JPH07162145A - Printed wiring board adhesive agent and manufacture of printed board using it - Google Patents

Abstract

PURPOSE:To remarkably shorten a time required for forming an adhesive agent layer by a method wherein adhesive agent which contains bisphenol A-type epoxy resin and micro-capsulated imidasole compound both specified in content is used. CONSTITUTION:Adhesive agent comprises 20-50% by weight of bisphenol A-type epoxy resin which is of epoxy equivalent 2000 or above and soluble in alkaline oxidizing agent after it is cured and 0.5 to 20% by weight of micro-capsulated imidazole compound as epoxy resin hardening agent or hardening accelerator. An adhesive agent layer 2 formed of the above adhesive agent is provided onto the surface of a board 1. The adhesive agent layer 2 is roughened by alkaline oxidizing agent, a hole 3 is bored in the board 1 as a plating through- hole, and palladium catalyst 4 is applied. A patterning operation is carried out with a plating resist 5, and a circuit and a through-hole are formed with electroless copper 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board adhesive and a method of manufacturing a printed wiring board using this adhesive.

[0002]

2. Description of the Related Art When an adhesive layer is formed on the surface of a laminated plate made of an insulating base material, if it is in the form of varnish or paste, it is dried after being applied by a curtain coater, a roller coater or a printing machine. 1 to above 150 ℃
Curing for several hours is required. Further, even in the case of a film, a curing step that requires a long time is also required after forming an adhesive layer on the surface of a laminated plate made of an insulating base material with a laminator or the like. That is, there is no thermosetting adhesive for printed wiring boards that can be applied to the additive method that has both fast curing property and life. Further, as a special system, there is a system that uses heat and ultraviolet rays in combination or utilizes ultraviolet rays as a curing system, but in each case, a special device is required.

Further, in a method of manufacturing a printed wiring board in which an adhesive layer is formed on the surface of a laminated board made of an insulating base material and a circuit and a through hole are formed by electroless plating, the plated circuit and the adhesive layer are used. In order to increase the adhesion of
It is known to roughen the adhesive layer with an oxidizing agent,
JP-B-63-10752, JP-A-63-2975
71, JP-A-64-47095, JP-A-3
As disclosed in Japanese Unexamined Patent Publication No. 18096, most of them contain a rubber component such as acrylonitrile butadiene rubber, a chromium-sulfuric acid aqueous solution is used as an oxidizing agent, and the surface of the adhesive is roughened by eluting the rubber component. Is to do.

However, an adhesive containing a rubber component has low reliability such as heat resistance and electric insulation (migration resistance), and a printed wiring board and a high density plated circuit which require high reliability are formed. There was a problem in using it for a printed wiring board.

Further, in a resin matrix excellent in heat resistance such as epoxy resin, phenol resin, melamine resin,
A method of roughening the adhesive layer by dispersing inorganic fine powder such as silica or calcium carbonate as an adhesive and selectively eluting the inorganic fine powder with a specific chemical, and JP-A-1-29479. As described in Japanese Patent Laid-Open Publication No. 2004-242242, there is a method in which a cured epoxy resin fine powder having different solubilities with respect to an oxidizing agent is dispersed in an epoxy resin matrix, and the epoxy resin fine powder is selectively eluted with the oxidizing agent. However, in these methods, in order to obtain good dimensional accuracy, it is necessary to uniformly disperse an amount of fine powder (on the order of a few microns) in the adhesive varnish that can obtain a sufficient roughening effect. Not only difficult, but also mechanical polishing for exposing the fine powder to the surface of the adhesive layer when roughening the adhesive layer formed by curing treatment, or described in Japanese Patent Publication No. 4-79160. Oxidation plasma treatment as described above is required.

In addition, among these methods, a strong oxidizing agent such as a hexavalent chromium-sulfuric acid aqueous solution is used except in the case where the inorganic fine powder is selectively dissolved and removed with a specific chemical, so that the working environment is Also, there are major safety and health problems. Furthermore, when roughening the adhesive layer formed on the multilayer substrate after forming holes for forming plated through holes, excessive unevenness is formed on the inner wall of the holes to reduce the connection reliability of the plated through holes. Since the electroless plating solution easily permeates along the glass cloth, there is a problem that the insulation reliability between the plated through holes is also greatly reduced.

As a method for coping with this, Japanese Patent Publication No. 5-4
As described in Japanese Patent Publication No. 840, a method has been proposed in which a substrate surface having a roughened adhesive layer is covered with a protective mask and then holes are formed for forming plated through holes. However, not only the step of covering the protective mask and the step of removing the protective mask again increase, but in order to maintain the roughened shape once formed in the adhesive layer in the state immediately after the roughening treatment,
You must be very careful.

[0008]

As described above, in the conventional adhesive for printed wiring boards and the method for producing a printed wiring board using this adhesive, in the case of an adhesive containing a rubber component, The problem that the reliability of the printed wiring board is reduced, it is very difficult to generate the fine powder with high accuracy and to disperse it evenly in the adhesive agent in which the fine powder that is selectively roughened by the oxidant is dispersed in the resin matrix. The problem is that the pretreatment step of exposing the fine powder before roughening with an oxidizing agent is increased, and the work environment and safety because a chromium-sulfuric acid aqueous solution is used as an oxidizing agent for roughening these adhesives. There is a problem in hygiene and in the roughening of the multi-layered substrate that has been subjected to the drilling treatment for forming the plated through hole, the inner wall of the hole is also roughened, which lowers the reliability of the plated through hole. The present invention solves all of the various problems described above.

[0009]

SUMMARY OF THE INVENTION The present invention provides a resin matrix that is sparingly soluble in an alkaline oxidant after curing, in a resin matrix that is cured after curing, such as a bisphenol A type epoxy resin having an epoxy equivalent of 2000 or more. Adhesive for printed wiring boards, characterized in that it is dispersed with a soluble resin, and the adhesive is applied onto a substrate and cured by heat to form an adhesive layer, or the adhesive After forming an adhesive film from the agent, laminating the adhesive film on the substrate, by an alkaline oxidizing agent,
A printed wiring board characterized by roughening the surface of the adhesive layer by dissolving and removing a resin portion soluble in an alkaline oxidant dispersed in the adhesive layer, and then performing electroless plating. The present invention relates to a manufacturing method of.

The present invention will be described in detail below. INDUSTRIAL APPLICABILITY The present invention makes it possible to roughen an adhesive layer formed on the surface of a substrate with an alkaline oxidizing agent such as an alkaline permanganate aqueous solution in a method for manufacturing a printed wiring board by the additive method. That is, in the present invention, a specific resin component in the adhesive component is selectively dissolved with an alkaline oxidizing agent to form a roughened shape. In this case, the selectively dissolved resin is microscopically or partially phase-separated from the resin forming the matrix of the adhesive to form a sea-island structure with the matrix resin as the sea, and It is considered that the resin is selectively dissolved.

A typical example of the resin component soluble in the alkaline oxidizing agent is a high molecular weight bisphenol A type epoxy resin having an epoxy equivalent of 2000 or more. The resin dissolved in the alkaline oxidizer has the above epoxy equivalent of 200.
A bisphenol A type epoxy resin of 0 or more is particularly preferable, but a brominated one thereof and a phenoxy resin having a very large molecular weight can also be used, and an epoxy equivalent of 2
000 or more bisphenol A type epoxy resins. The bisphenol A type epoxy resin needs to have an epoxy equivalent of 2000 or more, and when the epoxy equivalent is 2000 or less, the crosslinking density of the epoxy resin becomes high, so that roughening with an alkaline oxidizing agent becomes difficult.

The bisphenol A type epoxy resin having an epoxy equivalent of 2000 or more is excellent in uniform dispersibility of the adhesive in the resin matrix, and since it forms a micro separation layer in the resin matrix, it is melted by an alkaline oxidizing agent. The removed roughened portion is formed uniformly and finely.

The microencapsulated imidazole used as a curing agent or curing accelerator is a liquid bisphenol type epoxy resin (equivalent weight 1: 1) such as an extremely fast curing imidazole compound, specifically 2-methylimidazole.
80 to 200) and 4 to 6 phr, 150 ° C
It is obtained by microencapsulating imidazole having a gel time of several tens of seconds. This microcapsule preferably has a particle size suppressed to 10 μm or less.

Next, a method of manufacturing a printed wiring board according to the present invention will be described. The surface of the substrate 1 (one side or both sides)
Then, the adhesive layer 2 is formed. In this case, a general substrate may be used, and a glass epoxy laminated plate, a glass polyimide laminated plate, a glass polyester laminated plate, a paper phenol resin laminated plate, a ceramic substrate, or the like can be used.

In forming the adhesive layer, an adhesive varnish prepared by dissolving an adhesive component in a predetermined solvent at a predetermined concentration may be directly applied to the surface of the substrate 1 and dried and then cured. It is also possible to coat the film on the substrate 1 and dry it, and then laminate it on the substrate 1 and then cure it. In addition to the above components, a fine powder filler such as silica and additives such as a coupling agent and a stabilizer can be added to the adhesive, if necessary. The thickness of the adhesive layer 2 is 15 to
30 μm is preferable. After roughening the surface of the adhesive layer, holes 3 for plating through holes are provided, a palladium catalyst 4 is applied, patterning is performed with a plating resist 5, and circuits and plating through holes are formed with electroless plated copper 6.

[0016]

EXAMPLES The present invention will be described below with reference to examples. (Example 1) Bisphenol F type epoxy resin (epoxy equivalent 175 manufactured by Dainippon Ink and Chemicals, Inc., Epicron 8
30) 100 parts by weight (all addition amounts below represent parts by weight)
And bisphenol A type epoxy resin (epoxy equivalent 64
00, 50 parts by weight average molecular weight 30,000) was dissolved in 200 parts of methyl ethyl ketone with stirring. There, 15 parts of microencapsulated imidazole as a curing agent and a silane coupling agent (A-1 manufactured by Nippon Unicar Co., Ltd.)
87) 3 parts were added to prepare an adhesive varnish. next,
A carrier film having a thickness of 10 which has been subjected to release treatment on one side
A 0 μm polyethylene terephthalate film was coated with a roller coater so that the thickness after drying was 30 μm, and dried. Then, it is laminated on both sides of the glass epoxy resin multilayer substrate, and the carrier film is peeled off.
After heat-curing at 0 ° C. for 20 minutes, a hole having a diameter of 0.4 mm for a plated through hole was drilled on the multilayer substrate.

Then, 10 times in an alkaline aqueous solution at 80.degree.
After soaking for a minute, after degreasing and swelling the adhesive layer,
10 with an aqueous alkaline solution of potassium permanganate at 70 ° C
After roughening for a minute and washing thoroughly with water, it was immersed in a hydroxylamine sulfate aqueous solution at 50 ° C. for 10 minutes to neutralize and remove the permanganate remaining in the adhesive layer. Next, after being immersed in an alkaline degreasing solution at 75 ° C. for 5 minutes, it was thoroughly washed and immersed in a palladium-tin salt colloid catalyst solution for 5 minutes. After washing with water, the catalyst was immersed in a catalyst activation bath at room temperature for 8 minutes to remove excess tin salt from excess palladium-tin salt colloidal particles.
Then, a desired plating circuit and a plating resist for forming a plated through hole were formed by a known method. Then, it is immersed in an electroless copper plating solution at 70 ° C. for 10 hours to form an electroless copper plating film of about 20 μm on the entire surface of the multilayer substrate.
An additive method multilayer printed wiring board was produced.

Example 2 Epoxy equivalent 3000 to 40
The amount of bisphenol A type epoxy resin of 00 is 20
An additive-type multilayer printed wiring board was produced in exactly the same manner as in Example 1 except that the parts were used.

Example 3 A bisphenol A novolac type epoxy resin (epoxy equivalent 205 manufactured by Dainippon Ink and Chemicals, Inc.) was used instead of the bisphenol F type epoxy resin.
An additive-type multilayer printed wiring board was produced in exactly the same manner as in Example 1 except that 100 parts of Epiclon N-865) was blended.

Example 4 Instead of the bisphenol A type epoxy resin having a weight average molecular weight of 30,000 in the adhesive of Example 1, a bisphenol A type epoxy resin having an epoxy equivalent of 3000 to 4000 (Epicoat 1010 manufactured by Yuka Shell Epoxy Co., Ltd.) is used. ) An additive-type multilayer printed wiring board was produced in exactly the same manner as in Example 1 except that 50 parts were blended.

The additive-type multilayer printed wiring board thus obtained has the characteristics shown in Table 1.

[Table 1]

[0022]

As described above, according to the present invention, an adhesive method multilayer printed wiring board in which an adhesive layer is formed on the surface of a multilayer substrate and a plated circuit and a plated through hole are formed by electroless plating on the adhesive layer is manufactured. Regarding the method, as a method of roughening the adhesive layer, a pretreatment step such as mechanical polishing is not necessary before roughening, and since it can be roughened by an alkaline oxidizing agent such as potassium permanganate, a chromium-sulfuric acid aqueous solution is used. Compared with, the work environment and safety and health can be improved. Further, the additive method multilayer printed wiring board can be manufactured without impairing the reliability of the plated through holes. The adhesive of the present invention can be prepared by a very simple method of blending an uncured resin. Then, the alkaline oxidizing agent can form recesses on the order of submicrons to several microns on the entire surface of the adhesive layer. Moreover, by using microencapsulated imidazole, it is a fast-curing adhesive that has storage stability, so the time taken to form the adhesive layer is greatly shortened, which simplifies the process, reduces mass production, and reduces production costs. It can contribute to cost reduction.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a manufacturing process of an additive method multilayer printed wiring board according to the present invention.

[Explanation of symbols]

 1 Insulating substrate 2 Adhesive layer 3 Through-hole hole 4 Palladium catalyst 5 Plating resist 6 Electroless plating copper

Claims (3)

[Claims] 1. An adhesive for a printed wiring board comprising an epoxy resin composition, which has an epoxy equivalent of 200 which is soluble in an alkaline oxidizing agent after curing as an epoxy resin.
20-50 bisphenol A type epoxy resin of 0 or more
% Of the imidazole compound contained in an amount of 0.1 wt% and microencapsulated as an epoxy resin curing agent or a curing accelerator.
An adhesive for printed wiring boards, characterized by containing 5 to 20% by weight. 2. The adhesive according to claim 1, which is applied onto a substrate and cured by heat to form an adhesive layer, and then the alkaline oxidant dispersed in the adhesive layer with an alkaline oxidant. A method for manufacturing a printed wiring board, characterized in that the surface of the adhesive layer is roughened by dissolving and removing a soluble epoxy resin, and then electroless plating is performed. 3. A film comprising the adhesive according to claim 1, which is laminated on a substrate, cured by heat, and then dispersed in the adhesive layer with an alkaline oxidizing agent. A method for manufacturing a printed wiring board, characterized in that an adhesive layer surface is roughened by dissolving and removing an epoxy resin soluble in an alkaline oxidizing agent, and then electroless plating is performed.