JPS61261012A - Manufacture of laminated sheet and device thereof - Google Patents

Abstract

PURPOSE:To improve the heat resistance of a laminate sheet, by reducing the dimension-change and the warpage thereof by a method in which a plurality of prepregs made by impregnating base material with resin and drying them, are lapped and enclosed hermetically with films and then after being kept in reduced pressure, they are formed under heating and pressurizing. CONSTITUTION:The circumference of prepregs 1 is enclosed with an enclosing jig 6, and in this state, the prepregs are inserted into a space between two films 2, 2. An exhausting pipe 4 is fitted to one position of said enclosing jig 6 under penetrating the inner and outer circumferences thereof. In the state where the prepregs and the enclosing jig 6 are inserted into the space between two films 2, 2 in such a manner, an adhering tape 7 is stuck between the whole peripheries of the films 2, 2, and the space between two films 2, 2 is tightly closed, whereby the bag tightly closed by the films 2, 2 is formed. Next, the air in the space between two films 2, 2 is extracted and removed from an exhausting pipe 4. The pressure in the space between the films 2, 2 is reduced and then the prepregs between the films 2, 2 are formed under heating and pressurizing by heating plates 3, 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method and apparatus for manufacturing a laminate used as a substrate for a printed wiring board, etc.

[Background technology] Laminated boards used as substrates for printed wiring boards are made by impregnating a base material such as paper, lath woven cloth, or lath non-woven cloth with a face of thermosetting resin such as phenol resin, epoxy resin, or polyimide resin. By heating and drying the resin,
It is manufactured by creating prepreg (Lennon cloth) in a stage state, stacking multiple sheets of this prepreg, then layering metal foil such as copper foil on both or one side of this stack, and then heating and press-forming this. . 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 then this is heated and press-molded.

At Uni, heating and pressure during molding is performed using a hot platen such as a hydraulic press that uses steam, electricity, or oil as a heat source, but the pressure during this molding is usually 40°C.
This is done at a high pressure of K g/c+a" or higher. In other words, since air remains inside the prepreg, between the eyebrows of the prepreg, and between the inner layer circuits when using an inner layer circuit board, high pressure is applied during molding. If this residual air is not removed, defects such as voids and scratches will occur in the laminate.

However, when pressurized at such high pressure, the flow of resin increases during molding, and a large amount of residual strain remains in the laminate, resulting in variations in thickness, dimensional changes, warping, and twisting of the assembled laminate. Problems arise in that a large amount of resin is generated, and that the amount of resin in the laminate is substantially insufficient due to a large amount of resin flowing out, resulting in a decrease in heat resistance.

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

[Disclosure of the Invention] The method for manufacturing a laminate according to the present invention includes stacking a plurality of prepregs 1 created by impregnating and drying a base material with a resin,
The prepreg 1 is airtightly wrapped with a film 2 and set between heating plates 3, and after the inside of the film 2 is reduced in pressure, the prepreg 1 is heated and pressurized by the heating plate 3 to perform molding. The laminate manufacturing apparatus according to the above includes a film 2 for airtightly sealing a plurality of prepregs 1 made by impregnating and drying a base material with a resin, and an exhaust pipe 4 for exhausting air inside the film 2. and a pair of heating plates 3 for heating and pressurizing the prepreg 1 sealed in the film 2.The present invention will be described in detail below with reference to Examples.

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,
〃Resin is made into a B-stage state by impregnating it into a base material such as a lath nonwoven fabric and heating and drying it, and then it is prepared as a resin cloth.Multiple sheets of this are layered together, and metal foil such as copper foil is layered on one or both sides of the resin cloth. This plastic material is stacked in multiple stages via mold plates, and subjected to lamination molding by heating and pressing. In the present invention, this molding is performed using an apparatus as shown in FIG.

The apparatus shown in FIG. 1 is formed by a pair of upper and lower heating plates 3, 3, which are heated using steam, electricity, oil, etc. as a heat source, and are heated using a hydraulic press mechanism or the like. It is formed so that it can be pressurized. In addition, film 2 has heat resistance that can withstand temperatures of about 300°C.
A material having airtightness capable of maintaining a vacuum state of approximately Torr or higher, such as a triacetate film, a polyethylene terephthalate film, a polypropylene film, a polyamide film, etc., can be used.

Then, the loaded prepreg 1 is surrounded by a surrounding jig 6 as shown in FIG. 2, and in this state it is sandwiched between two films 2, 2. There are no particular restrictions on the shape, size or material of the surrounding jig 6 as long as it is annular enough to surround the prepreg 1; It must be durable.Also, an exhaust pipe 4 is attached to one part of the enclosure Jil-6, penetrating the inner and outer peripheries.

However, with the prepreg and the enclosure jig 6 sandwiched between the two films 2, 2 like a lever, adhesive tape 7 is pasted between the entire periphery of the films 2, 2 to seal the space between both films 2, 2. condition so that a sealed bag is formed by the film 2.2.

In this case, the adhesive tape 7 may not be used, as long as it can be made into a sealed state by a method such as thermocompression bonding. Then, the exhaust pipe 4 is connected to a pressure reducing device such as a vacuum pump, and as shown in Fig. 1, this is placed on a carrier plate 9 between a pair of upper and lower cushioning materials 8. g13. Set to 3 questions. Next, the air between the films 2 and 2 is extracted and removed from the exhaust pipe 4, the pressure between the films 2 and 2 is reduced, and the prepreg 1 between the films 2 and 2 is heated and press-molded using the hot platens 3 and 3.

In this case, even if the air between the films 2 and 2 is removed before the heat-pressing molding or during the heat-pressing molding, the resin of the prepreg 1 will not be melted. Either is fine as long as it is done before the

In this way, it is possible to obtain a laminate in which the prepregs 1 are laminated, but when performing this molding, the films 2, 2 are under reduced pressure, so the air between the films 2, 2 is removed, Molding is performed after the air remaining in the prepreg 1 or between the eyebrows of the prepreg 1 is removed, so there is no need to perform molding under high pressure to remove air.
Even with low pressure, there is a risk of defects such as voids and smearing (this means that molding can be performed. For example, conventionally, molding must be performed at a pressure of 40 kg/c + m2 or more, but with a pressure of 20 kg/c + m2 or more, This allows molding at a pressure of /cu2 or less.

Next, to explain the evaluation of the present invention, a 4-layer printed wiring board laminate using FR-4 class epoxy resin (size 510 x 340 mm, thickness after molding 1, 6
mm), when molding was carried out at a high pressure of 40 kg/am2 without the conventional depressurization (
Conventional example), when molding was performed at a low pressure of 20 kg/am2 without depressurization (comparative example), molding was performed at a low pressure of 20 kg/am'' while depressurizing using the equipment shown in Figures 1 and 2. As a result of measuring the characteristics for each case (Example), the results shown in the table above show that the example can be molded without generating voids, and there is little puffiness, warpage, or dimensional change in the plate thickness. Furthermore, it is confirmed that the heat resistance is also excellent.

C Effect of the invention] As described above, the method for manufacturing a laminate according to the present invention involves stacking a plurality of prepregs created by impregnating and drying a base material with a resin, airtightly wrapping the prepregs with a film, and placing them between hot platens. Set it to
After reducing the pressure inside the film, the prepreg is heated and pressurized using a hot platen to form the film, so the air remaining inside the prepreg and between the layers of the prepreg is removed before forming. , it is possible to perform molding even under low pressure without the risk of defects such as voids and scratches, and it reduces variations in the thickness of the laminate, dimensional changes, warping, etc., and also improves heat resistance. The laminate manufacturing apparatus of the present invention also includes a film in which a plurality of prepregs made by impregnating and drying a base material with a resin are stacked and airtightly sealed; The device is equipped with an exhaust pipe attached to the film to exhaust the air inside the film, and a pair of heating plates to heat and pressurize the prepreg sealed in the film, so the pressure reduction can be done by sealing the prepreg. It can be carried out within a film, the existing hot platen for laminate forming can be used as is, and there is no need to make major changes to the forming equipment.

[Brief explanation of the drawing]

FIG. 1 is an exploded sectional view of one embodiment of the present invention, and FIG. 2 is a plan view of a portion of the same. 1 is a prepreg, 2 is a film, 3 is a heating plate, and 4 is an exhaust pipe.

Claims (2)

[Claims] (1) Layer multiple sheets of prepreg created by impregnating and drying a resin on the base material, wrap it airtight with a film, set it between hot plates, reduce the pressure inside the film, and then use the hot plate to form the prepreg. A method for manufacturing a laminate, characterized by forming the laminate by heating and pressurizing it. (2) A film that airtightly seals multiple sheets of prepreg made by impregnating a base material with resin and drying it, an exhaust pipe for exhausting the air inside the film, and a prepreg sealed in this film. A laminate manufacturing apparatus characterized by comprising a pair of heating plates for heating and pressurizing.