JPH10287861A - Adhesive for electroless plating and printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject adhesive, capable of manifesting excellent leveling and defoaming properties and adhesion without deteriorating the light transmission properties and useful as a printed wiring board, etc., by including a silicone oil in a heat-resistant resin matrix. SOLUTION: This adhesive for electroless plating is obtained by dispersing (B) heat-resistant resin particles, soluble in (Z1 ) an acid or (Z2 ) an oxidizing agent and treated by curing in (A) an uncured heat-resistant resin matrix which becomes sparingly soluble in the acid Z1 or oxidizing agent Z2 by curing treatment. A silicone oil such as a compound represented by the formula [(n) is 1-5; (m) is 1-14; (x) is 1-80; (y) is 1-74] in an amount of, e.g. 0.1-50 wt.% based on the total amount of the adhesive is contained in the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for electroless plating and a printed wiring board, and more particularly to a method for forming an adhesive layer for electroless plating which is excellent in light transmittance and free from bubbles and undulations. It is a proposal for an effective adhesive.

[0002]

2. Description of the Related Art In recent years, electronic equipment has been reduced in size or increased in speed with the progress of the electronic industry. For this reason, printed circuit boards and wiring boards on which LSIs are mounted are also required to have higher densities and higher reliability using fine patterns.

[0003] One of the conventional methods for manufacturing a printed wiring board that meets this kind of demand is an additive method. In the additive method, an adhesive for electroless plating is applied to the surface of a substrate to form an adhesive layer, and after the surface of the adhesive layer for electroless plating is roughened, a conductor is formed by electroless plating. How to

In this method, since a conductor circuit is formed by electroless plating, a high-density wiring with high pattern accuracy can be formed easily and at low cost, compared with an etched foil method (subtractive method) in which a pattern is formed by etching. There is an advantage that it can be manufactured. Moreover, in this method, since the conductor circuit is firmly adhered to the roughened adhesive layer, excellent bonding between the two is ensured.
There is a feature that the conductor circuit is difficult to peel off from the adhesive layer.

As a conventional printed wiring board based on such an additive method, there is the following proposal regarding an adhesive for electroless plating. For example, JP-A-61-276875
No., JP-A-2-188992, USP 5055321, etc.
A printed wiring board using a photosensitive electroless plating adhesive formed by dispersing a heat-resistant resin fine powder in a photosensitive resin matrix has been proposed.

On the other hand, in the case of a printed wiring board using an adhesive for electroless plating, good leveling properties and defoaming properties of the adhesive are necessary in order to obtain wiring with high pattern accuracy even if it is multilayered. It is. That is, if the surface of the adhesive layer is not smooth, it is difficult to mount an IC chip or the like, and
This is because if air bubbles are present in the adhesive layer, water will accumulate in the air bubbles and cause cracks.

In this regard, an adhesive to which an antifoaming agent or a leveling agent has been added is considered. However, the adhesive layer to which an antifoaming agent or a leveling agent has been added has a disadvantage that light transmittance is reduced and good holes cannot be formed by exposure or laser irradiation.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an adhesive for electroless plating which is excellent in leveling property and defoaming property without lowering the light transmittance of the adhesive layer. I do. Another object of the present invention is to provide a printed wiring board having an adhesive layer for electroless plating which is excellent in light transmittance and free of bubbles and undulations.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies for realizing the above object. As a result, the following findings were obtained. . No devitrification occurs even when silicone oil is dissolved in an organic solvent in which a resin is dissolved. . A thermoplastic resin is added to a resin matrix to improve the strength, and an NMP (N-methylpyrrolidone) is used as an organic solvent to improve the compatibility of the composite resin based adhesive for electroless plating. In this case, the devitrification does not occur if a silicone oil having a specific structure is used. . Silicone oil has the effect of improving the strength of the resin.

The adhesive for electroless plating of the present invention developed on the basis of these findings is characterized by having the following constitution. (1) The adhesive for electroless plating of the present invention is an uncured heat-resistant resin matrix in which cured heat-resistant resin particles soluble in an acid or an oxidizing agent are hardly soluble in an acid or an oxidizing agent by the curing treatment. The adhesive for electroless plating dispersed therein is characterized in that the heat-resistant resin matrix contains silicone oil.

In the adhesive for electroless plating according to the above (1), the terminal group of the silicone oil is an epoxy group, a polyoxyalkylene group, an amino-containing group, a carboxy-containing group, a fatty acid-containing group, or an alcohol. It is desirable that the compound be modified with at least one kind of functional group selected from the contained groups. This silicone oil is preferably a polyether modified silicone oil having a polyethylene oxide structure or a polypropylene oxide structure. Further, the silicone oil preferably has the following structural formula (Chemical Formula 1). (Formula 1)

Further, the printed wiring board of the present invention is characterized by having the following configuration. (2) The printed wiring board of the present invention has, on a substrate, a surface-roughened cured electroless plating adhesive layer, and a conductor circuit on the roughened surface of the adhesive layer surface. In the printed wiring board formed, the adhesive layer is a cured heat-resistant resin soluble in an acid or an oxidizing agent in an uncured heat-resistant resin matrix which becomes hardly soluble in an acid or an oxidizing agent by the curing treatment. The heat-resistant resin matrix is composed of an adhesive in which particles are dispersed, and contains silicone oil.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The adhesive for electroless plating of the present invention is characterized in that a silicone oil is contained in a matrix of an uncured heat-resistant resin which becomes hardly soluble in an acid or an oxidizing agent by a curing treatment.

This silicone oil is a linear molecule having a siloxane bond (—Si—O) _n — and exhibits fluidity at room temperature. Therefore, when silicone oil is added to an uncured heat-resistant resin matrix containing an organic solvent, the silicone oil is finely dispersed and contained in the matrix. As a result, the adhesive layer formed using the adhesive for electroless plating containing such a silicone oil does not seem to be devitrified even if the silicone oil is present in the matrix, and is used for laser drilling, exposure, and development. Drilling by processing can be performed favorably, and via holes can be reliably formed.

As the heat-resistant resin containing the silicone oil, for example, a resin composite of a thermosetting resin and a thermoplastic resin is used, and N-methylpyrrolidone (N
When MP) is used, in such a composite resin system, the compatibility of the silicone oil is reduced, and the dispersed particles of the silicone oil become large, which tends to cause devitrification. In this regard, silicone oil having an ethylene oxide structure or a propylene oxide structure is preferable because it has an action of preventing devitrification even in the above-mentioned composite resin system. The reason for this is not clear, and it is presumed that ethylene oxide or propylene oxide is excellent in affinity with a composite resin or NMP.

As such a silicone oil, those having the following structural formula (formula 1) are most suitable. (Formula 1) Here, n is 1 to 5, m is 1 to 14, x is 1 to 80, and y is 1
It is desirably about 74. The optimal value is n = 1, m
= 7, x = 40, y = 37.

In addition, the silicone oil has an effect that fine particles enter the bubble film, and cracks are generated from the fine particles to eliminate bubbles in the interlayer insulating agent. Furthermore, since the silicone oil is finely dispersed in the form of islands in the heat-resistant resin matrix of the interlayer insulating agent, it also has the effect of improving the breaking strength (toughness) of the heat-resistant resin matrix.

In particular, as the silicone oil capable of improving the strength of the resin, any of the terminal groups selected from epoxy groups, polyoxyalkylene groups, amino-containing groups, carboxy-containing groups, fatty acid-containing groups and alcohol-containing groups is preferred. Or at least one functional group. For example, epoxy-modified silicone oils include KF101, KF102, and KF101 manufactured by Shin-Etsu Chemical.
105 and others. Examples of the polyoxyalkylene group-modified silicone oil include KF351 and KF353 manufactured by Shin-Etsu Chemical. Examples of the amino-containing modified silicone oil include KF393 and KF861 manufactured by Shin-Etsu Chemical. Examples of the carboxy-containing modified silicone oil include X-22-3701E manufactured by Shin-Etsu Chemical. Examples of the fatty acid-containing modified silicone oil include KF910 manufactured by Shin-Etsu Chemical. As alcohol-containing modified silicone oil,
Shin-Etsu Chemical's KF851.

As an example, the structural formula of the epoxy-modified silicone oil is shown in the following (Formula 2).

Embedded image

As described above, the silicone oil contained in the adhesive has both a function as an antifoaming agent and a function as an additive for improving the resin strength, and in particular, has a content of 0.1 to 5% by weight. %, Acts mainly as an antifoaming agent, and when more than 5% by weight and 50% by weight or less,
It mainly acts as an additive to improve resin strength.

In the adhesive for electroless plating of the present invention,
The cured heat-resistant resin particles soluble in an acid or an oxidizing agent constituting the adhesive have an average particle diameter of 10 μm.
The following heat-resistant resin powder, aggregated particles obtained by aggregating heat-resistant resin powder having an average particle size of 2 μm or less, average particle size of 2 to 10 μm
A mixture of a heat-resistant resin powder and a heat-resistant resin powder having an average particle size of 2 μm or less, and a heat-resistant resin powder having an average particle size of 2 μm or less or an inorganic powder on the surface of the heat-resistant resin powder having an average particle size of 2 μm to 10 μm. It is desirable to select from at least one kind of pseudo particles having attached thereto. This is because they can form more complex anchors.

As the heat-resistant resin particles, epoxy resin, amino resin (melamine resin, guanamine resin, urea resin), polyester resin and the like are preferably used. In particular, a resin obtained by curing a bisphenol A type epoxy resin with an amine curing agent is desirable. This is because these resin particles are easily decomposed or dissolved in an acid or an oxidizing agent and easily form a clear anchor.

In the adhesive for electroless plating of the present invention,
As an uncured heat-resistant resin matrix which becomes hardly soluble in an acid or an oxidizing agent by a curing treatment, a thermosetting resin,
A photosensitive thermosetting resin, or a composite of a photosensitive thermosetting resin and a thermoplastic resin can be used. The photosensitization is performed because a via hole can be easily formed by exposure and development. Further, the composite with the thermoplastic resin is because, by improving the toughness of the resin, the peel strength of the conductor circuit is improved, and the occurrence of cracks in the via holes due to the heat cycle can be prevented. Specifically, a polyimide resin, an epoxy resin, an epoxy acrylate obtained by reacting an epoxy resin with acrylic acid, methacrylic acid, or the like, or a composite of epoxy acrylate and polyether sulfone is preferable.

The epoxy resin used as the resin matrix is obtained by curing a cresol novolak type epoxy resin or a phenol novolak type epoxy resin with an imidazole curing agent or an acid anhydride, or an alicyclic epoxy resin. preferable. This is because these cured resins are hardly soluble in acids and oxidizing agents, and are excellent in base resistance. The electroless plating solution is strongly basic, and basic resistance is an essential property of the adhesive for electroless plating.

As the alicyclic epoxy resin, Araldite CY179 (manufactured by Ciba-Geigy), EPICLON HP-7200
(Manufactured by Dainippon Ink Co., Ltd.) is preferred. EPIC of these
The structural formula of LONHP-7200 is shown in (Formula 3).

Embedded image

When this alicyclic epoxy resin is mixed with silicone oil, the mixing ratio is desirably (alicyclic epoxy resin / silicone oil) = 9/1 to 8/2 by weight. The reason for this is that if there is too much silicone oil, it is difficult to mix with the alicyclic epoxy resin,
On the other hand, if the amount of the silicone oil is small, it is difficult to improve the strength.

The adhesive for electroless plating according to the present invention as described above may be applied to a substrate in an uncured state, or may be impregnated into a glass cloth and dried to form a B stage to form a prepreg. Alternatively, it may be applied to a base film such as polyethylene terephthalate or polypropylene and dried to form a B-stage, which may be formed into a film. Furthermore, it is also possible to shape it into a substrate shape.

The adhesive for electroless plating may contain a dye or a pigment. Further, the resin used for the adhesive for electroless plating may be halogenated to make it flame-retardant.

Next, one method of manufacturing a printed wiring board using the adhesive for electroless plating of the present invention will be described. The method according to this description is what is called a so-called full additive method. However, in the present invention, a method called a so-called semi-additive method can also be adopted.

(1) First, a wiring board having an inner copper pattern formed on the surface of a core board is manufactured. The copper pattern is formed on the core substrate by etching a copper-clad laminate, or a glass epoxy substrate, a polyimide substrate,
There is a method in which an adhesive layer for electroless plating is formed on a substrate such as a ceramic substrate or a metal substrate, the surface of the adhesive layer is roughened to a roughened surface, and electroless plating is performed thereon. Further, if necessary, an adhesive layer for electroless plating is formed on the wiring substrate, an opening for a via hole is formed in this layer, the surface of the layer is roughened, and electroless plating is performed thereon to form a copper pattern and a via. By repeating the step of forming holes, a multilayer wiring board can be obtained. Note that a through hole is formed in the core substrate, and the wiring layer on the front surface and the wiring layer on the back surface can be electrically connected through the through hole.

(2) Next, the adhesive layer for electroless plating according to the present invention is formed on the wiring board prepared in the above (1). (3) After drying the adhesive layer for electroless plating, an opening for forming a via hole is provided as necessary. At this time,
In the case of a photosensitive resin, by exposing and developing and then thermosetting, and in the case of a thermosetting resin, by thermosetting and then laser processing, an opening for forming a via hole is formed in the adhesive layer. Section is provided.

(4) Next, the heat-resistant resin particles present on the surface of the cured adhesive layer are dissolved and removed with an acid or an oxidizing agent to roughen the surface of the adhesive layer. Here, examples of the acid include phosphoric acid, hydrochloric acid, sulfuric acid, and organic acids such as formic acid and acetic acid, and it is particularly preferable to use an organic acid. This is because when the roughening treatment is performed, the metal conductor layer exposed from the via hole is hardly corroded. As the oxidizing agent, it is desirable to use chromic acid or permanganate (such as potassium permanganate).

(5) Next, a catalyst nucleus is applied to the wiring board whose surface of the adhesive layer is roughened. It is desirable to use a noble metal ion or a noble metal colloid for providing the catalyst nucleus, and generally, palladium chloride or a palladium colloid is used. Note that it is desirable to perform a heat treatment to fix the catalyst core. Palladium is preferred as such a catalyst core.

(6) Next, a plating resist is formed on the wiring substrate to which the catalyst nucleus has been applied. As the plating resist composition, a commercially available product can be used. In particular, a composition comprising cresol novolak, phenol novolak type epoxy resin acrylate, and an imidazole curing agent is preferable.

(7) Then, electroless plating is applied to the portion where the plating resist is not formed to form a conductor circuit and a via hole, thereby manufacturing a printed wiring board.

The printed wiring board according to the present invention manufactured as described above has a “hardened, electroless plating adhesive layer having a roughened surface on a substrate, and the surface of the adhesive layer is In a printed wiring board in which a conductor circuit is formed on a roughened surface, the adhesive layer is formed by an acid or an oxidizing agent in an uncured heat-resistant resin matrix which becomes hardly soluble in an acid or an oxidizing agent by a curing treatment. A printed wiring board comprising an adhesive obtained by dispersing soluble cured heat-resistant resin particles, wherein the heat-resistant resin matrix contains silicone oil.

This printed wiring board has a roughened layer formed by dissolving and removing the heat-resistant resin particles present on the surface of the adhesive layer, and the roughened layer has a takotsubo-shaped anchor. Therefore, the printed wiring board has excellent adhesion strength of the conductor because the anchor is filled with the electroless plating film of the conductor.

Further, this printed wiring board contains silicone oil in the heat-resistant resin matrix constituting the adhesive layer. Since the silicone oil is finely dispersed in the matrix, the adhesive layer does not apparently devitrify. Therefore, the printed wiring board according to the present invention can favorably perform perforation by laser, perforation by exposure and development processing, and can surely form via holes. This silicone oil has the effect of causing fine particles to enter the bubble film, and starting from this as a starting point, cracks are generated to eliminate bubbles in the interlayer insulating agent. Therefore, in the printed wiring board according to the present invention, no void is generated in the adhesive layer, and water does not collect even under high temperature and high humidity conditions, so that cracks are not easily generated. This silicone oil is
Since it is finely dispersed in the form of islands in the heat-resistant resin matrix of the adhesive layer, there is an effect of improving the breaking strength (toughness) of the heat-resistant resin matrix. Therefore, the printed wiring board according to the present invention can suppress cracks generated in the adhesive layer between the layers from the boundary between the plating resist and the conductive circuit due to the heat cycle.

[0039]

【Example】

[Synthesis of Silicone Oil A] (1) 0.1N hydrochloric acid and 10 parts by weight of water were added to an alkoxysilane composed of 8.12 parts by weight of dimethylmethoxysilane and 1.38 parts by weight of methylchloroethylmethoxysilane, and the mixture was stirred at 50 ° C. and then allowed to stand for 24 hours. did. (2) After 1N KOH was added, 17.6 parts by weight of ethylene oxide was added, and the mixture was stirred at 50 ° C. and allowed to stand for 8 hours. (3) After further adding 1N KOH, 21.5 parts by weight of propylene oxide was added, and the mixture was stirred at 50 ° C. and allowed to stand for 8 hours.

The ¹ H-NMR, ¹³ C-NMR and IR spectrum of the silicone oil thus synthesized were measured. The measurement results are shown in FIGS. FT
-IR uses PERKIN ELMER 1650, transmission method (KR
S-5). NMR is made by JEOL EX
Using the -400, observation frequency, ¹ H is 400 MHz, ¹³ C
Is 100 MHz, pulse width is 45 °, measurement solvent is deuterated chloroform, and the chemical shift standard is 7.25 ppm for ¹ H and 7 for ¹³ C.
7.05 ppm. The measurement temperature is room temperature. From these figures, the silicone oil synthesized here had n = 1, m = 7, x = 40, and y = 37 in the structural formula shown in Chemical Formula 1.

[Preparation of Adhesive B-1 for Electroless Plating] D
35 parts by weight of a 25% acrylate of a cresol novolak type epoxy resin (manufactured by Nippon Kayaku, molecular weight 2500) dissolved in MDG (diethylene glycol dimethyl ether), 12 parts by weight of polyether sulfone (PES), an imidazole curing agent (manufactured by Shikoku Chemicals, Product name: 2E4MZ-CN) 2 parts by weight,
4 parts by weight of caprolactone-modified tris (acroxyethyl) isocyanurate (produced by Toagosei Co., Ltd., trade name: Aronix M325) as a photosensitive monomer, 2 parts by weight of benzophenone as a photoinitiator (manufactured by Kanto Kagaku), as a photosensitizer 0.2 parts by weight of Michler's ketone (manufactured by Kanto Chemical Co., Ltd.) and 10.3 parts by weight of epoxy resin particles (manufactured by Sanyo Chemical Co., trade name: Polymer Pole) having an average particle size of 3.0 μm were added to the mixture. After mixing 3.09 parts by weight of 0.5 μm and 0.5 part by weight of the synthesized silicone oil of A, the mixture was further mixed while adding NMP, and the viscosity was adjusted to 7 Pa · s with a homodisper stirrer. The mixture was kneaded to obtain an adhesive for electroless plating.

[Manufacture of Printed Wiring Board] (Example 1) (1) 18 μm on both sides of a substrate 1 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 1 mm.
A copper-clad laminate on which m copper foils 8 were laminated was used as a starting material (see FIG. 1). The copper-clad laminate was drilled, subjected to electroless plating, and etched in a pattern to form an inner copper pattern 4 and through holes 9 on both surfaces of the substrate 1.

(2) On the other hand, bisphenol F type epoxy monomer (manufactured by Yuka Shell, molecular weight 310, trade name: YL983U)
100 parts by weight, 6 parts by weight of an imidazole curing agent (manufactured by Shikoku Chemicals, trade name: 2E4MZ-CN), and 1.5 parts by weight of an antifoaming agent (manufactured by San Nopco, trade name: Perenol S4) were mixed. On the other hand, SiO ₂ spherical particles having an average particle diameter of 1.6 μm coated with a silane coupling agent on the surface (manufactured by Admatech, CRS 1101-CE, where the maximum particle size is not more than the thickness (15 μm) of the inner layer copper pattern described later) By mixing 170 parts by weight and kneading with three rolls, the viscosity of the mixture is 45,000 to 49,000 at 23 ± 1 ° C.
Adjust to cps and use resin filler 10 for substrate surface smoothing
I got This resin filler is solventless. If a resin filler containing a solvent is used, the solvent is volatilized from the resin filler layer when the interlayer agent is applied, heated and dried in a later step, so that the space between the resin filler layer and the interlayer material is reduced. This causes peeling.

(3) The substrate on which the inner layer copper pattern 4 was formed was washed with water and dried, and then NaOH (10 g / l) and NaClO ₂ (40 g)
/ L), Na ₃ PO ₄ (6 g / l) in an oxidation bath (blackening bath), NaOH
(10 g / l) and NaBH ₄ (6 g / l) as a reducing bath, a roughened layer 11 was provided on the entire surface of the inner conductor circuit 4 and the through hole 9 (see FIG. 2).

(4) The resin filler 10 obtained in the above (2) is applied to one surface of the substrate provided with the roughened layer using a roll coater, so that the resin filler 10 is provided between the inner layer conductor circuits 4 or through holes 9.
, And temporarily cured at 120 ° C. for 20 minutes. The other surface is similarly filled with the resin filler 10 between the inner conductor circuits 4 or the through holes 9 and temporarily cured at 120 ° C. for 20 minutes. (See FIG. 3).

(5) One surface of the substrate after the treatment of the above (4) is subjected to belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku) to form the surface of the inner layer copper pattern 4 and the through holes 9. Polishing was performed so that the resin filler 10 did not remain on the land surface, and then buffing was performed to remove scratches due to the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate (see FIG. 4). Then 100 ° C for 1 hour, 120 ° C for 3 hours, 150 ° C
For 1 hour and a heat treatment at 180 ° C. for 7 hours to completely cure the resin filler 10.

In this manner, the surface layer of the resin filler 10 filled in the through holes 9 and the like and the roughened layer 11 on the upper surface of the inner conductor circuit 4 are removed to smooth both surfaces of the substrate.
A wiring board is firmly adhered to the side surface of the inner conductor circuit 4 via the roughened layer 11 and the inner wall surface of the through hole 9 is tightly adhered to the resin filler 10 via the roughened layer 11. Obtained. That is, by this step, the surface of the resin filler 10 and the surface of the inner layer copper pattern 4 become flush with each other. Here, the Tg point of the filled cured resin is 155.6 ° C., and the coefficient of linear thermal expansion is 44.5 × 10 ⁻⁶ /
° C.

(6) A thickness of 2.5 μm is formed on the upper surface of the land of the inner conductor circuit 4 and the through hole 9 exposed in the processing of (5).
A roughened layer (concavo-convex layer) 11 made of a Cu—Ni—P alloy was formed, and a Sn layer having a thickness of 0.3 μm was formed on the surface of the roughened layer 11 (see FIG. 5; Is not shown). The formation method is as follows. That is, the substrate is acid-degreased and soft-etched, and then treated with a catalyst solution comprising palladium chloride and an organic acid to provide a Pd catalyst. After activating this catalyst, copper sulfate 8 g / l, nickel sulfate 0.6 g / l, citric acid 15 g / l, sodium hypophosphite 29 g / l, boric acid 31 g / l, surfactant 0.1
Plating was performed in an electroless plating bath having g / l and pH = 9 to form a roughened layer 11 of a Cu—Ni—P alloy on the upper surface of the copper conductor circuit 4 and the upper surface of the land of the through hole 9. Then
Tin borofluoride 0.1 mol / l, thiourea 1.0 mol / l, temperature
A Cu—Sn substitution reaction was performed at 50 ° C. and pH = 1.2 to provide a 0.3 μm thick Sn layer on the surface of the roughened layer 11 (the Sn layer is not shown).

(7) 25% of cresol novolak type epoxy resin (Nippon Kayaku, molecular weight 2500) dissolved in DMDG
35 parts by weight of acrylate, 12 parts by weight of polyether sulfone (trade name: PES1010P, manufactured by Mitsui Toatsu), 2 parts by weight of imidazole hardener (trade name: 2E4MZ-CN, manufactured by Shikoku Chemicals), caprolactone as a photosensitive monomer Modified tris (acryloxyethyl) isocyanurate (manufactured by Toa Gosei,
Trade name: Aronix M325) 4 parts by weight, 2 parts by weight of benzophenone as a photoinitiator (manufactured by Kanto Kagaku), and 0.2 parts by weight of Michler's ketone as a photosensitizer (manufactured by Kanto Kagaku) are mixed. Epoxy resin particles (manufactured by Sanyo Chemicals, trade name: polymer pole) average particle size 0.5 μm
After mixing 12.0 parts by weight of the above and 0.5 part by weight of the silicone oil of A, they were mixed while further adding NMP.
Interlayer insulator with viscosity of 1.5 Pa · s and 7.0 Pa · s (lower layer)
I got

(8) The interlayer insulating agent (lower layer) having a viscosity of 7.0 Pa · s obtained in the above (7) is applied on both surfaces of the substrate of the above (6) by a roll coater, and left in a horizontal state for 20 minutes. 60 ℃
To form an insulating agent layer 2a. Further, the adhesive of B-1 is applied to both sides of the substrate, left in a horizontal state for 20 minutes, dried at 60 ° C. for 30 minutes, and an adhesive layer having a thickness of 60 μm is formed.
2b was formed (see FIG. 6).

(9) A photomask film on which a black circle of 100 μmφ is printed is brought into close contact with both surfaces of the substrate on which the insulating layer 2a and the adhesive layer 2b are formed, and 500mJ is applied by an ultra-high pressure mercury lamp.
/ Cm ² . Next, this was spray-developed with a DMTG solution, and the substrate was further cleaned with an ultra-high pressure mercury lamp.
Exposure at 100 mJ / cm ² and heat treatment at 100 ° C. for 1 hour and then at 150 ° C. for 5 hours to provide a 100 μmφ opening with excellent dimensional accuracy equivalent to a photomask film (via hole forming opening 6). Was formed with a thickness of 50 μm (see FIG. 7).

(10) The substrate in which the openings are formed is immersed in chromic acid for 2 minutes to dissolve and remove the epoxy resin particles on the surface of the adhesive layer 2b, thereby making the surface of the resin insulating layer 2 rough. Then, it was immersed in a neutralizing solution (manufactured by Shipley) and washed with water (see FIG. 8). Further, by applying a palladium catalyst (manufactured by Atotech) to the surface of the substrate subjected to the surface roughening treatment (roughening depth: 6 μm), a catalyst nucleus was attached to the surface of the resin insulating layer 2 and the via hole opening 6. .

(11) On the other hand, 40% by weight dissolved in DMDG
Cresol novolak epoxy resin (Nippon Kayaku)
100% by weight of a photosensitizing oligomer (molecular weight 4000) obtained by acrylizing 50% of the epoxy groups of epoxy resin, and 20% by weight of a bisphenol A type epoxy resin (trade name: Epicoat 1001 manufactured by Yuka Shell Co.) dissolved in methyl ethyl ketone 32 parts by weight, imidazole curing agent (Shikoku Chemicals, trade name: 2E4MZ
-CN) 3.4 parts by weight, 6.4 parts by weight of a polyacrylic monomer which is a photosensitive monomer (trade name: R604, manufactured by Nippon Kayaku)
3.2 parts by weight of a polyvalent acrylic monomer (manufactured by Kyoeisha Chemical; trade name: DPE6A), which is also a photosensitive monomer, is mixed with 100 parts by weight of the mixture, and a leveling agent (manufactured by Kyoeisha Chemical; trade name: Polyflow No. 75) 0.5 part by weight was mixed and stirred to obtain a mixed solution A. On the other hand, 4.3 parts by weight of benzophenone as a photoinitiator (manufactured by Kanto Chemical) and 0.4 parts by weight of Michler's ketone as a photosensitizer (manufactured by Kanto Chemical) are dissolved in 6.4 parts by weight of diethylene glycol dimethyl ether (DMDG) heated to 40 ° C. Thus, a mixed solution B was obtained. The mixed liquid A and the mixed liquid B were mixed and stirred to obtain a liquid resist.

(12) The above liquid resist is applied to both surfaces of the substrate, which has been subjected to the catalyst nucleation treatment in the above (10), using a roll coater, dried at 60 ° C. for 30 minutes, and dried to a thickness of 30 μm. A resist layer is formed. Next, a photomask film on which a conductive circuit pattern was drawn was placed on the resist layer, and the resist layer was exposed to ultraviolet light of 400 mJ / cm ² . Then, after removing the photomask film, the resist layer is dissolved and developed with DMTG to form a plating resist on the substrate where the conductor circuit pattern portion has been removed, and further exposed to 6000 mJ / cm ² using an ultra-high pressure mercury lamp. A heat treatment was performed at 100 ° C. for 1 hour and then at 150 ° C. for 3 hours to form a permanent resist 3 on the interlayer insulating layer 2 (see FIG. 9).

(13) Pre-plating treatment (specifically, activation of catalyst nuclei) is applied to the substrate on which the permanent resist 3 is formed, in advance.
Then, primary plating was performed using an electroless copper-nickel alloy plating bath having the following composition to form a copper-nickel-phosphorous plating thin film having a thickness of about 1.7 μm on the non-resist-forming portion. At this time, the temperature of the plating bath was 60 ° C,
The plating immersion time was 1 hour. Complexing agent: Na ₃ C ₆ H ₅ O ₇ : 0.23 M (60 g / l) Reducing agent: NaPH ₂ O ₂ .H ₂ O: 0.19 M (20 g / l) pH regulator: NaOH: 0.75 M (pH = 9.5) Stabilizer: Lead nitrate: 0.2 mM (80 ppm) Surfactant: 0.05 g / l Precipitation rate is 1.7 μm / hour

(14) The substrate subjected to the primary plating is lifted from the plating bath, the plating bath attached to the surface is washed away with water, and the substrate is treated with an acidic solution to obtain copper-nickel-phosphorus. The oxide film on the surface of the plating thin film was removed. Then, without performing Pd substitution, a secondary plating is performed on the copper-nickel-phosphorous plating thin film using an electroless copper plating bath having the following composition, so that the outer layer conductor pattern 5 required as a conductor layer by the additive method is formed. And via holes (BVH) 7 were formed (see FIG. 10). At this time, the temperature of the plating bath was 50 to 70 ° C., and the plating immersion time was 90 to 360 minutes. Metal salts _{... CuSO 4 · 5H 2 O:} 8.6 mM Complexing agent ... TEA: 0.15 M reducing agent ... HCHO: 0.02 M Others ... stabilizer (bipyridyl, potassium ferrocyanide and the like): a small amount deposition rate, 6 [mu] m / Time

(15) After the conductive layer is formed by the additive method in this manner, one surface of the substrate is subjected to belt sander polishing using # 600 belt polishing paper so that the surface layer of the permanent resist and the copper layer in the via hole are removed. Polishing was performed until the upper surface was aligned. Subsequently, buffing was performed to remove the scratches caused by the belt sander (only buffing may be performed). Then, the other surface was similarly polished to form a printed wiring board having both surfaces smooth.

(16) Copper sulfate 8 g / l, nickel sulfate 0.6 g / l, citric acid 15 g / l, sodium hypophosphite 29 g / l, boric acid 31 g / l, surfactant 0.1 g / l Immersed in an electroless plating solution having a pH of 9 and a thickness of 3 μm
A roughened layer 11 made of a Cu—Ni—P alloy was formed (see FIG. 11). Further, by repeating the above steps (however, the lower interlayer insulating agent used has a viscosity of 1.5 Pa · s
Was used. ), A further conductive layer was formed by the additive method, and the wiring layer was built up in this way to obtain a six-layer multilayer printed wiring board.

(17) On the other hand, 60% by weight dissolved in DMDG
Cresol novolak epoxy resin (Nippon Kayaku)
46.67 g of a photosensitizing oligomer (molecular weight 4000) obtained by acrylizing 50% of the epoxy groups of epoxy resin, 15.0 g of an 80 wt% bisphenol A type epoxy resin (made by Yuka Shell, Epicoat 1001) dissolved in methyl ethyl ketone, imidazole curing 1.6 g of an agent (manufactured by Shikoku Chemicals, trade name: 2E4MZ-CN), 3 g of a polyacrylic monomer which is a photosensitive monomer (trade name: R604, manufactured by Nippon Kayaku), and a polyacrylic monomer (manufactured by Kyoeisha Chemical, trade name) : DPE6A) 1.5 g and 0.71 g of a dispersion antifoaming agent (manufactured by San Nopco, trade name: S-65), and 2 g of benzophenone (manufactured by Kanto Chemical) as a photoinitiator was added to the mixture. Add 0.2 g of Michler's ketone (manufactured by Kanto Kagaku) as a photosensitizer to increase the viscosity.
A solder resist composition adjusted to 2.0 Pa · s at 25 ° C. was obtained. The viscosity was measured using a B-type viscometer (Tokyo Keiki, DVL
-B type) in case of 60rpm, rotor No.4 and in case of 6rpm, rotor No.3.

(18) A Pd catalyst was applied to the multilayer printed wiring board obtained in (16) above, and after activating this catalyst, copper sulfate 8 g / l, nickel sulfate 0.6 g / l, and citric acid 15 g
/ L, sodium hypophosphite 29g / l, boric acid 31g /
1 and a surfactant made of a Cu-Ni-P alloy in an electroless plating bath consisting of 0.1 g / l and pH = 9 to form a roughened layer 11 on the surface of the conductor circuit. The solder resist composition was applied to both sides of the multilayer printed wiring board in a thickness of 20 μm. Next, after performing a drying treatment at 70 ° C. for 20 minutes and at 70 ° C. for 30 minutes, it was exposed to ultraviolet light of 1000 mJ / cm ² , DM
TG development processing was performed. And then at 80 ° C for 1 hour at 100 ° C
For 1 hour, 120 ° C. for 1 hour, and 150 ° C. for 3 hours to form a solder resist layer (opening diameter: 200 μm) 14 (opening diameter: 200 μm) with a pad portion opened.

(19) Next, the substrate on which the solder resist layer 14 was formed was treated with a pH of 30 g / l of nickel chloride, 10 g / l of sodium hypophosphite, and 10 g / l of sodium citrate.
= 5 for 20 minutes to form a nickel plating layer 15 having a thickness of 5 μm at the opening. Further, the substrate was placed on an electroless gold plating solution comprising 2 g / l of potassium gold cyanide, 75 g / l of ammonium chloride, 50 g / l of sodium citrate, and 10 g / l of sodium hypophosphite at 93 ° C. for 23 seconds. By dipping, a gold plating layer 16 having a thickness of 0.03 μm was formed on the nickel plating layer 15.

(20) Then, a solder paste was printed in the opening of the solder resist layer 14 and reflowed at 200 ° C. to form a solder bump 17, thereby manufacturing a multilayer printed wiring board having the solder bump 17 ( See FIG. 12).

Comparative Example 1 A printed wiring board was manufactured in the same manner as in Example 1 except that the silicone oil of A was not added.

With respect to the printed wiring boards of Example 1 and Comparative Example 1 thus manufactured, the undulation of the wiring board surface was visually observed. The fracture surface was observed with an electron microscope to confirm the presence of bubbles in the adhesive layer. Further, a weather resistance test was performed on ten printed wiring boards manufactured according to Example 1 and Comparative Example 1 under the conditions of a temperature of 135 ° C., a humidity of 85%, a bias of 3.3 V, and a duration of 48 hours. After this test, a short circuit (presence or absence of conduction) between the conductor circuits was confirmed using a checker probe, and the occurrence ratio of the short circuit was examined. Table 1 shows the results.

[0065]

[Table 1]

(Example 2) [Preparation of adhesive B-2 for electroless plating] An alicyclic epoxy resin (EPICLON HP-7200 manufactured by Dainippon Ink Co., Ltd.) was used.
35 parts by weight, imidazole curing agent (Shikoku Chemicals, trade name:
2E4MZ-CN) 2 parts by weight, 6.0 parts by weight of polyvalent acrylic monomer as photosensitive monomer (manufactured by Kyoeisha Chemical, trade name: DPE6A), polyvalent acrylic monomer (manufactured by Nippon Kayaku, trade name: R)
604) 1.5 parts by weight, photoinitiator (Ciba Geigy, trade name: Irgacure 907) 2 parts by weight, photosensitizer (Nippon Kayaku, trade name: DETX-S) 0.2 part by weight, silicone oil (Shin-Etsu Chemical) 8.75 parts by weight manufactured by Sanyo Kasei Co., Ltd., trade name: KF-101) and an average particle size of epoxy resin particles (manufactured by Sanyo Chemical Co., Ltd .: polymer pole) of 3.0 μm
After mixing 10.3 parts by weight of the above and 3.09 parts by weight of an average particle size of 0.5 μm, further mix by adding 30 parts by weight of NMP, and adjust the viscosity to 7 Pa · s with a modisper stirrer to bond for electroless plating. Agent was obtained.

[Manufacture of Printed Wiring Board] Soldering was performed in the same manner as in Example 1 except that the adhesive for electroless plating of B-2 was used and the following interlayer insulating agent was used. A multilayer printed wiring board having bumps was manufactured. 25% acrylate of alicyclic epoxy resin (Dai Nippon Ink Co., Ltd., trade name: EPICLON HP-7200)
35 parts by weight, 12 parts by weight of polyether sulfone (trade name: PES1010P, manufactured by Mitsui Toatsu), 2 parts by weight of imidazole hardener (trade name: 2E4MZ-CN, manufactured by Shikoku Chemicals), and caprolactone-modified Tris (a photosensitive monomer) 4 parts by weight of (acroxyethyl) isocyanurate (manufactured by Toagosei Co., Ltd., trade name: Aronix M325), 2 parts by weight of benzophenone (manufactured by Kanto Chemical) as a photoinitiator, 0.2 part by weight of Michler's ketone (manufactured by Kanto Chemical) as a photosensitizer Parts, and then mix the epoxy resin particles (manufactured by Sanyo Chemical Co., trade name:
12.0 parts by weight of a polymer pole having an average particle size of 0.5 μm, silicone oil (trade name: KF-10, manufactured by Shin-Etsu Chemical Co., Ltd.)
1) After mixing 8.75 parts by weight, NMP was further added and mixed to obtain an interlayer resin insulating material (lower layer) having a viscosity of 1.5 and 7.0 Pa · s.

Comparative Example 2 A printed wiring board was manufactured in the same manner as in Example 2 except that no silicone oil was added.

The printed wiring boards thus manufactured in Example 2 and Comparative Example 2 were subjected to heat cycle tests at -55 ° C. to 125 ° C. 1,000 times and 2,000 times. At this time, the presence or absence of cracks in the adhesive layer for electroless plating located between the layers was checked. Table 2 shows the results.

[0070]

[Table 2]

Since the tensile strength and the elongation at break are improved by the presence of the silicone oil, it is considered that the generation of cracks generated in the adhesive for electroless plating between layers starting from the interface between the plating resist and the conductor circuit can be suppressed.

In this embodiment, the printed wiring board manufactured by the full additive method has been described.
The present invention can be applied to a printed wiring board manufactured by a so-called semi-additive method or a partly additive method.

[0073]

As described above, according to the present invention, it is possible to prevent the surface of the adhesive layer for electroless plating from undulating and to suppress the generation of bubbles. Furthermore, according to the present invention, since the resin strength of the adhesive layer for electroless plating is improved, cracks in the adhesive layer for electroless plating that occur from the boundary between the plating resist and the conductor circuit by a heat cycle are suppressed. be able to.

[Brief description of the drawings]

FIG. 1 is a view showing one process in manufacturing a printed wiring board according to the present invention.

FIG. 2 is a view showing one step in manufacturing a printed wiring board according to the present invention.

FIG. 3 is a view showing one step in the manufacture of a printed wiring board according to the present invention.

FIG. 4 is a view showing one step in the manufacture of a printed wiring board according to the present invention.

FIG. 5 is a view showing one step in the manufacture of a printed wiring board according to the present invention.

FIG. 6 is a view showing one step in the manufacture of the printed wiring board according to the present invention.

FIG. 7 is a view showing one step in the manufacture of a printed wiring board according to the present invention.

FIG. 8 is a view showing one step in the manufacture of the printed wiring board according to the present invention.

FIG. 9 is a view showing one step in the manufacture of a printed wiring board according to the present invention.

FIG. 10 is a diagram showing one step in the manufacture of a printed wiring board according to the present invention.

FIG. 11 is a view showing one step in the manufacture of the printed wiring board according to the present invention.

FIG. 12 is a view showing one step in the manufacture of the printed wiring board according to the present invention.

FIG. 13 is a spectrum diagram showing a measurement result of FT-IR.

FIG. 14 is a spectrum chart showing the measurement results of ¹ H-NMR.

FIG. 15 is a spectrum chart showing measurement results of ¹³ C-NMR.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Resin insulating layer 2a Insulating agent layer (layer of interlayer insulating agent) 2b Adhesive layer 3 Plating resist 4 Inner layer conductor circuit (Inner layer copper pattern) 5 Outer layer conductor circuit (Outer layer copper pattern) 6 Opening for via hole 7 Via hole (BVH) 8 Copper foil 9 Through hole 10 Filled resin (resin filler) 11 Roughened layer 14 Solder resist layer 15 Nickel plated layer 16 Gold plated layer 17 Solder bump

Claims (5)

[Claims] 1. An adhesive for electroless plating in which cured heat-resistant resin particles soluble in an acid or an oxidizing agent are dispersed in an uncured heat-resistant resin matrix which becomes hardly soluble in an acid or an oxidizing agent by the curing treatment. An adhesive for electroless plating, comprising: a silicone oil in the heat-resistant resin matrix. 2. The silicone oil according to claim 1, wherein a terminal group of the silicone oil is at least one selected from an epoxy group, a polyoxyalkylene group, an amino-containing group, a carboxy-containing group, a fatty acid-containing group and an alcohol-containing group. The adhesive for electroless plating according to claim 1, wherein the adhesive is modified by a base. 3. The adhesive for electroless plating according to claim 1, wherein the silicone oil is a polyether-modified silicone oil having a polyethylene oxide structure or a polypropylene oxide structure. 4. The adhesive for electroless plating according to claim 1, wherein the silicone oil has the following structural formula. Embedded image 5. A printed wiring having a roughened surface of an electroless plating adhesive layer having a roughened surface on a substrate, and a conductor circuit formed on the roughened surface of the adhesive layer surface. In the plate, the adhesive layer is obtained by dispersing cured heat-resistant resin particles soluble in an acid or an oxidizing agent in an uncured heat-resistant resin matrix that becomes hardly soluble in an acid or an oxidizing agent by a curing treatment. A printed wiring board comprising an adhesive, wherein the heat-resistant resin matrix contains silicone oil.