JP3007648B2 - Method for manufacturing adhesive printed wiring board for electroless plating and printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an anchor effect (adhesion of an electroless plating film).
Excellent adhesive and a method of manufacturing a high-precision printed wiring board using this adhesive, especially the heat resistance, electrical insulation, chemical stability is good, especially the sharpness of the anchor shape plating film The present invention relates to a method for producing a printed wiring board using the adhesive, and a method and a printed wiring board for advantageously producing a high-precision printed wiring board using the adhesive.

[Conventional technology]

2. Description of the Related Art In recent years, progress in electronics has been remarkable, and with this, electronic devices need to be further reduced in size or speed. For this reason, printed wiring boards, especially ICs and
For printed wiring boards equipped with parts such as LSI,
High density and high reliability by fine patterns are required.

Conventionally, as a technique for forming a conductor circuit (pattern) on a printed wiring board, a method called an etched foil method of forming a thin copper layer on a substrate and then performing photoetching is typical. This method has the characteristic that a conductor pattern with excellent adhesion to the substrate can be formed, but on the other hand, it has a major disadvantage that it is difficult to obtain a high-precision fine pattern by etching due to the thick copper foil. In addition, there are problems that the manufacturing process is complicated and the efficiency is not good.

Therefore, recently, in order to form a conductive circuit on a wiring board, an adhesive containing a diene-based synthetic rubber is applied to the substrate surface to form an adhesive layer, and after the surface of the adhesive layer is roughened, The additive method of forming a conductive circuit pattern by performing electrolytic plating has been spotlighted.

However, since the adhesive used under this known method contains a synthetic rubber in the composition, for example, the adhesive strength is greatly reduced at a high temperature, and the electroless plating film is swollen at the time of soldering. was there. In addition, the heat resistance is low, and the electrical characteristics such as surface resistance are not sufficient.

As a “resin composition for printed wiring boards” used to form a conductor pattern by such electroless plating,
The one disclosed in Japanese Patent Application Laid-Open No. 53-140344 has been proposed. However, this composition is insoluble in a so-called oxidizing agent in which the thermosetting resin component forming the spherical particles in the composition has not been etched (treated with an oxidizing agent). Since the adhesive layer on the substrate obtained by etching and roughening the resin composition is uneven at a depth of about 20 μm, it is difficult to obtain a conductor formed on the adhesive layer with a fine pattern. The insulation between the patterns tends to be poor, and the heat resistance and the electrical characteristics are poor. Therefore, there is a disadvantage that it is not preferable for mounting components and the like.

[Problems to be solved by the invention]

The present inventors have conducted various studies in order to solve such a problem. As a result, the inventors have found that the heat resistance, the electrical insulation, and the chemical stability are good, and the adhesion between the substrate and the electroless plating film is particularly high. Invented an adhesive for electroless plating which is excellent and easy to handle at the time of plating, and a method for manufacturing a printed wiring board using such an adhesive, is disclosed in JP-A-61-276875 and JP-A-1-2756.
No. 82, JP-A-1-301774, JP-A-2-8281 and JP-A-2-8283.

However, prior to the present invention, the adhesives of the present invention proposed before the present invention and the methods for manufacturing printed wiring boards using these adhesives are disclosed in US Pat. And an adhesive dispersed in an uncured matrix-forming heat-resistant resin having a property of being hardly soluble in an oxidizing agent by curing, and applying the adhesive on a substrate and drying. Forming an adhesive layer by curing, roughening the surface of the adhesive layer by dissolving and removing at least a part of the fine powder scattered on the surface of the adhesive layer, and then performing electroless plating. Method.

Therefore, in these methods, it is necessary to use an oxidizing agent such as chromic acid to dissolve and remove a part of the heat-resistant fine powder to roughen the surface of the adhesive layer.

However, regarding the use of oxidizing agents such as chromic acid,
High costs and oxidizing agents such as chromic acid are harmful substances.
Various problems have been left in terms of manufacturing, for example, handling is difficult and special equipment and attention are required for the working environment. Furthermore, since this oxidizing agent has a tendency to slightly dissolve the heat-resistant resin forming the matrix, there is also a problem that the shape of the formed anchor loses sharpness. There were inconveniences such as the use of particles to complicate the anchor shape.

An object of the present invention is to solve the above-described various problems of the prior art and to have excellent heat resistance and electrical characteristics, as well as a particularly excellent anchor shape due to a good anchor shape, and easy implementation. It is an object of the present invention to propose an adhesive for electroless plating, a high-precision printed wiring board using this adhesive, and a method for easily manufacturing the same.

[Means for solving the problem]

The present invention aims at improvement of the invention proposed by the present inventors earlier, is lower in cost and does not cause a problem of pollution, work environment, etc., and the anchor shape is always good in plating adhesion. As a result of intensive research to develop an adhesive devised to have an appropriate shape to be obtained, it was found that sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, and at least one acid selected from among formic acid. On the other hand, it has been found that the use of a soluble heat-resistant resin powder can solve all of the above problems.

That is, the present invention provides an epoxy resin powder which is soluble in at least one kind of acid selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid and formic acid and which has been cured beforehand by curing. An adhesive is proposed which is dispersed in an uncured matrix-forming heat-resistant resin having a property of being hardly soluble or insoluble in an acid.

Then, using such an adhesive, the adhesive is first applied to a substrate, and then dried and cured to form an adhesive layer. Then, the surface of the adhesive layer is polished, By exposing at least a part of the epoxy resin powder scattered on the surface part of the adhesive layer to the surface of the adhesive layer, and in this state, part of the resin powder, sulfuric acid, hydrochloric acid, nitric acid, Roughening the surface of the adhesive layer by dissolving and removing it with at least one acid selected from phosphoric acid, acetic acid and formic acid, and subjecting the surface of the roughened adhesive layer to electroless plating Thus, a desired printed wiring board and a method for manufacturing the same have been developed by forming a required conductor pattern.

(Operation)

The adhesive for electroless plating according to the present invention is a precured epoxy resin powder which is soluble in at least one acid selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid and formic acid. Are dispersed in an uncured matrix-forming heat-resistant resin having a property of being hardly soluble or insoluble in the acid by curing treatment.

Here, "soluble in acid" means a property that the resin is decomposed and dissolved by the acid.

The reason for using such an adhesive during electroless plating of a printed wiring board is that when forming an electroless plating film on a substrate, the adhesion strength of a plated conductor is increased, and as a result, a conductor pattern having high reliability is used. Because it is obtained.
In other words, epoxy resin powder that has been previously cured, dispersed in a matrix-forming heat-resistant resin liquid,
Heat-resistant resin that forms a matrix when applied on a substrate, dried and cured (heat-resistant resin for matrix formation)
An adhesive layer in which epoxy resin powder is uniformly scattered is formed. On the other hand, since the epoxy resin powder and the matrix-forming heat-resistant resin are caused to have an extreme difference in solubility in acid, when the adhesive layer is treated with acid, the surface of the adhesive layer Of the powder dispersed in the part, only those that are soluble in acid are dissolved and removed.

As a result, sharp anchors (dents) are formed on the surface of the adhesive layer, and the roughened surface of the adhesive layer becomes sharp.

In the case of manufacturing a printed wiring board having via holes as in Example 6, after forming an opening for a via hole, a roughening treatment is performed. Therefore, the lower conductive circuit is exposed at the opening (see FIG. 6). If the roughening treatment is performed with an oxidizing agent, the exposed conductor circuit is also treated with the oxidizing agent, so that an oxide film is formed on the surface of the conductor circuit, which causes a conduction failure.

In the present invention, since the acid treatment is performed, the conduction reliability can be secured without forming an oxide film on the surface.

The epoxy resin powder used in the present invention has been subjected to a curing treatment in advance. If this epoxy resin powder is not subjected to oxidation treatment, it will be dissolved in the heat-resistant resin liquid for matrix formation or when the resin is added to a liquid obtained by dissolving the resin using a solvent. Therefore, when an adhesive containing such an uncured resin powder is applied to a substrate and dried and cured, the adhesive layer becomes a state in which the matrix-forming heat-resistant resin and the epoxy resin powder for dispersion are eutectic. As a result, during the above-described acid treatment, the adhesive layer is almost uniformly dissolved, and the surface of the adhesive layer required for roughening cannot be selectively dissolved and removed. In other words, it prevents formation of an anchor for ensuring plating adhesion.

On the other hand, the epoxy resin powder used in the present invention is hardly soluble or insoluble in a heat-resistant resin liquid or a solvent that dissolves this resin because the epoxy resin powder has been cured beforehand. It is in a state of being uniformly dispersed in the matrix heat-resistant resin liquid dissolved as it is. Therefore, if such an adhesive layer is treated with an acid,
Only the soluble and uniformly dispersed resin powder is dissolved, and a clear, uniform and sharp anchor can be formed as described above.

As the epoxy resin powder used in the present invention,
Agglomerated particles obtained by aggregating epoxy resin powder having an average particle diameter of 2 μm or less to have an average particle diameter of 2 to 10 μm; epoxy resin powder having an average particle diameter of 2 to 10 μm and epoxy resin powder having an average particle diameter of 2 μm or less; A mixture of 2 μm on the surface of an epoxy resin powder having an average particle size of 2 to 10 μm
Pseudo particles obtained by adhering at least one of the following epoxy resin fine powder or inorganic fine powder having an average particle diameter of 2 μm or less;
Seeds can be used. The use of such an epoxy resin powder is preferable because the sharpened anchor shape can be further complicated by using an acid instead of an oxidizing agent. In particular, it is more preferable to use the above mixture as an epoxy resin powder.

Here, among the epoxy resin powders, the reason why the size of the epoxy resin powder in the pseudo particles, the aggregated particles and the mixture is 2 to 10 μm in average particle size is more than 10 μm in average particle size. This is because if it is large, the anchor formed by dissolution and removal during the oxidation treatment is small and tends to be unevenly distributed. In such a case, the adhesion strength of the plating film is deteriorated, the reliability of the product is reduced, and the unevenness of the surface of the adhesive layer becomes more intense than necessary, and it becomes difficult to obtain a fine pattern of the conductor, and Inconvenience is likely to occur when mounting components and the like. On the other hand, when the average particle size is 2
This is because if it is smaller than μm, the anchor tends to be unclear. More preferably, those having a size of 3 to 8 μm are suitable.

On the other hand, the reason why it is necessary to set the average particle size of the epoxy resin powder in the mixture to 2 μm or less in the size of the attached powder of the pseudo particles, the epoxy resin powder constituting the aggregated particles, and the epoxy resin powder in the mixture is more than 2 μm. Is too large, the anchor effect decreases, and the adhesion strength of the plating film deteriorates. More preferably, the size is 0.8 μm or less.

Further, the particle diameter of the pseudo particles and the aggregated particles is desirably about twice or more the size of the powder adhered to the base particles of the pseudo particles and each epoxy resin powder constituting the aggregated particles.

The mixture of the epoxy resin powder having an average particle diameter of 2 to 10 μm and the epoxy resin powder having an average particle diameter of 2 μm or less is required to make the shape of the formed anchor extremely complicated. Powder content 50-85
% By weight.

Such an epoxy resin powder is a resin having excellent heat resistance and electrical insulation properties and showing stable properties with respect to chemicals other than acids. It is necessary to use a resin which is hardly soluble in a matrix-forming heat-resistant resin solution or a solvent by being cured in advance, but is soluble in an acid. For example, as the epoxy resin, a bifunctional bisphenol-based epoxy resin such as a bisphenol A epoxy resin or a bisphenol F epoxy resin is preferable. Because they are linearly bonded, they are easily decomposed by acids, and among them, polyphenol-based curing agents, polyamine-based curing agents, carboxylic acid hydrazides, diaminomaleonitrile, dicyandiamide, imidazole polyamine nylon salts Epoxy resins cured or cross-linked with a curing agent such as a phosphate, Lewis acid, and an amine complex thereof or a cross-linking agent are also excellent in characteristics and are suitable.

As the inorganic powder, for example, calcium carbonate can be used.

Further, the agglomerated particles and the pseudo particles need to be bonded to each other with an adhesive force that does not dissociate and return to the primary particles during mixing.

The pseudo particle may be one in which the fine powder to be attached is simply attached to the surface of the mother particle using a binder,
When the base particles are still in a somewhat soft state with respect to the cured epoxy resin powder (base particles) which are soluble in an acid, various kinds of the powders are sprinkled and adhered, so that the surface of the base particles slightly increases. It may be cured in the state of being entrapped, and in the case of agglomerated particles, the resin fine powder itself is heated and fused or adhered via a binder, and bonded with an adhesive force like a single particle All of them may be equally excellent in the anchor forming effect.

As such an epoxy resin fine powder, for example, a material obtained by hardening an epoxy resin and then finely pulverizing the epoxy resin with a jet mill, a freeze pulverizer, or the like is used. In addition, primary particles obtained by spraying an epoxy resin solution before curing treatment and then drying, or adding a water-soluble curing agent to an uncured epoxy resin emulsion and stirring are dried and heated by a hot air dryer or the like. It can also be prepared by pulverizing a dried product, or a product obtained by adding and mixing various binders, drying the product using a ball mill, an ultrasonic disperser, or the like, and further classifying the product using an air classifier or the like.

The shape of the epoxy resin powder obtained in this way is
Since it has various complicated shapes as well as spherical shapes, the shape of the anchor formed by this becomes more complicated,
High adhesion strength, such as high peel strength and pull strength.

Further, the epoxy resin powder (pseudo particle) according to the present invention
It is preferable that the particles have a variation such that 60% by weight or more exists within a range of ± 2 μm based on the center particle size. The reason for limiting to such a variation is that if the variation is larger than the above range, the reliability of the product is reduced.

The surface of the epoxy resin powder (base particles and adhered powder) is coated on the surface of the epoxy resin powder so as not to dissolve in the matrix in order to improve the bonding with the matrix-forming heat-resistant resin.
A semi-cured layer or an unreacted functional group may be provided in advance.

Next, the heat-resistant resin for matrix formation on the side where the epoxy resin powder and the same kind of powder are dispersed and held will be described. This resin must be excellent in heat resistance, electrical insulation, chemical stability and adhesiveness, and must have a property of being hardly soluble or insoluble in an acid when cured. For example, at least one selected from an epoxy resin, an epoxy-modified polyimide resin, a polyimide resin, and a phenol resin
Use seeds. A resin obtained by imparting photosensitivity to these resins is suitable as an adhesive for an interlayer insulating material of a build-up wiring board.

As described above, the epoxy resin powder and the matrix-forming heat-resistant resin after the curing treatment have a large difference in the dissolution characteristics in acid. Therefore, when the adhesive layer is treated with an acid, the epoxy resin powder dispersed on the surface portion of the layer is dissolved and removed, while the heat-resistant resin for forming a matrix that is hardly soluble or insoluble in the acid is used. In the case of the resin powder, the resin powder hardly dissolves and remains as a base material, and the portion of the resin powder dissolved and removed becomes a depression to form an anchor. Incidentally, even with the same kind of heat-resistant resin, for example, an epoxy resin that is easily soluble in acid is used as the epoxy resin powder, and an epoxy resin that is relatively insoluble in acid is used in combination as the matrix heat-resistant resin. Thus, the same anchor forming effect can be obtained.

As the heat-resistant resin liquid for dispersing the fine powder, a heat-resistant resin liquid containing no solvent can be used as it is, but a heat-resistant resin liquid obtained by dissolving a heat-resistant resin in a solvent has a low viscosity. Therefore, the powder can be advantageously used because it is easy to uniformly disperse the powder and easily applied to the substrate.

Examples of the solvent used for dissolving the heat-resistant resin include ordinary solvents such as methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, butyl carbitol,
Butylcellulose, tetralin dimethylformamide,
Normal methylpyrrolidone and the like can be used.

The heat-resistant resin liquid serving as a matrix may appropriately contain a filler composed of an inorganic fine powder such as silica, alumina, titanium oxide, and zirconia.

The amount of the epoxy resin powder to be mixed with the matrix-forming heat-resistant resin is preferably in the range of 2 to 350 parts by weight based on 100 parts by weight of the matrix-forming heat-resistant resin solids. The reason is that if the amount of the epoxy resin fine powder is less than 2 parts by weight, the density of the anchor formed by dissolution and removal becomes low, and sufficient adhesion strength between the substrate and the electroless plating film cannot be obtained. If it exceeds 350 parts by weight, the surface of the adhesive layer will be almost dissolved,
This is because the formation of the anchor is substantially inhibited.

In particular, the amount of the epoxy resin powder to be mixed with the heat-resistant resin for forming a matrix is preferably in the range of 5 to 200 parts by weight based on 100 parts by weight of the solid content of the matrix heat-resistant resin. This is because if the amount is within this range, the adhesion strength between the substrate and the electroless plating film can be increased.

Next, a method for manufacturing a printed wiring board using the above adhesive will be described.

(A) First, an adhesive in which the epoxy resin powder is dispersed in a heat-resistant resin liquid serving as a matrix is applied to a substrate, followed by drying and curing to form an adhesive layer. As a method of this application, for example, 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 are used.

In the treatment in this step, the thickness of the adhesive layer obtained on the substrate by applying and drying and curing the adhesive is usually 2 to 2.
It is about 40 μm. However, when this adhesive layer is used also as an interlayer insulating film of a metal substrate or a multilayer wiring board, it is effective to apply a thicker adhesive layer.

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

It is desirable that the surface of these substrates is roughened in advance. Thereby, the adhesion strength between the substrate and the adhesive layer is increased. Further, it is desirable that these substrates be sufficiently dried before applying the adhesive. The reason for this is that if the dry moisture is insufficient, the residual moisture inhibits the curing of the resin.

In the present invention, using these substrates, a single-sided wiring board,
A double-sided through-hole wiring board, for example, a multilayer printed wiring board such as a Cu / polyimide multilayer printed wiring board can be manufactured. Alternatively, the adhesive itself may be formed into a plate shape or a film shape, or by impregnating an adhesive solution into a glass woven fabric to form a prepreg,
A substrate having an adhesive property that can be subjected to electroless plating can also be used.

Note that a catalyst (core) for electroless plating may be mixed in advance with the adhesive. When such an adhesive is used, the step of providing a catalyst (core) can be omitted.

(B) Next, by polishing the surface of the adhesive layer formed as described above, the epoxy resin powder dispersed on the surface portion is exposed on the surface of the adhesive layer.

In this step, since the heat-resistant resin for forming a matrix is hardly soluble or insoluble in an acid, if the epoxy resin powder is covered with the resin, the epoxy resin powder is dissolved and removed with an acid. Is difficult. That is, by exposing the epoxy resin powder in this step in advance, it can be easily and efficiently dissolved and removed,
Moreover, since the dissolution is carried out using an acid, the heat-resistant resin for forming the matrix does not dissolve, so that the shape of the anchor becomes sharp.

As a method for polishing the adhesive layer, a known method such as polishing with various fine abrasives or liquid honing is used.

(C) Next, at least a part of the epoxy resin powder exposed on the surface is dissolved and removed using an acid.

In the treatment with an acid, for example, at least one selected from inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid and organic acids such as acetic acid and formic acid is used, and the inorganic acid is particularly effective. .

If the concentration of the acid is less than 1%, it takes a long time to perform the treatment. When the temperature of the acid exceeds 70 ° C., a part of the matrix resin starts to be dissolved.

As a method for dissolving and removing the resin particles by the acid, the acid solution is used, and the substrate having the adhesive layer is immersed in the solution, or the solution is sprayed on the substrate. This treatment does not require the use of harmful substances such as chromic acid, so there is no disposal time for the treatment waste liquid, and the surface of the substrate, that is, the surface of the adhesive layer, is roughened without using chromic acid, which is difficult to treat. It can be said that it is more effective than the conventional technology.

(D) Next, electroless plating is performed on the substrate having the surface of the adhesive layer roughened. Examples of the electroless plating include electroless copper plating, electroless nickel plating, electroless tin plating, electroless gold plating, and electroless silver plating. In particular, at least one of electroless copper plating, electroless nickel plating, and electroless gold plating is preferable. Note that, after the electroless plating is performed, different types of electroless plating or electroplating may be performed, or solder may be coated.

The printed wiring board obtained by carrying out the method of the present invention can form a conductor circuit by other known methods, for example, a method of etching a circuit after applying electroless plating to a substrate, or a method of electroless plating. At the time of application, a method of directly forming a circuit or the like can be applied.

When a conductor circuit is formed by a full additive method using the adhesive for electroless plating of the present invention, a plating resist is formed, but the thickness of the plating resist may be larger than the thickness of the electroless plating conductor layer. desirable.

The reason is explained as follows. Various electronic components are mounted on the surface of the printed wiring board. Solder is coated on a mounting portion of the printed wiring board, and at the time of mounting, the solder is melted by thermocompression to connect the terminals. At this time, in the conventional printed wiring board, a phenomenon that the solder on the surface of the adjacent conductor layer melts and flows, and a bridge is often formed to short-circuit between the wirings, which is a cause of lowering the yield. I have. However, by making the thickness of the plating resist larger than the thickness of the electroless plating conductor layer, such a solder bridge can be prevented and the yield can be improved.

Further, the printed wiring board obtained by using the adhesive for electroless plating of the present invention, the heat-resistant resin powder which has been cured in advance and is soluble in acid for the substrate is hardly soluble in acid or An adhesive layer dispersed in a cured heat-resistant resin having the property of being insoluble is formed, and at least a portion of the heat-resistant resin powder exposed on the surface portion of the sap layer is dissolved and removed with an acid. Then, the surface of the adhesive layer is roughened, and the roughened surface is subjected to electroless plating to form a conductor layer.

Since a sharp anchor is formed on the surface and the roughened surface is sharp, a high peel strength is obtained as shown in Examples 1 to 8. Further, the printed wiring board of the present invention may be multilayered, and among them, a build-up multilayer printed wiring board is preferable.

The build-up multilayer printed wiring board has the following steps, namely, forming an adhesive layer for electroless plating on a conductor layer and forming a via hole before or after roughening the layer with an acid. , Applying a catalyst (nucleus), performing electroless plating, and forming a conductor layer.

In the present invention, since the acid treatment is performed as the roughening treatment, the exposed conductor is not oxidized even if the roughening treatment is performed after forming the holes for forming the via holes.
This is because the conduction reliability of the via hole is superior to the case where the surface is roughened with an oxidizing agent.

It is desirable that the matrix-forming heat-resistant resin of the adhesive for electroless plating used when manufacturing the build-up multilayer printed wiring board has photosensitivity. This is because when a photosensitive resin is used for the matrix, holes for via holes can be formed with high precision by performing exposure and development processing. In addition, the build-up multilayer printed wiring board includes a form in which only a mounting pad for mounting an electronic component is formed on the surface layer, not a conductive circuit, and the pad is connected to an inner layer circuit by a via hole. It is. In such a multilayer wiring board, since only mounting pads are formed on the surface layer, the density of mounting pads increases compared to a case where mounting pads and conductive circuits coexist as in a conventional printed wiring board. Thus, high-density mounting of electronic components becomes possible.

 Examples will be described below.

Example 1 (1) Epoxy resin particles soluble in acid (average particle size of 3.9 μm)
200 g of m) are dispersed in 5 of acetone to form a suspension of epoxy resin particles, in which a suspension of epoxy resin particles as follows: A suspension prepared by dispersing 300 g of acid-soluble epoxy resin fine powder (average particle size: 0.5 μm) in an acetone solution in which 30 g of an epoxy resin is dissolved, is stirred using a Henschel mixer. After the epoxy resin fine powder was adhered to the surface of the epoxy resin particles by dropping, the acetone was removed, and then heated to 150 ° C. to produce pseudo particles.
The pseudo particles had an average particle size of 4.3 μm, and about 75% by weight was in a range of ± 2 μm around the average particle size.

(2) Butyl carbitol was added to a mixture of 50 parts by weight of the pseudo particles prepared in (1) above, 60 parts by weight of a phenol novolak type epoxy resin, 40 parts by weight of a bisphenol A type epoxy resin, and 4 parts by weight of an imidazole curing agent. Viscosity
The mixture was adjusted with a homodisper disperser to 120 cp to prepare an adhesive solution.

(3) Butyl carbitol was added to 50 parts by weight of the pseudo particles prepared in (1) above, 60 parts by weight of phenol novolak type epoxy resin, 40 parts by weight of bisphenol A type epoxy resin, and 4 parts by weight of imidazole curing agent, Viscosity
The mixture was adjusted to 120 cp with a homodisper disperser to obtain an adhesive solution.

(4) After the adhesive solution obtained in the above (3) is applied to the glass polyimide substrate 1, the adhesive is applied at 100 ° C. for 1 hour, and then at 150 ° C.
For 5 hours to form an adhesive layer 2 having a thickness of 20 μm.

(5) The surface of the adhesive layer 2 was polished with a rotating brush polisher using # 1000 alumina fine powder.

(6) The substrate obtained in (5) was immersed in a 50% aqueous sulfuric acid solution at room temperature for 20 minutes to roughen the surface of the adhesive layer, and then washed with water.

(7) The surface of the roughened adhesive layer 3 which was roughened by applying a palladium catalyst to the substrate 1 on which the roughened surface 4a of the adhesive layer 2 obtained in the above (6) was formed was activated.

(8) A photosensitive dry film was laminated on the substrate 1 and exposed to ultraviolet light through a mask film on which a desired conductive circuit pattern was drawn, to print an image. Subsequently, the resist was developed with chlorocene to form a resist 5 for electroless plating.

(9) The substrate 1 after the treatment (8) is immersed in an electroless copper plating solution for an additive method having a composition shown in Table 1,
An electroless plating having a plating film thickness of 20 μm was applied to form a conductor layer (pattern) 6, and a printed wiring board as shown in FIG. 1 (e) was manufactured.

Example 2 (1) Epoxy resin particles soluble in acid (average particle size 0.5 μm)
m) was placed in a hot-air dryer, and heat-treated at 180 ° C. for 3 hours to cause cohesion and bonding. The cohesively bonded epoxy 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 have an average particle size of about 3.5 μm,
About 68% by weight was in the range of ± 2 μm around the average particle size.

(2) Add butyl carbitol to 50 parts by weight of the pseudo particles prepared in (1) above, 60 parts by weight of phenol novolak type epoxy resin, 40 parts by weight of bisphenol A type resin, and 4 parts by weight of imidazole curing agent, and adhere. Solution.

(3) After the surface of the glass epoxy substrate 1 is roughened by wet polishing, it is dried by heating at 80 ° C. for 3 hours to remove moisture that inhibits curing, and then the adhesive solution prepared in the above (2) is removed. Apply with roll coater, 100 ℃ for 1 hour, 150 ℃
For 5 hours to form an adhesive layer 2 having a thickness of 20 μm.

(4) The surface of the adhesive layer 2 was polished with a rotary brush polisher using # 1000 alumina fine powder.

(5) The substrate 1 obtained in the above (4) was immersed in a 6N hydrochloric acid aqueous solution at room temperature for 20 minutes to roughen the surface of the adhesive layer 2 to form a roughened surface 3 and then washed with water.

(6) The substrate 1 having the roughened surface 4b of the adhesive layer 2 obtained in the above (5) was activated by applying a palladium catalyst to the surface of the adhesive layer.

(7) A photosensitive dry film was laminated on the substrate 1 and exposed to ultraviolet light through a mask film on which a desired conductive circuit pattern was drawn, to print an image. Subsequently, development was performed with chlorocene to form a resist 5 for electroless plating having a thickness of 40 μm.

(8) The substrate 1 after the treatment of the above (7) is immersed in an electroless copper plating solution for an additive method having a composition shown in Table 1,
Then, using the electrolytic plating solution shown in Table 2, electrolytic plating was performed with a plating film having a thickness of 30 μm to form a conductor layer (pattern) 6.
Was formed.

(9) Next, a 5 μm-thick solder plating was further performed on the conductor layer 6 to obtain a printed wiring board as shown in FIG. 2 (e).

Example 3 (1) A glass epoxy substrate 1 in which inner conductor layers 6 were formed on both sides according to a conventional method was prepared.

(2) 60 parts by weight of a phenol novolak type epoxy resin,
40 parts by weight of bisphenol A type epoxy resin, 4 parts by weight of imidazole curing agent, acid-soluble epoxy resin powder as coarse particles and fine powder for forming an anchor, having an average particle size of 3.9
Butyl carbitol was added to 10 parts by weight of μm and 25 parts by weight of 0.5 μm in average particle size to prepare an adhesive solution.

(3) By the same method as (4) and (5) in Example 1,
After forming the adhesive layer 2, the adhesive layer was roughened with a phosphoric acid aqueous solution to form a roughened surface 4c.

(4) A through hole 16a for forming the through hole 16 was formed by a drill.

(5) A palladium catalyst was applied to the substrate 1 to activate the roughened surface 3 of the adhesive layer.

(6) The thickness of 30 μm was obtained by the method of (8) or (9) of Example 1.
m, a 25 μm-thick electroless plating is performed to form the second plating conductor layer 9,
A multilayer printed wiring board as shown in FIG. 3 (e) was manufactured.

Example 4 (1) The adhesive solution obtained in the same manner as in Example 1 was added so as to contain 1% by weight of a thixotropic agent and 0.5% by weight of a leveling agent, respectively, to prepare an impregnating solution.

(2) A coupling agent (PhSi (OEt)
_The glass woven fabric 8 coated with ₃ ) was dipped. Next, this was dried at 150 ° C. for 70 minutes to prepare a prepreg.

(3) The prepreg is superposed on the double-sided wiring board of the substrate 1 on which the inner conductor layer 6 has already been formed, two by two on each side,
The adhesive layer 2 was formed by pressing at 0 ° C. and 40 kg / cm ² for 200 minutes.

(4) The adhesive layer 2 is roughened with an aqueous phosphoric acid solution to roughen the surface 4a.
I got

(5) A through hole for forming the through hole 16 was formed by a drill.

(6) The roughened surface 3 of the adhesive layer was activated by applying a palladium catalyst to the substrate 1.

(7) According to the method of (8), (9) of Example 1, the thickness is 30 μm.
After the formation of the plating resist 5 of m, the second plating conductor layer 9 was formed by performing electroless plating with a thickness of 25 μm, thereby producing a multilayer printed wiring board as shown in FIG.

Example 5 (1) An adhesive solution was prepared in the same manner as in Example 3.

(2) The adhesive was applied to one side of the polyethylene film 14 and then dried at 100 ° C. for 1 hour to make the adhesive film 14 in a semi-cured state.

(3) After the surface of the glass epoxy substrate 1 is roughened by wet polishing, it is heated and dried at 80 ° C. for 3 hours to remove moisture that inhibits curing, and then the adhesive film 14 obtained in the above (2) is removed.
Were laminated and pressurized at 150 ° C. and 40 kg / cm ² for 200 minutes to form an adhesive layer 2.

(4) After peeling off the polyester film 14, the surface of the adhesive layer 4 was polished with a rotary brush polisher using # 1000 alumina fine powder.

(5) The substrate obtained in the above (4) was immersed in a 6N hydrochloric acid aqueous solution at room temperature for 20 minutes to roughen the surface of the adhesive 3, and then washed with water.

(6) By applying a palladium catalyst to the substrate 1 having the roughened surface 4c of the adhesive layer 2 obtained in the above (5),
The roughened surface 3 of the adhesive layer was activated.

(7) A photosensitive dry film was laminated on the substrate 1 and exposed to ultraviolet light through a mask film on which a desired conductive circuit pattern was drawn, to print an image. Subsequently, development was performed with chlorocene to form a resist 5 for electroless plating having a thickness of 40 μm.

(8) It was immersed in an electroless copper plating solution for an additive method having a composition shown in Table 1 and subjected to electroless plating with a plating film thickness of 30 μm to form a conductor pattern.

(9) A 5 μm-thick solder plating was performed to obtain a printed wiring board in which a solder plating layer 7 was further formed on the conductor layer 6 as shown in FIG. 5 (h).

Example 6 (1) The glass epoxy copper clad laminate 1 was etched to form a wiring board.

(2) In the same manner as in Example 1, pseudo particles were formed. These pseudo particles have an average particle size of about 4.3 μm and about 75% by weight.
Was present in a range of ± 2 μm around the average particle size.

(3) 60 parts by weight of a 50% acrylate of a cresol novolac type epoxy resin, 60 parts by weight of a 50% acrylate of a bisphenol A type epoxy resin, 40 parts by weight of a bisphenol A type epoxy resin, 15 parts by weight of sialyl terephthalate, 4 parts by weight of 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 4 parts by weight of imidazole, 50 parts of pseudo particles prepared in the above (2)
After mixing the parts by weight, the viscosity was adjusted to 250 cp with a homodisper stirrer while adding butyl cellosolve, and then kneaded with three rollers to prepare a solution of the photosensitive resin composition.

(4) An alkaline sodium chlorite solution was prepared by dissolving 60 g of sodium chlorite, 18 g of sodium hydroxide, 5 g of sodium phosphate, and 5 g of sodium carbonate in water to obtain a solution of 1.

(5) 30 ml of a 30% by weight aqueous solution of formalin, 38 g of KOH in water 1
To prepare an aqueous solution of an alkaline reducing agent.

(6) The wiring board prepared in (1) was immersed in the alkaline sodium chlorite solution obtained in (4) for 2 to 3 minutes. Then, it was immersed in the aqueous solution of the alkaline reducing agent prepared in the above (5) at 70 ° C. for 15 minutes for roughening.

(7) The solution of the photosensitive resin composition prepared in the above (3) is applied on the wiring board prepared in the above (6) using a knife coater, and left in a horizontal state for 20 minutes. To form a photosensitive resin insulating layer having a thickness of about 50 μm.

(8) A photomask film on which a black circle having a diameter of 100 μm was printed was brought into close contact with the printed circuit board subjected to the treatment of (7), and exposed to light at 500 mJ / cm ² using an ultra-high pressure mercury lamp. This is subjected to ultrasonic development with a chlorocene solution, so that
An opening 17a to be a via hole 17 of 0 μmφ was formed.

This wiring board is exposed at about 3000 mJ / cm ² by an ultra-high pressure mercury lamp, and further heated at 100 ° C. for 1 hour and then at 150 ° C. for 10 hours to form an opening 17a having excellent dimensional accuracy equivalent to a photomask film. A resin insulating layer (adhesive layer) 21 as shown in FIG. 6 (b) was formed.

(9) After the resin insulation layer 21 is polished with # 1000 alumina powder, the resin insulation layer is immersed in a nitric acid solution at 70 ° C. for 15 minutes to roughen the surface of the interlayer resin insulation layer 3. It was immersed in a neutralization solution and washed with water.

The surface of the insulating layer 2 'is activated by applying a palladium catalyst to the substrate 1 on which the resin insulating layer 2' is roughened 4a, and a plating resist is formed according to a conventional method. Immerse in an electrolytic copper plating solution for 11 hours to achieve a plating film thickness of 25
A second plating conductor layer 9 was formed by performing electroless copper plating of μm.

By repeating the steps (4) to (9) twice, a third plating conductor layer 10 and a fourth plating conductor layer 11 are sequentially formed, and a build-up multilayer wiring board as shown in FIG. Was manufactured.

Embodiment 7 This embodiment is basically the same as Embodiment 6, except that a pad (via a via hole and electrically connected to a lower conductor circuit) is used instead of the plated conductor layer 9 formed on the second layer. 12), apply a solder coat 13 to this,
Only pads for mounting semiconductor parts were formed,
A printed wiring board as shown in FIG. 9 was manufactured.

Example 8 This example is basically the same as Example 1, but in this example, a palladium catalyst was added to the electroless plating adhesive, and the step of applying the palladium catalyst was omitted.

Comparative Example 1 This comparative example is basically the same as Example 1,
Instead of using epoxy resin particles having an average particle diameter of 3.9 μm and an average particle diameter of 0.5 μm, the epoxy resin particles having an average particle diameter of 3.9 μm and an average particle diameter of 0.5 μm are used. Particles were prepared and subjected to a roughening treatment using chromic acid (oxidizing agent) instead of 50% sulfuric acid to produce a printed wiring board as shown in FIG.

Comparative Example 2 This comparative example is basically the same as Example 2, but
Agglomerated particles having an average particle size of about 3.5 μm were prepared by using epoxy resin particles soluble in an oxidizing agent having an average particle size of 0.5 μm instead of acid-soluble epoxy resin particles having an average particle size of 0.5 μm. Roughening treatment was performed using chromic acid (oxidizing agent) instead of 6N hydrochloric acid to produce a printed wiring board as shown in FIG.

Comparative Example 3 This comparative example is basically the same as Example 3, but
Instead of acid-soluble epoxy resin particles having an average particle size of 3.9 μm and an average particle size of 0.5 μm, an epoxy resin soluble in an oxidizing agent having an average particle size of 3.9 μm and an average particle size of 0.5 μm is used. Instead, a roughening treatment was performed using chromic acid (oxidizing agent) to produce a printed wiring board as shown in FIG.

(C) The adhesion strength between the substrate and the copper plating film of the printed wiring boards obtained in Examples 1 to 8 and Comparative Examples 1 to 3 was measured by the method of JIS-C-6481.

In addition, a change in the surface resistance of the adhesive layer was measured by immersing the printed wiring board in boiling water at 100 ° C.

 Table 3 shows the results.

[Effects of the Invention] As described above, according to the present invention, the heat resistance, the electrical characteristics, and the adhesion between the substrate and the electroless plating film are both extremely excellent, and particularly, when the surface is roughened, the matrix is additionally dissolved. Therefore, the anchor shape becomes sharp, and an adhesive for electroless plating with extremely excellent plating adhesion can be provided.

Moreover, the use of such an adhesive eliminates the need for complicated conditions for sufficiently roughening the surface when manufacturing a printed wiring board, and does not use harmful substances such as chromic acid. In addition, the time and effort for disposal and disposal can be eliminated, and no special equipment or care is required for the working environment.

In addition, since the exposed conductor is not oxidized during the roughening treatment, the conduction reliability is excellent.

In this sense, the present invention is widely applied to high-precision printed wiring boards, hybrid IC wiring boards, multilayer wiring boards on which LSIs are mounted, and is extremely useful in industry.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) to 1 (e) are views showing the manufacturing steps of Example 1, and FIGS. 2 (a) to 2 (e) are the manufacturing steps of Example 2. FIGS. FIGS. 3 (a) to 3 (e) are views showing the manufacturing process of Example 3, FIG. 4 is a cross-sectional view of the printed wiring board obtained in Example 4, FIG. 5 (a) 6 (a) to 6 (h) are diagrams showing the manufacturing process of the fifth embodiment, FIGS. 6 (a) to 6 (d) are diagrams showing the manufacturing process of the sixth embodiment, and FIG. 8 is a cross-sectional view of a printed wiring board based on Comparative Example 1, FIG. 9 is a cross-sectional view of a printed wiring board based on Comparative Example 2, and FIG. FIG. 2 is a cross-sectional view of a printed wiring board based on FIG. 1 ... substrate, 2 ... adhesive layer, 2 '... insulating layer, 3 ...
Roughened surface, 4a: Adhesive layer containing pseudo particles, 4b: Adhesive layer containing aggregated particles, 4c ... Adhesive layer containing two types of particles having different particle diameters, 5: Plating resist, 6 ... Conductor layer, 7: Solder plating layer, 8: Glass woven fabric, 9: Second plating conductor layer, 10: Third plating conductor layer, 11: Fourth plating conductor layer, 12: Pad, 13 …… Solder coat, 14 …… Polyethylene film, 15a …… Pseudo-particle-containing adhesive layer roughened by oxidizing agent, 15b …… Pseudo-particle-containing adhesive layer roughened by oxidizing agent, 15c …… Roughing by oxidizing agent Adhesive layer containing two types of particles with different particle diameters, 16: through-hole, 17a: opening

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-235384 (JP, A) JP-A-1-275682 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09J 9 / 00,163 / 00,5 / 00 C23C 18/00 H05K 3/18

Claims (10)

(57) [Claims] 1. An epoxy resin powder which has been cured beforehand and which is soluble in at least one acid selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid and formic acid. An adhesive for electroless plating, which is dispersed in an uncured matrix-forming heat-resistant resin having a property of being hardly soluble or insoluble in water. 2. The epoxy resin powder has an average particle size of 10 μm.
The adhesive according to claim 1, which is not more than m. 3. An epoxy resin powder having an average particle size of 2 to 10 μm by aggregating an epoxy resin powder having an average particle size of 2 μm or less; an epoxy resin powder having an average particle size of 2 to 10 μm; Diameter 2μ
A mixture with an epoxy resin powder having an average particle diameter of 2 μm or less or an epoxy resin powder having an average particle diameter of 2 μm or less
3. The adhesive according to claim 1, wherein the adhesive is at least one selected from the group consisting of pseudo particles obtained by adhering at least one of inorganic powders having a particle size of m or less. 4. 4. The heat-resistant resin for forming a matrix in which the epoxy resin powder is scattered is at least one resin selected from an epoxy resin, an epoxy-modified polyimide resin, a polyimide resin, and a phenol resin. The adhesive according to any one of Items 1 to 3. 5. A method for producing a printed wiring board on which a conductive layer is provided via an adhesive for electroless plating, wherein at least the following steps (a) to (d) are performed: (a) sulfuric acid, hydrochloric acid, Precuring epoxy resin powder soluble in at least one acid selected from nitric acid, phosphoric acid, acetic acid and formic acid becomes hardly soluble or insoluble in the acid by curing. A step of forming an adhesive layer by applying an adhesive dispersed in an uncured heat-resistant resin liquid having characteristics, followed by drying and curing. (B) polishing the surface of the cured adhesive layer to expose a part of the epoxy resin powder scattered on the surface of the adhesive layer to the surface of the adhesive layer; (C) dissolving and removing at least a part of the epoxy resin powder exposed on the surface of the adhesive layer with at least one acid selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid and formic acid; And a step of roughening the surface of the adhesive layer. (D) A step of applying electroless plating to the roughened surface. A method for manufacturing a printed wiring board using an adhesive characterized by passing through. 6. The epoxy resin powder has an average particle size of 10 μm.
The production method according to claim 5, wherein m is equal to or less than m. 7. An epoxy resin powder comprising an agglomerated particle obtained by aggregating an epoxy resin powder having an average particle size of 2 μm or less to have a size of 2 to 10 μm; Diameter 2μ
A mixture with an epoxy resin powder having an average particle diameter of 2 μm or less or an epoxy resin powder having an average particle diameter of 2 μm or less
7. The method according to claim 5, wherein the particles are at least one kind selected from the group consisting of pseudo particles obtained by adhering at least one kind of inorganic powder having a particle size of m or less. 8. The heat-resistant resin liquid for forming a matrix in which the epoxy resin powder is dispersed is at least one resin liquid selected from an epoxy resin, an epoxy-modified polyimide resin, a polyimide resin and a phenol resin. Item 8. The method according to any one of Items 5 to 7. 9. The method according to claim 5, wherein the electroless plating is at least one of electroless copper plating, electroless nickel plating, and electroless gold plating. 10. A method according to claim 1, wherein said substrate is sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid,
A pre-cured epoxy resin powder soluble in at least one acid selected from acetic acid and formic acid has a property of being hardly soluble or insoluble in the acid. An adhesive layer dispersed in a resin is formed, and at least a portion of the epoxy resin powder exposed on the surface portion of the adhesive layer is dissolved and removed with the acid to roughen the surface of the adhesive layer. And a conductor layer formed by electroless plating the roughened surface.