JPH0261639A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To make it possible to form the org. insulating layer with excellent heat-resisting property and flexibility by incorporating specified photopolymerizable compd. and photoploymerization initiator in the subject composition. CONSTITUTION:Each of hydroxy groups of a compd. (A) having a bisphenol skelton added ethylene oxide at the end groups thereof respectively are related with each hydroxyl groups contd. in a polyhydric (meth)acrylate compd. (B), and a polyisocyanate compd. (C) having plural isocyanate groups is interposed between each of the hydroxyl groups of the compds (A) and (B). Each of the hydroxyl groups of the compds. (A) and (B) are allowed to react with the isocyanate groups of the polyisocyanate compd. (C) respectively to form the photopolymerizable compd. The resin composition contains the photopolymerizable compd. and the photopolymerization initiator capable of generating a radical by activated rays. As the skelton of the photopolymerizable compd. constituting the main part of the composition is composed of a bisphenol skelton, the heat-resisting property of the resin composition is improved, and as the ethylene oxide is added to each end hydroxyl groups of the compd. (A) having the bisphenol skelton respectively, the sticking property of the composition is improved. As a urethane binding is formed between the bisphenol skelton and a (meth)acryloyl group which is a photopolymerization reactive group, the heat and impact resistance of the composition is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photosensitive resin composition, and more particularly to a photosensitive resin composition for forming an interlayer insulation coating used in the production of multilayer printed wiring boards.

(Prior Art) In recent years, multilayer printed wiring boards in which wiring circuits are formed in multiple layers have been used in printed wiring boards for the purpose of increasing density.

Conventionally, a multilayer printed wiring board has been used in which a plurality of circuit boards on which inner layer circuits have been formed are laminated and pressed together using prepreg as a vIA edge lit, and then the inner layer circuits are connected through through holes. was.

However, in such a multilayer printed wiring board, since through holes passing through the wiring board are formed to connect desired inner layer circuits, each inner layer circuit becomes a complicated circuit that bypasses through holes that do not require connection. It has been difficult to increase the density of circuits.

As a multilayer printed wiring board that can solve this difficulty, recently there has been active development of multilayer printed wiring boards that alternately build up conductor circuits and organic insulating layers formed from photosensitive resin compositions. is recommended. This multilayer printed wiring board is suitable for ultra-high density.

Conventionally, photosensitive resin compositions for forming the above-mentioned organic insulating layer include photosensitive polyimide resins, photosensitive resins containing acrylic polymers and photopolymerizable monomers as main components, and epoxy resins to which photosensitive groups have been added. Photosensitive resins containing as a main component are known.

However, the resin compositions have the following drawbacks, and the field of application is limited to a very limited range.

That is, the photosensitive polyimide resin scatters the photosensitive groups when cured, making it difficult to form a thick glabellar insulating film.Furthermore, since the resin has low alkali resistance, the wiring pattern is formed by chemical copper plating. I can't.

Since the photosensitive resin whose main components are an acrylic polymer and a photopolymerizable monomer contains a large amount of an acrylic polymer, the cured film does not have sufficient heat resistance.

The photosensitive resin whose main component is an epoxy resin to which a photosensitive group has been added has a problem in that the cured film is relatively brittle because it is based on a novolane epoxy resin.

As mentioned above, it is a photosensitive resin composition for forming an organic insulating layer of a multilayer printed wiring board in which a conventional conductor circuit and an organic insulating layer are alternately built up, and is an organic material with excellent heat resistance and flexibility. A photosensitive resin composition capable of forming an insulating layer is not yet known.

(Problems to be Solved by the Invention) The present invention provides a photosensitive resin composition that eliminates the drawbacks of the prior art as described above and is capable of forming an organic insulating layer with excellent heat resistance and flexibility. The purpose is to

(Means for Solving the Problems) The present invention provides that a poly(meth)acrylate compound having at least one hydroxyl group corresponds to each hydroxyl group of a bisphenol skeleton compound having an oxirane compound added to both ends. , a photopolymerizable compound in which a polyisocyanate compound having at least two isocyanate groups is interposed between the hydroxyl groups of both the compounds, and the hydroxyl groups of both the compounds react with the isocyanate groups of the polyisocyanate compound, and actinic light. The present invention relates to a photosensitive resin composition containing a photopolymerization initiator that generates radicals.

In the photosensitive resin composition of the present invention, a polyvalent (meth)acrylate compound having at least one hydroxyl group corresponds to each hydroxyl group of a bisphenol skeleton compound having an oxirane compound added to both ends, and both of the above-mentioned A photopolymerizable compound (hereinafter referred to as photopolymerizable compound) in which a polyisocyanate compound having at least two isocyanate groups is interposed between the hydroxyl groups of the compound, and the hydroxyl groups of both of the compounds react with the isocyanate groups of the polyisocyanate compound. (referred to as a chemical compound).

By the way, Japanese Unexamined Patent Publication No. 57-78415 discloses that a photosensitive resin/composition composed of diol urethane (tagne acrylate and ketone resin) is used for permanent protection of printed wiring circuits and between circuits when soldering parts. It is disclosed that the resin described in this publication is used as a solder resist for the purpose of preventing solder bridges.However, while the resin described in the publication uses a diol having an aliphatic hydrocarbon skeleton, The resin composition described in the same publication and the resin of the present invention are completely different in that the resin of the invention uses a bisphenol skeleton compound with an oxirane compound added to both ends.Moreover, the resin composition described in the publication is heat resistant. In contrast, the resin composition of the present invention has high heat resistance, and is completely different in terms of operation and effect.

In the present invention, the compound having a bisphenol skeleton with oxirane compounds added to both ends thereof is represented by the general formula shown in Formula 1.

H-(-011!, C,-)-0-0-R-0-0-(
-C, lIK, 07, -H21 Clyu HS n and n' are the same or different integers of 1 or more, m is an integer of 1 or more] Here, the reason for using a compound with a bisphenol skeleton is This is because this skeleton can improve the heat resistance after curing.

Furthermore, in the present invention, oxirane compounds are added to both ends of this bisphenol skeleton. This is because the chain structure of the oxirane compound increases the flexibility of the cured product, thereby increasing the adhesion to the object to be coated. Therefore, a bisphenol skeleton compound with an oxirane compound added to both ends can have both high heat resistance and flexibility. Here, oxirane compounds include ethylene oxide,
It is a general term for compounds having an oxirane ring such as propylene oxide and butylene oxide.

The polyisocyanates of the present invention having at least two isocyanate groups are, for example, 2,4-toluene diisocyanate, 2,6-1-toluene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, methylcyclohexane-2,4-diisocyanate. , inphorone diisocyanate, etc. It is also possible to use these polymers.

Furthermore, the polyvalent (meth)acrylate having at least one hydroxyl group used in the present invention is generally referred to as epoxy acrylate or epoxy ester, and for example, manufactured by Kyoeisha Yushi Kagaku Kogyo ■: Trade name: Evolai) 80MF and Nippon Kayaku ■: Product name:
There are KAYARAD, PET-BO, etc.

Next, an example of the method for producing the photopolymerizable compound of the present invention will be briefly described. First, at least one compound having a bisphenol skeleton with oxirane compounds added to both ends was heated at 50°C.
1 to 5 polyisocyanates having at least 2 isocyanate groups at a temperature of from 1 to 150°C.
Allow time to react.

At this time, the equivalence relationship between the hydroxyl group and the isocyanate group is such that the isocyanate group is in excess of the hydroxyl group.6 Next, the poly(meth)acrylate having at least one hydroxyl group is added to the isocyanate group of this reactant. react. The reaction temperature is 1 to 5 at 50°C to 150°C.
Allow time to react.

At this time, the equivalent relationship between the isocyanate group and the hydroxyl group is
Mix so that the amounts are approximately equivalent. When producing this photopolymerizable compound, a solvent such as methyl ethyl ketone, toluene, methyl isobutyl ketone, etc. can be used.

In this way, a photopolymerizable compound which is an essential component of the photosensitive resin composition of the present invention is obtained.

The photosensitive resin composition of the present invention uses a photopolymerization initiator (hereinafter referred to as a photopolymerization initiator) that generates radicals when exposed to actinic rays.
It is necessary to contain

Examples of the photopolymerization initiator include benzophenone, 1
-Hydroxycyclohexylphenylketone, penzyldialkylketone, 2-hydroxy-2-methylpropiophenone, Michler's ketone, benzoin ethyl ether, 2,4-dialkylthioxanthone, 2-methyl-1[4-(methylthio)phenyl ]-2-morpholinopropanone and the like. Furthermore, by combining the photopolymerization initiator with a sensitizer having a different absorption wavelength of actinic rays, the polymerization initiation efficiency can be improved and the sensitivity can be further increased. For example, benzophenone and triethanolamine,
2-Methyl-1[4-(methylthio)phenylco2-
Examples include combinations of morpholinopropanone and thioxanthone, and pendyl dialkyl ketol and Michler's ketone.

The amount of the photopolymerization initiator is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the photopolymerizable compound,
Among these, 1 to 15 parts by weight is advantageous.

The photosensitive resin composition of the present invention preferably contains at least one selected from particulate fillers and particulate fillers that can be dissolved and removed by chemical conversion treatment.

The cured product obtained from the photosensitive resin composition containing the fine particle filler has even better mechanical impact resistance due to the stress dispersion effect of the fine particle filler, and even better thermal shock resistance due to the suppression of thermal expansion9. Examples of the particle filler include silica, alumina, talc, antimony dioxide, antimony pentoxide, aluminum hydroxide, and calcium carbonate. The particle size of the particulate filler is preferably 0.01 to 15 μm, more preferably 0.01 to 2.5 μm, from the viewpoint of resolution, adhesion of the cured film, and the like. A suitable amount of the fine particle filler is 10 to 60 parts by weight based on 100 parts by weight of the photopolymerizable compound. It is desirable that the particulate filler is uniformly dispersed in the photosensitive resin composition, and for this purpose it is advantageous to treat the surface of the particulate filler with a coupling agent having a functional group such as an amino group or a hydroxyl group. It is. Examples of the coupling agent include γ-ruaminopropyltriethoxysilane β-aminoethyl-T-
Examples include aminopropyltriethoxysilane and T-methacryloxypropyltrimethoxysilane.

Further, the particulate filler that can be dissolved and removed by the chemical conversion treatment (hereinafter referred to as the dissolvable particulate filler) includes inorganic particulates such as silica and calcium carbonate, heat-resistant resin particulates, and the like. An insulating layer formed using a photosensitive resin composition containing these dissolving and removable particulate fillers can be formed by chemical conversion treatment on the surface and dissolving and removing the particulate fillers exposed on the surface. The surface of the insulating layer can be uniformly roughened, and a plating film can be formed on the insulating layer with high reliability.

The heat-resistant resin fine particles among the dissolving and removable fine particle fillers must be heat-resistant resin fine particles that have been hardened in advance.The reason is that if heat-resistant resin fine particles that have not been hardened in advance are used, the photosensitive resin This is because when dispersed in the composition, it dissolves in the resin liquid, making it impossible to selectively dissolve and remove it by chemical conversion treatment. If heat-resistant resin fine particles that have been cured in advance are used, they will not dissolve in the resin liquid even if they are dispersed in a photosensitive resin composition, and an insulating layer in which the heat-resistant resin fine particles are uniformly dispersed can be formed. .

The material of the heat-resistant resin fine particles is a resin that has excellent heat resistance and electrical properties, does not dissolve even when dispersed in a photosensitive resin composition by curing treatment, and has the property of being soluble in a specific chemical solution used for chemical conversion treatment. Any material may be used, and examples thereof include epoxy resins, polyester resins, bismaleimide-triazine resins, and the like. Methods for the curing treatment include a method of curing by heating and a method of curing by adding a catalyst. In addition, specific chemical solutions used for chemical conversion treatment include, for example,
Oxidizing agents such as chromic acid, chromates, permanganates, etc. can be used.

The particle size of the heat-resistant resin fine particles is preferably 15 μm or less, more preferably 5 μm or less. The reason for this is that the roughened surface formed by dissolving and removing fine particles having a particle size of 15 μm or more becomes non-uniform, making it impossible to form a plating film with good chain reliability.

A suitable amount of the dissolvable particulate filler is 10 to 60 parts by weight based on 100 parts by weight of the photopolymerizable compound.

Furthermore, the photosensitive resin composition of the present invention may contain a polymerizable compound having at least two terminal ethylene groups, such as dipentaerythritol hexaacrylate, 1.6 -hexanediol diacrylate, tris(2-7cryloxyethylene) isocyanurate, neopentyl glycol diacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, diallyl terephthalate,
Examples include N,N-methylenebisacrylamide and the like.

By blending this polymerizable compound, the crosslinking density in the cured product can be increased, and the heat resistance of the cured film can be improved. The preferred amount of this polymerizable compound is 30 parts by weight or less per 100 parts by weight of the photopolymerizable compound.

This is because if the amount exceeds 30 parts by weight, the crosslinking density becomes too high, resulting in a decrease in thermal shock resistance and the like.

Furthermore, the photosensitive resin composition of the present invention may contain other subsidiary components. Examples of the subsidiary components include thermal polymerization inhibitors, pigments, coloring agents, coatability improvers, antifoaming agents, adhesion improvers, leveling agents, and the like.

In addition, if necessary, bisphenol A type epoxy resin,
Various epoxy resins such as novolac type epoxy resin and alicyclic epoxy resin can be used in combination.

The photosensitive resin composition of the present invention can be applied onto a substrate by a conventional method such as a DIN-de coating method, a flow coating method, or a screen printing method. When applying, the composition can be diluted with a solvent if necessary. Examples of the solvent include butyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, methyl ethyl ketone, cyclohexanone, and the like.

(Action of the invention) The photosensitive resin composition of the present invention has high heat resistance because the skeleton of the photopolymerizable compound constituting the main component is composed of a bisphenol skeleton, and moreover, the photosensitive resin composition has high heat resistance and has an oxirane compound added to both ends. Therefore, it also has excellent adhesion to the object to be coated due to this chain-like structure. Furthermore, since this bisphenol skeleton and the (meth)acryloyl group, which is a photopolymerization reaction group, are bonded via an isocyanate group by a so-called urethane bond, it exhibits an excellent effect on thermal shock resistance. This is compared with Talesol novolac type epoxy resin, which is the backbone of the photopolymerizable compound that constitutes the main component of the photosensitive resin composition for forming a protective film, which is conventionally used in the production of printed wiring boards. In particular, the difference in flexibility becomes obvious.

Furthermore, the photosensitive resin composition of the present invention has extremely high sensitivity since it uses a polyvalent (meth)acrylate compound as the photosensitive resin composition.

Furthermore, the particulate filler contained in this photopolymerizable compound etc. controls the thermal expansion of the insulating layer and provides excellent adhesion to the underlying conductor.

Furthermore, since the photosensitive resin composition contains a particulate filler that can be dissolved and removed by chemical conversion treatment, slight irregularities are formed on the surface of the cured film by applying chemical conversion treatment to the cured film of the photosensitive resin composition. . When plating is applied to such a surface, a plating film is formed even on the minute irregularities.

When an attempt is made to peel off this plating film, the minute unevenness becomes a catch and acts as a so-called anchor.

Furthermore, when this plating film is peeled off, the minute irregularities act as anchors, so the breaking strength of the cured film will control the peeling strength of the plating film. At this time, the cured product of the photopolymerizable compound that constitutes the main part of the photosensitive resin composition of the present invention has particularly excellent flexibility compared to the cured product of ordinary Talesol novolac type epoxy resin. Therefore, when the plating film is peeled off, breakage occurs at a deeper position in the cured film, and the adhesion strength is correspondingly higher.

In this way, the plating film formed on the cured film of the photosensitive resin composition of the present invention is firmly adhered, and the effects of the invention by the photosensitive resin composition of the present invention are produced.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these.

Parts used as numerical units in the examples mean parts by weight.

In a flask equipped with a thermometer, a stirrer, and a cooling tube, 348 parts of tolylene diisocyanate (Japan Polyurethanes, trade name: TDI-80), 1 part of dibutyltin dilaurate, and 1 part of hydroquinone were placed.

Add 350 parts of methyl ethyl ketone and stir.
The temperature was raised to 0°C to form a homogeneous solution. Separately, 344 parts of bisphenol A (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name: KB-300K) with propylene oxide added to both ends and 344 parts of methyl ethyl ketone are mixed to prepare a homogeneous solution.

2) Next, the tolylene diisocyanate? A bisphenol A solution in which propylene oxide was added to both ends of the solution was uniformly dropped into the solution over a period of 2 to 3 hours, and then kept at 60'C for 3 hours. The reactant obtained by this reaction is shown in Formula 2.

C11゜ CH.

C=0 11aCs HO O Formula 2 3) Next, hydroxy polyacrylate having one hydroxyl group and three acryloyl groups (manufactured by Nippon Kayaku, trade name: KAYARAD-PET-30) 59
After adding 6 parts dropwise over 15 hours and keeping the temperature for an additional 5 hours, 10 parts of methanol was added to obtain a photopolymerizable compound.

The photopolymerizable compound thus obtained is shown in Formula 3.

0 Formula 3 4) 100 parts (solid content equivalent) of the photopolymerizable compound (shown in Formula 3), 2-methyl-1-(4-(methylthio)phenyl]-2-morpholinopropanone-1 (Ciba Geigy) (manufactured by Nippon Shokubai Chemical Co., Ltd., trade name: Irgacure 907) 4 parts, fine silica powder (manufactured by Nippon Shokubai Chemical Co., Ltd., trade name: NS Silica x-
05, average particle size 0.5 μm) 25 parts, epoxy resin fine powder (manufactured by Toshi, trade name: Treval EP-B, average particle size 5)
After mixing 25 parts of 6 μm) and adding butyl cellosolve, the mixture was heated to a viscosity of 250 CP using a homodisper stirrer.
S, and then kneaded with three rolls to prepare a solution of the photosensitive resin composition.

5) Next, a solution of the photosensitive resin composition was applied using a knife coater onto a printed wiring board obtained by photo-etching the surface of the copper-clad laminate using a conventional method, and left in a horizontal position for 20 minutes. The photosensitive resin layer was dried to the touch at 70° C. to form a photosensitive resin layer with a thickness of about 50 μm.

6) Next, a photomask film with a cumulative thickness of 1100jIφ was attached to this and heated for 20 minutes using an ultra-high pressure mercury lamp.
Exposure was performed at 0 mj/c4. This was applied to a printed wiring board with a thickness of 100 μm by ultrasonic treatment with a chlorocene solution.
After forming a via hole of φ, this wiring board was illuminated with 500 m j /dflr using an ultra-high pressure mercury lamp, and further 1
By heat-treating at 00'C for 1 hour and then at 150C for 2 hours, a glabellar insulating coating with excellent dimensional accuracy and having via holes corresponding to a photomask film was obtained.

7) Next, this glabellar insulating coating is roughened with chromic acid at a temperature of 70'C and a fi of 800 g/l for 30 minutes, immersed in a neutralizing solution (manufactured by Sibley, trade name: PM950), and washed with water. Since this coating contains fine silica particles that are unnecessary for chromic acid and fine epoxy resin particles that are soluble in chromic acid, by treating the surface of the coating with chromic acid, a roughened surface with a very rough shape was obtained.

8) Next, palladium catalyst (
After activating the surface by applying Cataposit 44 (manufactured by Sibley) and immersing it in a chemical copper plated plate with the following composition for 15 minutes, 20 μm of copper was deposited inside the pie hole using an electrolytic copper plating solution with the following composition. The beer strength under normal conditions was 1.70 kg/cm. Also,
M I L-3TD-202Method 107c
In the thermal shock test according to condition B, 50
It was revealed that no disconnection occurred even after 0 cycles, and the long-term reliability was excellent.

Chemical copper plating solution composition Sibley 32BA 12.5% Sibley 328L 12.5% Sibley 32BC1
,5% pure water 73.5% temperature
Degree 25℃ Electrolytic copper plating solution composition CuSO4-5L0 150 g/1) 1iS
O<40 g/eCl-2
0ppm additive predetermined amount temperature
25°C, negative current density 2A/dm” The photosensitive resin composition of this example has excellent heat resistance and flexibility, so the photopolymerizable compound used as an essential component has excellent heat resistance and flexibility. It has good adhesion to objects and excellent thermal shock resistance.Also, because it has a polyvalent (meth)acryloyl group, it has extremely high sensitivity.

In addition, since chromic acid contains unnecessary silica particles and chromic acid-soluble epoxy resin particles, the roughened surface shape becomes very complex, and when a conductor is formed on an insulating layer, high adhesion strength can be obtained. The insulating film has high hot hardness because it contains fine inorganic silica particles, and has excellent thermal shock resistance because thermal expansion is controlled.

(Effects of the Invention) When the glabellar insulating film obtained using the photosensitive resin composition of the present invention is used, the adhesion between the conductor circuit made of plating 119 and the insulating layer is extremely excellent, and it has particularly good heat resistance and thermal shock resistance. It is possible to create ultra-high-density multilayer wiring boards with excellent performance.

Furthermore, by adding the photopolymerizable compound of the present invention as a modifier to other photosensitive resin compositions, it is possible to particularly improve heat resistance, impact resistance, etc., so it can also be treated as an additive component. , the application of the present invention is extremely wide.

Furthermore, the protective film obtained using the photosensitive resin composition of the present invention can also be used as a permanent protective film for plating resists, solder masks, etc., and is extremely useful industrially.

that's all

Claims (1)

[Scope of Claims] 1. A polyvalent (tag) acrylate compound having at least one hydroxyl group corresponds to each hydroxyl group of a bisphenol skeleton compound with an oxirane compound added to both ends, and Between the hydroxyl groups, at least 2
contains a photopolymerizable compound formed by reacting the hydroxyl groups of both compounds with the isocyanate groups of the polyisocyanate compound, and a photopolymerization initiator that generates radicals when exposed to actinic rays. A photosensitive resin composition characterized by: 2. The photosensitive resin composition according to claim 1, which contains at least one selected from the group consisting of a particulate filler and a particulate filler that can be dissolved and removed by chemical conversion treatment.