JPS6149111B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a method for manufacturing a polyimide resin single-sided copper-clad laminate for use in printed circuit boards that require heat resistance. [Technical Background of the Invention] Conventionally, methods for producing single-sided copper-clad laminates made of polyimide resins have been conducted using polyimide resins (resins having imide bonds in their main chains, or reaction products or mixtures of these and other resins). ) impregnated into a glass cloth base material, etc.
The required number of semi-cured prepregs are stacked, one side of the prepreg is laminated with copper foil, and then the prepreg is laminated with copper foil, which is then inserted between the stainless steel plates, and then the whole is placed between the molding press heating plate with a cushion material on the top and bottom side.
This is a method in which the single-sided copper-clad laminate obtained after heating and pressure molding and cooling is released from the stainless steel plate and taken out. At this time, there is a tendency that the substrate surface of the single-sided copper-clad laminate and the stainless steel plate are in close contact with each other, making it difficult to release from the mold. [Problems in the background art] Until now, there have been no reports on literature or patents regarding mold release methods for polyimide resin laminates, but it is known that triacetyl cellulose film is used as a mold release film for epoxy resin laminates. (Special Publication No. 14034, Showa 47). However, when this film is used as a release film for polyimide-based resin single-sided copper-clad laminates, it impairs the electrical properties, especially the surface resistance of the board surface, and also affects the copper foil side, resulting in poor soldering heat resistance and peeling. This lowered the strength and also caused problems in terms of work because the release film peeled off from the substrate surface and the mold release from the stainless steel plate was poor. [Purpose of the Invention] As a result of examining various release films for this problem, the present inventors found that the soldering heat resistance, peel strength, etc. of polyimide resin prepregs decrease in proportion to the amount of moisture absorbed. If a polyvinyl alcohol film with a relatively large number of OH groups is used, the film will completely adhere to the substrate surface, and the soldering heat resistance and peel strength will be significantly reduced.
Furthermore, triacetylcellulose films have similar tendencies, such as the fact that cellulose's OH groups remain, so if you select a release film that does not have groups that act on imide bonds, such as OH groups, you will get good results. The present invention was completed by discovering that the following can be obtained. Based on the above findings, the present invention aims to provide a method for producing a single-sided copper-clad laminate made of polyimide resin that has excellent electrical properties such as surface resistance, soldering heat resistance, peel strength, and mold release properties. [Summary of the Invention] The present invention involves laminating copper foil on one side of a polyimide resin-impregnated base material, and interposing a poly-4-methylpentene-1 film between the other side of the base material and a stainless steel plate. This is a method for producing a single-sided copper-clad laminate made of polyimide resin, characterized in that the film is laminated using a polyimide resin, and the film is peeled off after hot-pressure molding. The polyimide resin used in the present invention is a resin having an imide bond in its main chain, or a reaction product or mixture of this and other resins, such as polyimide resin, polyamideimide resin, polyesterimide resin, polyimide epoxy resin, These include polysulfonimide resin, polyacrylimide resin, bismaleimide triazine resin, polyallylbisphenol A bismaleimide resin, and the like. The base material used in the present invention may be an inorganic base material such as glass cloth or glass paper, or an organic base material such as paper or synthetic fiber, as desired, and the polyimide resin is impregnated into the base material by an appropriate means. The copper foil used in the present invention can be normally electrolyzed or rolled copper foil, and may be surface-treated or annealed if necessary. Poly-4-methylpentene-1 used in the present invention
The film has the following structural formula, It has good properties, is easy to peel from the substrate surface, and has a particularly good surface appearance. The thickness of the poly-4-methylpentene-1 film is preferably 0.03 to 0.10 mm.
If it is thinner than this, it is easy to tear and has poor workability, and if it is thicker than this, it is uneconomical. Polyimide resin laminates are manufactured by interposing a poly-4-methylpentene-1 film between a polyimide resin-impregnated base material and a stainless steel plate, without using copper foil, and peeling off the film after lamination heating and pressure molding. If this method is used, the electrical characteristics and
A polyimide resin laminate with excellent heat resistance and surface appearance can be obtained. According to the present invention, poly-4-methylpentene-1 film is used as a release film for a polyimide resin single-sided copper-clad laminate, so polyimide has excellent properties such as surface resistance, soldering heat resistance, and peel strength. A single-sided copper-clad laminate made of resin based resin can be obtained, and the peeling from the substrate surface and mold release from the stainless steel plate are good. Hereinafter, the advantages of the present invention will be explained in detail with reference to Examples. Example 1 As shown in Fig. 1, the thickness of the substrate after molding the glass cloth base polyimide resin prepreg 6 was 0.2 mm.
18μ electrolytically treated copper foil 5 is placed on one side and poly-4-methylpentene-1 film 4 0.04mm thick is placed on the other side. Insert this between two stainless steel plates 3,
Furthermore, the cushion material 2 is arranged on the upper and lower sides, and placed between the press heating plate 1, and the heating plate temperature is 175-195℃, the pressure is 40℃.
The product is heated and pressure-molded at Kg/cm ² for 120 minutes, then cooled until the laminate temperature reaches 40°C, decompressed, and the polyimide resin single-sided copper-clad laminate is taken out. The properties were measured according to JISC 6481. The result is
The first results were compared with the results obtained using polyvinyl alcohol film, triacetyl cellulose film, poly-1-fluoroethylene film, and biaxially oriented polypropylene film of the same thickness and under the same conditions as in Example 1. Shown in the table. Example 2 The same procedure as in Example 1 was conducted using a glass base bismaleimide triazine resin prepreg. The results are shown in Table 2.

【table】

[Table] Looking at the releasability from the stainless steel plate and from the substrate surface, when polyvinyl alcohol film is used, the mold releasability is good, but it adheres tightly to the substrate surface and cannot be peeled off. When triacetylcellulose film is used, it has poor mold releasability and peelability, which poses a problem in work. When poly-1-fluoroethylene film is used, there is no problem in mold releasability and peelability, but cloudiness occurs on the stainless steel plate after mold release, requiring mechanical removal. When a biaxially stretched polypropylene film is used, the parts protruding from the stainless steel plate melt and adhere to other parts and become dirty, and the stainless steel plate also becomes somewhat cloudy after being released from the mold. Compared to these, when poly-4-methylpentene-1 film is used, the mold releasability, peelability, and condition of the stainless steel plate are all the best. Regarding the surface appearance of the laminate surface, Japanese Patent Publication No. 47-14034 mentioned above states that when a polypropylene film is used as a release film for an epoxy resin laminate, the eyes of the glass cloth base material are exposed on the laminate surface. It is stated that this may damage the appearance. However, when a poly-4-methylpentene-1 film is used in a polyimide resin laminate as in the present invention, even though the molding temperature is as high as 175 to 195°C, the eyes of the substrate do not form in the laminate. It is not exposed on the surface and there is no problem with the surface appearance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the lamination state in the production of a single-sided copper-clad laminate according to the present invention. 1...Press heating plate, 3...Stainless steel plate, 4...
...Release film (poly-4-methylpentene-1
film), 5... copper foil, 6... polyimide resin impregnated base material.

Claims (1)

[Claims] 1 Copper foil is laminated on one side of a polyimide resin-impregnated base material, and a poly-4-methylpentene-1 film is interposed between the other side of the base material and a stainless steel plate, and then heated and pressure molded. A method for manufacturing a polyimide resin single-sided copper-clad laminate, which comprises then peeling off the film.