JP3219827B2 - Heat-resistant resin particles for anchor formation, adhesive for electroless plating, method for manufacturing printed wiring board using this adhesive, and printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel technology for providing a printed wiring board having an ultra-high-density conductor pattern having a high peel strength, and more particularly to forming an effective anchor on the surface of an adhesive layer. Heat-resistant resin particles used for, and an adhesive for electroless plating containing the heat-resistant resin particles dispersed therein, a method of manufacturing a printed wiring board using the adhesive, and manufactured based on the manufacturing method And a printed wiring board.

[0002]

2. Description of the Related Art In recent years, with the advance of the electronics industry, downsizing or speeding up of electronic equipment has been promoted. For this reason, printed wiring boards and printed wiring boards on which LSIs are mounted have high densities and high densities by fine patterns. Reliability has come to be required.

Conventionally, as a method of forming a conductor circuit in manufacturing a printed wiring board, there is known an "etched foil method" in which a conductor circuit is formed by laminating a copper foil on a substrate and then performing photoetching. Have been. According to this method, a conductor circuit having excellent adhesion to a substrate can be formed, but there is a major drawback that a high-precision fine pattern is difficult to be obtained by etching due to a large thickness of a copper foil. There were problems that the process was complicated and the efficiency was not good.

For this reason, recently, as a method of forming a conductor on a substrate for a printed wiring board, an adhesive containing a diene-based synthetic rubber is applied to the surface of the substrate to form an adhesive layer. A so-called “additive method” is used, in which a conductor is formed by roughening the surface and then performing electroless plating. However, since the adhesive used in this method generally contains a synthetic rubber, for example, the adhesion strength is greatly reduced at a high temperature,
There are drawbacks in that the heat resistance is low, for example, the electroless plating film bulges when soldering, and that the electrical characteristics such as surface resistance are not sufficient, and the range of use is considerably limited.

On the other hand, the present inventors have solved the above-mentioned drawbacks of the adhesive for performing electroless plating, and have extremely excellent heat resistance, electric characteristics and adhesion to the electroless plating film. An adhesive for electroless plating that can be implemented relatively easily and a method for manufacturing a wiring board using the adhesive have been proposed (see Japanese Patent Application Laid-Open No. 61-276875).

That is, in the prior art proposed by the present inventors, the heat-resistant resin particles which have been cured in advance and are soluble in an acid or an oxidizing agent are hardened by the curing treatment. An adhesive characterized by being dispersed in an uncured heat-resistant resin liquid having a property of becoming soluble, and after applying the adhesive to a substrate, drying and curing to form an adhesive layer, A method for manufacturing a wiring board, comprising: dissolving and removing at least a part of the resin particles dispersed in a surface portion of an adhesive layer to roughen the surface of the adhesive layer; and then performing electroless plating. .

According to this prior art, the adhesive is prepared by dispersing heat-resistant resin particles previously cured in a heat-resistant resin liquid, and applying the adhesive to a substrate and drying and curing the adhesive to form a matrix. Is formed in a state in which the heat-resistant resin particles are uniformly dispersed in the heat-resistant resin. Since the heat-resistant resin particles and the matrix heat-resistant resin have different solubility in an oxidizing agent, the resin dispersed in the surface portion of the adhesive layer by treating the adhesive layer with the oxidizing agent. Particles are mainly dissolved and removed, and an effective anchor depression is formed, so that the surface of the adhesive layer can be uniformly roughened. As a result, high adhesion strength and high reliability between the substrate and the electroless plating film can be obtained.

[0008]

By the way, with the fine patterning and ultra-high density of such printed wiring boards, the following matters have been required more. that is, . Reducing the dielectric constant of the adhesive layer in order to eliminate interference between conductors; To reduce the weight of the printed wiring board in order to facilitate the handling and reduce the size and weight of the electronic equipment; (C) improving the strength of the adhesive layer so as to withstand the stress applied to the substrate when the IC chip or the like is mounted on the printed wiring board; While preventing erosion by acid and oxidizing agent of the substrate,
In order to improve the productivity, it has been required to shorten the time for roughening the adhesive layer.

[0009] However, the conventional techniques for realizing the above-mentioned requirements are: A method of adding particles for lowering the dielectric constant to the adhesive layer; How to thin the adhesive layer,
. A method of adding particles for improving the strength to the adhesive layer,
. For example, there is a method of forcibly shortening the roughening time, and each method has a common problem that it causes a decrease in the adhesion strength (peel strength) of the electroless plating film.

[0010] An object of the present invention is to develop and provide a technique that advantageously solves the above-mentioned unresolved problems of the prior art, and in particular, has high productivity, is lightweight, and has a high peel strength. An anchor-forming heat-resistant resin particle ( first invention ) and an adhesive for electroless plating containing the heat-resistant resin particle for easily manufacturing an excellent, highly reliable, ultra-high-density printed wiring board. A second invention ), a method of manufacturing a printed wiring board using the adhesive ( third invention ), and a printed wiring board ( fourth invention ).

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, when resin particles having at least internal voids are used as heat-resistant resin particles used for the adhesive, the additive method is used. It has been found that a desirable insulating adhesive can be obtained, and thus a desired printed wiring board can be obtained. This has been found to lead to the solution of all the above-mentioned unsolved problems, and the present invention has been reached.

That is, the heat-resistant resin particles for forming an anchor according to the present invention are: (1) dispersed in a resin matrix having a property of being hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment; Cured heat-resistant resin particles that constitute an adhesive and are soluble in an acid or an oxidizing agent .
And the ratio of the particle size r _A to the wall thickness r _B is
hollow particles with r _B / r _A = 4/10 to 1/20, volume ratio
Particles with closed cells at 20-95 vol% or ratio table
Any of particles having open cells having an area of 2 to 2000
It is characterized by being composed from one.

Further, the adhesive for electroless plating of the present invention comprises: (2) hardening heat-resistant resin particles which are soluble in acid or oxidizing agent; A resin composition dispersed in a resin matrix exhibiting characteristics of becoming soluble, wherein the heat-resistant resin particles are heat-resistant resin particles as described in (1) above.
It is characterized by using a child.

Further, the method for manufacturing a printed wiring board according to the present invention comprises the steps of: (3) forming an adhesive layer on a substrate, roughening the surface of the adhesive layer, and applying electroless plating to form a conductor circuit; In the method of manufacturing a printed wiring board by forming a heat-resistant resin particle as described in the above (1) on the substrate, a property that becomes hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment. The method is characterized in that an adhesive solution dispersed in a resin matrix as shown is applied to form an adhesive layer, and then roughened according to a conventional method, and then subjected to electroless plating.

[0015] Then, the product obtained by the production method of (3) above is obtained.
The printed wiring board of the present invention, (4) an adhesive layer provided on at least one substrate surface,
In a printed wiring board on which a conductive circuit is formed, the adhesive layer has heat resistance as described in (1) above.
A printed wiring board characterized by being formed by dispersing resin particles in a resin matrix exhibiting a property of being hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment.

[0016]

The present inventors have found that the reliability of the printed wiring board according to the present invention is greatly affected by the electroless plating property of the adhesive layer, and thus the reliability of the conductor adhesion strength and the like is impaired. In order to improve the productivity and reduce the weight of printed wiring boards, the research focused on adhesives. In particular, we focused on the process of roughening the adhesive layer, which is the most important factor for electroless plating, and conducted intensive research. as a result,
It has been found that the role of the heat-resistant resin particles forming the roughened surface is important. Therefore, as a result of further research on the shape, structure, and properties of the heat-resistant resin particles, the heat-resistant resin particles effective for improving the productivity and reducing the weight of the printed wiring board have various voids from the surface to the inside. Resin particles are effective, and the ratio of the particle size r _A to the wall thickness r _B is r
Hollow particles with _B / r _A = 4/10 to 1/20, volume ratio of 20
It has been found that it is most effective to use particles having closed cells of up to 95 vol% or particles having open cells having a specific surface area of 2 to 2000 (see FIG. 1).

That is, the present invention employs resin particles having voids on the outer surface and inside of the particles as heat-resistant resin particles. Since air having a low dielectric constant is taken into the adhesive layer, the dielectric constant of the adhesive layer is reduced, interference between conductors is eliminated, and. Since the weight of the adhesive layer and, consequently, the printed wiring board is reduced, it has become possible to cope with the reduction in size and weight of electronic devices. Since the resin particles in the adhesive layer have voids, the adhesive layer of the printed wiring board can sufficiently withstand the stress when mounting electronic circuit components such as IC chips. Because the solubility of the resin particles in the roughening solution is improved, without lowering the adhesion with the electroless plating film,
The time for roughening the adhesive layer can be shortened, and as a result, the productivity can be improved, and the erosion of the substrate by the acid or the oxidizing agent can be prevented. It has been found that an ultra-high-density printed wiring board having excellent electrical insulation and strength, high productivity, light weight, and excellent reliability such as strength can be easily manufactured.

The heat-resistant resin particles for anchor formation have a ratio of particle size r _A to wall thickness r _B of r _B / r _A = 4 /.
Hollow particles with a volume ratio of 10 to 1/20 and void volume of 20 to 95 vol
% Of the particles having closed cells or the specific surface area of 2 to 2%.
It is preferably selected from among particles having open cells of 2000.

The heat-resistant resin particles are resins having excellent heat resistance and electrical insulation properties and exhibiting properties stable to chemicals other than an oxidizing agent. On the other hand, it is necessary to use a resin that is hardly soluble in oxidizing agents but soluble in oxidizing agents.

Examples of such a resin include a melamine resin, an epoxy resin, a polyester resin, a bismaleimide-triazine resin and the like. Among them, the melamine resin is most preferable because of its excellent characteristics. .

The average particle size of the heat-resistant resin particles for forming an anchor is preferably 10 μm or less, more preferably 5 μm or less. The reason is that if the average particle diameter is larger than 10 μm, the density of the anchor formed by dissolution and removal becomes small and tends to be non-uniform, so that the adhesion strength and its reliability are reduced. In addition, the irregularities on the surface of the insulating adhesive layer become severe, so that it is difficult to obtain a fine pattern of the conductor, and this is not preferable for mounting components and the like.

The amount of the heat-resistant resin particles for forming the anchor is preferably in the range of 10 to 100 parts by weight based on 100 parts by weight of the total solid content of the resin matrix. The reason for this is that if the amount of the resin particles is less than 10 parts by weight, an anchor formed by dissolution and removal is not clearly formed.
On the other hand, if the amount of the resin particles is more than 100 parts by weight, the surface of the insulating adhesive layer becomes porous, and the adhesion strength (peel strength) between the adhesive layer and the electroless plating film decreases.

The heat-resistant resin particles include, for example,
Add a foaming agent such as chlorofluorocarbon and a surfactant to the resin monomer, pulverize the cured resin coarse particles or block resin, and classify as necessary. Mixture of the resin monomer, foaming agent and surfactant Is polymerized by suspension polymerization or emulsion polymerization, and a resin monomer and a foaming agent,
It is obtained by heating and cooling a mixture of surfactants while spraying them to form resin particles.

The shape of the heat-resistant resin particles obtained in this way has not only a spherical shape but also various complicated shapes, so that the shape of the anchor formed thereby becomes complicated accordingly. It works effectively to improve the adhesion strength of the plating film such as the peel strength and the pull strength.

The heat-resistant resin particles obtained as described above are added to a heat-resistant resin solution for forming a matrix or a solution in which the heat-resistant resin for forming the matrix is dissolved by using a solvent, and then uniformly dispersed. By doing so, a mixed solution is produced.

Next, the resin matrix in which the heat-resistant resin particles are dispersed is excellent in heat resistance, electric insulation, chemical stability and adhesiveness, and is hard to resist acid and oxidizing agent by curing. Any uncured resin having the property of becoming soluble can be used, and in particular, a polyfunctional epoxy resin, or a resin having an epoxy group and an acrylic group, and / or a mixed resin of an acrylic resin, Alternatively, it is desirable to use a resin mixture of at least one of the above resins and at least one of bifunctional epoxy resins and acrylic resins.

The mixing ratio of the heat-resistant resin in the resin matrix is preferably such that the polyfunctional resin is a solid resin and the mixed resin is 20 wt% or more and the bifunctional resin is less than 80 wt%. . The reason is that the solid content of the polyfunctional resin is 20%.
If the amount is less than wt%, the hardness of the adhesive decreases and the chemical resistance decreases.

As the curing agent for the resin matrix, DICY, amine curing agents, acid anhydrides, imidazole curing agents and the like are preferable. Particularly, in the case of an epoxy resin, 2 to 10% by weight based on the total solid content of the matrix.
It is preferable to include an imidazole-based curing agent.
The reason is that if it exceeds 10 wt%, it will be too hard and brittle,
If the content is less than 2% by weight, the curing is insufficient.

The mixture obtained by dispersing the cured heat-resistant resin particles in at least one kind of heat-resistant resin matrix selected from an uncured polyfunctional epoxy resin and a bifunctional epoxy resin is as follows: It is desirable to separately store the imidazole-based curing agent and store them separately, and to mix and use the two immediately before use.

Next, as the electroless plating adhesive of the present invention, the above-mentioned heat-resistant resin particles having voids, which have been cured and soluble in an acid or an oxidizing agent, are subjected to an acid or Adhesives which are dispersed in a resin matrix exhibiting properties which make them sparingly soluble in oxidizing agents are advantageously suitable. Further, in the present invention, not only such an adhesive, but also an adhesive film in which the adhesive solution is in a semi-cured state, or a prepreg in which the adhesive solution is impregnated into fibers such as glass cloth. Those are also preferably used. This adhesive can also be used as a base.

Next, a method of manufacturing the printed wiring board of the present invention will be described. The method for manufacturing a printed wiring board according to the present invention comprises: first, curing, on a substrate, cured heat-resistant resin particles having voids soluble in an acid or an oxidizing agent; The process is started by applying an adhesive obtained by dispersing in a heat-resistant resin matrix by a roll coater or the like, drying and curing to form an adhesive layer.

As a method of forming the above-mentioned adhesive layer on the substrate, for example, an uncured photosensitive resin or a thermosetting resin whose properties after curing are hardly soluble in the oxidizing agent may be added to the oxidizing agent. On the other hand, a method of applying an adhesive in which heat-resistant resin particles having soluble voids are dispersed, an adhesive film obtained by processing the adhesive into a film, or a fiber such as glass cloth impregnated with the adhesive. A method of attaching a prepreg can be applied. As the coating method, for example, a roller coating method, a dip coating method,
Various means such as a spray coating method, a spinner coating method, a curtain coating method, and a screen printing method can be applied.

As the heat-resistant resin liquid to which the heat-resistant resin particles are added, a heat-resistant resin containing no solvent can be used as it is. Particularly, a heat-resistant resin obtained by dissolving a heat-resistant resin in a solvent is usable. Since the viscosity of the liquid can be easily adjusted, heat-resistant particles can be uniformly dispersed, and the liquid can be easily applied to a substrate, so that the liquid can be advantageously used. As the solvent used for dissolving the heat-resistant resin, a common solvent such as methyl ethyl ketone, methyl cellosolve,
Examples thereof include ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, butyl cellulose, tetralin, dimethylformamide, and normal methylpyrrolidone.

An organic filler such as a fluororesin, a polyimide resin or a benzoguanamine resin, or a filler composed of an inorganic fine powder such as silica, alumina, titanium oxide or zirconia is appropriately blended with the above-mentioned heat-resistant resin liquid. You may. In addition, additives such as a coloring agent (pigment), a leveling agent, an antifoaming agent, an ultraviolet absorber, and a flame retardant can be used.

In the manufacturing method of the present invention, it is preferable that the thickness of the adhesive layer is usually about 20 to 100 μm, but it is also possible to increase the thickness if a particularly high insulating property is required. it can.

When the multilayer printed wiring board is manufactured as described above, the adhesive layer is provided with a via hole for connecting the conductive layers. As a method for forming the via hole, when a photosensitive resin is used as the heat-resistant resin constituting the matrix, a method of exposing a predetermined portion, and then developing and etching is preferable. A method of forming a via hole can also be applied. On the other hand, when a thermosetting resin is used as the heat-resistant resin, a method of processing a predetermined portion using a laser or a drill is preferable. The method of forming via holes by laser processing can be applied before or after roughening the surface of the resin insulating layer.

As the substrate used in the present invention, for example, a plastic substrate, a ceramic substrate, a metal substrate, a film substrate and the like can be used. Specifically, a glass epoxy substrate, a glass polyimide substrate, an alumina substrate, a low-temperature fired ceramic A substrate, an aluminum nitride substrate, an aluminum substrate, an iron substrate, a polyimide film substrate, or the like can be used.

Next, the heat-resistant resin particles scattered on the surface of the adhesive layer are dissolved and removed using an acid or an oxidizing agent. As a method of dissolving and removing, the substrate on which the adhesive layer is formed is immersed in a solution of an acid or an oxidizing agent, or a solution of an acid or an oxidizing agent is sprayed on the surface of the adhesive layer. As a result, the surface of the adhesive layer can be roughened. For the purpose of effectively dissolving and removing the heat-resistant resin particles, the surface portion of the adhesive layer is lightly roughened by performing polishing or liquid honing using, for example, a fine abrasive. It is extremely effective.

As an oxidizing agent for roughening the adhesive layer, chromate, chromate, permanganate, ozone and the like are preferable. Further, as the acid, hydrochloric acid, sulfuric acid, organic acids and the like are preferable.

Next, after the surface of the adhesive layer is roughened, the roughened surface is subjected to electroless plating to form a conductor circuit. Examples of the electroless plating method in this step include, for example, electroless copper plating, electroless nickel plating, electroless tin plating, electroless gold plating, and electroless silver plating. It is preferable that at least one of electroless nickel plating and electroless gold plating is used. It should be noted that, after the electroless plating is performed, another type of electroless plating or electroplating may be further performed, or solder may be coated.

The wiring board obtained by the method of the present invention as described above can be used to form a conductor circuit by any of various methods used for known printed wiring boards. And then a method of directly forming a circuit when performing electroless plating.

The printed wiring board of the present invention obtained by the above-described manufacturing method is, for example, a single-sided printed wiring board formed by forming a plating resist and a conductive circuit on a substrate via an adhesive layer, A double-sided printed wiring board in which a plating resist and a conductor circuit are formed through an adhesive layer on both sides and a through hole, and an interlayer insulating layer having a via hole (an adhesive layer) on a substrate on which a first conductor layer is formed. ) Is a build-up multi-layer wiring board formed by forming a multi-layered conductive circuit, wherein the adhesive is cured, in any case, by curing heat-resistant resin particles soluble in an acid or an oxidizing agent. Resin particles which are dispersed in a resin matrix exhibiting a property of being hardly soluble in acids and oxidizing agents when subjected to the treatment, and as the heat-resistant resin particles, resin particles having voids in the particles For the use characterized by, resin particles having the voids, the ratio of the particle size r _A and the thickness r _B is r _B /
Hollow particles with r _A = 4/10 to 1/20, volume ratio of 20 to 95
It is desirable to use either a particle having closed cells of vol% or a particle having open cells having a specific surface area of 2 to 2000.

[0043]

【Example】

(Example 1) (1) A photosensitive dry film (manufactured by DuPont) is laminated on a glass epoxy copper-clad laminate (manufactured by Toshiba Chemical Co., Ltd.), and is exposed to ultraviolet light through a mask film on which a desired conductive circuit pattern is drawn to print an image. . Then, 1,
After developing with 1,1-trichloroethane and removing copper in the non-conductor portion using a cupric chloride etching solution, the dry film is peeled off with methylene chloride. Thereby, wiring board 1 having first conductor layer 4 composed of a plurality of conductor patterns
Was obtained (see FIG. 2 (a)). (2) 60 parts by weight of a 50% acrylate of a cresol novolak type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell), 15 parts by weight of diallyl terephthalate, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1
After mixing 4 parts by weight (manufactured by Ciba-Geigy), 4 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals), and 30 parts by weight of melamine resin particles (particle diameter: 3 μm) having open cells, while adding butyl cellosolve, The mixture was stirred with a homodisper stirrer. Thereafter, the mixture was kneaded with three rollers to prepare a photosensitive adhesive solution having a solid content of 70%. The viscosity of this solution was 5.0 Pa · s at 6 rpm and 2.5 Pa · s at 60 rpm, and its SVI value was 2.0. Here, the melamine resin particles having the open cells are a blowing agent (CFC).
After foaming and solidifying a melamine resin solution to which a surfactant and a surfactant have been added, the obtained resin mass is pulverized and classified. The reason why the resin particles having the open cells can hold air in the particles is that the air bubbles are fine and do not take in the matrix resin. In this example, the specific surface area of the obtained melamine resin particles having open cells was 1200. (3) The adhesive solution of the photosensitive resin composition prepared in (2) is applied on the wiring board 1 obtained in (1) using a roll coater, and then dried at 80 ° C. for 1 hour. About 50μ thick
m of the photosensitive resin insulating layer 2 was formed (see FIG. 2B). (4) A photomask film on which a black circle having a diameter of 100 μm was printed was brought into close contact with the wiring board 1 that had been subjected to the treatment of (3), and was exposed at 500 mj / cm ² using an ultra-high pressure mercury lamp. This is
By performing ultrasonic development treatment with 1,1-trichloroethane, an opening serving as a 100 μmφ via hole was formed on the wiring board 1, and further, about 3000 mj / cm ² by an ultra-high pressure mercury lamp.
Then, heat treatment was performed at 100 ° C. for 1 hour and then at 150 ° C. for 10 hours to form an interlayer insulating layer 2 having openings 7 having excellent dimensional accuracy corresponding to a photomask film (FIG. 2C). reference). (5) The wiring board 1 having been subjected to the treatment of (4) is replaced with chromic acid (C
The surface of the interlayer insulating layer 2 was roughened by immersion in an oxidizing agent consisting of an aqueous solution of rO ₃ (500 g / l) at 70 ° C. for 15 minutes, and then immersed in a neutralizing solution (manufactured by Shipley) and washed with water. A palladium catalyst (manufactured by Shipley Co., Ltd.) is applied to the substrate 1 having the roughened interlayer insulating layer 2 to activate the surface of the insulating layer 2.
Heat treatment was performed at 30 ° C for 30 minutes. (6) A photosensitive dry film (manufactured by San Nopco) was laminated on the wiring board 1 after the processing of (5), and the conductor pattern was exposed and developed (see FIG. 2 (d)). (7) Next, the film was immersed in an electroless copper plating solution having the composition shown in Table 1 for 11 hours to perform electroless copper plating with a plating film 6 having a thickness of 25 μm (see FIG. 2E). (8) Further, the surface of the wiring board 1 is polished by a buffing machine,
Thereafter, by performing the same processing as in the above (3) to (7), a build-up multilayer wiring board having six wiring layers (4, 6, 8) was manufactured (see FIG. 2).

[0044]

[Table 1]

(Example 2) (1) 60 parts by weight of a 50% acrylate of a phenol aralkyl type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell), 15 parts by weight of diallyl terephthalate Part, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1
After mixing 4 parts by weight (manufactured by Ciba-Geigy), 4 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals) and 30 parts by weight of a melamine resin powder having closed cells (cell volume fraction: 50%, particle size: 2 μm) While adding butyl cellosolve acetate, the mixture was stirred with a homodisper stirrer. Thereafter, the mixture was kneaded with three rollers to prepare a photosensitive adhesive solution having a solid content of 60%. The viscosity of this solution was 5.0 Pa at 6 rpm.
S, 2.5 Pa · s at 60 rpm, and its SVI value is 2.
It was 0. (2) In the same manner as in Examples 1 (3) to (8), a build-up multilayer wiring board having six wiring layers (4, 6, 8) was manufactured.

Example 3 (1) 60% by weight of 50% acrylate of cresol novolak type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell), 15 parts by weight of diallyl terephthalate Part, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1
4 parts by weight (manufactured by Ciba-Geigy), 4 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals), and a commercially available hollow melamine resin having a ratio r _B / r _{A of} particle size r _A to wall thickness r _B of 3/10 After mixing 50 parts by weight of powder (made by Honen, particle size: 5 μm),
While adding butyl cellosolve acetate, the mixture was stirred with a homodisper stirrer. Thereafter, the mixture was kneaded with three rollers to prepare a photosensitive adhesive solution having a solid content of 60%. The viscosity of this solution was 5.0 Pa · s at 6 rpm and 60 rpm.
2.5 Pa · s, and its SVI value was 2.0. (2) An insulating layer 2 was formed in the same manner as in Examples 1 (3) and (4). (3) After lightly polishing the surface of the insulating layer 2 by buff polishing,
The surface of the insulating layer 2 was roughened by immersion in a 60% sulfuric acid solution at room temperature for 10 minutes and then washed with water. Next, a palladium catalyst (manufactured by Shipley) was applied to the substrate 1 having the roughened interlayer insulating layer 2 to activate the surface of the insulating layer. (4) Example 1 In the same manner as in (6) to (8), a build-up multilayer wiring board having six wiring layers (4, 6, 8) was manufactured.

Example 4 (1) Bisphenol F type epoxy resin (made by Yuka Shell)
100 parts by weight, 8 parts by weight of a chain fatty acid polyamine (diethylene triamine, manufactured by Sumitomo Chemical Co., Ltd.) as a curing agent, chlorofluorocarbon as a foaming agent, and a surfactant were mixed at 100 ° C.
Dry for hours and foam harden. This foamed and hardened epoxy resin is roughly pulverized, and then finely pulverized using a supersonic jet pulverizer (manufactured by Nippon Pneumatic) while being frozen with liquid nitrogen, and further a wind classifier (manufactured by Nippon Donaldson) To obtain an epoxy resin fine powder having an average particle size of 1.7 μm. The specific surface area of the obtained resin particles having open cells was 800. (2) Dissolve 60 parts by weight of phenol novolak type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell) and 5 parts by weight of imidazole-based curing agent (manufactured by Shikoku Kasei) in butyl cellosolve acetate Then, based on 100 parts by weight of the solid content of the composition, (1)
Was mixed with three rolls at a ratio of 50 parts by weight, and butylcellosolve acetate was further added to prepare an adhesive solution having a solid content of 75%. The viscosity of this solution was measured using a digital viscometer (DVL-B) manufactured by Tokyo Keiki Co., Ltd. at 20 ° C. for 60 seconds according to JIS K7117.
It was 5.2 Pa · s at m and 0.05 Pa · s at 60 rpm. SVI
The value was 2. (3) Next, the glass epoxy substrate 1 is roughened by polishing, and JI
After forming a rough surface of S B0601 R _max = 2 to 3 μm, the solution of the adhesive composition prepared in the above (2) was applied to the roughened surface of the substrate using a roll coater. This application uses a coating roll for resist for medium and high viscosity (manufactured by Dainippon Screen) as a coating roll, 0.4 mm between the coating roller and the doctor bar, 1.4 mm between the coating roller and the backup roller, and a transport speed of 400 mm /
Performed under the conditions of S. Then, after standing for 20 minutes in a horizontal state, the adhesive layer 2 was further dried at 70 ° C. to form an adhesive layer 2 having a thickness of about 50 μm on the roughened surface of the substrate (see FIG. 3A). (4) The substrate 1 after the treatment of the above (3) is drilled and immersed in an oxidizing agent composed of 500 g / l aqueous solution of chromic acid (CrO ₃ ) at 70 ° C. for 15 minutes to form the adhesive layer 2. After the surface was roughened, it was immersed in a neutralization solution (manufactured by Shipley) and washed with water.
The surface of the adhesive layer 2 was activated by applying a palladium catalyst (manufactured by Shipley) to the substrate 1 having the roughened adhesive layer 2 (see FIG. 3 (c)). (5) The substrate 1 is placed in a nitrogen gas atmosphere (10 ppm oxygen) for 12 hours.
A heat treatment for immobilizing the catalyst was performed at 0 ° C. for 30 minutes. Thereafter, a photosensitive dry film was laminated, exposed, developed with modified chlorocene, and plated resist 3 (thickness:
40 μm) (see FIG. 3D). (6) The substrate 1 on which the plating resist 3 has been formed is immersed in an electroless copper plating solution having the composition shown in Table 1 for 11 hours to perform electroless copper plating with a plating film 4 having a thickness of 25 μm. A wiring board was manufactured (see FIG. 3).

Comparative Example (1) 60 parts by weight of a 50% acrylate of a cresol novolak type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of bisphenol A type epoxy resin (manufactured by Yuka Shell), 15 parts by weight of diallyl terephthalate , 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1
After mixing 4 parts by weight (manufactured by Ciba-Geigy), 4 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals) and 100 parts by weight of melamine resin powder (manufactured by Honen, particle size: 3 μm), while adding butyl cellosolve acetate, The mixture was stirred with a homodisper stirrer. Thereafter, the mixture was kneaded with three rollers to prepare a photosensitive adhesive solution having a solid content of 60%. The viscosity of this solution was 5.0 Pa · s at 6 rpm and 2.5 at 60 rpm.
Pa · s, and its SVI value was 2.0. (2) In the same manner as in Examples 1 (3) to (8), a build-up multilayer wiring board having six wiring layers (4, 6, 8) was manufactured.

The adhesion (peel strength), the total weight, the electrical characteristics (dielectric constant) of the electroless plating film of the printed wiring board manufactured as described above, and the roughening time of the adhesive layer in the manufacture of the wiring board were evaluated. However, the results shown in Table 2 were obtained.

As is clear from the results shown in Table 2, in the case of the present invention, not only a high adhesion strength of the conductor is obtained, but also the dielectric constant is low, the insulation reliability between the conductors is excellent, and the high density is obtained. This is particularly advantageous in producing a flexible printed wiring board.
Moreover, since the printed wiring board of the present invention uses heat-resistant resin particles having voids in the adhesive layer of the wiring board,
It can be seen that the weight is lower than that of the comparative example, and the time required for roughening the adhesive layer in the production of the wiring board is shorter than that of the comparative example, and the productivity is improved.

[0051]

[Table 2]

[0052]

As described above, according to the present invention,
By using the heat-resistant resin particles having voids in the adhesive for forming the insulating layer, the solubility of the resin particles in a roughening liquid is increased, and the roughening time of the adhesive layer can be reduced without eroding the substrate. , Effective anchor recesses can be easily formed, as a result, the adhesive layer has excellent electrical insulation and strength, high productivity, light weight, excellent reliability such as strength, ultra high A printed wiring board having a high density can be easily manufactured.

[Brief description of the drawings]

FIG. 1 shows specific examples of the heat-resistant resin particles of the present invention, (a) and (d) hollow particles, (b) and (e) particles having closed cells, and (c) and (f) particles having open cells. FIG.

FIG. 2 is a process chart showing one embodiment of the present invention.

FIG. 3 is a process chart showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate (wiring board) 2 adhesive layer 3 plating resist 4, 6, 8 wiring layer (plating layer, conductor layer) 7 opening for via hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H05K 3/18 C23C 18/18

Claims (4)

(57) [Claims] 1. An adhesive for electroless plating which is dispersed in a resin matrix exhibiting a property of being hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment. Cured heat-resistant resin particles having at least internal voids and a particle size rA
Hollow having a thickness rB ratio of rB / rA = 4/10 to 1/20
Particles with closed cells with a volume fraction of 20 to 95 vol%
Having open cells having a specific surface area of 2 to 2000
Heat-resistant resin particles for forming an anchor, which are any one of particles. 2. A heat-resistant resin particle which has been cured and which is soluble in an acid or an oxidizing agent is dispersed in a resin matrix which has a property of being hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment. A resin composition, wherein the heat-resistant resin particles have voids at least inside.
At the same time, the ratio of the particle diameter rA to the wall thickness rB is rB / rA = 4 /
Hollow particles with a volume ratio of 10 to 1/20 and a volume fraction of 20 to 95 vol%
Particles with closed cells or specific surface area of 2 to 2000
An adhesive for electroless plating, comprising any one of particles having certain open cells . 3. A printed wiring board is manufactured by forming an adhesive layer for electroless plating on a substrate, roughening the surface of the adhesive layer, and applying electroless plating to form a conductor circuit. In the method, on the substrate, at least a void is provided inside.
In addition, the ratio of the particle diameter rA to the wall thickness rB is rB / rA = 4 / 10-1.
/ 20 hollow particles, independent volume fraction 20-95 vol%
Particles having air bubbles or reams having a specific surface area of 2 to 2000
An acid or acid consisting of any one of the particles with open cells
Is a cured heat-resistant resin that is soluble in oxidizing agents
An adhesive solution is prepared by dispersing the particles in an uncured resin matrix that exhibits a property of being hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment, thereby forming an adhesive layer. A method for manufacturing a printed wiring board, comprising roughening according to a method and then performing electroless plating. 4. A printed wiring board comprising an adhesive layer provided on at least one substrate surface and a conductor circuit formed thereon, wherein said adhesive layer has at least a void inside.
In addition, the ratio of the particle diameter rA to the wall thickness rB is rB / rA = 4 / 10-1.
/ 20 hollow particles, independent volume fraction 20-95 vol%
Particles having air bubbles or reams having a specific surface area of 2 to 2000
An acid or acid consisting of any one of the particles with open cells
Is a cured heat-resistant resin that is soluble in oxidizing agents
A printed wiring board comprising particles dispersed in a resin matrix exhibiting a property of being hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment.