JP3137483B2 - Multilayer printed wiring board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board and a method of manufacturing the same, and more particularly, to a multilayer printed wiring board having a conductor circuit composed of a plurality of electroless plated films electrically insulated by a resin insulation layer composed of a heat-resistant resin. A printed wiring board and a method for manufacturing the same are proposed.

[0002]

2. Description of the Related Art In recent years, with the advance of electronic technology, electronic devices such as large-sized computers have been increasing their density or operating functions. As a result, in recent years, multilayer printed wiring boards in which wiring circuits are formed in multiple layers have come into the spotlight in response to the above-described high density and high-speed operation of printed wiring boards.

[0003] As such a multilayer printed wiring board,
Conventionally, a plurality of circuit boards on which an internal circuit is formed are laminated and pressed using a prepreg as an insulating layer, and then each of the internal circuits is connected through a through hole to conduct electricity.

However, in such a multilayer printed wiring board of this type, a plurality of internal circuits are connected and conducted through through holes, so that the wiring circuit becomes too complicated to increase the density or speed. Is difficult to realize.

As a multilayer printed wiring board which can overcome such problems, a multilayer printed wiring board in which conductive circuits and organic insulating films are alternately built up has recently been developed. Certainly, this multilayer printed wiring board
It is suitable for ultra-high density and high speed. However, there is a drawback that it is actually difficult to form an electroless plating film on an organic insulating film with high reliability. Therefore, in such a multilayer printed wiring board, the conductor circuit is formed by a PVD method such as vapor deposition or sputtering, or a combination of the PVD method and electroless plating. However, such a method of forming a conductor circuit by the PVD method has a disadvantage that productivity is poor and cost is high.

On the other hand, the inventors of the present invention have made various studies for the purpose of solving the above-mentioned drawbacks of the conventional multilayer printed wiring board, and have previously described JP-A-63-126297 and JP-A-2-126297. Japanese Patent Application No. 188992 proposed various inventions relating to a multilayer printed wiring board and a method for manufacturing the same.

That is, these prior arts provide a multilayer printed wiring board in which a plurality of conductor circuits obtained by electroless plating are electrically insulated by a resin insulating layer made of a heat-resistant resin. In the uncured heat-resistant resin liquid having the property of being hardly soluble in an acid or an oxidizing agent by curing the layer, heat-cured resin particles previously cured and soluble in the acid or the oxidizing agent. A multilayer printed wiring board composed of an adhesive obtained by dispersing the above, and after applying the adhesive to a substrate, drying and curing to form a resin insulating layer, and the resin insulating layer is dispersed on a surface portion of the resin insulating layer. This is a method of manufacturing a multilayer printed wiring board by dissolving and removing at least a part of resin particles to roughen the surface, and then performing electroless plating on the roughened surface.

The feature of the prior art is that the resin insulating layer in a state where the heat-resistant resin particles are uniformly dispersed in the heat-resistant resin forming the matrix is formed by preliminarily curing the heat-resistant resin particles in the heat-resistant resin liquid. The adhesive is formed by applying an adhesive dispersed on a substrate and drying and curing the applied adhesive. That is, since the heat-resistant resin particles and the heat-resistant resin matrix have different solubility in an acid or an oxidizing agent, when treated with an acid or an oxidizing agent, the resin particles dispersed on the surface portion of the adhesive layer Only the main component is dissolved and removed, and an effective anchor depression is formed. As a result, high adhesion strength and high reliability between the substrate and the electroless plating film can be obtained.

[0009]

By the way, in the above-mentioned adhesive, general-purpose and easily available as heat-resistant resin particles soluble in an acid or an oxidizing agent, and furthermore, chemical resistance, heat resistance, electric characteristics, hardness and the like. Epoxy resin, which is an excellent resin, was used. However, in recent years, the density of printed circuit boards has rapidly increased, and when a multilayer printed wiring board manufactured using an epoxy resin as the heat-resistant resin particles is used in an environment with high temperature and humidity,
It has been found that copper, which is a conductor circuit, dissolves and precipitates, lowering the surface resistance value, and eventually causing a short circuit between the patterns.

[0010] The reason for this is that when an epoxy resin particle soluble in an acid or an oxidizing agent is produced, an ionic compound is used, so that sodium ions and chlorine ions remain in the epoxy resin particle. This is because the residual ions cause a migration reaction as shown in the following formulas (see FIG. 5). Na ⁺ + Cl ⁻ + H ₂ O → NaOH + HCl ... Cu + 2NaOH → Cu (OH) ₂ + 2Na ⁺ ... Cu + 2HCl → CuCl ₂ + 2H ⁺ As described above, the conventional multilayer printed wiring board is more reliable depending on the use environment. Unsolved problem that the performance is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to advantageously solve the above-mentioned unsolved problems. In particular, the present invention has found a component of heat-resistant resin particles which is not influenced by the use environment, An object of the present invention is to establish a technique for reliably and inexpensively providing a multilayer printed wiring board having excellent environmental characteristics and high reliability by forming the resin insulating layer by employing conductive resin particles.

[0012]

Means for Solving the Problems As the present inventors proceeded with research for realizing the above-mentioned object, the epoxy resin for heat-resistant resin particles soluble in an acid or an oxidizing agent became ionic at the time of production. Na, chloride ions, etc. remain in the resin, and the molecular weight between cross-linking points of the epoxy resin decreases
It has been determined that, due to being above 1000, the ions are mobile in the resin and therefore cause the reaction as described above. Therefore, as a result of intensive research on a resin not using such an ionic compound, melamine resin particles and / or urea resin particles (hereinafter, referred to as “melamine resin particles”) as heat-resistant resin particles soluble in an acid or an oxidizing agent. It has been newly found that the use of a high-reliability multilayer printed wiring board which does not cause the above-mentioned migration reaction, has an extremely high density, and is excellent in chemical resistance, heat resistance, electrical properties and hardness, can be obtained. The present invention has been made.

That is, the present invention relates to a multilayer printed wiring board in which a conductor circuit formed of a plurality of layers obtained by electroless plating is electrically insulated by a resin insulating layer made of a heat-resistant resin. In an uncured resin matrix which becomes hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment, particles such as melamine resin are blended in an amount of 10 to 100 parts by weight based on 100 parts by weight of the solid content of the resin matrix. And composed of dispersed adhesive, and the particles of the melamine resin or the like on the surface of the resin insulating layer on which the electroless plating film is formed, are treated with an acid or an oxidizing agent to be dissolved and removed, so that the anchor-forming concave portion is formed. It is a multilayer printed wiring board characterized by doing.

The method for manufacturing a multilayer printed wiring board according to the present invention comprises:
In a method of manufacturing a multilayer printed wiring board having a plurality of conductor circuits made of an electroless plating film electrically insulated by a resin insulating layer made of a heat-resistant resin, at least the following steps (a) to (c); (A) On an uncured resin matrix which becomes hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment on a substrate on which a conductive circuit is formed, particles such as melamine resin are added to a solid content of 100 parts by weight of the resin matrix. A step of forming a resin insulating layer by one or more adhesives in which 10 to 100 parts by weight are mixed and dispersed, (b) melamine resin scattered on the surface of each resin insulating layer (C) electroless plating on the roughened resin insulating layer by dissolving and removing only the uniform particle portions using an acid or an oxidizing agent to roughen the surface on which the electroless plating film is formed; Apply By a method for manufacturing a multilayer printed wiring board, characterized in that through the process, to form a conductor circuit.

[0015]

The known adhesive for printed wiring boards using epoxy resin as the heat-resistant resin particles shows a phenomenon that the surface resistance decreases due to the above-mentioned migration reaction. From this, the inventors conducted a long-term deterioration test on various resins under the conditions of a temperature of 40 ° C., a humidity of 90% and a voltage of 24 V, and examined the change over time in the resistance value. As a result, polyimide resin,
Epoxy resins and the like are known, but among them, as a resin that is soluble in an oxidizing agent and has no change in resistance value with time, that is, a resin that does not cause the above-mentioned migration reaction, a resin such as a melamine resin is the most effective resin. It was found that it was.

That is, by employing particles of melamine resin or the like as heat-resistant resin particles, even when used in a use environment, particularly in a high-temperature, high-humidity atmosphere, migration occurs, the conductor circuit is melted, and the surface resistance is reduced. Thus, a multilayer printed wiring board having sufficient adhesion strength of the conductor without lowering the value and having excellent chemical resistance, heat resistance, electrical characteristics and hardness can be obtained.

Examples of such melamine resin particles for forming an anchor include agglomerated particles obtained by aggregating fine powder such as melamine resin having an average particle size of 2 μm or less to an average particle size of 2 to 10 μm, A particle mixture of a powder of melamine resin such as 2 to 10 μm and a powder of melamine resin such as melamine having an average particle size of 2 μm or less, or a melamine resin having an average particle size of 2 μm or less on the surface of the powder of melamine resin such as melamine resin having an average particle size of 2 to 10 μm It is desirable that the particles are at least one selected from pseudo particles obtained by adhering at least one of a fine powder and an inorganic fine powder.

The average particle diameter of the particles of the anchor-forming melamine resin or the like is preferably 10 μm or less.
It is particularly preferable that the thickness be 5 μm or less. The reason is,
If the average particle diameter is larger than 10 μm, the density of the anchor formed by dissolving and removing becomes small and tends to be non-uniform, so that the adhesion strength and its reliability are reduced. In addition, since the surface of the resin insulating layer becomes very uneven, it is difficult to obtain a fine pattern of the conductor, and this is not preferable in mounting components and the like.

The amount of the melamine resin particles for forming an 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 resin insulating layer becomes porous, and the adhesion strength (peel strength) between the adhesive layer and the electroless plating film decreases.

The particles of the melamine resin or the like employed as the heat-resistant resin particles in the present invention are resin fine particles having an amino group capable of reacting with formaldehyde. The reason is that these resins have excellent heat resistance, large surface hardness,
This is because it is excellent in mechanical strength, excellent in electric insulation, particularly excellent in arc resistance, good in organic solvent resistance, and highly soluble in acids or oxidizing agents.

Among these resins, the melamine resin is an addition condensation product of melamine and formaldehyde, and produces a white and water-insoluble resin when reacted with an acid, and a transparent and water-soluble resin when reacted with an alkali. Produce resin. That is, as shown in (Chemical Formula 1), a melamine resin is obtained by reacting melamine with formaldehyde under neutral or alkaline conditions to obtain methylol melamine. It is obtained by forming a bond and an ether bond to form a macromolecule.

Further, the melamine resin is generally used as a molding material in a formaldehyde to melamine molar ratio of about 1: 2 to 1: 3. Suitable for making. Therefore, melamine and formaldehyde in the above molar ratio range are kept neutral or slightly alkaline with ammonia or the like, and reacted at 80 to 90 ° C., and the resulting syrup is rayon, pulp cloth strip, asbestos, A base material such as fiber is added, dried and crushed, and a pigment, a release agent, a curing agent and the like are added and finely crushed to obtain a molding material. It should be noted that curing is sufficiently performed by heating and pressing without adding a curing agent, but a curing agent such as citric acid, phthalic acid, or organic carboxylic acid ester is generally used.

[0023]

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The urea resin is a thermosetting resin produced by the condensation polymerization of urea and formaldehyde (see Chemical Formula 2).
As a method for producing the fine particles composed of the urea resin, for example,
First, urea and formalin are mixed at a molar ratio of about 1: 2, and heated by neutral or alkaline to prepare a liquid containing 45 to 50% of an initial polymer via monomethylol urea and dimethylol urea, Thereafter, a filler such as pulp or wood flour is added to and mixed with the initial polymerized product, and the mixture is further heated to proceed with polymerization, dried, and ground to obtain resin particles.

[0025]

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The epoxy resin fine particles, for example, bisphenol A type epoxy resin (made by Yuka Shell) particles are:
The concentration of sodium ion and chlorine ion remaining in the resin is about 5 ppm, and the resin cured with a dicyanic curing agent and soluble in acid or oxidizing agent has a molecular weight between crosslinking points of 1900. In addition, the ions easily move in the resin.
Therefore, when an epoxy resin is used as the heat-resistant resin particles for forming the anchor, a migration reaction is caused. On the other hand, an epoxy resin insoluble in an acid or an oxidizing agent used as a heat-resistant resin matrix has a molecular weight between cross-linking points of about 600, and sodium ions and chloride ions are fixed in the resin, so that a migration reaction is hardly caused.

Next, the resin matrix in which the particles such as the melamine resin are dispersed is excellent in heat resistance, electrical insulation, chemical stability and adhesiveness, and is hard to resist acid and oxidizing agent by curing. Any uncured resin having the property of being soluble can be used. In particular, a polyfunctional epoxy resin, a resin having an acrylic group,
It is desirable to use at least one resin selected from acrylic resins or a mixed resin of at least one selected from the above resins and at least one difunctional epoxy resin or acrylic resin.

Among them, thermosetting resins such as bisphenol A type, bisphenol F type, phenol novolak type and cresol novolak type epoxy resin, bismaleid triazine resin, polyimide resin and phenol resin, phenol aralkyl type and phenol novolak type A photosensitive resin such as a resin obtained by converting an epoxy resin into an acrylate, an acrylic resin, and a photosensitive polyimide resin is preferably used.

The mixing ratio of the heat-resistant resin in the resin matrix is preferably such that the polyfunctional resin is a solid content and the mixed resin is 20 wt% or more and the bifunctional resin is less than 80 wt%. is there. The reason for this is that if the polyfunctional resin is less than 20 wt% solids, the hardness of the adhesive will decrease,
Moreover, chemical resistance is reduced.

As the curing agent for the resin matrix, DICY, amine curing agents, acid anhydrides and imidazole curing agents 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.

A mixture obtained by dispersing particles of a cured melamine resin or the like in at least one 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, and to mix and use them immediately before use in order to increase the pot life (usable time).

Next, a method for manufacturing the multilayer printed wiring board of the present invention will be described. The production method of the present invention first disperses heat-resistant resin particles soluble in an acid or an oxidizing agent in a heat-resistant resin matrix that is hardly soluble in an acid or an oxidizing agent on a substrate on which a conductive circuit is formed. The process is started by applying the obtained adhesive by a roll coater or the like, drying and curing to form a resin insulating layer.

As a method of forming the resin insulating layer on the substrate on which the conductor circuit is formed, for example, an uncured photosensitive resin whose properties after curing are hardly soluble in an oxidizing agent is added to the oxidizing agent. On the other hand, a method of applying an adhesive in which soluble heat-resistant resin particles are dispersed, or a resin film obtained by processing the adhesive into a film, or a prepreg in which fibers such as glass cloth are impregnated with the adhesive is attached. The method can be applied. As a method for forming this, various means such as a roller coating method, a dip coating method, a spray coating method, a spinner coating method, a curtain coating method, and a screen printing method can be applied.

The above-mentioned particles such as a melamine resin soluble in an acid or an oxidizing agent are all made of a cured heat-resistant resin. The heat-resistant resin constituting the particles such as the melamine resin is limited to the one subjected to the curing treatment. The use of the non-cured resin results in a heat-resistant resin liquid forming a matrix or a heat-resistant resin forming the matrix. When added to a solution dissolved using a solvent, the heat-resistant resin constituting the particles such as the melamine resin also dissolves in the heat-resistant resin liquid or solution, and exerts the function as the particles such as the melamine resin. It becomes impossible.

The particles of the melamine resin or the like are, for example, heat-cured and then pulverized by a jet mill or a freeze-pulverizer, or spray-dried and then cured by a solution of the melamine resin before the curing treatment. Particles obtained by adding an aqueous curing agent to an emulsion such as an uncured melamine resin or the like and stirring the resulting mixture are classified by an air classifier or the like.

As a method of curing the heat-resistant resin constituting the particles such as the melamine resin, there is a method of curing by heating or a method of curing by adding a catalyst. Among them, a method of curing by heating is preferred. It is practical.

Among the particles of the melamine resin or the like, as a method of forming pseudo particles obtained by adhering at least one of a fine powder such as a melamine resin and an inorganic fine powder to the surface of the powder such as a melamine resin, for example, a melamine resin It is advantageous to apply a method in which a fine powder such as a melamine resin or an inorganic fine powder is sprinkled on the surface of such a powder and then heated and fused or bonded via a binder.

Among the above-mentioned particles of the melamine resin or the like, as a method of forming fine particles of the melamine resin or the like into agglomerated particles, for example, the fine powder of the melamine resin or the like is simply heated by a hot air drier or the like, or various binders are used. Is added, mixed and dried to cause agglomeration. And then
It is advantageous to disintegrate using a ball mill, an ultrasonic dispersing machine or the like, and further classify by using an air classifier or the like.

The shape of the particles of the melamine resin or the like 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 particles of the melamine resin or the like produced 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. Let it.

As the heat-resistant resin liquid to which the particles such as the melamine resin 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 used. 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 a solvent used to dissolve the heat-resistant resin,
Usually, solvents such as methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol, butyl cellulose, tetralin, dimethylformamide, normal methylpyrrolidone and the like can be mentioned.

Further, an organic filler such as a fluororesin or a polyimide resin, or a filler composed of an inorganic fine powder such as silica, alumina, titanium oxide or zirconia may be appropriately blended into the heat-resistant resin liquid. . 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.

The preferred thickness of the resin insulating layer in the present invention is about 20 to 100 μm, but it can be larger if particularly high insulation is required.

The resin insulating layer is provided with via holes for connecting conductor 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.

The next step is a treatment for dissolving and removing particles of the melamine resin or the like scattered on the surface of the resin insulating layer using an acid or an oxidizing agent. As a method of dissolving and removing in this step, the substrate on which the resin insulating 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. For example, the surface of the adhesive layer can be roughened. For the purpose of effectively dissolving and removing particles such as the melamine resin, 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 the oxidizing agent for roughening the resin insulating 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, in the present invention, after the surface of the resin insulating layer is roughened, the roughened surface is subjected to electroless plating to form a conductor circuit. Examples of the method of electroless plating include electroless copper plating, electroless nickel plating, electroless tin plating, electroless gold plating, and electroless silver plating. Particularly, electroless copper plating, electroless nickel It is preferable that at least one of plating and electroless gold plating is used. Further, after the electroless plating is performed, different types of electroless plating or electroplating can be performed, or a solder can be coated.

In the method of the present invention, the above-described conductor circuit can be formed by other methods that are used for a known printed wiring board. For example, a method of performing electroless plating on a substrate and then etching the circuit. For example, a method of directly forming a circuit when performing electroless plating or the like may be applied.

[0050]

EXAMPLES (Example 1) (1) A photosensitive dry film (manufactured by DuPont) is laminated on a glass epoxy copper-clad laminate (manufactured by Toshiba Chemical) and exposed to ultraviolet light through a mask film on which a desired conductive circuit pattern is drawn. And burn the image, then 1,1,
After developing with 1-trichloroethane and removing the copper in the non-conductor portion using a cupric chloride etching solution, the remaining photosensitive dry film was removed with methylene chloride. Thus, the wiring board 1 having the first conductor layer 4 including a plurality of conductor patterns was obtained (see FIG. 1A). (2) 60 parts by weight of a 60% acrylated 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 50 parts by weight of hollow melamine resin particles (manufactured by Honen: particle size 2 μm), homogenous solution was added while adding butyl cellosolve. The mixture was stirred with a disper 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. (3) The adhesive solution of the photosensitive resin composition prepared in (2) was applied on the wiring board 1 obtained in (1) using a roll coater, and then left in a horizontal state for 20 minutes. After, 70 ℃
To form a photosensitive resin insulating layer 2 having a thickness of about 50 μm (see FIGS. 1B and 1C). (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.
And then heat-treated at 100 ° C. for 1 hour and then at 150 ° C. for 10 hours to form an interlayer resin insulating layer 2 having openings 7 having excellent dimensional accuracy equivalent to a photomask film (FIG. 1 (d)). )). (5) The wiring board 1 prepared in the above (4) is immersed in an oxidizing agent composed of a 500 g / l aqueous solution of chromic acid at 70 ° C. for 15 minutes to roughen the surface of the interlayer resin insulating layer 2 and then neutralized. (Made by Shipley) and washed with water. A palladium catalyst (manufactured by Shipley) is applied to the substrate 1 having the roughened interlayer resin insulating layer 2.
To activate the surface of the resin insulating layer 2, and immersed in an electroless copper plating solution having the following composition for 11 hours to perform electroless copper plating of the plating film 6 with a thickness of 25 μm (FIG. 1). (e).) (6) By repeating the steps (3) to (5) two more times, a build-up multilayer wiring board having four wiring layers (4, 6, 8, 10) was manufactured (FIG. 1 ( f)).

[Aqueous solution of electroless copper plating] Copper sulfate 0.06 / l Formalin 0.30 / l Sodium hydroxide 0.35 / l EDTA 0.35 / l Additive A little Plating temperature 70-72 ° C pH 12.4

Example 2 (1) 1275 parts by weight of a melamine resin, 1366 parts by weight of 37% formalin, and 730 parts by weight of water were mixed, and the pH was adjusted with 10% sodium carbonate.
= 9.0 and maintained at 90 ° C. for 60 minutes, and then 109 parts by weight of methanol was added. (2) The resin liquid was dried by a spray drying method to obtain a powdery resin. (3) The resin powder obtained in the above (2), the release agent, and the curing catalyst were pulverized and mixed by a ball mill to obtain a mixed powder of the above resin. (4) Put the above mixed powder in a mold heated to 150 ° C,
A compact was obtained by applying a pressure of 250 kg / cm2 and holding for 60 minutes. During the molding, the mold was opened to release gas. (5) The above molded product is pulverized with a ball mill and the particle size is 0.5 μm
And 5.5 μm heat-resistant resin particles were obtained. (6) Next, 60 parts by weight of a phenol novolak type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of a bisphenol A type epoxy resin (manufactured by Yuka Shell) and 5 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Kasei) are butyl cellosolve. It was dissolved in acetate to obtain a resin matrix composition. And
With respect to 100 parts by weight of the solid content of this composition, the resin particles prepared in the above (5) were mixed at a ratio of 15 parts by weight with a particle size of 0.5 μm and 30 parts by weight with a particle size of 5.5 μm. Thereafter, the mixture was kneaded with three rolls, and butyl cellosolve acetate was further added to prepare an adhesive solution having a solid content concentration of 75%. The viscosity of this solution was measured using a digital viscometer manufactured by Tokyo Keiki Co., Ltd. at 20 ° C. for 60 seconds in accordance with JIS-K7117. The viscosity was 5.2 Pa · s at 6 rpm and 2.6 Pa · s at 60 rpm. The value (thixotropic property) was 2.0. (7) The resin surface of the substrate 1 manufactured in the same manner as (1) of the first embodiment,
Roughening the conductor circuit surface by polishing, JIS B0601 R max =
After forming a rough surface of 2-3 μm, on the substrate 1
The adhesive solution of the resin composition prepared in (6) was applied using a roll coater. At this time, the coating method uses a resist coating roll for medium and high viscosity resist (manufactured by Dainippon Screen) as the coating roll, the gap between the coating roller and the doctor bar is 0.4 mm, and the gap between the coating roller and the backup roller is 1.4 mm. And the transport speed was 400 mm / s. Then, after standing for 20 minutes in a horizontal state, it was dried at 70 ° C. to form a resin insulating layer 2 having a thickness of about 50 μm (see FIGS. 2B and 2C). (8) The substrate 1 on which the resin insulating layer 2 is formed is immersed in an oxidizing agent composed of a 500 g / l chromic acid aqueous solution at 70 ° C. for 15 minutes to roughen the surface of the resin insulating layer 2 and then neutralized. (Made by Shipley Co.) and washed with water. Further, an opening 7 for a via hole is formed by a laser (see FIG. 2 (d)), and then a palladium catalyst (manufactured by Shipley Co., Ltd.) is applied to the substrate 1 having a roughened insulating layer surface, and the resin insulating layer 2 is formed. Was activated. (9) Next, this substrate 1 is placed in a nitrogen gas atmosphere (10 ppm oxygen).
Heat treatment at 120 ° C for 30 minutes in the catalyst, then laminating a photosensitive dry film,
After exposure, it was developed with denatured chlorocene to form a plating resist 3 (40 μm thick) (see FIG. 2 (e)). (10) The substrate 1 on which the plating resist 3 had been formed 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. 2 (f)). (11) Further, the above (7) to (10) were repeated twice to produce a multilayer printed wiring board (see FIG. 2 (g)).

(Example 3) (1) 60 parts by weight of a 60% acrylate of a phenol novolak type epoxy resin (manufactured by Yuka Shell), 40 parts by weight of a bisphenol A epoxy resin (manufactured by Yuka Shell), an imidazole-based curing agent 4 parts by weight (manufactured by Shikoku Chemicals), 15 parts by weight of diallyl terephthalate and 4 parts by weight of 2-methyl-1- [4- (methylthio) phenyl] -2morpholinopropanone-1 (manufactured by Ciba Geigy) were dissolved in butyl cellosolve. With respect to 100 parts by weight of the solid content of the composition, 15 parts by weight of melamine resin particles (made by Honen) having a particle size of 0.5 μm and 30 parts by weight of those having a particle size of 5.5 μm were mixed with a ball mill, After kneading with three rolls, butyl cellosolve was further added to prepare an adhesive solution having a solid concentration of 55%. The viscosity of this solution is 2.6 Pa · s at 60 rpm and 60 r.
It was 1.0 Pa · s at pm, and its SVI value (thixotropic property) was 2.6. (2) Apply this adhesive to a polyethylene film 12 coated with silicon using a roll coater,
For 30 minutes to produce an adhesive film (Fig. 3
(See (a), (b)). (3) This film was placed on an insulating plate (substrate 1) on which a conductor circuit was formed, and after the polyethylene film 12 was peeled off, it was heated and pressed to obtain a resin insulating layer 2 (FIGS. 3C and 3D). , (e)). (4) A multilayer printed wiring board was manufactured in the same manner as in Example 1 (see FIG. 3).

Example 4 (1) Melamine resin particles (average particle size: 3.9 μm) prepared in the same manner as in Example 2 were charged into a hot air drier and heated at 180 ° C.
For 3 hours for coagulation bonding. The coagulated and bonded melamine resin particles were dispersed in acetone, crushed by a ball mill for 5 hours, and then classified using an air classifier to prepare coagulated particles. The aggregated particles had an average particle size of about 3.5 μm, and about 68% by weight was in a range of ± 2 μm around the average particle size. (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 Chemicals) in methyl ethyl ketone. Then, 50 parts by weight of the agglomerated particles prepared in the above (1) were mixed with 100 parts by weight of the solid content of this composition, and kneaded with a ball mill. Was prepared. The viscosity of this solution is
It was 0.6 Pa · s at 6 rpm and 0.5 Pa · s at 60 rpm, and its SVI value (thixotropic property) was 1.2. (3) This adhesive solution was impregnated in a glass cloth and dried to prepare a prepreg 11 (see FIG. 4 (a)). (4) Glass epoxy substrate 1 on which conductive circuit 4 is formed
Then, a prepreg 11 was overlaid and heated and pressed to form a resin insulating layer 2 (see FIG. 4B). (5) Next, the substrate 1 on which the resin insulating layer 2 has been formed is drilled by a drill, and is immersed in an acid composed of a 6N hydrochloric acid aqueous solution at 70 ° C.
After the surface of the resin insulating layer 2 was roughened by immersion for 15 minutes, it was immersed in a neutralizing solution (manufactured by Shipley) and washed with water. The surface of the resin insulating layer 2 was activated by applying a palladium catalyst (manufactured by Shipley) to the substrate 1 having the insulating layer whose surface was roughened (see FIG. 4 (c)). (6) The substrate 1 is placed in a nitrogen gas atmosphere (10 ppm oxygen) for 12 minutes.
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. 4 (d)). (7) The substrate 1 on which the plating resist has been formed is placed in Table 1
11 hours in an electroless copper plating solution having the composition shown in Table 1 and a 30 μm-thick electroless copper plating film was formed on both surfaces to form a conductor circuit and a through hole 5 to produce a double-sided printed wiring board. (See FIG. 5 (e)).

Example 5 (1) An adhesive solution A was prepared by performing the same treatments as in (1) to (6) of Example 2 (excluding the curing agent). (2) An adhesive solution B was prepared by dissolving 5 parts by weight of an imidazole-based curing agent in butyl cellosolve. (3) The adhesive solution A and the adhesive solution B were stored at room temperature for one month, and then mixed to obtain an adhesive solution. The characteristics were the same as in Example 2. (4) Using this adhesive solution, a multilayer printed wiring board was manufactured in the same manner as in Example 2.

Example 6 (1) Flame retardant novolak type epoxy resin (Nippon Kayaku) 10
0 parts by weight and 7 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals) were dissolved in butyl cellosolve acetate, and the resin particles prepared in (5) of Example 2 were added to 100 parts by weight of the solid content of this composition. 15 parts by weight with a particle size of 0.5 μm, particle size 5.
A mixture of 5 μm was mixed at a ratio of 30 parts by weight, and then kneaded with three rolls, and butyl cellosolve acetate was further added to prepare an adhesive solution having a solid content of 75%. The viscosity of this solution was 5.2 Pa · s at 6 rpm and 2.5 at 60 rpm.
Pa · s and its SVI value (thixotropic property)
Was 2.0. (2) Using this adhesive, a multilayer printed wiring board was manufactured in the same manner as in Example 2.

(Example 7) (1) Melamine resin particles (average particle size of 3.9 μm) prepared in the same manner as in (1) to (5) of Example 2 in 5 l of acetone
While stirring 200 g of the suspension in a Henschel mixer (manufactured by Mitsui Miike Kakoki Co., Ltd.), 10 l of acetone was added.
A suspension in which 300 g of melamine resin fine powder (average particle size: 0.5 μm) obtained in the same manner as in (1) to (5) of Example 2 was dispersed was dropped and mixed, thereby obtaining the melamine resin. After the melamine resin fine powder was adhered to the particle surface, acetone was removed and then heated to 150 ° C. to produce pseudo particles. The pseudo particles had an average particle size of about 4.3 μm, and about 75% by weight was in a range of ± 2 μm around the average particle size. (2) 100 parts by weight of 60% acrylate of ortho-cresol novolac type epoxy resin (manufactured by Nippon Kayaku), 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), 50 parts by weight of the photoinitiator (manufactured by Ciba-Geigy) and the melamine resin particles of the above (1), butyl cellosolve Was added and 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 5.1 Pa · s at 6 rpm and 2.6 at 60 rpm.
Pa · s, and its SVI value was 2.0. (3) Using this adhesive solution, a multilayer printed wiring board was manufactured in the same manner as in Example 1.

(Example 8) This example is basically the same as Example 1, except that 60 parts by weight of a phenol novolak type epoxy resin (manufactured by Yuka Shell) is used as an adhesive solution. 40 parts by weight of an acrylic resin (manufactured by Yuka Shell) and 5 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals) are dissolved in butyl cellosolve acetate, and melamine resin particles are added to 100 parts by weight of the solid content of this composition. 15 parts by weight of 0.5 μm diameter, particle size
A mixture of 5.5 μm and 30 parts by weight was mixed with a three-roll mill, and butylcellosolve acetate was further added to adjust the solid content to 75%.

Example 9 This example is basically the same as Example 1, except that a 60% acrylated phenol novolak type epoxy resin (manufactured by Yuka Shell Co.) was used as an adhesive solution. Of a bifunctional acrylic resin (manufactured by Yuka Shell) and 5 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals) were dissolved in butyl cellosolve acetate. 15 parts by weight of melamine resin particles having a particle size of 0.5 μm and 30 parts by weight of those having a particle size of 5.5 μm
The mixture was mixed with this roll, and butyl cellosolve acetate was further added to adjust the solid content to 75%.

Example 10 This example is basically the same as Example 1, except that 60 parts by weight of an acrylic resin (manufactured by Yuka Shell) and a bisphenol A type epoxy resin ( Oiled shell)
40 parts by weight and imidazole-based curing agent (Shikoku Chemicals) 5
Parts by weight were dissolved in butyl cellosolve acetate, and 15 parts by weight of melamine resin particles having a particle size of 0.5 μm and 15 parts by weight of
The mixture was mixed with three rolls at a ratio of 30 parts by weight, and butylcellosolve acetate was further added to adjust the solid content to 75%.

Example 11 This example is basically the same as Example 1, except that 60 parts by weight of an acrylic resin (manufactured by Yuka Shell) was used as the adhesive solution. 40 parts by weight (manufactured by Yuka Shell) and 5 parts by weight of an imidazole-based curing agent (manufactured by Shikoku Chemicals) were dissolved in butyl cellosolve acetate, and melamine resin particles having a particle size of 0.5 were added to 100 parts by weight of the solid content of this composition.
A mixture having a particle size of 15 μm and a mixture having a particle size of 5.5 μm at a ratio of 30 parts by weight were mixed with a three-roll mill, and butylcellosolve acetate was added to obtain a solid concentration of 75%.

Example 12 This example is basically the same as Example 1, except that 100 parts by weight of an acrylic resin (made by Yuka Shell) and an imidazole-based curing agent (Shikoku) were used as the adhesive solution. 5 parts by weight of a chemical compound) was dissolved in butyl cellosolve acetate, and the melamine resin particles had a particle size of 100 parts by weight of the solid content of the composition.
A mixture having a solid content of 75% was prepared by mixing 15 parts by weight of 0.5 μm and 30 parts by weight of a particle having a particle size of 5.5 μm with three rolls, and further adding butyl cellosolve acetate. .

Example 13 (1) Urea, isothiourea and formalin were mixed in a ratio of 1: 1: 2
The mixture was heated at 80 ° C. and co-condensed to obtain urea-thiourea co-condensed resin particles. (2) This embodiment is basically the same as the fourth embodiment,
The urea-thiourea co-condensation resin particles obtained in the above (1) were used as the amino resin particles. Also, 100 parts by weight of a phenol novolak type epoxy resin was used, and no bisphenol A type epoxy resin was used. The viscosity of the adhesive solution in this example was measured at 20 ° C. for 60 seconds using a digital viscometer manufactured by Tokyo Keiki according to JIS-K7117, and it was 0.05 Pa · s at 6 rpm.

Comparative Example (1) A multilayer printed wiring board was manufactured in the same manner as in Example 1 except that an epoxy resin cured with a dicyanic curing agent was used as heat-resistant resin particles.

The adhesion (peel strength), electrical characteristics (electrical insulation), hardness (Barcol hardness), and migration resistance (influence of impurities) of the electroless plated film of the multilayer printed wiring board manufactured as described above. Rate of amino resin particles in water and acid and oxidizing agent (dissolution rate of amino resin)
Was evaluated, and the results shown in Table 1 were obtained.

As is apparent from the results shown in Table 1,
In the case of the present invention, not only high adhesion strength of conductors can be obtained, but also insulation reliability between conductors is excellent, which is particularly advantageous for manufacturing a high-density printed wiring board. In addition, since it has a high surface hardness, it has excellent wire bonding properties, and can be advantageously used as a bare chip mounting substrate.

[0067]

[Table 1]

Next, the multilayer printed wiring board of the present invention was
As a result of examining the change in the surface resistance of the adhesive layer by immersing it in boiling water at 2 ° C. for 2 hours, no change occurred as compared with the initial value. Further, in the example of the present invention, the surface of the wiring board is brought into close contact with a hot plate whose surface temperature is maintained at 300 ° C.
No abnormalities were observed after a heat resistance test of heating for 1 minute.

Each test method for the adhesion strength (peel strength) of the electroless plating film, the electrical insulation, the hardness, and the influence of impurities (migration resistance) will be described. (1) Adhesion strength (peel strength) of electroless plating film JIS-C-6481 (2) Electrical insulation L / S = 100/100 μ formed on printed wiring board
A DC voltage or a sine-wave AC peak voltage at a frequency of 50 Hz or 60 Hz is applied to the comb pattern of m, and 500 V is applied. The voltage is gradually increased to the specified voltage in about 5 seconds, charged for 1 minute, and checked for abnormalities such as mechanical damage, flashover, and dielectric breakdown (when a current of 0.5 mA or more is applied). (3) Hardness (Barcol hardness) Device: Type A Indicated value of aluminum alloy reference piece 85-87 (hard), 43-48
(Soft) Model: GYZJ934-1 Adjustment: Using a glass plate, adjust so as to have an indicated value of 100 ± 1, then use an aluminum alloy reference piece to adjust so as to be the indicated value of the reference piece. Operation: Press the indenter of the hardness tester so as to be perpendicular to the sample surface, and read the indicated value of the maximum value. The measurement position should be a smooth surface at least 3 mm inside from the sample end.
When measuring with the same sample, it must be at least 3 mm away from the pit defined by the regulations. Measurement: The substrate is heated to 150 ° C., kept for 5 minutes, and the hardness is measured. (4) Influence of impurities (migration resistance) Specimen: Printed wiring board with L / S = 50/50 μm comb-shaped Measurement: Temperature and humidity of 85 ± 1 ° C, 85-90% relative humidity And leave it with a bias of 30V. After 1000 hours, check for migration between patterns.

[0070]

As described above, according to the present invention,
By using melamine resin and / or urea resin as heat-resistant resin particles, sufficient adhesion strength of conductor can be obtained without being affected by use environment, and chemical resistance, heat resistance, electrical properties and hardness And a stable multilayer printed wiring board can be provided.

[Brief description of the drawings]

FIG. 1 is a process chart showing one embodiment of the present invention.

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

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

FIG. 4 is a process chart showing another embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a migration reaction of a printed wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (wiring board) 2 Adhesive layer (insulating layer) 3 Plating resist 4, 6, 8, 10 Wiring layer (plating layer, conductor layer) 5 Through hole hole 7 Via hole opening 11 Prepreg 12 Polyethylene film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 3/46 H05K 3/38 H05K 3/18

Claims (2)

(57) [Claims] 1. A multilayer printed wiring board in which a conductor circuit formed by a plurality of layers obtained by electroless plating is electrically insulated by a resin insulation layer made of a heat-resistant resin. In the uncured resin matrix that becomes hardly soluble in acids or oxidizing agents when exposed to
Lamin resin particles and / or urea resin particles are blended and formed of an adhesive dispersed therein, and the melamine resin particles and / or urine on the electroless plating film forming surface of the resin insulating layer.
A multilayer printed wiring board, characterized in that base resin particles are treated with an acid or an oxidizing agent and dissolved and removed to form anchor forming recesses. 2. A method for manufacturing a multilayer printed wiring board having a plurality of conductive circuits formed of an electroless plating film electrically insulated by a resin insulating layer made of a heat-resistant resin, comprising at least the following steps (a) to (c): Steps: (a) melamine resin particles and / or urea resin are added to an uncured resin matrix which becomes hardly soluble in an acid or an oxidizing agent when subjected to a curing treatment on a substrate on which a conductive circuit is formed;
By blending a fat particles, a step of forming a resin insulating layer according to one or more layers of adhesive are dispersed, camera that are scattered on the surface portion of the (b) each of the resin insulating layer
A step of dissolving and removing only the min resin particles and / or urea resin particles using an acid or an oxidizing agent to roughen the surface on which the electroless plating film is formed; (c) the roughened resin insulation Forming a conductive circuit by applying electroless plating on the layer. A method for manufacturing a multilayer printed wiring board, the method comprising: