JPH0987366A - Photopolymer composition and method for preparing multilayered printed wiring board by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photopolymer composition which can be plated without being swollen or dissolved in an electroless plating solution which in an alkaline aqueous solution and can be subjected to exposure and development by using a noncombustible aqueous developing solution. SOLUTION: This resin composition comprises an epoxy resin of an epoxy equivalent of 250-500g/eq., an epoxy resin of an epoxy equivalent of 160-250g/eq., a resin having phenolic hydroxyl groups and being soluble in an alkaline aqueous solution, at least one inorganic compound selected from among hydroxides, oxides and carbonates of elements of groups IIa, IIIa and IVa in the periodic table and a photoinduced acid generator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition which is a material for forming a photo via hole having excellent heat resistance and a multilayer wiring board using the same.

[0002]

2. Description of the Related Art Photosensitive epoxy resins are widely known, and examples thereof include JP-B-49-17040, JP-A-50-158698, and JP-A-56-5542.
No. 0 and JP-A-63-71840.

Many of these photosensitive epoxy resins require the use of organic solvents for development. At present, chlorine-based organic solvents have no choice but to use general-purpose organic solvents due to environmental problems such as water pollution. However, the use of such organic solvents poses a risk of ignition and explosion. JP-A-63-71
Since the resin composition of Japanese Patent No. 840 uses polyphenol as a base polymer, it can be developed with an alkaline aqueous solution.

However, when the resin composition contains a hydroxyl group so that it can be easily dissolved in an alkaline aqueous solution, it is considered difficult to perform electroless plating which is advantageous for fine wiring. That is, the produced relief pattern may swell and deform in an electroless plating solution which is an alkaline aqueous solution.

On the other hand, on a printed wiring board, surface mounting of an integrated circuit is actively carried out for the purpose of high-density mounting.
In the surface mounting of such an integrated circuit, a solder reflow step of providing a solder bump between the integrated circuit and a substrate, melting the solder in a heating furnace, and adhering them together is essential. At this time, the substrate is heated for 1 minute to several minutes at a temperature equal to or higher than the melting point of solder (190 ° C. for tin 6 / lead 4 alloy). For this reason, a thermosetting resin such as a thermally stable epoxy resin has been used for such a substrate material.

[0006]

An object of the present invention is to perform plating with an incombustible aqueous solution which can be plated without swelling or dissolving in an electroless plating solution which is an alkaline aqueous solution. It is to provide a possible photosensitive resin composition.

Another object of the present invention is to provide a thermally stable multilayer wiring board using the above photosensitive resin composition.

[0008]

The gist of the present invention to achieve the above object is as follows.

[1] (a): Epoxy equivalent 250 to 5
00 g / eq epoxy resin, (b): epoxy equivalent 160-250 g / eq epoxy resin,
(C): a resin having a phenolic hydroxyl group and soluble in an aqueous alkaline solution, and (d): at least one inorganic compound selected from hydroxides, oxides, and carbonates of the IIa, IIIa, and IVa groups. And (e): a photosensitive resin composition comprising a photo-acid generator.

[2] 10 to 50 parts by weight of (a),
(B) is 10 to 80 parts by weight, (c) is 10 to 40 parts by weight, the total amount of the components (a), (b) and (c) is 100 parts by weight, and (d) is 3 to 100 parts by weight, (E) is 3 to 3
The said photosensitive resin composition which is 0 weight part.

[3] The photosensitive resin composition, wherein (a) is a bisphenol type epoxy resin and (b) is a novolac type epoxy resin.

[4] The photosensitivity selected from the group consisting of a novolac resin, a resole resin, a hydroxystyrene (co) polymer, and a hydroxyphenylmaleimide (co) polymer in which (c) may have a substituent. Resin composition.

[5] The photosensitive resin composition as described above, wherein (d) is at least one inorganic compound selected from calcium carbonate, magnesium hydroxide, aluminum hydroxide and silicon oxide.

[6] The above-mentioned photosensitive resin composition containing 30 to 400 parts by weight of an organic solvent based on 100 parts by weight of the photosensitive resin composition.

[7] (1) (a): Epoxy equivalent 25
0 to 500 g / eq of epoxy resin, (b): epoxy equivalent of 160 to 250 g / eq of epoxy resin,
(C): a resin having a phenolic hydroxyl group and soluble in an aqueous alkaline solution, and (d): at least one inorganic compound selected from hydroxides, oxides, and carbonates of the IIa, IIIa, and IVa groups. And (e): a step of coating the surface of the substrate having inner layer wiring with a photosensitive resin composition containing a photo-acid generator, (2) a step of exposing through a via hole mask, (3) an unexposed portion is alkali A step of developing with an aqueous solution to form a via hole, (4) a step of roughening the inside of the via hole and the surface of the photosensitive resin layer, (5) a step of applying a plating catalyst to the inside of the via hole and the surface of the photosensitive resin layer, (6) via hole A method for producing a multilayer wiring board, comprising: a step of forming a conductor layer on the inside and on the surface of the photosensitive resin layer by chemical plating, or by using chemical plating and electroplating together to establish conduction between the layers.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the above, the bisphenol type epoxy resin as the component (a) is to improve the adhesiveness to a glass cloth substrate and the like and the crack resistance. In particular, it has an effect of suppressing a rapid increase in the elongation (coefficient of linear expansion α) above the glass transition temperature, and has an epoxy equivalent of 250 to 500 g / eq.
Is an epoxy resin. This shortens the cross-linking point distance and raises the glass transition temperature of the cured product. Examples of the epoxy resin include bisphenol A type, bisphenol F type,
There are bisphenol S type and their halides. For example, Epicoat 801, 80 made of Yuka Shell
7, 828, 834, 1001, 5045-B-80,
5046-A-70, Epichron 830, 850, 860, ExA-1514, 4004 manufactured by Dainippon Ink and Chemicals.
Etc.

The novolac type epoxy resin as the component (b) increases the crosslink density of the cured product and raises the glass transition temperature, and preferably has an epoxy equivalent of 160 to 2.
It is an epoxy resin of 50 g / eq. This increases the crosslink density and raises the glass transition temperature of the cured product. Examples of the epoxy resin include phenol novolac type, cresol novolac type, and halides thereof. For example, ESCN-195 manufactured by Sumitomo Chemical, Epicoat 152, 180S65, 180H6 manufactured by Yuka Shell.
5, Dainippon Ink and Chemicals N-665, 673, 69
0,738,770,865, ECN-made by Asahi Kasei
268, 273, 292, 299 and so on.

The resin having a phenolic hydroxyl group as the component (c) enhances the solubility in an aqueous developing solution and also reacts with the epoxy resin during curing to increase the crosslink density of the cured product and raise the glass transition temperature. Examples of the resin include phenol novolac resin, cresol novolac resin, resole resin, polyhydroxystyrene, and polyhydroxyphenylmaleimide.

The inorganic filler as the component (d) reduces tackiness of the photosensitive resin composition coated and dried on the substrate to improve tack-free property, and at the same time enhances the surface roughening efficiency of the substrate plating surface. Calcium carbonate, magnesium hydroxide, aluminum hydroxide, silicon oxide and the like are preferable because they improve. The particle size of the inorganic filler is preferably smaller than the thickness of the photosensitive resin layer formed on the substrate, and further preferably smaller than the hole diameter of the via hole formed by exposure and development.

The photo-acid generator as the component (e) is one which forms an latent image by generating an acid catalyst which is a polymerization catalyst of the epoxy resin at the time of exposure, and is represented by, for example, formulas [1] and [2].

[0021]

Embedded image

An onium salt represented by the formula (X represents PF ₆ or SbF ₆ ) is used.

Examples of such a photo-acid generator include DTS-102, 103 and TPS-102, 10 manufactured by Midori Kagaku.
3, UVI-6970, 697 manufactured by Union Carbide
There are 4 etc.

The above-mentioned photosensitive resin composition satisfies heat resistance, plating solution resistance, and developability with an aqueous developer unless the compounding amounts of the respective components are extremely biased. The preferable composition range is 10 to 50 parts by weight of the component (a), 10 to 80 parts by weight of the component (b), and 10 to 40 parts by weight of the component (c), and the above (a), (b) and (c). When the total amount of the components is 100 parts by weight, the component (d) is 3 to 100 parts by weight and the component (e) is 3 to 30 parts by weight.

When the above components (a), (b) and (c) deviate from the above ranges, problems may occur in any of heat resistance, plating solution resistance and developability with an aqueous developer.

If the component (d) is small, the tack-free property is deteriorated, and if it is large, the developability is deteriorated. When the amount of the component (e) is small, the photosensitivity is lowered, and when it is large, the solubility of the exposed portion in the aqueous developer is increased and the developability is lowered.

Conventional additives may be further added to the above-mentioned photosensitive resin composition. For example, there are dyes such as phthalocyanine blue and phthalocyanine green for facilitating identification of development defects and the like, triarylphosphines for promoting thermal curing of epoxy resins, and curing catalysts for various imidazoles. Since these additives inhibit the photoreaction, it is preferable to add them in an amount of 1 part by weight or less.

The aqueous developer of the above-mentioned photosensitive resin composition is a mixed aqueous solution of an alkaline aqueous solution and a water-soluble organic solvent, and the alkaline component is potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide or the like, As the water-soluble organic solvent, 2-butoxyethanol, 2- (2-
Butoxyethoxy) ethanol and the like. The concentration of the above-mentioned alkali component is in the range of 1 to 20% by weight, and the concentration of the aqueous organic solvent is in the range in which the developing solution is not flammable while maintaining the developing property, that is, 10 to 50% by weight. Is desirable.

The present photosensitive resin composition is stored and used in the form of a solution or a dry film. In the case of a solution state, it is desirable that the resin component in the photosensitive resin composition is dissolved and dispersed in 30 to 400 parts by weight of an organic solvent, based on 100 parts by weight. As a result, the film thickness of the photosensitive resin composition after coating and drying is about 20 to 100 μm in coating the substrate.
It is possible to form an m-shaped product with good workability. Further, when forming a dry film, the film thickness of the photosensitive layer is 20 to 10
It is desirable to adjust the thickness to about 0 μm.

Examples of the above organic solvent include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, cellosolves such as cellosolve and butyl cellosolve, carbitols such as carbitol and butyl carbitol, ethyl acetate. , Butyl acetate, cellosolve acetate and other acetic acid esters, and tetrahydrofuran and other cyclic ethers.

Next, an example of producing a multilayer wiring board using the photosensitive resin composition of the present invention will be described with reference to the schematic sectional view of FIG.

In the step (A), the surface of the substrate 2 having the internal wiring 1 is covered with the photosensitive resin composition 3, and in the step (B), it is exposed and developed through a via hole photomask (not shown). Then, the photosensitive resin composition 3 in the unexposed portion is dissolved and removed to form the via hole 4, and the thermal curing is completed. Then, in the step (C), the photosensitive resin composition 3
After roughening the surface of the above and applying a plating catalyst, electroless plating (or a combination of electroless plating and electroplating) is applied to make the inside of the via hole 4 conductive, and to cure the surface of the photosensitive resin composition 3. Circuits such as the wiring 5, the land 6, and the pad 7 are formed.

As the internal wiring board which is a starting material of the present invention, a copper-clad laminated board obtained by etching or a laminated board on which wiring is formed by an additive method can be used. When the wiring is copper, known copper surface roughening, formation of an oxide film, reduction of the oxide film, or nickel plating increases the adhesive force between the photosensitive resin composition and the base copper, and causes solder reflow. It is possible to more effectively prevent peeling due to thermal stress.

The photosensitive resin composition solution is dip coated,
A film is formed by a known method such as curtain coating, roll coating, knife coating, screen printing, etc., and dried at a temperature at which the epoxy resin does not cure, for example, 80 ° C to 120 ° C,
Be tack free. Similarly, in the case of a dry film of a photosensitive resin composition, laminate coating is performed with a heating roll having a surface temperature at which the epoxy resin does not cure. Then exposure,
Develop to form via holes. After development, heating at a temperature of 130 ° C. or higher for 20 minutes or longer accelerates the curing of the photosensitive resin composition.

The roughening of the surface of the photosensitive resin composition in the via hole can be performed with a chromic acid mixed solution or a permanganate aqueous solution. After the roughening, pre-plating treatments such as neutralization, removal of roughening residue, addition of a plating catalyst and activation are performed.

Conduction in the via hole and formation of surface wiring are performed by electroless plating, or by a known etching method or additive method using both electroless plating and electroplating.
When the heat curing after development is insufficient, it may be heated at 160 ° C. or higher after the wiring is formed to further accelerate the curing of the photosensitive resin composition.

The characteristic feature of the photosensitive resin composition of the present invention lies in the fact that several kinds of general-purpose epoxy resins are used in combination as described above. Since a special chemical is not added or special treatment is required, a cured product which is easy to manufacture and handle and has excellent heat resistance is provided. Therefore, the insulating layer made of the photosensitive resin composition is not liable to be corroded in the solder reflow, and a multilayer wiring board having excellent characteristics can be obtained.

[0038]

EXAMPLES Next, the present invention will be described more specifically based on examples.

[Examples 1 to 8 and Comparative Examples 1 to 4] Table 1
The compositions of the photosensitive resin compositions of Examples 1 to 8 of the present invention and Table 2 are shown in Table 2. All numerical values in the table are weight (g).

[0040]

[Table 1]

[0041]

[Table 2]

Ep828: Oiled shell, bisphenol A type epoxy resin (189 g / eq) Ep1001: Oiled shell, bisphenol A type epoxy resin (475 g / eq) ESCN-195-6: Sumitomo Chemical, Orthocresol Novolac Type epoxy resin (195 g / eq) HP180R: Hitachi Chemical, Resol resin Nitrex-23P: Nitto powder, calcium carbonate UVI-6974: Union Carbide, hexafluoroantimony-triphenylsulfonium salt (photoacid generator) P100: Hokuko Kasei, triphenylphosphine (curing catalyst) Metal foil having a two-layer structure of aluminum and copper (Mitsui Metals, U
The present photosensitive resin composition solution is applied to a copper surface of TC foil (50 μm) with a bar coater, and the temperature is kept at 120 ° C. for 10 hours at room temperature for 10 hours.
A test piece was prepared by drying for a minute.

(1) Evaluation of resolution (developability) The above-mentioned test piece was irradiated with light of an ultra-high pressure mercury lamp at 3 J / cm ² through a Photovia mask having a diameter of 10 μm to 160 μm, and then heated at 120 ° C. for 10 minutes. The curing of the exposed area was promoted, and development was performed with an aqueous developer described below while magnetically stirring. The developable via hole diameter is shown in Table 3 as the resolution. Samples that could not be developed are marked with X. A MAP-1300 scanning exposure machine manufactured by Dainippon Kaken was used for the exposure.

Aqueous developer composition 2-butoxyethanol: 10 g 15% by weight-tetramethylammonium hydroxide aqueous solution:
10 g Ion-exchanged water: 10 g (2) Evaluation of tack-free property When peeling off the photovia mask from the exposed sample piece, the sample in which the photosensitive resin composition in the unexposed area adhered to the photovia mask was judged to have poor tack-free property. It shows with a mark. Samples that did not stick are indicated by a circle.

(3) Measurement of film thickness The test piece after the development treatment was heated at 180 ° C. for 2 hours to accelerate curing, and then an aqueous sodium hydroxide solution (100 g / l)
Soak for 2 hours to remove the aluminum layer of the base material, and after washing, immerse in an etching solution consisting of 100 g of sulfuric acid, 200 g of 35% hydrogen peroxide and 700 g of ion-exchanged water for 2 hours to remove the copper layer of the base material. Then, only the cured film of the photosensitive resin composition was sampled and the film pressure thereof was measured. The results are also shown in Table 3.

(4) Measurement of glass transition temperature The hole-free portion of the cured film whose film thickness was measured is 30 mm.
A sample was prepared by cutting into a size of 3 mm. The glass transition temperature was measured by observing the dynamic viscoelasticity using DVA200 manufactured by IT Measurement and Control Co., Ltd. The measurement conditions are a fulcrum distance of 20 mm, a measurement frequency of 10 Hz, a heating rate of 5 ° C./min, and a measurement range of room temperature to 300 ° C.

[0047]

[Table 3]

Each of Examples 1 to 8 can be developed with an aqueous developing solution, and exhibits good tack-free property and a glass transition temperature of 190 ° C. or higher. The resolution at a film thickness of about 50 μm was 40 to 100 μm, which showed characteristics equivalent to those of the conventional photosensitive resin, and all satisfied the target.

On the other hand, Comparative Example 1 does not contain the resol resin (HP180R) which is an alkali-soluble component and therefore has poor developability and a low glass transition temperature. In addition, the tack-free property was poor because it did not contain an inorganic additive (Nitrex-23P).

Comparative Example 2 is HP which is an alkali-soluble component.
Since the content of 180R was large, the exposed portion was dissolved during development, resulting in poor development.

In Comparative Example 3, since the amount of the thermosetting catalyst (P100) added as a conventional additive was large, the photopolymerization reaction was hindered and the exposed portion was dissolved during development, resulting in poor development.

In Comparative Example 4, since a large amount of Nitrex-23P was added, Nitrex-2P was formed in the via hole during development.
A large amount of 3P remained, resulting in poor development. In addition, the glass transition temperature was too brittle to measure.

Example 9 A copper-clad glass epoxy substrate having a thickness of 18 μm was subjected to an etching treatment to produce an inner wiring board. After roughening this copper surface with an aqueous solution of ammonium persulfate, an oxide film was formed with an aqueous solution containing sodium perchlorate as a main component. Then, reduction treatment was performed with an aqueous solution of dimethylamine borane.

A solution of the photosensitive resin composition of Example 1 was applied to the surface of the inner layer substrate by screen printing, and the solution was kept at room temperature for 1 hour.
It was dried at 120 ° C. for 10 minutes. The thickness of the photosensitive resin layer was about 50 μm.

Exposure was performed at ³ J / cm ² through a via hole mask, and heating was performed at 120 ° C. for 10 minutes to accelerate curing of the exposed portion. Then, 2-butoxyethanol 10 g, 15
Spray development was performed at 30 ° C. for 5 minutes with a developer containing 10 g of a wt% tetramethylammonium aqueous solution and 10 g of ion-exchanged water to form a via hole of 60 μm. After washing with water and drying, it was heated at 150 ° C. for 30 minutes to accelerate the curing of the photosensitive resin layer.

After roughening the surface of the photosensitive resin layer and the inner wall of the via hole with an aqueous solution of potassium permanganate, neutralization treatment,
After applying a plating catalyst and activating treatment, electroless plating and electroplating were used in combination to perform panel plating with a thickness of 20 μm. Then, the exterior wiring was formed with an aqueous solution of iron chloride. Then, post-curing was performed at 180 ° C. for 2 hours to complete a multilayer wiring board having via holes.

The adhesion between the inner wiring copper and the photosensitive resin layer of the obtained multilayer wiring board was measured, and the result was 0.78 kgf / c.
m was shown. This adhesiveness value is measured by removing the glass epoxy resin as a starting material by polishing to expose the back surface of the inner layer wiring copper and measuring the copper foil by the method of JISC6481.

This multilayer wiring board was held in a solder reflow bath at 200 ° C. for 10 minutes and then its appearance was observed. It was found that the inner wiring copper and the photosensitive resin layer and the photosensitive resin layer and the outer wiring copper were No peeling was observed. In particular, haloing around the via hole, and impregnation of the pretreatment liquid and the plating liquid were not observed.

[0059]

According to the present invention, it is possible to obtain a photosensitive resin composition having a high glass transition temperature after curing (190 ° C. or higher), and a multilayer wiring board having a via hole produced by using this composition is resistant to heat. Due to its excellent properties, surface mounting using solder reflow suitable for improving mounting density becomes possible.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a manufacturing process of a multilayer wiring board of the present invention.

[Explanation of symbols]

1 ... Inner layer wiring, 2 ... Substrate, 3 ... Photosensitive resin composition, 4 ...
Via hole, 5 ... Wiring, 6 ... Land, 7 ... Pad.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location H05K 3/46 H05K 3/46 ET (72) Inventor Mineo Kawamoto 7, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1-1 Hitachi Ltd., Hitachi Research Laboratory (72) Inventor Masanori Nemoto 7-11 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Akio Takahashi Hitachi City, Ibaraki Prefecture 7-1 Omika-cho, Hitachi Ltd., Hitachi, Ltd. (72) Inventor Shin Nishimura 7-1-1, Omika-cho, Hitachi, Ibaraki Prefecture Hitachi Ltd., Hitachi, Ltd.

Claims (7)

[Claims] 1. (a): Epoxy equivalent of 250 to 500 g
/ Eq epoxy resin, (b): Epoxy equivalent 16
0 to 250 g / eq of epoxy resin, (c): a resin having a phenolic hydroxyl group and soluble in an alkaline aqueous solution,
(D): at least one inorganic compound selected from hydroxides, oxides, and carbonates of the IIa group, IIIa group, and IVa group,
And (e): a photosensitive resin composition comprising a photo-acid generator. 2. The (a) is 10 to 50 parts by weight, (b)
Is 10 to 80 parts by weight, (c) is 10 to 40 parts by weight, the total amount of the components (a), (b) and (c) is 100 parts by weight, and (d) is 3 to 100 parts by weight, (e). Is 3 to 30 parts by weight, the photosensitive resin composition according to claim 1. 3. The photosensitive resin composition according to claim 1, wherein the (a) is a bisphenol type epoxy resin and the (b) is a novolac type epoxy resin. 4. The (c) is at least one selected from a novolac resin which may have a substituent, a resole resin, a hydroxystyrene (co) polymer, and a hydroxyphenylmaleimide (co) polymer. Item 2. The photosensitive resin composition according to item 1. 5. The photosensitive resin composition according to claim 1, wherein (d) is at least one inorganic compound selected from calcium carbonate, magnesium hydroxide, aluminum hydroxide and silicon oxide. 6. Based on 100 parts by weight of the photosensitive resin composition,
The photosensitive resin composition according to claim 1, comprising 30 to 400 parts by weight of an organic solvent. 7. (1) (a): Epoxy equivalent 250 to 5
00 g / eq epoxy resin, (b): epoxy equivalent 160-250 g / eq epoxy resin,
(C): a resin having a phenolic hydroxyl group and soluble in an aqueous alkaline solution, and (d): at least one inorganic compound selected from hydroxides, oxides, and carbonates of the IIa, IIIa, and IVa groups. And (e): a step of coating the surface of the substrate having inner layer wiring with a photosensitive resin composition containing a photo-acid generator, (2) a step of exposing through a via hole mask, (3) an unexposed portion is alkaline A step of developing with an aqueous solution to form a via hole, (4) a step of roughening the inside of the via hole and the surface of the photosensitive resin layer, (5) a step of applying a plating catalyst to the inside of the via hole and the surface of the photosensitive resin layer, (6) via hole A method for producing a multilayer wiring board, comprising: a step of forming a conductor layer by chemical plating or a combination of chemical plating and electroplating on the inside and on the surface of the photosensitive resin layer to establish conduction between the layers.