JPH045890A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To prevent the generation of a void, the positional displacement of an internal-layer conductor layer, etc., to reduce the dispersion of the degree of cure of a resin, to facilitate etching, burying, etc., and to improve reliability and productivity by using a semirigid resin copper-clad laminated board. CONSTITUTION:A semirigid resin copper-clad laminated board having the adhesive force of 0.85kg/cm of a copper foil and a glass transition temperature of 92 deg.C (136 deg.C after full cure) is employed. Wiring patterns are formed on the semirigid resin copper- clad laminated board through an etching method, and press-molded at surface pressure of 75kg/cm<2> at a temperature of 170 deg.C, thus manufacturing a smooth printed board 1 for an internal layer. Two boards 1 and two copper foils 3 for external layers on the outsides of the boards 1 are used, glass woven-fabric epoxy-resin prepregs 2 in thickness of 0.2mm are arranged one by one for interlaminar bonding, and the boards 1, the copper foils 3 and the prepregs 2 are laminate-molded for ninety min at pressure of 40kg/cm<2> at a temperature of 170 deg.C, thus manufacturing the multilayer shield board of six layers. Accordingly, the generation of voids, the positional displacement of an internal-layer conductor layer, etc., are prevented, the dispersion of the degree of cure of a resin is reduced, etching and burying are facilitated, and reliability and productivity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is a method of manufacturing a highly reliable multilayer printed wiring board using a thin interlayer bonding prepreg.

[Conventional technology and its problems]

Conventionally, multilayer printed wiring boards are manufactured using printed wiring boards in which a desired printed wiring pattern is formed on a completely cured copper clad laminate as an inner layer board or an intermediate layer board.

In this method, adhesive prepreg with a predetermined impregnated resin flow is applied at twice the desired amount in order to completely fill the spaces between the printed wiring conductors in the inner layer, maintain a distance from the adjacent printed wiring conductors, and ensure reliability. In addition, depending on the shape of the printed wiring pattern, vacuum lamination molding is essential to avoid the occurrence of voids.

As a result, the distance between printed wiring layers becomes wider, resulting in the disadvantage that only thick multilayer boards can be manufactured.

[Failure to solve the problem]

The inventors of the present invention have conducted intensive studies on a method for manufacturing thin multilayer printed wiring boards with narrow conductor layer spacing. As a result, the above-mentioned problems can be easily solved by a method using semi-cured resin laminates that can be easily manufactured by a continuous method. found that it is possible to solve
The present invention has now been completed.

That is, the present invention provides a multilayer laminate by combining an inner layer board forming a printed wiring network for the inner layer, a prepreg for interlayer adhesion, and a copper foil or single-sided copper-clad laminate or printed wiring board for the outer layer in a desired multilayer board configuration. In a method of manufacturing a multilayer printed wiring board by molding, a desired printed wiring network is formed on a semi-cured resin copper-clad laminate as the inner layer board, and press molding is performed so that the conductor surface and the board surface are on substantially the same plane. This is a method for manufacturing a multilayer printed wiring board characterized by using a printed wiring board (hereinafter referred to as a smooth printed wiring board) made of a semi-hardened resin copper clad laminate having a copper foil peel strength of 0°2. kg
/ cm or more, and the semi-cured resin copper clad laminate is heated and pressurized to a range of 90% or less of the fully cured state, and the semi-cured resin copper clad laminate has a thickness of at least 20 mm between the copper foil and the base material.
The semi-cured resin copper clad laminate shall have a semi-cured resin layer of Il- or more, and the semi-cured resin copper clad laminate shall be manufactured by continuous pressing using the double bell I press method or pressed between a pair of hot plates.
This is a method for producing a multilayer printed wiring board, characterized in that the multilayer printed wiring board is produced by a batch rapid press forming method in which two laminates are press-formed.

First, the semi-cured resin copper-clad laminate used for manufacturing the smooth printed board of the present invention has a copper foil peel strength of 0.2 kg/c.
m or more, preferably 0.3 kg/cm or more, and 90% or less of the peel strength after complete curing.

When a thermosetting resin-based composition is used as the matrix resin, the standard for the copper foil peel strength can be determined from the glass transition temperature of the matrix resin (glass transition temperature (TgsoC)/perfect Glass transition temperature of matrix resin after curing Tgf'C) -0,5
This corresponds to a range of 5 to 0.90. In particular, when using a method of forming a printed wiring pattern using an organic solvent type resist stripper, Tg'/Tg"4.65 to 0
．． A range of about 85 is preferable.

In addition, a resin layer of 20. As mentioned above, pattern embeddability can be improved even when the degree of curing is high, for example by using adhesive-coated copper foil or resin layer prepreg, or by using non-woven fabric prepreg for the copper foil bonding area. An improved version is desirable. Here, if the copper foil peel strength is less than 0.2 kg/cm, it is difficult to form a printed wiring network, which is undesirable, and if it exceeds 90% of the peel strength after complete curing, the curing will proceed too much, making it difficult to manufacture. This is not preferred because it becomes difficult to embed the printed wiring network in the insulating resin layer by heating and pressurizing. In addition, when using conventional epoxy prepreg for multi-stage presses,
At 200°C, the peel strength of copper foil is 0.3 to 1.5 kg/cm after heating for 1 to 3 minutes (peel strength of copper foil is 2.0 kg/cm or more after complete curing), TgS/Tg' = 0.
It will be about 70 to 0.85, and 2 to 4 at 180°C.
Peel strength is 0.4 to 1.0 kg/cm after heating for 1 minute.
, Tg"/Tg' = about 0.6 to 0.75. The resin used may be any conventional resin, and is particularly limited to polyester, epoxy, polyimide, cyanate ester, etc. Not done.

The printed wiring network of the present invention may be formed by a conventional method of forming a printed wiring network using a semi-cured resin copper clad laminate. However, when using a semi-cured resin copper-clad laminate manufactured by the preferred manufacturing method of the present invention, the variation in the degree of curing is significantly smaller than that of the conventional method. More stringent conditions are available.

The printed wiring board produced as described above, in which the conductor layer is raised above the resin surface of the substrate, is press-molded to form a smooth printed wiring board with the printed wiring conductor layer embedded in the insulating layer.

The conditions used for embedding may be the same as the manufacturing method for conventional smooth printed boards (-flange circuit), but
In the case of a semi-cured resin laminate manufactured by the preferred manufacturing method of the present invention,
Since basically one sheet is pressed at a time, the range of variation in the degree of semi-curing of the resin is small, and it is possible to use a lower pressure than in the past. Furthermore, even if the embedding is insufficient compared to conventional flash circuits, it can be used in the present invention without any particular problem. For example, if the gap between the substrate and the insulating resin surface is about 10/7 TII or less, , Absolute 8. ! There is virtually no problem of thinning of the paint layer.

From the above two conditions, it is understood that the smooth printed board used in the present invention can be manufactured with extremely high productivity. □Also, if care is taken to avoid misalignment of the conductor layer when embedding the printed wiring conductor, there will be virtually no misalignment of the conductor layer due to forces such as resin flow of interlayer adhesive prepreg during multi-layer molding. It doesn't really work.

Furthermore, since the conductor layer forms a substantially flat surface with the substrate surface, even if the resin flow of the interlayer bonding prepreg is small, voids are less likely to occur, making lamination molding extremely easy.

〔Example〕

The present invention has been described in detail above, and embodiments will now be described using the accompanying drawings.

FIG. 1 is an example of a cross-sectional view of the arrangement of laminated molding materials of a multilayer printed wiring board using the smooth printed board of the present invention, and FIG.
The figure is an example of a layout cross-sectional view when using a conventional printed wiring board with conductor foil protruding from the board surface.

In Figure 1, three sheets of glass woven epoxy resin prepreg with a thickness of 0.2 mm are layered with copper foil of 35 cape thickness on both sides, and are continuously fed into a double belt press at a temperature of 20 mm.
Semi-hardened resin copper clad with a copper foil adhesive strength of 0.85 kg/cm and a glass transition temperature of 92°C (after complete curing = 136°C) by heating and pressure molding at 0°C5 and a pressure of 50kg/cJ for 1 minute. After forming a printed wiring pattern on this semi-cured resin copper-clad laminate by etching using a laminate, it was press-formed at a temperature of 170°C and a surface pressure of 75 kg/(NL) to form a smooth printed board for the inner layer []] I got it.

During etching, there were no problems such as peeling due to poor adhesion of the pattern, and there were no gaps due to embedding.
~10 (nn), and there was substantially no displacement of the conductor pattern due to embedding.

Next, using 12 of these smooth printed boards and 2 pieces of copper foil [3] for the outer layer on the outside, a thickness of 0.2 m was used for bonding between the layers.
Temperature: 170° C. Pressure: 40 k
A six-layer multilayer shield plate was manufactured by lamination molding at g/cm2 for 90 minutes.

The obtained multilayer shield plate was inspected for occurrence of voids, inner conductor layer spacing, etc., and was found to be good.

Fig. 2 shows a case where a conventional printed wiring board for inner layer [1'] with a protruding conductor layer is used. It is necessary to sandwich three sheets of 2mm+ glass woven epoxy resin prepreg [2] and two sheets of prepreg between the outer layer copper foil, and in order to avoid defects such as voids, It is necessary to perform laminated molding.

[Operations and Effects of the Invention] As is clear from the detailed description of the invention, a smooth printed board (-flash circuit) is manufactured using the semi-cured resin copper clad board of the present invention, and this is used for inner layer printing. According to the method for manufacturing a multilayer printed wiring board used as a wiring board,
There is no occurrence of voids or displacement of the inner conductor layer due to resin flow of the prepreg, and multilayer lamination molding can be achieved with good reliability using a small amount of interlayer bonding prepreg.

In addition, since the semi-cured resin copper-clad laminate preferably used in the present invention is manufactured by a double belt press method or a method of continuously laminating one laminate at a time, There is little variation in the degree of curing of the resin, and etching, embedding, etc. are extremely easy.

As a result, multilayer printed wiring boards can be manufactured with high reliability and high productivity, and this has great industrial significance.

[Brief explanation of drawings]

Fig. 1 is an example of a cross-sectional view of the arrangement of a laminate for a multilayer board using the smooth printed board of the present invention, and Fig. 2 shows a case where a conventional printed wiring board with conductor foil protruding from the surface of the board is used. FIG. 2 is an example of a cross-sectional view of the arrangement of laminated materials for a multilayer board. Patent applicant Mitsubishi Gas Chemical Co., Ltd. agent (9070) Patent attorney Hand-drawn Orthogonal Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. Multilayering by combining an inner layer board forming a printed wiring network for the inner layer, prepreg for interlayer adhesion, copper foil or single-sided copper-clad laminate or printed wiring board for the outer layer in a desired multilayer board configuration. In a method of manufacturing a multilayer printed wiring board by lamination molding, a desired printed wiring network is formed on a semi-cured resin copper clad laminate as the inner layer board, and press molding is performed so that the conductor surface and the board surface are substantially on the same plane. A method for manufacturing a multilayer printed wiring board characterized by using a printed wiring board made of 2. The semi-cured resin copper-clad laminate has a copper foil peel strength of 0.
2. The method for producing a multilayer printed wiring board according to claim 1, wherein the multilayer printed wiring board is heated and pressurized at a pressure of 2 kg/cm or more to achieve a hardening rate of 90% or less. 3. The method for manufacturing a multilayer printed wiring board according to claim 2, wherein the semi-cured resin copper-clad laminate has a semi-cured resin layer with a thickness of at least 20 μm between the copper foil and the base material. 4. The method for producing a multilayer printed wiring board according to claim 2, wherein the semi-cured resin copper-clad laminate is produced by continuous pressing using a double belt press method. 5. The method for manufacturing a multilayer printed wiring board according to claim 2, wherein the semi-cured resin copper-clad laminate is manufactured by a batch continuous press molding method in which one laminate is press-molded between a pair of hot platens.