formula in which R1 is H or methyl; R2 is a>=4C saturated hydrocarbon group; n is an integer of 2 - 5; and m is an integer of 1 - 4. It contains, when needed, a vinyl compound, such as tetraethyleneglycol dimethacrylate, a plasticizer, a thermopolymerization inhibitor, a dye, a pigment, a filler, an adhesion giving agent, and the like. A surface of a metal, such as copper, is coated with a coating material comprising this composition as a liquid resist and dried, or a support film made of polyester is coated with it and after drying, a protective film, such as a polyester film, is laminated when needed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a photosensitive resin composition and a photosensitive film using the same, and more specifically to a photosensitive resin composition with excellent plating resistance and flexibility. and relates to photosensitive films.

[Conventional technology]

Conventionally, in the field of manufacturing printed circuit boards, photosensitive resin compositions and photosensitive films obtained using the same have been widely used as resist materials used for etching, plating, etc. After laminating a photosensitive film on a copper substrate and exposing it to pattern light,
It is manufactured by removing the unexposed areas with a developer, performing etching or plating to form a pattern, and then peeling off the cured areas from the substrate.

Currently, as patterns of printed wiring boards become thinner, plating methods (hereinafter abbreviated as plating methods) are becoming mainstream. Photosensitive films used in plating methods are required to have resistance to plating chemicals, but with conventional technology, as the resistance increases, the cured film becomes harder and more brittle. Some defects occurred such as peeling or chipping.

[Problem to be solved by the invention]

The present invention solves the problems of the prior art described above and provides a photosensitive resin composition with excellent plating resistance and flexibility of a cured film, and a photosensitive film using the same.

[Means to solve the problem]

The present invention provides (A) a carboxyl group-containing film-like property-imparting polymer, (B) a photopolymerization initiator or a photopolymerization initiator system, and (C) - Funazura (I) [wherein R1 represents hydrogen or a methyl group, R2 represents a saturated hydrocarbon chain having 4 or more carbon atoms, n represents an integer of 2 to 5, and m represents an integer of 1 to 14. The present invention relates to a photosensitive resin composition and a photosensitive film formed by laminating a layer of the photosensitive resin composition on a support film.

Next, each component used in the present invention will be explained.

Examples of the carboxyl group-containing film properties imparting polymer [component (A)] used in the present invention include (meth)acrylic acid (meaning methacrylic acid or acrylic acid),
Copolymers of alkyl esters and (meth)acrylic acid (same hereinafter), copolymers of alkyl (meth)acrylic esters, (meth)acrylic acid, and vinyl monomers copolymerizable with these, and the like. Examples of the (meth)acrylic acid alkyl ester include (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester,
(meth)acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, etc. are mentioned. Also,
Examples of vinyl monomers that can be copolymerized with (meth)acrylic acid alkyl esters and (meth)acrylic acid include:
(meth)acrylic acid tetrahydrofurfuryl ester,
(meth)acrylic acid dimethylaminoethyl ester, (
Meth)acrylic acid diethylaminoethyl ester, (meth)acrylic acid glycidyl ester, 2゜2.2-1 trifluoroethyl (meth)acrylate, 2. 2. 8
．． Examples include 3-tetrafluoropropyl (meth)acrylate, acrylamide, diacetone acrylamide, styrene, vinyltoluene, and the like.

Photoinitiator or photoinitiator system used in the present invention [
Component (B)] includes, for example, benzophenone, N,
N'-tetramethyl-4,4°-diaminobenzophenone (Michler's ketone), N.

Aromatic ketones such as No-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4°-dimethylaminobenzophenone, 2-ethylanthraquinone, and phenanthrenequinone; benzoins such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; Ethers, benzoins such as methylbenzoin and ethylbenzoin, diester compounds of β-(acridin-9-yl)acrylic acid, acridine compounds such as 9-phenylacridine and 9-pyridyl acridine, 2-
(o-chlorophenyl)-4,5-diphe and limidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(
o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-
Diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2
, 4-di(p-methoxyphenyl)5-phenylimidazole dimer, 2-(2,4-dimethoxyphenyl)-
2.4.5-) Realarylimidazole dimers such as 4,5-diphenylimidazole dimer and 2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimer.

The blending amount of component (A) is preferably 10 to 80 parts by weight based on 100 parts by weight of the total amount of component (A) and component (C), and 3
More preferably 0 to 70 parts by weight. If the amount is too small, the strength of the film tends to decrease, and if it is too large, the sensitivity tends to decrease.

In addition, the weight average molecular weight of the siloxane-based polymer of component (A) is 10,000 from the viewpoint of coating properties, film strength, and developability.
A range of 0 to 200,000 is preferred.

The blending amount of component (B) is preferably 0.03 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the total amount of component (A) and component (C).

If this amount is too small, sufficient sensitivity may not be obtained, and if it is too large, light absorption at the surface of the composition may increase during exposure, resulting in insufficient photocuring of the interior.

In the vinyl compound represented by the general formula (1) [component (C)] used in the present invention, the number of carbon atoms in the saturated hydrocarbon chain of R2 in the general formula 1) is 4 or more. Below 3,
It is highly volatile and inconvenient. The upper limit of the number of carbon atoms is usually 20, preferably 12. Examples of R2 include a butyl group, a sec-butyl group, a tert-butyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, a decyl group, a dodecyl group, and an eicosyl group.

In general formula (J), n is 2 to 5, or if n=1, it is difficult to obtain the compound, and if n is 6 or more, developability is poor. m is 1 to 14, but when m is 15 or more, handling is difficult and plating resistance is poor.

The compound (C) used in the present invention includes 2-
Ethylhexylcarpitol acrylate (general formula (1)
), R = HSR2 = 2-ethylhexyl group, n = 2,
m = 2 to 4, manufactured by Toagosei Kagaku Kogyo Co., Ltd., trade name Aronix M-120), butyl carpitol acrylate (R1 = H, R2 = butyl group, n = 2, m-
2 to 4), etc.

The blending amount of component (C) is preferably 1 to 40 parts by weight, and 5 to 40 parts by weight, based on 100 parts by weight of the total amount of component (A) and component (C).
20 parts by weight is more preferred. If it is less than 1 part by weight, peelability, plating resistance, etc. may be poor, and if it exceeds 40 parts by weight, the resin will become too soft, causing problems in storage stability.

The photosensitive resin composition of the present invention may optionally contain a vinyl compound other than component (C) such as tetraethylene glycol dimethacrylate, a plasticizer, a thermal polymerization inhibitor, a dye, a pigment,
Fillers, adhesion agents, etc. can be blended.

The photosensitive resin composition of the present invention is applied as a liquid resist onto a metal surface, such as copper, nickel, or chromium, preferably copper, and used after drying, or used as a photosensitive film. The thickness of the photosensitive resin composition layer varies depending on the application, but the thickness after drying is about 10 to 100 μm. When a liquid resist is used, an inert polyolefin film such as polyethylene or polypropylene is used as a protective film. The photosensitive film is obtained by coating a photosensitive resin composition on a support film such as polyester, and after drying, laminating a protective film such as polyethylene as necessary. The photosensitive resin composition may be mixed with other solvents and applied as a solution, if necessary.

The photosensitive resin composition layer is irradiated with actinic light through a negative or positive mask pattern called artwork, and then developed with a developer to form a resist pattern. As the active light rays used in this case, for example, those that effectively emit ultraviolet rays, such as carbon arc lamps, ultra-high pressure mercury lamps, high pressure mercury lamps, and xenon lamps, are used.

As the developer, one that is safe, stable, and has good operability is used, and in the case of an alkaline development type photoresist as in the present invention, a dilute solution of sodium carbonate or the like is used. Development methods include a dip method, a paddle method, a spray method, etc., and a high-pressure spray method is most suitable for improving resolution.

Electroplating performed after development includes copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-slow solder plating, nickel plating such as Watt bath (nickel sulfate-nickel chloride) plating, and nickel sulfamate plating. There are gold platings such as gold plating and soft gold plating.

〔Example〕

Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Methacrylic acid/methyl methacrylate/butyl methacrylate/2-ethylhexyl acrylate copolymer (weight ratio 2
515015/2 o, average weight molecular weight 80,000), 150 g of 40 wt% methyl cellosolve/toluene (weight ratio 6/4) solution (solid content 60 g), 0.1 g of bis-4-(N,N-diethylamino)benzophenone , benzyl dimethyl ketal (manufactured by Ciba Geigy, trade name Irgacure 651) 5 g, benzophenone 4 g, tribromomethyl phenyl sulfone 1 g 10 icocrystal violet 1 g 1 malachite green 0.05 g 1 methyl engineered methyl ketone 15 g, ) toluene 10 g 1 methanol 3 g and bisphenol A poly 20 g of oxyethylene dimethacrylate (Shin Nakamura Chemical Industries, Ltd., trade name BPE-10) was blended to obtain a solution containing components (A) and (B). As shown in Table 1, 2-ethylhexylcarpitol acrylate (Toagosei Kagaku Kogyo Co., Ltd., trade name M-120) was added to this solution.
) was dissolved to obtain a photosensitive resin composition solution.

Next, this photosensitive resin composition solution was uniformly applied onto a 25 μm thick polyethylene terephthalate film, and 1
A photosensitive film was obtained by drying for about 10 minutes in a hot air convection dryer at 00°C. Note that the film thickness of the photosensitive resin composition layer after drying was 50 μm.

On the other hand, the copper surface of a copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., trade name MCL-E-61), which is a glass epoxy material with copper foil (thickness 35 μm) laminated on both sides, was polished with a brush equivalent to #800. The copper-clad laminate obtained by polishing with a machine (manufactured by Sankeisha), washing with water, and drying with air flow was heated to 80°C, and the photosensitive resin composition layer was applied on the copper surface for 120°C. The layers were laminated while heating to °C.

Next, a negative film was applied to the substrate thus obtained, and an 8 kW high-pressure mercury lamp (manufactured by Oak Seisakusho Co., Ltd., H
MW-201B) was used for exposure at 60 mJ/cd. At that time, in order to evaluate the sensitivity, the negative film (optical density 0.05
was used as the first stage, and a step tablet in which the optical density increased by 0.15 with each stage was used.

The polyethylene terephthalate film was then removed, and the unexposed areas were removed by spraying a 1% aqueous sodium carbonate solution at 30°C. At that time, the time taken for the unexposed areas to be removed was measured, and the values are shown in Table 1 as the development time.

Furthermore, the sensitivity of the photosensitive resin composition was evaluated by measuring the number of step tablets of the photocured film formed on the copper-clad laminate. The results are shown in Table 1. Sensitivity is indicated by the number of steps on the step tablet, and the higher the number of steps on the step tablet, the higher the sensitivity.

Next, the developed product was degreased, washed with running water for 1 minute, and then immersed in a hydrogen peroxide/sulfuric acid, 10/20 vol. % aqueous solution for 2 minutes. Furthermore, after washing with running water for 1 minute, it was immersed in a 10% sulfuric acid aqueous solution bath for 1 minute, and washing with running water was performed again for 1 minute.

Next, copper sulfate plating bath [copper sulfate 75g/], sulfuric acid 19
0 g/I! Copper sulfate plating was performed at 25°C and 3A/dm2 for 40 minutes at 25°C and 3A/dm2 for 40 minutes. 10
% borofluoric acid aqueous solution bath for 1 minute, followed by solder plating bath [45% tin borofluoride 64mj#, 45% lead borofluoride 22-/I! , 42% fluoroboric acid 20
0ml/l, Plutin LA Conductivity Salt (trade name, Meltex), 20g #, Pultin LA Starter (tradename, Meltex) 40mj/I, and the mixture was heated at 25°C and 2A/dm2 for 20 minutes.

After completing solder plating, it was washed with water and dried.

To examine plating resistance, sellotape was applied immediately after drying, and this was peeled off in the vertical direction to check for peeling of the resist (tape test).

After that, the presence or absence of any cracks in the solder plating was observed from above using an optical microscope. If solder plating cracks, it can be observed underneath through the transparent resist. The results are shown in Table 1.

In addition, a flexible circuit board (MCL-I-6
7, manufactured by Hitachi Chemical Co., Ltd.) was laminated with a photosensitive film, and exposed to light at 60 mJ/car in the same manner as above. After exposure,
A cross-cut test was conducted according to JIS K5400.

After that, a mandrel test was performed using an iron rod with a diameter of 6 yen,
The area where the cross-cut test was performed was observed. If the resist is brittle, the resist will peel off during the mandrel test and the crosscut test results will deteriorate. The results are shown in Table 1.

From the results in Table 1, the photosensitive resin composition of Example 1 had good sensitivity, good plating resistance, and produced a flexible cured film because there was no decrease in cross-cutting properties after the mandrel test. is shown.

Example 2 and Comparative Examples 1 to 2 The components (A) and (B) in the present invention were added as shown in Table 1 to a solution containing components (A) and (B) obtained in the same manner as in Example 1.
The vinyl compound of C) and a compound not corresponding to the vinyl compound were added to obtain each photosensitive resin composition solution, and these were evaluated in the same manner as in Example 1. The results are shown in Table 1.

(The following is a blank space) [Effects of the Invention] The photosensitive resin composition of the present invention and the photosensitive film using the same can provide a photosensitive layer with excellent plating resistance and flexibility.

-・Yo:・T

Claims (2)

[Claims] 1. (A) Carboxyl group-containing film properties-imparting polymer, (B) Photoinitiator or photoinitiator system, and (C) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [R_1 in the formula represents hydrogen or a methyl group, R_2 represents a saturated hydrocarbon chain having 4 or more carbon atoms, n represents an integer of 2 to 5, and m represents an integer of 1 to 14]. A photosensitive resin composition characterized by containing: 2. A photosensitive film comprising a layer of the photosensitive resin composition according to claim 1 laminated on a support film.