JPH03191595A - Manufacture of one-sided metal-clad laminated board for multilayer circuit board use - Google Patents

Abstract

PURPOSE:To obtain a one-sided metal-clad laminated board whose interlayer exfoliation defect is small when an outer layer is formed by a method wherein a prepreg face of a one-sided metal-clad laminated-sheet constitution body composed of a specific prepreg sheet and of a metal foil placed on its one side is arranged so as to be faced, via a sheet of mold- releasing paper whose surface has been roughened, with a prepreg face of another similar one-sided metal clad laminated-sheet constitution body and both sides are heated and pressurized. CONSTITUTION:A thermoset resin whose glass transition temperature is at 60 to 90% of a glass transition temperature at perfect hardening is arranged so as to be faced with the side of a prepreg sheet face of a one-sided metal-clad laminated-sheet constitution body which is composed of one to several prepreg sheets impregnated with a base material and of a metal foil placed on its one side in such a way that they sandwich a sheet of mold releasing paper whose surface has been roughened; the whole is heated and pressurized via a mirror-finished plate; a hardening reaction is stopped at the intermediate stage in a process in which the reaction progresses; and the mold releasing paper or a mold releasing film for roughened surface formation use is held on the side of a one-sided copper-clad laminated sheet until the sheet is used as a multilayer circuit board. As a result, it is possible to prevent the resin from absorbing moisture and to form the one-sided copper-clad laminated sheet in which a deterioration of the resin is small and whose curl is small. Thereby, it is possible to reduce that an interlayer exfoliation is caused.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a single-sided metal-clad laminate that is suitably used as a circuit board constituting a circuit on the surface layer of a multilayer circuit board when manufacturing a multilayer circuit board. This relates to a manufacturing method.

[Prior art and its problems] Multilayer circuit boards are generally made by stacking single-sided copper-clad laminates, which form the outer layer, on one or both sides of a circuit board, which forms the inner layer, with prepreg sheets interposed between them, and then pressurize and heat them from above and below to harden them. After that, an electrical connection is made with the circuit pattern on the inner layer by through-hole plating, etc., and a circuit pattern is formed on the copper foil on the outer surface to form a desired multilayer circuit board.

Since the thickness of each layer of this multilayer circuit board is determined from the overall thickness, the thickness of the single-sided copper-clad laminate that constitutes the outer layer becomes thinner and tends to curl. There is a problem in that curled materials are difficult to handle.

In addition, in order to increase the adhesive strength at the interface between the back side of the single-sided copper-clad laminate, which is the adhesive surface, and the prepreg sheet, the adhesive side of the single-sided copper-clad laminate is generally roughened to increase the bonding area and the roughened surface Although attempts have been made to improve adhesive strength through the anchoring effect of the unevenness, there is still a problem in that sufficient adhesive strength has not been obtained.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a manufacturing method for obtaining a single-sided metal-clad laminate that can reduce glabella peeling defects when forming the outer layer of a multilayer circuit board.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides that the glass transition temperature is 60% to 90% of the glass transition temperature at the time of complete curing.
The prepreg surface of a single-sided metal-clad laminate structure consisting of one to several prepreg sheets impregnated with a thermosetting resin as a base material and a metal foil placed on one side of the prepreg sheet is The prepreg surface of a single-sided metal-clad laminate structure is placed facing the prepreg surface with a release paper or film with a roughened surface interposed therebetween, and the entire surface is heated and pressurized via a mirror plate, and then the release paper with a roughened surface is placed. The method of manufacturing a single-sided metal-clad laminate for a multilayer circuit board is characterized in that the single-sided metal-clad laminate is peeled from the substrate.

In addition, the prepreg sheets are composed of two types of prepreg sheets with different curing speeds, and the prepreg sheets with the faster curing speed are stacked on the metal i side.

In addition, the release film with a roughened surface is made of polymethylpentene.

[Function] Before using the single-sided copper-clad laminate produced by this manufacturing method in a multilayer circuit board after forming the single-sided copper-clad laminate, a release paper or release film for forming a roughened surface is placed on the single-sided copper-clad laminate side. By holding the resin, moisture absorption can be prevented, so that it is possible to form a single-sided copper-clad laminate with less resin deterioration and less curling.

Since the surface to be adhered to this single-sided copper-clad laminate is a roughened surface, the bonding area is widened, and the adhesive strength can be improved due to the anchoring effect with the adhesive resin.

This single-sided steel clad laminate is heated and pressurized to advance the curing reaction, which stops at an intermediate stage, that is, at 60% to 90% of the glass transition temperature at the time of complete curing, leaving an unreacted portion. When used for the outer layer of a circuit board, during reheating and pressurization, a part of the unreacted resin of the single-sided steel clad laminate is sandwiched between one or both sides of the inner layer circuit board.The process of curing of the prepreg resin of the prepreg sheet It chemically bonds with the prepreg resin to improve adhesive strength.

In addition, if many unreacted groups of the resin of the single-sided steel clad laminate remain on the outer surface of the resin side, many chemical groups will form with the prepreg resin during the curing process of the prepreg resin of the prepreg sheet sandwiched between one or both sides of the inner layer circuit board. As a result, the adhesive strength can be further improved.

[Example 1] A single-sided copper-clad laminate structure consisting of one prepreg sheet and an electrolytic copper foil with a thickness of 18 μm was placed facing the prepreg sheet side with a release paper having a roughened surface sandwiched therebetween, and the entire structure was assembled. A single-sided copper-clad laminate is obtained by stopping the reaction at an intermediate stage in the process of heating and pressurizing the hardening reaction through a mirror plate. 70% of the glass transition temperature of fully hardened single-sided steel clad laminate
Met.

This single-sided steel-clad laminate was stacked with prepreg sheets sandwiched between each side of the inner layer circuit board, and the whole was heated and pressurized via a mirror plate to complete the curing reaction to obtain a multilayer circuit board with inner layer circuits.

[Example 2] Two types of prepreg sheets with different curing speeds were prepared,
A single-sided copper-clad laminate structure is obtained by stacking these two types of prepreg sheets with the faster-curing side facing the 18 μm thick electrolytic steel foil. A single-sided copper-clad 8-layer board was obtained by disposing the board in pairs and heating and pressurizing the whole body through a mirror plate to advance the curing reaction, stopping the reaction at an intermediate stage. The glass transition temperature of this single-sided steel-clad laminate was 88% and 64% of the glass transition temperature of the fully cured single-sided copper-clad laminate that had completed the curing reaction.

This single-sided copper-clad laminate was stacked with prepreg sheets sandwiched between each side of the inner layer circuit board, and the whole was heated and pressurized via a mirror plate to complete the curing reaction, thereby obtaining a multilayer circuit board with inner layer circuits.

[Comparative Example] A single-sided copper-clad laminate structure consisting of one prepreg sheet and 18 μm thick electrolytic copper foil was placed facing the prepreg sheet side with a release paper with a roughened surface sandwiched in between, and the whole was mirrored. A curing reaction was progressed by applying heat and pressure through the face plate to obtain a single-sided copper-clad laminate that was almost completely cured under normal conditions.

The glass transition temperature of this single-sided copper-clad laminate is 98% higher than the glass transition temperature of a fully cured single-sided steel-clad laminate that has completed the curing reaction.
%Met.

This single-sided copper-clad laminate was stacked with prepreg sheets sandwiched between each side of the inner layer circuit board, and the whole was heated and pressurized via a mirror plate to complete the curing reaction, thereby obtaining a multilayer circuit board with inner layer circuits.

The outer layer copper foil of these multilayer circuit boards of Example 1, Example 2, and Comparative Example was removed by chemical etching, and a 50 mm
A sample was obtained by cutting into X5 (1+m), and the sample was boiled, immersed in a solder bath, and visually observed for the presence or absence of glabellar peeling. The results are shown in Table 1.

[11 lines below] Table 1 ◎... No delamination ○... Slight delamination occurred △... Partial delamination ×... Severe delamination [Effects of the invention] This invention The single-sided metal-clad laminate for multilayer circuit boards of the present invention can improve adhesive strength and reduce the occurrence of glabella peeling when integrated by pressurizing and heating as an outer layer material. Since the laminate has less resin deterioration and less curl, it can reduce the cause of poor adhesion when used as an outer layer material under pressure and heat.

Furthermore, the single-sided metal-clad laminate for multilayer circuit boards of the present invention can improve productivity by shortening the heating time during heating and pressurization.

Claims (3)

[Claims] (1) One to several prepreg sheets whose base material is impregnated with a thermosetting resin whose glass transition temperature is 60% to 90% of the glass transition temperature when fully cured, and metal placed on one side of the prepreg sheet. The prepreg surface of a single-sided metal-clad laminate structure made of foil is placed opposite to the prepreg surface of another similar single-sided metal-clad laminate structure with a release paper or film with a roughened surface interposed therebetween. , after heating and pressurizing the entire body through a mirror plate,
A method for manufacturing a single-sided metal-clad laminate for a multilayer circuit board, comprising peeling the single-sided metal-clad laminate from a release paper with a roughened surface. (2) The multilayer circuit according to claim 1, characterized in that the prepreg sheet is composed of two types of prepreg sheets with different curing speeds, and the prepreg sheet with the faster curing speed is stacked with the metal foil side facing. A method for producing a single-sided metal-clad laminate for a substrate. (3) A single-sided metal-clad laminate for a multilayer circuit board according to claim 1 or 2, wherein the release film with a roughened surface is formed using polymethylpentene. Production method.