JPS6262738A - Manufacture of laminated plate - Google Patents

Abstract

PURPOSE:To make molding under low pressure possible, to decrease variability of plate thickness, dimensional variation and warp and to improve heat resistance, by putting air-tightly a laminated body, where metal foils are being laminated on one or both sides of a prepreg laminated body, in a plastic package, by keeping the inside of the plastic package to a reduced pressure and by pressing them set between hot plates under heating. CONSTITUTION:Metal foils 6 such as cupper foil are laminated on one or both sides of a prepreg laminated body 4 obtained by laminating a plurality of a prepreg 1 and mold plates 7, 7 are piled up on the upper and bottom surfaces of this laminated body 5. The whole laminated body is thereafter put into a plastic package 2, where the air is then evacuated to get a state of reduced pressure. This package 2 places between a pair of cushion materials 8, 8 are put on a carrier plate 9 and the whole laminated body is then set between a pair of hot plates 3, 3 and the laminated body 5 in the package 2 is molded under heating and pressing.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a laminated board used as a substrate for a printed wiring board, etc. ! It is related to the method of sending.

[Background technology 1] Laminated boards used as substrates for printed wiring boards are made by impregnating a base material such as paper, lath fabric, or lath nonwoven fabric with a thermosetting resin face such as phenol resin, epoxy resin, or polyimide resin. By heating and drying the resin, B
Prepare prepreg (resyncloth) in steno state, stack multiple sheets of this prepreg, and then stack this stacked agO
It is manufactured by layering metal foil such as copper foil on both sides or one side of the plate, and then molding it under heat and pressure. When used as a substrate for a multilayer printed wiring board, the circuit pattern on the inner layer is created by etching the laminate produced in this way with metal foil on one or both sides and etching the metal foil. This is used as an inner layer circuit board, and a metal foil is layered on the outer surface of this inner layer circuit board via a plurality of prepregs, and this is manufactured by heating and press molding.

Here, the heating and pressurizing during molding is performed using an 8-press machine such as a hydraulic press that uses steam, electricity, or oil as a heat source, but the pressurizing during this molding is usually 40°C.
It is carried out at high pressures of K g/cm2 or higher. That is,
When using an inner layer circuit board, air may remain inside the prepreg, between the layers of the prepreg, or in the inner layer circuit board.
Unless this residual air is expelled by applying high pressure during molding, defects such as voids and scratches will occur in the laminate.

However, when pressurized at such high pressures, the flow of resin during molding becomes large, and a large amount of internal residual strain remains in the laminate, resulting in variations in the thickness and dimensional changes of the assembled laminate.
Problems such as severe warpage and twisting occur, and a problem that a large amount of resin leaks out causes a substantial shortage of resin in the laminate, resulting in a decrease in heat resistance.

[Object of the Invention] The present invention has been made in view of the above points, and can perform molding at low pressure, and eliminates variations in plate thickness, dimensional changes, and
It is an object of the present invention to provide a method for manufacturing a laminate that can reduce warping and the like and improve heat resistance.

[Disclosure of the Invention] Accordingly, the method for producing a laminate according to the present invention involves piling up a plurality of prepregs 1 made by impregnating and drying a base material with a resin, and adding metal i6 on one or both sides of the prepreg stack 4. is loaded, and then this laminate 5 is airtightly stored in the plastic package 2, the inside of the plastic package 2 is reduced in pressure, and then the plastic package 2 is heated to gI:
It is characterized in that the laminate 5 is heated and pressurized by a hot platen 3 to form the laminate 5. ! By heating and pressurizing the layered body 5 housed in the plastic package 2 under reduced pressure, the air inside the layered body 5 can be smoothly removed, thereby achieving the above object. The present invention will be explained in detail below.

Prepreg 1 is a fabric made of thermosetting resin such as phenolic resin, epoxy resin, or polyimide resin, and is made of paper, lath woven cloth,
The resin is made into a B-stage state by impregnating it into a base material such as glass non-woven fabric and heating and drying it, and it is manufactured as Resin Cloth 511. A metal foil 6 such as copper foil is layered on one or both sides of the prepreg loaded material 4 obtained by (FIG. 1(b)), and this laminate 5 is stacked in multiple stages via a mold plate 7 as one layer. It is used for lamination molding by heating and pressurizing. In the present invention, after the layers 7 and 7 are stacked on the upper and lower surfaces of the laminate 5, this is stored inside the plastic package 2, and in this state, the inside of the plastic package 2 is depressurized using a vacuum pump or the like. The air inside the plastic package 2 is evacuated (thereby reducing the pressure) using a device. Next, the plastic package 2 is separated into a pair of upper and lower parts as shown in FIGS. It is placed on the carrier plate 9 between the cushioning materials 8, 8, and further set between the pair of heating plates 3, 3 as shown in FIG.
3, the laminate 5 inside the plastic package 2 is molded under heat and pressure. Here, the plastic packaging body 2 has a heat resistance that can reach a temperature of about 150°C and a temperature of 300 Torr.
A film having airtightness capable of maintaining a vacuum state of a certain level or higher, such as a triacetate film, a polyethylene terephthalate film, a polypropylene film, a polyamide film, etc., can be used. Also, hot plate 3
, 3 are formed so that they can be heated using steam, electricity, oil, etc. as a heat source, and can be pressurized using a hydraulic press mechanism or the like. Thereafter, the laminate is taken out from inside the plastic package 2 and cut into a predetermined size.

In this way, a laminate in which the prepreg 1 and the metal M6 are laminated can be obtained, but when performing this molding, the inside of the plastic package 2 is in a reduced pressure state, so the air inside the plastic package 2 is is removed, and inside prepreg 1, between the layers of prepregs 1 and 1, and in prepreg 1
The molding is performed after the air remaining between the metal foil 6 and the metal foil 6 is removed, and therefore there is no need to perform molding under high pressure to remove air. This means that molding can be performed even under high pressure without the risk of defects such as voids and scratches.For example, molding that conventionally required molding at a pressure of 40 Kg/0 m2 or more has been reduced to 20 Kg/cm2. This allows molding with a pressure of -2 or less.

In addition, by installing a pressure reducing device in front of the molding equipment in the heat exchanger 3, the pressure inside the plastic packaging body 2 can be reduced, and there is no need to improve the molding equipment itself, and the existing heat exchanger 3 can be used. No. 13 can be used as is, and there is no need to change the molding equipment.

Moreover, since the cushioning material 8 is not placed inside the plastic package 2, there is no need to take special measures against the steam generated from the cushioning material 8.Next, the evaluation of the present invention will be explained.FR-=> Laminated board for 4wI printed wiring board using class epoxy resin (size 51
0x340non, thickness 1.6 mIn after molding), the pressure was 40 K without the conventional depressurization.
When molding is performed at a high pressure of g/cm2 (conventional example), when molding is performed at a low pressure of 20 KH/cm2 without depressurization (comparative example), the laminate 5 is placed inside the plastic package 2. After being stored, the air inside the plastic package 2 is removed, and then the package is placed between hot plates 3 and 20 Kg/3.
As a result of measuring the characteristics of each of the cases where molding was carried out at a low pressure of "cm" (Example), the results shown in the following table were obtained.

As shown in the table above, it was confirmed that the products of the examples could be molded without voids, had little variation in plate thickness, warpage, and dimensional changes, and had excellent heat resistance in terms of ν. .

[Effects of the Invention] As described above, the present invention has a method in which metal foil is loaded on one or both sides of a prepreg stack formed by stacking a plurality of prepregs, and then this laminate is airtightly housed in a plastic package. After that, the pressure inside the plastic package was reduced, and then the plastic package was placed between hot platens, and the laminate was heated and pressurized to perform molding. Forming is performed with air remaining between the metal foil and the like removed (this means that molding can be performed without the risk of defects such as voids and scratches even under low pressure). Therefore, it is possible to reduce variations in plate thickness, dimensional changes, warpage, etc. of the laminate, and to improve heat resistance.

[Brief explanation of drawings]

NS1 diagrams (,) to (e) are of one embodiment of the present invention! l!
FIG. 2 is an explanatory diagram showing the construction Jj method, and FIG. 2 is an exploded cross-sectional view of the same. 1 is prepreg, 2 is plastic packaging, 3 is extrathermal,
4 is a plastic load, 5 is a stack of 84 wood, and 6 is a metal foil.

Claims (1)

[Claims] (1) A plurality of prepregs made by impregnating and drying a base material with resin are stacked, metal foil is loaded on one or both sides of the prepreg stack, and then this laminate is airtightly housed in a plastic package. A method for manufacturing a laminate, comprising: reducing the pressure inside the plastic package, then setting the plastic package between hot plates, and heating and pressurizing the laminate with the hot plate to perform molding.