JPH0328287B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing multilayer printed wiring boards and laminates such as copper-clad laminates and non-copper-clad laminates.

Conventional Technology Conventionally, a hot plate press method is generally known as a technique for laminating and forming sheets to be formed for use in multilayer printed wiring boards and laminates such as copper-clad laminates and non-copper-clad laminates used in multilayer printed wiring boards. It is being

This hot platen press method involves stacking a large number of sheets to be formed to be used for the above-mentioned laminate between hot plates via a plurality of plate molds, and then applying heat and pressure to the resin part of the prepreg in the plate to be formed. Once softened,
After that, it is cured and the plate to be molded is adhesively molded.

Problems to be Solved by the Invention However, this method has the following problems.

Since multiple laminated plates (sheets to be formed) are simultaneously formed using plate molds between the hot platens adjacent to the top and bottom of the press, the temperature of the outer layer plate close to the hot platen and the inner layer plate far from the hot platen increases. As a result, a large amount of resin resin flows out of the laminated plate near the heating plate, causing a deviation in thickness from the inner layer plate, resulting in quality problems.

When the prepreg in the laminate is heated and pressurized between hot platens, heat is radiated at the ends (periphery) of the prepreg, resulting in a lower heating temperature. On the other hand, the central part of the prepreg accumulates heat and the heating temperature becomes high, the molten viscosity of the impregnated resin is low, and the molten resin of the prepreg flows out due to the pressure applied by the hot platen, resulting in the thickness of the laminate end being smaller than that of the central part. Finished thinly.

In addition, the resin that flows out hardens and forms burrs that adhere to the press, heating platen, and plate mold, causing problems during the next molding process and leaving dents in the laminate, resulting in poor appearance.

Therefore, various improvement measures have been taken in the past, but
Each has its advantages and disadvantages, and appropriate improvement measures are desperately needed.

An object of the present invention is to provide a method for manufacturing a laminate that solves the above-mentioned problems.

Means for Solving the Problems In the method for manufacturing a laminate according to the present invention, in laminating a plate to be formed to be used for a laminate, the plate to be formed is coated and sealed in a vacuum bag and housed in a pressure vessel. After reducing the pressure in the container and the vacuum bag, steam is applied to the container to heat and pressurize the plate to be formed.

By doing so, the heating and pressurizing energy possessed by the steam is applied to the entire outer circumferential surface of the plate to be formed, and the plate to be formed is uniformly heated and bonded and hardened. It is.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First, prior to the explanation, the laminate as used in the present invention will be explained.

The laminate used in the present invention refers to a multilayer printed wiring board and a laminate such as a copper-clad laminate, a non-copper-clad laminate, etc. used in the multilayer printed wiring board, and a molded board on which the laminate is laminated and molded. Examples include the copper-clad laminate, non-copper-clad laminate, prepreg, and copper foil.

Prepreg is made by impregnating a base material such as paper or glass cloth with thermosetting resin varnish such as phenolic resin varnish or epoxy resin varnish to create a resin-impregnated sheet, and then drying this resin-impregnated sheet to make it into a B-stage. .

The copper-clad laminate is produced by cutting the above prepreg to a fixed size, stacking a plurality of prepregs, pasting copper foil on one or both sides of the prepreg, and bonding and hardening the prepreg by applying heat and pressure.

A multilayer printed wiring board, for example, is one in which a single-sided copper-clad laminate, a prepreg, an inner-layer circuit board, a prepreg, and a single-sided copper-clad laminate are laminated in sequence, heated and pressed, and adhesively cured and molded.

Next, the configuration of the embodiment will be explained.

As shown in Figures 1 and 2, 1 is a board to be formed such as a copper-clad laminate, an inner layer circuit board, a prepreg, a copper foil, etc., 2 is a pressure vessel that accommodates the board to be formed, and 3 is a sealed container 2. This is a door for opening and closing.

A is a heating and pressurizing means for supplying steam into the container 2, and the steam is supplied through an automatic valve 4 and discharged through an automatic valve 5.

B is a pressure reducing means for reducing the pressure inside the container 2 and the vacuum bag 10, and the pressure reducing means is branched from a vacuum pump 6 installed outside the container 2, as shown in FIG. It is piped to communicate with the inside of the container 2 via the valve 9. One of the branched pipes is used as a means to reduce the pressure inside the container 2, and the other pipe is connected to the side of each fixed plate so that it can be attached and detached using a coupler in order to reduce the pressure inside the vacuum bag 10 of the plate equipment member to be formed, which will be described later. .

C is a fixed plate 11 on which a plurality of plates 1 to be formed are stacked and arranged.
and forming plate equipment, which covers and seals the plate 1 to be formed with a vacuum bag 10 on the fixed plate, and is provided with an air passage 12 for reducing the pressure inside the vacuum bag 10, and is provided so as to be able to move in and out of the container 2. It is a member.

The plate equipment member C to be formed is made by placing a breathable glass cloth 13 and a mirror plate 14 on the fixed plate 11, as shown in FIGS. 3 and 4, and then placing a copper foil 15 and a plurality of pieces of Prepreg 16, copper foil 15, mirror plate 14, and cushion material 17 are laminated in order, and the mirror plate corresponds to the plate mold described above and is generally a flat plate made of stainless steel with a diameter of about 1.0 to 2.0 mm. .

Next, the stacked laminates are covered in a vacuum bag 10 made of, for example, a plastic film that is flexible in steam, and then, as shown in FIG. A certain sealant 19 is applied to the sealant 19, and the outer periphery of the vacuum bag 10 is adhered to the sealant 19 so that the laminate plate, which is the plate 1 to be formed, can be sealed. The air inside the vacuum bag 10 passes through a shallow groove provided on the upper surface of the fixed plate 11 or passes through the glass cloth 13 shown in FIG.
It is guided to a coupler 20 provided on the side of the.
As shown in FIG. 2, the coupler 20 is provided so as to be able to communicate with and shut off the vacuum pump 6 outside the container 2.

Furthermore, the plate equipment member C to be formed is mounted on a frame 2 of a multi-stage shelf on a trolley 21 as shown in FIGS. 1 and 2.
The cart 21 is provided so that it can be inserted into and taken out from the container 2.

Next, its effect will be explained.

First, plates 1 to be formed to be formed into a laminate on a fixed plate 11 are sequentially stacked in multiple layers, for example as shown in FIG. The molded plate 1 is sealed with adhesive. Next, the plate 1 to be formed is placed on a shelf of a cart 21 and carried into the container 2 as shown in FIGS. Connect one side of the pipe and close the door 3.

Next, the vacuum pump 6 is operated, and then the automatic valves 8 and 9 are operated to remove the inside of the container 2 and the vacuum bag 1.
Reduce the pressure within 0. Here, preferably, after operating the vacuum pump 6, the automatic valve 8 is operated first to reduce the pressure inside the container 2, and after the pressure has been sufficiently reduced, the automatic valve 9 is operated to reduce the pressure inside the vacuum bag 10.
At first, the pressure inside the vacuum bag is high and the vacuum bag expands as shown in Figure 4. Therefore, the vacuum bag 1
The air inside the vacuum bag 10 and in the gaps between the stacked plates 1 to be formed is reliably exhausted without being trapped, making it possible to create a high vacuum inside the vacuum bag 10.

Further, the purpose of reducing the pressure inside the container 2 is to exhaust the air inside the container so that the steam is evenly distributed inside the container, so that the plate to be formed can be heated uniformly.

Next, the automatic valve 8 is closed to stop the pressure reduction inside the container 2. Next, while reducing the pressure inside the vacuum bag 10, the automatic valve 4 is operated to supply steam into the container 2, and the vacuum bag 10 is brought into close contact with the plate 1 to be formed as shown in FIG. Heat and pressurize the molded plate from the entire outer circumferential surface as shown by the arrow.

The heating and pressurizing conditions are such that the temperature and pressure are gradually increased as shown in the graph shown in FIG.

Then, when the resin part of the prepreg reaches the minimum value of melt viscosity, the air bubbles existing in the resin part move to the periphery of the prepreg and are discharged to the outside through the air passage 12.

Subsequently, the temperature is raised to a specified temperature at which the resin hardens, and this state is maintained for a while. Then, the plate to be formed is bonded and cured. The prescribed temperature for curing the adhesive is determined by the material of the resin.

After heating and pressurizing for a certain period of time, the temperature and pressure are lowered to cool the plate to be formed.

When the cooling is completed, the door 3 is opened and the plate 1 to be formed is taken out and one forming process is completed.

Here, the dimensions of the two-layer copper-clad laminate: 500 x 500 mm,
When prepreg: G-10 was molded according to the conditions shown in Figure 6, there was no burr at the end of the laminate.
A copper-clad laminate with uniform thickness was obtained.

Note that the heating and pressurizing conditions may be, for example, as shown in the graph shown in FIG. 7, and are not limited to the embodiments of the present invention.

Effects of the Invention As described above, according to the present invention, when a plate to be formed to be used for a laminate is laminated and molded, the plate to be formed is covered and sealed in a vacuum bag and housed in a pressure vessel, and the plate to be formed is coated and sealed in a vacuum bag, and the bag is sealed between the inside of the container and the vacuum bag. After reducing the pressure inside the container, steam is applied to the container to heat and pressurize the plate to be formed, so that the heating and pressurizing energy held by the steam can be applied uniformly to the entire circumference of the plate to be formed. Since the plate to be formed is heated both from the outer peripheral surface and from the inner surface via the plate mold (mirror plate), there is almost no temperature difference between the ends and the center of the plate to be formed. Therefore, the deviation in thickness between the outer layer and the inner layer of the laminate, which has conventionally occurred, is eliminated, and the thickness at the ends and center of the laminate is uniform, making it possible to provide a laminate of good quality.

Further, there is no heat dissipation from the ends of the plate to be molded, and since the molded plate is pressurized, the resin does not flow out and the occurrence of burrs can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway schematic side view showing one embodiment of the present invention. FIG. 2 is a schematic vertical sectional view of FIG. 1. Figure 3 shows an example of a laminated plate in which plates to be formed are stacked in two layers. FIG. 4 is a diagram showing the state inside the vacuum bag when the pressure inside the pressure vessel is first reduced. FIG. 5 is a diagram showing a state in which steam is supplied into the pressure vessel and the pressure inside the vacuum bag is reduced. FIG. 6 is a diagram showing an example of a heating and pressing program for molding a plate to be molded. FIG. 7 is a diagram showing another embodiment of the heating and pressurizing program. In these figures, A: heating and pressurizing means, B:
Pressure reducing means, C: Formed plate equipment member, 1: Formed plate, 2: Pressure vessel, 3: Door, 4, 5, 8, 9: Automatic valve, 6: Vacuum pump, 10: Vacuum bag, 1
1: fixed plate, 12: ventilation path, 13: glass cloth,
14: Mirror plate, 15: Copper foil, 16: Prepreg,
17: Cushion material, 19: Sealant, 2
0: Coupler, 21: Dolly, 22: Frame.

Claims (1)

[Claims] 1. In laminating and molding a plate to be formed to be used for a laminate, the plate to be formed is coated and sealed in a vacuum bag and housed in a pressure vessel, and after reducing the pressure in the container and the vacuum bag, A method for producing a laminated board, characterized by applying steam inside the board to heat and pressurize the board to be formed.