JPH0721046B2 - Resist composition for producing printed wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition comprising a photosensitive resin composition and a thermosetting resin composition, and in particular, it withstands alkaline plating conditions and has good workability. And a resin composition for producing a printed wiring board, which exhibits excellent resolution.

[Conventional technology]

The fact that thermosetting epoxy resin-based ink can be used as a resist material such as solder resist for printed wiring boards
It is already well known. On the other hand, when a solder resist is used as the resist material, it is strongly required to improve the pattern accuracy of the solder resist formed on the circuit as the wiring density increases.

In order to meet this demand, an attempt to obtain a highly accurate resist pattern by exposing and developing using a photosensitive solder resist instead of a thermosetting resist has been proposed. , For example, JP-A-54-
94595, JP-A-58-62636, JP-A-59-22047 and the like can be mentioned.

[Problems to be Solved by the Invention]

However, although the above-mentioned conventional technique can form a resist pattern by exposure and development, sufficient consideration must be given to low cost, workability, reliability, etc., which are important factors in the production of high-density multilayer wiring boards. It wasn't done.

First, in order to form an exposed and developed resist pattern on a wiring board, at least a step of forming a resist film on the entire surface of the wiring board, a step of exposing using a negative mask or the like, and a step of developing with a developing solution or the like. It is necessary to go through the process of performing. In order to form a resist film on the entire surface of the wiring board, the resist may be formed into a film and laminated, or the resist may be liquefied and applied. When the film is formed, workability is good and exposure is performed. Although there is an advantage that it can be exposed in close contact with a negative mask, in addition to the difficulty of forming a film itself, there is a problem that the cost required for forming a film becomes large, on the other hand, when using a liquid resist, Although the cost is low, the liquid resist has a fatal drawback that it cannot be exposed in close contact with the negative mask.

Also, due to the restrictions on the resist composition, screen printing, which has good workability, cannot be used as a coating method.Therefore, methods with poor workability, such as spraying a resist diluted with a solvent or applying by curtain coating, have been adopted. There was a problem that I had no choice.

In addition, since a highly flammable organic solvent is used in the development process, there is a fire safety risk.
Development with a chlorine-based solvent such as trichloroethane has been desired.

In addition to the above workability problem, conventional resists have
When chemical copper plating is applied to a wiring board on which a resist pattern is formed, there is a very serious defect that the resist is peeled off by being immersed in a high-temperature, highly alkaline plating solution for a long time. Such a problem of resist plating solution resistance has been particularly recognized in recent years, but a method for solving this problem with a resist composition that can be exposed and developed has not been known so far.

The object of the present invention is to solve the various problems found in the above-mentioned prior art, while being an inexpensive coating resist, it also has the excellent workability of a filmized resist, and is resistant to plating solutions. Another object of the present invention is to provide a resin composition having a high resolution that solves the above problem.

[Means for Solving the Problems]

The above-mentioned object is a resin composition comprising a prepolymer of diallyl phthalate, a polyfunctional unsaturated compound, a photoradical polymerization initiator, an epoxy resin, a photocationic polymerization initiator and a predetermined curing agent. Can be achieved by

The prepolymer of diallyl phthalate in the above composition is β-
Since it is also called a polymer, for example, "Diallyl phthalate resin" written by Naoki Yoshimi, published by Nikkan Kogyo Shimbun (sho 44), describes its detailed properties and production method, and is obtained from Osaka Soda Co., Ltd., for example. can do. The prepolymer of diallyl phthalate used in the present invention preferably has a molecular weight of 3,000 to 30,000, but is not necessarily limited to this range. In addition, the expression including the prepolymer in the present specification does not prevent inclusion of a small amount of a diallyl phthalate monomer or a so-called γ-polymer having a three-dimensional network structure, which remains or is formed with the synthesis of the prepolymer. .

The polyfunctional unsaturated compound in the resin composition is a polyfunctional unsaturated compound having at least two ethylene bonds in the molecule, and as one example of such a compound, an unsaturated carboxylic acid is used. A compound obtained by an esterification reaction of an acid and a polyhydroxy compound having a valence of 2 or more can be mentioned. Here, as the unsaturated carboxylic acid, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, etc., and as the polyhydroxy compound having two or more valences, ethylene glycol, propylene glycol, triethylene glycol, hydroxy, etc. Non, pyrogallol, and the like, and as the compound obtained by the esterification reaction of these unsaturated carboxylic acid and polyhydroxy compound, diethylene glycol diacrylate,
Polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1,5 pentanediol diacrylate, 1,6 hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, 1, 3 Butanediol Dimethacrylate and other diacrylate, dimethacrylate compounds and dipentaerythritol tree, tetra-, penta-acrylate or -methacrylate, sorbitol tree, tetra-, pentar, hexa-acrylate or -methacrylate, etc. Polyvalent acrylate or methacrylate compounds, oligoester acrylates, oligos Such as methacrylate, also, and epoxy acrylates or epoxy methacrylates are produced by the reaction of epoxy resin with acrylic acid or methacrylic acid. Note that the above examples do not limit the addition of the monofunctional unsaturated compound, and if necessary, a mixture of polyfunctional unsaturated compounds can be used. The photoradical polymerization initiator in the resin composition is acetophenone and its derivative, benzophenone and its derivative, Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyl alkyl ketal, thioxanthone and its derivative, tetramethyl thiuram mono. Sulfide, 1-hydroxycyclohexyl phenyl ketone,
2-Methyl-1- [4- (methylthio) phenyl] -2
And α-aminoketone compounds represented by morphol-1-propene-1. If necessary, a mixture of the above compounds can be used, and if necessary, an amine compound can be added for the purpose of increasing or decreasing the action of the photoradical polymerization initiator.

Further, the epoxy resin and the predetermined curing agent in the resin composition are added to prevent the solder resist on the copper foil from peeling off when immersed in the alkaline plating solution. Those having two or more epoxy groups per molecule, such as bisphenol A,
Polychrysidyl ethers or polychrysidyl esters obtained by reacting polyhydric phenols such as halogenated bisphenol A, catechol, resorcinol, etc. or polyhydric alcohols such as glycerin with epichlorhydrin in the presence of a basic catalyst, Epoxy novolac obtained by condensing a novolak type phenolic resin and epichlorhydrin, an epoxidized polyolefin epoxidized by a peroxide method, an epoxidized polybutadiene, a dicyclopentadiene oxide, an epoxidized vegetable oil, or the like can be used. Further, as the curing agent, a mixture of a diaminotriazine-modified imidazole compound and dicyandiamide is suitable for preventing peeling of the solder resist. Here, as the diaminotriazine-modified imidazole compound, a compound having a latent curability with respect to an epoxide compound and represented by the following general formula can be used.

(R represents an imidazole compound.) For example, 2,4-diamino-6 {2'-methylimidazole- (1 ')} ethyl-S-triazine, 2,4-diamino-6 {2'-ethyl-4 ′ -Methylimidazole-
(1 ′)} Ethyl-S-triazine, 2,4-diamino-
6 {2'-untecylimidazole- (1 ')} ethyl-S-triazine or 2,4-diamino6 {2'-methylimidazole- (1')} ethyl-S-triazine / isocyanuric acid adduct Is.

Further, the photocationic polymerization initiator in the resin composition is added in order to prevent the elution of epoxy during chlorocene development and the omission of other additives, such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts. Salts can be used. In particular, the aromatic sulfonium salt is
It is preferable because it has high reactivity and good thermal stability. The general formula of the aromatic sulfonium salt is as follows.

Furthermore, the resin composition of the present invention, if necessary, an organic solvent and a colorant as a diluent, a defoaming agent, a filler,
A thixotropic agent can be included. However, inclusion of these is not a feature of the present invention.

Among them, suitable examples of the organic solvent include high boiling point solvents such as cellosolve, cellosolve acetate, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, and terpineol as preferable examples. However, acetone, methyl ethyl ketone, ethanol, etc. are not to be excluded.

As the coloring agent, a coloring material such as phthalocyanine green or phthalocyanine blue may be used as appropriate.

As the defoaming agent, an organic silicon compound having a siloxane bond, which is represented by silicone oil, is used.

The filler is added to the resin composition as an inorganic filler, and fine powder of silica, alumina, talc or the like is used.

The thixotropic agent is used for improving the viscosity of the resin composition, particularly thixotropic property, and it is preferable to use ultrafine silica.

The content of the components of the resin composition of the present invention has been described above, but the preferable composition ratio is 100 parts by weight of the diallylphthalate prepolymer, and the polyfunctional unsaturated compound 1 to 30.
Parts by weight, 0.5 to 20 parts by weight of a radical photopolymerization initiator, and 5 to 30 parts by weight of an epoxy resin. Further, the diaminotriazine-modified imidazole compound used as a curing agent for the epoxy resin, dicyanamide, and a cationic photopolymerization initiator are mixed in an amount of 1 part with respect to 100 parts by weight of the epoxy resin, respectively.
2 to 0.5 parts by weight, 0.5 to 15 parts by weight, and 0.5 to 20 parts by weight.

Incidentally, the lower limit and the upper limit of the above composition are the values obtained under the conditions that the photosensitivity of the resin composition is not insufficient and the contact exposure property, plating resistance, and heat resistance of the resin composition can be secured. .

[Action]

Since the resin composition according to the present invention contains a large amount of diallyl phthalate prepolymer which is solid in the state, it is possible to impart fluidity to the composition by adding a solvent, and a substrate by a screen printing method. It can be easily applied to the top. In addition, after application, the film is easily solidified by predrying before exposure, so that a negative mask can be closely attached to the surface for exposure.

Further, the polyfunctional unsaturated compound and the photoradical polymerization initiator in the resin composition of the present invention are added so that the photocuring reaction with the diallylphthalate prepolymer is completed within a practical time. It acts to prevent the photo-cured part from being dissolved or swelled in the developing solution in the process. Further, the cationic photopolymerization initiator has a function of polymerizing the epoxy resin at the time of exposure and preventing the epoxy resin from being eluted and other additives from being dropped off during the development in the subsequent step. The addition of an appropriate amount of epoxy resin and a predetermined curing agent has the effect of preventing peeling of the cured resin layer on the copper foil during immersion in an alkaline plating solution, so that the resin composition of the present invention is applied to a portion not requiring plating. By coating, it becomes possible to plate only the necessary portions thereafter.

Further, regarding the development, it was found that only in a composition of a combination of a diallyl phthalate prepolymer, a polyfunctional unsaturated compound and an epoxy resin, it becomes soluble in a chlorine-based solvent such as 1,1,1-trichloroethane, and, It was also found that the surface of the exposed cured product was not dissolved by the addition of the photocationic polymerization initiator, and this enabled development with a chlorine-based solvent.

Since the resin composition of the present invention has the above-described actions and characteristics, it is particularly suitable for high-density, low-cost printed wiring board production, but it does not lose its effectiveness for other applications. Absent.

〔Example〕

Hereinafter, examples of the resin composition of the present invention will be described together with comparative examples.

Example 1 First, a resin composition consisting of the following (A) to (G) was prepared. The compounding ratio of each component is as shown in Table 1.

(A) diallyl phthalate prepolymer (b) trimethylolpropane trimethacrylate (trifunctional methacrylate) (c) epoxy resin (d) 2-methyl-1 [4- (methyl) phenyl]-
2-morpholino-propane-1 (photopolymerization initiator) (e) dicyandiamide (curing agent) (f) 2,4-diamino-6 [2'-methylimidazole- (1 ')] ethyl-S-triazine (curing Agent) (to) Bis- [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluorophosphate (photocationic polymerization initiator) Here, as the diallyl phthalate aprepolymer,
The prepolymer having an average molecular weight of about 7,000 (Osaka Soda Co., Ltd.)
Manufactured by Isodap), and the epoxy resin used was phenol novolac epoxy (trade name: Epicoat 142, manufactured by Yuka Shell Epoxy Co., Ltd.).

The resin composition was prepared by the following procedure.

That is, first, (a) to (d) were mixed and heated and stirred at about 80 ° C. for 30 minutes. At this time, in order to further improve the coating characteristics of the composition, an appropriate amount of a solvent (ethyl cellosolve), a colorant (phthalocyanine green), and an antifoaming agent (silicone oil) was added and dispersed and dissolved in the above main component. . Then, after cooling the above composition to room temperature, (e),
(F) and (G) were added in appropriate amounts and mixed to obtain a final resin composition.

The above resin composition was printed on the entire surface of a printed wiring board on which a circuit was formed using a screen printing machine using a 180 mesh stainless screen plate, and then pre-dried at about 80 ° C. for 30 minutes. In this state, the resin surface solidifies,
It was decided that the contact exposure property was good if the exposure was possible by closely contacting the negative mask.

Then, after passing through a negative mask and exposing to ultraviolet light for 0.5 to 2 minutes using a 400W high-pressure mercury lamp, 1,1,1-
Spray development was performed using trichloroethane. After forming the resin pattern by development, the resin layer surface is observed with a microscope, and in this state, the surface is determined to be good even if the surface is not rough, and the elution of the epoxy resin and the addition of other additives It was decided that it would not fall out.

The sample after the development was further subjected to thermosetting treatment at 150 ° C. for 30 minutes to manufacture a printed wiring board. At this time, 0.1m
Depending on whether it is possible to develop patterns with m intervals,
It was decided to judge whether the developability was good or bad.

Then, the printed wiring board was immersed in a plating solution having the following composition for 30 hours, and then the presence or absence of peeling of the resin layer on the copper foil was inspected to determine the resistance to the plating solution.

Plating solution composition CuSO ₄・ 5H ₂ O …… 13g / EDTA ・ 2Na …… 40g / NaOH …… 11.5g / Polyethylene glycol stearylamine …… 0.1g / α-α′-dipyridyl …… 5mg / formalin (37%) …… 3ml / water ・ ・ ・ Total volume is 1 Liquid temperature ・ ・ ・ 70 ℃ PH = 12.3 Furthermore, the printed wiring board is immersed in the solder solution at 260 ℃ for 10 seconds, and heat resistance depends on whether the resin layer is peeled or not. A judgment was made.

The characteristics of the resin layer obtained by the above determination method are shown in Table 1.

Comparative Example 1 In the case of the same components as in Example 1 but the compounding ratio of the components deviates from the range of the compounding ratio of the present invention described above,
A printed wiring board was manufactured in the same manner as in Example 1, and the obtained resin layer was evaluated under the same conditions as in Example 1. The results are shown in Table 1.

From the results shown in Table 1, in the case of Example 1, all show excellent characteristics, while in Comparative Example 1, the photocuring is not sufficient when the polyfunctional unsaturated compound is not contained. Because it is impossible to develop, epoxy resin, dicyandiamide, diaminotriazine modified imidazole, in a system that does not contain an appropriate amount of any of the photocationic polymerization initiator, peeling occurs by immersion in an alkaline plating solution, the amount of the epoxy resin If the amount is too large, swelling occurs during the phenomenon and pattern formation is impossible, and if the amount of the radical photopolymerization initiator is less than 0.5 parts by weight, the light Insufficient curing, and when it is more than 20 parts by weight, it is impossible to form a fine pattern due to excessive absorption of ultraviolet rays, and the same results as the photo radical polymerization initiator for the photocationic polymerization initiator. Is known, and so on.

Example 2 A resin composition consisting of the following (a) to (g) was prepared in the same manner as in Example 1. Further, the compounding ratio of each component is determined with reference to the case of Example 1.

(A) Diallyl phthalate prepolymer (average molecular weight
3,500, manufactured by Osaka Soda Co., Ltd., trade name Daiso Dup) (b) Polyfunctional unsaturated compounds (total of 5 acrylates and methacrylates shown in Table 2) (c) Epoxy resin (epibis type epoxy resin, oil-based shell) Epoxy Co., Ltd., trade name Epikote 828) (d) Benzoin isopropyl ether (e) Dicyandiamide (f) 2,4-Diamino-6 {2'-ethyl-4'-methylimidazole- (1 ')} ethyl- S-triazine (to) bis- [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluoroantimonate The properties of the resulting resin layer are shown in Table 2.

From the results shown in the table, when the compounding ratio of the polyfunctional unsaturated compound to 100 parts by weight of the diallyl phthalate prepolymer was fixed to the optimum amount of 4 parts by weight, the compounding ratio of the epoxy resin was 5
It is preferable that the blending ratio of the epoxy resin to 100 parts by weight of the diallyl phthalate prepolymer is 15 parts by weight, which is the optimum amount, and the blending ratio of the polyfunctional unsaturated compound is preferably 1 to 30 parts by weight. That is, the compounding ratio of the radical photopolymerization initiator is diallyl phthalate prepolymer 10
0.5 to 20 parts by weight is preferable with respect to 0 parts by weight, and
The compounding ratio of the curing agent is preferably 1 to 20 parts by weight of the diaminotriazine-modified imidazole compound, 0.5 to 15 parts by weight of dicyandiamide, and 0.5 to 20 parts by weight of the photocationic polymerization initiator with respect to 100 parts by weight of the epoxy resin. Is known.

Further, it has been known that a resin composition having these composition ratios can form a film that exhibits a sharp optical image having excellent resolution and that does not peel even when immersed in an alkaline plating solution.

Comparative Example 2 A resin composition was prepared in the case where the compounding ratio was the same as in Example 2 but the composition ratio deviated from the range of the present invention, a printed wiring board was produced in the same manner as in Example 2, and the characteristics were evaluated. I went.

The results are as shown in Table 2, and like the case of Comparative Example 1, satisfactory characteristics could not be secured.

〔The invention's effect〕

As described above, by using the resin composition of the present invention, it is possible to screen-print, exhibit sufficient solidification upon exposure, and can be easily developed with a chlorine-based solvent, Furthermore, it shows sufficient resistance to alkaline plating solutions, and does not elute or drop additives during the development process. Therefore, it was possible to obtain a high-resolution resin composition without peeling of the film due to penetration of the plating solution.

Having these characteristics can solve the problems found in the prior art, form a highly accurate resist pattern, and significantly improve workability in printed wiring board manufacturing,
This shows that the cost can be reduced.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03F 7/027 512 7/032 501 H05K 1/02 A 8824-4E (72) Inventor Sai Oka Kanagawa No. 292, Yoshida-cho, Totsuka-ku, Yokohama, Japan (56) References JP-A-62-265321 (JP, A) JP-A-60-206823 (JP, A) JP-A-60- 199025 (JP, A) JP 59-166526 (JP, A) JP 58-8723 (JP, A) JP 62-253613 (JP, A) JP 56-100817 (JP, A)

Claims (2)

[Claims] 1. A prepolymer of diallyl phthalate, a polyfunctional unsaturated compound, a photoradical polymerization initiator, an epoxy resin, a photocationic polymerization initiator, and a curing agent which is a mixture of dicyandiamide and diaminotriazine modified imidazole. A resist composition for producing a printed wiring board, comprising: 2. The prepolymer of diallyl phthalate is a prepolymer of diallyl phthalate having a molecular weight of 3,000 to 30,000, and the polyfunctional unsaturated compound is an acrylate or methacrylate of a hydroxy compound.
The printed wiring board according to claim 1, which is at least one polyfunctional unsaturated compound selected from oligoester-acrylate or -methacrylate, epoxy-acrylate or -methacrylate. Resist composition.