JPH01157822A - Manufacture of laminated sheet - Google Patents

Abstract

PURPOSE:To remove voids contained in resin efficiently and control the generation of thin spots developed by the voids on a molded laminated sheet by pressurizing the sheet with a low initial pressure to the state of a given reduced pressure and then pressurizing with a pressure higher than the initial pressure. CONSTITUTION:A laminated material is pressurized with a low initial pressure up to the state of given reduced pressure and then pressurized with a pressure higher than the initial pressure in the manufacturing method of a laminated sheet in which a plurality of laminated material consisting of piled up inner layer materials, resin impregnating bases, metal foils and the like are heated and pressurized under the pressure reduced atmosphere. A plurality of piled up resin impregnating bases are disposed between hot platens to vacuum atmosphere and a laminated sheet is manufactured by heating and pressurizing under the pressure reduced atmosphere. The degree of vacuum is 100Torr or less, and lowering pressure is 5-150kg/cm<2>, while molding temperature is 100-200 deg.C and molding time is around 30-100min. The initial pressure is 5-10kg/cm<2> and the pressure is applied until the degree of vacuum comes up to 500-100Torr.

Description

[Detailed description of the invention] 【Technical field】

The present invention relates to a method for manufacturing a laminate used as a printed wiring board or the like.

[Background technology]

Conventionally, multiple sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, metal foil, etc., are placed between hot plates equipped with a vacuum enclosing press mechanism, and heated and pressurized under reduced pressure to produce a laminate. However, due to unevenness in the resin content of the resin-impregnated base material, differences in temperature rise within the heating plate, and other factors, voids caused scratches in the molded laminate. In order to prevent this blurring, high-pressure molding is used.
In this case, there was a problem in that the laminate would be greatly warped and twisted.

[Purpose of the invention]

The present invention has been made in view of the above circumstances. The goal is to avoid blurring and warping.
The purpose is to manufacture laminates with small twists.

[Disclosure of the invention]

The method for manufacturing a laminate of the present invention is a method for manufacturing a laminate in which multiple sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, metal foil, etc., are heated and pressurized in a reduced-pressure atmosphere, and a predetermined level is achieved at a low initial pressure. This feature is characterized in that the pressure is increased until a reduced pressure state is reached, and then the pressure is increased at a pressure higher than the initial pressure, and this configuration achieves the above object. In the present invention, the resin-impregnated base material may be paper, cloth made of organic a-fiber, non-woven fabric, or cloth made of inorganic fibers such as glass or asbestos alone or in a blend, or non-woven fabric, and the like is dipped in a resin face to soak the resin. Formed by impregnation and drying. The thickness of the base material is preferably 0.10-0.
30+am and weighs 100-300 g/m". Glass cloth other than this specific thickness and weight has poor resin impregnation properties and contains a large number of air bubbles. As a resin for a resin face. Thermosetting resins such as epoxy resins, polyimide resins or modified products thereof, phenolic resins, and unsaturated polyester resins can be used for the resin.In this case, the resin is impregnated into the base material under reduced pressure by reducing the pressure in the varnish bath. Alternatively, pressure is applied by passing the base material between two upper and lower rolls arranged in a varnish tank, and then the pressure is removed.In the case of pressurization, for example, there are three rolls, and impregnation is carried out under a pressure of 10 kg/am2. The amount of resin impregnated is 35 to 65% by weight in terms of solid content.By carrying out the process under reduced pressure or increased pressure, it is possible to reduce the entrainment of air bubbles into the base material in the varnish bath. Impregnation may also be carried out under pressure. A plurality of laminates made by stacking a plurality of these resin-impregnated substrates are placed between heating platens, a so-called vacuum is enclosed between the heating plates, and the laminate is heated and pressurized in a reduced pressure atmosphere. Form.Vacuum degree is 1
00'rorr or less, and the molding pressure is 5-150
kg/am2, molding temperature is 100-200°C, and molding time is about 30-100 minutes. The initial pressure is 5-10 kg/am2, and the degree of vacuum is 5
Pressurize until the pressure reaches 00 to 100 Torr. in this case,
A metal foil may be placed on the outermost layer of the laminate. Metal foils include copper foil, aluminum foil, brass foil,
Nickel foil, stainless steel copper foil, iron foil, etc. can be used, and an adhesive layer may be provided on one side of this metal foil to improve adhesion.Also, the laminate may have a resin-impregnated base on both sides of the inner layer material. It may also be one in which metal foil is layered on the outermost layer. The metal foil-clad laminate thus obtained is used in practical use as a printed wiring board or a multilayer printed wiring board by forming an outer layer circuit pattern by a conventional method. Next, examples of the present invention will be specifically described. (Example 1) A plurality of resin-impregnated base materials obtained by impregnating glass cloth with epoxy resin and drying them were stacked, and the plurality of sets were placed between heating plates, and the initial pressure was set at a temperature of 165 to 175°C. 5
After pressurizing at 30 kg/am2, when the degree of vacuum reached 100 Torr, pressurizing at 30 kg/am2 and reducing the thickness to 1.
61 laminates were obtained. The degree of vacuum was 100 Torr, and the molding time was about 120 minutes (see Figure 1). The rate of occurrence of peeling of this laminate, the warping of the 1 w x 1 m product under normal conditions, and the variation in plate thickness were measured. The results are shown in Table 1i. (Example 2) Initial pressure 10 kg/0 m2 and vacuum degree 300 Tor
A laminate was produced in the same manner as in Example 1, except that the pressure was applied until it reached r. The same measurements as in Example 1 were also performed on this laminate. The results are shown in Table 1. (Example 3) A laminate was manufactured in the same manner as in Example 1 except that the initial pressure was 10 kg/am2 and the pressure was turned off when the degree of vacuum reached 500 Torr. The same measurements as in Example 1 were also performed on this laminate. The results are shown in Table 1. (Comparative Example) A laminate was produced in the same manner as in Example 1 except that the degree of vacuum was 100 Torr and the pressure was 60 kg/0 m2 (see FIG. 2). The same measurements as in Example 1 were also performed on this laminate. The results are shown in Table 1. Table 1 Example Comparative Example Fading incidence 0 0 4 5 (%) Warpage 8 8 10 15
(Import) Dispersion width of plate thickness 0.08 0.08 0.09 0.1
5all+1 All of the examples of the present invention have a higher blurring occurrence rate than the comparative example.
It can be seen that the variations in warpage and plate thickness are small. and,
It is understood that these characteristics are better as the initial pressure is smaller and the degree of vacuum is smaller when the initial pressure is released. This is due to the increased pressure reduction effect.

【Effect of the invention】

The present invention is a method for manufacturing a laminate in which multiple sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, metal foil, etc., are heated and pressed in a reduced pressure atmosphere under a laxative. Then, since the pressure is applied at a higher pressure than the initial pressure, the pressure is reduced in the normal state where the resin in the resin-impregnated base material is molten, and the voids contained in the resin can be efficiently removed and molded. It is possible to suppress the occurrence of scratches due to voids in the laminate, and since the voids are removed by removal rather than efficiency, the molding pressure can be lowered to that extent, and the warpage of the laminate and the width of variation in board thickness can be reduced. It is something.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between pressure and vacuum degree in an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between pressure and vacuum degree in a conventional example. Agent Patent Attorney Ishi 1) Ai Shichi

Claims (4)

[Claims] (1) A method for manufacturing a laminate in which multiple sets of laminates, each consisting of an inner layer material, a resin-impregnated base material, metal foil, etc., are heated and pressurized in a reduced pressure atmosphere, and the pressure is applied at a low initial pressure until a predetermined reduced pressure state is reached. , and then pressurizing at a higher pressure than the initial pressure. (2) The method for manufacturing a laminate according to claim 1, wherein the laminate is formed by stacking a plurality of resin-impregnated base materials and overlapping a metal foil on the outermost layer. (3) The method for manufacturing a laminate according to claim 1, wherein the laminate is formed by disposing resin-impregnated base materials on both sides of an inner layer material and overlapping metal foil on the outermost layer. (4) The method for manufacturing a laminate according to claim 1, wherein the laminate is formed by stacking a plurality of resin-impregnated base materials.