JPH01270394A - Multilayer interconnection board - Google Patents

Abstract

PURPOSE:To prevent the separation between an inner layer material and a resin impregnated base material and cracks from occurring to the base material in a hole boring process, and restrain the corrosion of a circuit caused by penetration of a plating solution so as to improve a board in reliability by a method wherein an interconnection board is formed into one piece in such a manner that outer layer materials are provided to an inner material interposing resin impregnated materials between the outer layer materials and the upside and the underside of the inner layer material respectively, where the thickness of attached resin of the resin impregnated material in contact with the inner layer material is made equal to or more than a specified value. CONSTITUTION:Circuits 2 formed of a metal foil of copper or the like are provided to the upside and the underside of an inner layer material 1, and resin impregnated materials 3 are provided onto the upside and the underside of the inner layer material 1 provided with the circuit 2. In this process, a resin 5 of epoxy resin, polyimide resin, polyamide resinresin, polyester resin, or the like impregnated into a base material 4 formed of glass cloth, glass mat, paper, or the like is made to adhere is thick as 20mum or more. Therefore, this resin layer alleviates the shock at a hole boring process by a drill or the like through a stress relaxation to prevent the separation of the circuit 2 of the inner layer material 1 and the resin impregnated base material 3 and the occurrence of cracks. By these processes, the corrosion of the circuit 2 due to penetration of a plating solution is also restrained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a multilayer wiring board.

More specifically, the present invention relates to a multilayer wiring board that prevents the occurrence of cracks at the interface between an inner layer material and a resin-impregnated base material and has improved acid resistance.

(Prior Art) With regard to wiring boards used in computers, communication equipment, electronic devices, etc., there is a trend toward high-density packaging, and demand for multilayer wiring boards is increasing.

As shown in FIG. 2, for example, such a multilayer wiring board is made of a resin-impregnated base material (glass cloth impregnated with vIJ resin) on both upper and lower surfaces of an inner layer material (b) having a circuit (a). outer layer material (e) with metal foil (1)
It is known that the laminate is laminated and colored in one piece. For this multilayer wiring board, as shown in FIG. 2, after the layers are laminated and colored, holes are formed using a drill, punch, etc., and through holes are plated to form a plated layer.

For such multilayer wiring boards, the inner layer material (
When placing the resin-impregnated base material (a) in (a), no particular attention was paid to the state of the contact interface between the two.

However, as the demand for higher density and higher speed wiring boards increases, more attention is paid to their reliability, and as a result, the inner layer of the resin-impregnated base material is damaged due to the impact caused by drilling holes in multilayer wiring boards. A new problem has emerged: microcracks occur in the contact area, and the plating liquid from the plating process invades the crank, corroding the circuit (a) of the inner layer material (a).

(Problems to be Solved by the Invention) This invention was made in view of the above-mentioned circumstances, and it uses a plating solution for circuits provided on the inner layer material of multilayer wiring boards, which has not conventionally received special attention. The purpose of this invention is to provide a highly reliable multilayer wiring board that prevents corrosion caused by corrosion.

More specifically, this invention solves the problem that the inner layer is damaged due to the impact caused by drilling, which was unavoidable in the case of a multilayer wiring board in which a resin-impregnated base material with a thickness of approximately 4 to 7 μm in contact with the inner layer material is attached. A circuit due to the occurrence of plating cracks at the material interface and the intrusion of plating liquid into these cracks (preventing corrosion,
The objective is to provide a highly reliable multilayer wiring board with improved IT acidity.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the multilayer wiring board of the present invention has an outer layer material disposed integrally with a resin-impregnated base material interposed between the upper and lower surfaces of the inner layer material. This multilayer wiring board is characterized in that the resin-impregnated base material in contact with the inner layer material has a resin thickness J2 of 20 μm or more.

FIG. 1 is an enlarged view of the main parts of the multilayer wiring board of the present invention. As shown in Fig. 1, the inner layer material (1
) has a circuit (2) formed from gold foil such as copper on the upper and lower surfaces.
A resin-impregnated base material (3) is provided on the upper and lower surfaces of the inner layer material (1) having the circuit (2). In this arrangement, in the present invention, the base material (4) made of, for example, glass cloth, glass mat, paper, etc. is impregnated with epoxy resin, polyimide resin, polyamide resin,
The thickness of the resin (5) such as polyester resin is 20μ.
m or more. Therefore, at the interface of the resin-impregnated base material (3) in contact with the inner layer material (1), the inner layer material (1) and the base material (4
), a resin having a thickness of at least 20 μm is interposed between the two.

In such a multilayer wiring board of the present invention, there are usually two things:
As the inner layer material (1), a double-sided or single-sided metal-clad laminate plate with MII (2) formed on the surface by etching or the like is used. Moreover, as this inner layer material (1),
In order to improve the adhesion to the resin-impregnated base material (3), those subjected to surface roughening treatment (blackening treatment) with an acid or an oxidizing agent are preferably used.

As the resin-impregnated base material (3), as described above, a resin face of epoxy resin, polyimide resin, unsaturated polyester resin, phenol resin, etc. is applied to a base material such as glass cloth or paper, and the amount of resin after drying is about 40 to It is possible to use a plurality of sheets, for example, about 2 to 3 sheets, impregnated to a concentration of about 50% by weight.

However, also in this case, for the resin-impregnated base material (3) in contact with the inner layer material (1), the amount of resin adhered, that is, the resin thickness is 20 μm or more, preferably 20 to 40 μm.

The amount of resin impregnated for this purpose is preferably about 50 to 60 weight.

Further, as the outer layer material of the wiring board of the present invention, a metal foil such as copper or aluminum, or a single-sided metal-clad laminate with the metal side as the outermost layer can be used.

Laminate molding can be carried out appropriately under conventionally known pressures, temperatures, and the like.

(Function) In the multilayer wiring board of the present invention, the thickness of the resin-impregnated base material (3) in contact with the inner layer material (1) is set to 20 μm or more, so that the impact during drilling with a drill etc. is absorbed by the resin. layer of the inner layer material (1) undergoes stress relaxation, and the circuit (2) of the inner layer material (1)
) and the resin-impregnated base material (3) to prevent peeling and cracking.

This also suppresses erosion of the circuit (2) due to penetration of the plating liquid.

Next, examples of the present invention will be shown, and the multilayer wiring board of the present invention will be explained in more detail. Of course, the invention is not limited to the following examples.

(Example) Both sides of a double-sided steel-clad glass cloth epoxy laminate with an open thickness of 0.8 were etched and blackened to obtain an inner layer material.

Separately, glass cloth was impregnated with a resin having the following formulation.

Epoxy resin 100 (parts by weight) (Epicote 1001 Nigel Chemical) Dicyandiamide
4 Benzyldimethylamine 0.2 Methyloxytol 100 The resin-impregnated glass cloth in contact with the inner layer material has a thickness of 0.1
oim, resin 1 = 1 piece thickness 25 μm (eJ fat appearance 55 weight j
(L%), and other materials with a thickness of 0.1
City, VA grease adhesion thickness 5 B m glass cloth (V!j
Fatty 45-layer Ji′′! ,;) was used. Furthermore, a copper foil with a thickness of 35 μm was placed on the outermost layer, and the m carcass made of these was heated and pressed at a molding pressure of 40 kg/cd and 165° C. for 100 minutes to obtain a four-layer multilayer wiring board.

For comparison, all resin-impregnated base materials have a thickness of 0.1 nin and 11! l Fat adhesion thickness 5 μm (r!
! A multilayer wiring board was manufactured in the same manner as above using an epoxy resin-impregnated glass cloth manufactured by J.

Regarding these multilayer wiring boards, as is clear from Table 1, the degree of intrusion of plating liquid into the drilled hole portion and corrosion due to hydrochloric acid, in the case of the embodiment of the present invention, penetration of plating liquid was small. , and no circuit corrosion due to hydrochloric acid was observed.

(Effects of the Invention) In the multilayer wiring board of the present invention, the inner layer material and l! Peeling from the base material impregnated with I resin and cracking of the base material are prevented, and circuit erosion due to penetration of the plating liquid is significantly suppressed. A multilayer wiring board with high reliability is realized.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of a multilayer wiring board according to the present invention. FIG. 2 is a partial cross-sectional view showing an example of a conventional multilayer wiring board. ■...Inner layer material 2...Circuit 3...Resin-impregnated base material 4...Base material 5...Resin agent Patent attorney Toshi Nishizawa 1 Figure 2

Claims (1)

[Claims] (1) In a multilayer wiring board formed by integrating an outer layer material with a resin-impregnated base material interposed between the upper and lower surfaces of an inner layer material, the resin adhesion thickness of the resin-impregnated base material in contact with the inner layer material must be 20 μm or more. A multilayer wiring board featuring: