JPS61290036A - Molding method for laminated plate - Google Patents

Abstract

PURPOSE:To enable to mold a voidless laminated plate whose thickness is uniform within a predetermined period of time, by a method wherein the inside of an airtight chamber, which is openable and closable, is depressurized and then a material to be molded is pressurized, heated, stuck and cured by giving high-pressure steam within a vessel. CONSTITUTION:A material 1 to be molded is pressurized and heated by a heating means A by feeding high-pressure steam within a pressure vessel 2 provided with an airtight chamber E holding the material 1 to be molded and pressure is applied to the material 1 to be molded by feeding hihg-pressure air within the vessel 2 by a high-pressure air feeding means B. Air cooled by a cooling means C cooling the high-pressure air fed within the vessel2 through a heat exchanger 4 is circulated within the vessel 2 by a circulation means D. The airtight chamber E which has been so constituted that the material 1 to be molded is pressurized from the top and pressure from the side can be prevented and an external depressurizing means G are made communicatable and interruptable by attaching and detaching them by an attaching and detaching means F. The depressurizing means G makes the inside of the airtight chamber E and that of the vessel 2 into high vacuum by depressurizing them. The material to be molded is molded by these means.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for molding, in an autoclave, multilayer printed wiring boards, copper-clad laminates, non-copper-clad laminates, and other laminates used as electronic device parts. be.

BACKGROUND ART Conventionally, a hot plate press method is generally known as a technique for molding multilayer printed wiring boards and laminates such as copper-clad laminates and non-copper-clad laminates used in multilayer printed wiring boards.

The hot platen press method uses multiple plate molds (#
After stacking a large number of sheets between hot platens via a face plate (also referred to as a face plate), the resin portion of the prepreg in the material to be molded is temporarily softened by heating and pressurizing in the atmosphere.

After that, it is cured to bond and harden the material to be molded and then molded.

Furthermore, a technique is also known in which a material to be molded is vacuum-heated and pressurized to shape it.

In this technique, materials to be formed 1 are stacked and arranged in multiple stages on a surface plate (platen) 20 with a mirror plate 30 interposed therebetween.

Furthermore, after covering the breather 41 with a heat-resistant and flexible vacuum bag film 42 and sealing with a sealant 43, the container is placed in a pressure vessel and sealed.
The pressure inside the vacuum bag film is reduced and high pressure gas is supplied into the container.

The gas is heated to heat and pressurize the material to be molded to harden the adhesive and form it.

Problems to be Solved by the Invention However, these techniques have the following problems.

In general, the prepreg material to be molded is molded under heat and pressure while containing some moisture, air during lamination, air contained in the coated paper fabric, and volatile substances from unreacted resin raw materials as air bubbles. As a result, voids are generated inside the laminate (material to be formed), which significantly deteriorates the properties of the laminate.

Therefore, in the hot plate press method, in order to eliminate the air bubbles, an attempt has been made to flow the impregnated resin of the prepreg, which has been softened by heating, at high pressure and push out the air bubbles contained in the prepreg. The end of (
The surrounding area) is radiated with heat and the heating temperature is lower.

On the other hand, the central part of the prepreg accumulates heat and the heating temperature becomes high. Therefore, at this time, although the central part of the prepreg is heated to a high temperature and the melt viscosity of the impregnated resin becomes high, the heating temperature at the end part of the prepreg becomes high. is not high temperature,
The melt viscosity of the impregnated resin is low, and a large amount of the molten resin from the prepreg flows out due to the high pressure (generally 40 kg/cm or more) from the hot platen, resulting in the thickness of the laminate ends being thinner than the center, resulting in variations in board thickness. Furthermore, since the multilayer circuit board is pressurized at high pressure, the stress causes a large amount of contraction, which causes the circuit wires of the multilayer circuit board to become misaligned, as well as warping and twisting, which poses problems as a product.

Therefore, conventionally, Japanese Patent Application Laid-Open No. 121734/1983.

Although various improvement measures have been taken, such as those shown in Japanese Patent Application Laid-open No. 59-62113 and Japanese Patent Application Laid-Open No. 59-76257, each has its advantages and disadvantages, and issues remain to be solved.

For example, there are 9 techniques for molding by vacuum heating and pressurizing.

When a material to be formed is heated and pressurized according to a heating and pressing program, the material to be formed is generally as thin as about 1 to 2 μm even if it is formed into 4 or 6 layers.

Area is 330wX500n+m, 500m1+X500
mn+.

The range is 600ffIffl x 600ffI11, etc., and since hot air is used for heating, the surface of the material to be formed is heated. Therefore, as shown in FIG. 11, the material to be formed is heated from the upper and lower surfaces and the west side of the material to be formed, which are stacked in multiple stages, but at the core of the material to be formed. End (peripheral) 3
5 to the central portion 36 is slow.

Therefore, a temperature difference occurs between the end portion (peripheral portion) 35 and the center portion 36 of the material to be formed, as shown by the solid line and the two-dot chain line in the graph of FIG.

Due to this temperature difference, the material to be molded, prepreg, is impregnated with thermosetting resin.

Due to its characteristics, even though the edges (periphery) 35 of the material to be formed are melted, the central part 36 is not yet melted, and therefore, pressure from above due to pressurization and vacuum from the side due to reduced pressure Even if a pulling means is used, the bubbles (gas) contained in the prepreg cannot be pushed out, and therefore, it is difficult to discharge them into the vacuum outside the prepreg, and the bubbles remain inside the prepreg.

Therefore, in order to eliminate the residual air bubbles, the rate of temperature increase of the material to be formed 1 is slowed down and the edge (periphery) 3 of the material to be formed is reduced.
Although the temperature difference between the central part 36 and the central part 36 is reduced to prevent bubbles from remaining,9 the temperature rise is slow, resulting in a longer molding time and a new problem of lowering production efficiency.

Furthermore, since expensive vacuum bag film is used, reuse is not effective and it is uneconomical, and furthermore, the workability of making and sealing bags with vacuum bag film is poor and cannot be automated. I am holding.

Under these circumstances, in recent years, with the development of semiconductor technology, circuits have become denser and the width of the circuits has become narrower.

Circuit spacing is also becoming narrower.

Furthermore, with the trend toward multilayering, the diameter of the drill during processing is decreasing, and mounting of small chip parts using NG machines is becoming widespread.Coupled with the high density of 1 circuit, the board thickness is uniform, 2 there is less warping and twisting, and multilayer circuit boards. There is a strong need for a multilayer printed wiring board with good dimensional stability without misalignment of circuit lines.

The present invention was developed with the aim of solving the various problems mentioned above.

Means for Solving the Problems The method of forming a laminate according to the present invention involves vacuum heating and pressure forming of a laminate in an autoclave.

An airtight chamber that can be opened and closed is provided in which the material to be formed can be accommodated with a gap, the material to be formed can be pressurized from the top surface, and pressure from the sides can be prevented, and the airtight chamber and external pressure reducing means can be attached and detached. The material to be formed is housed in the airtight chamber, sealed and carried into a pressure vessel, and the airtight chamber is connected to a pressure reducing means to reduce the pressure in the airtight chamber. The material to be molded is heated under pressure by applying high-pressure steam to the material to cure the adhesive and then molded.

Example Hereinafter, the present invention will be described in detail 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 copper-clad laminate used for the multilayer printed wiring board.

Refers to laminates such as non-copper-clad laminates (for example, aluminum-clad laminates).

The material to be molded is a material for molding the above-mentioned laminate, and includes an inner layer circuit board, and is composed of prepreg, copper foil, etc.

What is prepreg? 2 A resin-impregnated sheet is created by impregnating a base material such as paper or glass cloth with thermosetting resin varnish such as phenolic resin varnish or epoxy resin varnish, and this resin-impregnated sheet is dried to become B-staged. It is.

A copper-clad laminate is obtained by cutting the above prepreg into a fixed size, stacking a plurality of sheets of the prepreg, pasting #lWi on one or both sides of the prepreg, and applying heat and pressure to adhesively cure and mold.

Examples of multilayer printed wiring boards include single-sided copper-clad laminates,
Prepreg, inner layer circuit board, prepreg.

Single-sided copper-clad laminates are sequentially laminated, heated and pressed to harden the adhesive, and then formed.Then, the process is followed by drilling, honing, plating, laminating, baking, developing, and secondary copper plating.
-It becomes a product after going through various processing steps such as external processing.

In addition, we will explain the special terms used in the present invention.6 Void refers to the presence of some moisture in the prepreg used for the laminate, air during lamination, air contained in coated paper cloth, and unreacted resin raw materials. This is a gaseous substance that contains volatile substances as bubbles and is generated inside the laminate when it is heated and press-molded in that state. The remaining voids significantly deteriorate the properties of the laminate.

A vacuum bag film is a heat-resistant and flexible film that isolates a material to be molded from the outside and brings it into close contact with the material by vacuum pressure. Generally, plastic films such as nylon 6, nylon 66, and polytetrafluoroethylene are used.

A breather is a device that allows air and gas (bubbles) generated by a reaction to pass through to maintain a uniform pressure load even when the inside of the vacuum bag film is reduced in pressure and pressure is applied to the container.

Heat-resistant glass cloth is used.

The sealant completely seals the material to be molded to the platen and ensures hermeticity during molding, and generally a sticky clay-like substance is used.

A surface plate (platen) is a flat jig that stacks materials to be formed and receives pressure from the top surface of the materials. A flat, smooth metal plate is used.

Next, the configuration of the embodiment will be explained.

The apparatus according to the embodiment of the present invention includes a pressure vessel 2 in which an airtight chamber containing a material to be formed 1 can be carried in and out by placing it on a shelf on a trolley 38, and a pressure vessel 2 in which high-pressure steam is supplied into the container 2. A pressurizing and heating means A that pressurizes and heats the molded material 1; a high-pressure air supply means B that supplies high-pressure air into the container 2 to apply pressure to the molded material 1 during cooling; A cooling means C cools the supplied high-pressure air via a heat exchanger 4 installed at the rear inside the container 2, and the air cooled by the cooling means C is blown into an airtight chamber carried into the container 2. A circulation means provided for circulation, and an openable and closable airtight chamber E that can accommodate the material to be formed 1 with a gap and can pressurize the material to be formed from the top surface while preventing pressure from the sides.
and connecting and detaching the airtight chamber E and an external pressure reduction means,
It is composed of detachable attachment/detachment means F which can be shut off, and depressurization means G which reduces the pressure inside the airtight chamber E and the inside of the container 2 to create a high vacuum.

Next, details of each means and each member will be explained.

The material to be formed 1 is made of an inner layer circuit board, prepreg, copper foil, etc., and is stacked and formed.

As shown in FIGS. 1 and 2, the pressurizing heating means A is generally provided to supply high-pressure steam of around 10 kg/- into the container 2 via an automatic valve 5. 6 and the condensate is drained through trap 7. Furthermore, a safety valve 11 is provided to reduce the pressure inside the container 2 when it exceeds a predetermined pressure.

The high-pressure air supply means B is provided so that a compressor 12 disposed outside the container 2 communicates with the inside of the container 2 via an automatic valve 13, and the supplied high-pressure air is exhausted by the automatic valve 9.

The cooling means C is configured to supply cooling water from the outside of the container 2 to the heat exchanger 4 inside the container 2, and an automatic valve 14 for supplying cooling water is passed through the container 2 and communicated with the heat exchanger 4. established,
Furthermore, an automatic drainage valve 15 is provided to communicate with the lower part of the container 2 from below the heat exchanger.

As another example of the cooling means, instead of the heat exchanger 4 and the circulation means, a pressure pump 16 is provided outside the container 2 as shown in FIG. Pressurized cold water is supplied to the inside of the container 2 via the automatic valve 17, and the airtight chamber E is
The molded material 1 accommodated therein may be cooled.

Furthermore, high pressure air may be used to pressurize the material to be formed 1 during cooling, and the pressurized state may be controlled.

Further, as another example of the cooling means, cooling means may be provided outside the container 2 and cooling gas (air) may be supplied into the container 2.

The circulation means includes a fan 18 provided inside the container 2, and a motor 19 for driving the fan installed outside the container 2 so as to be airtight. and,
The cooling gas sent by the fan 18 passes through the outer periphery of the wind barrel plate 21 shown in FIG. 1, and is configured to circulate between the wind barrel plate and the material to be formed 1 by making a U-turn as shown by the arrow. It is.

As shown in FIGS. 4 and 5, the airtight chamber E surrounds the material to be formed 1 loaded on a surface plate 20 with an appropriate gap provided by a side pressure prevention member H made of a rectangular frame.

The surface plate 2o and the lateral pressure prevention member H are sealed by a sealing member, and the molded material 1 is further sealed.

A flat plate-shaped suppression member J that presses the material to be formed 1 is provided on the upper part of the lateral pressure prevention member H so as to be movable up and down on the lateral pressure prevention member H.
It is provided so that the inside of the side pressure prevention member H is sealed by sealing with the seal member K.

The molded material 1 can be easily inserted and removed, and the airtight chamber E can be easily disassembled and assembled.

The attachment/detachment means F is for reducing the pressure inside the airtight chamber 2.

The coupler 27 at the outlet of the vacuum path 22 of the surface plate 20 is attached to and detached from the coupler 27 at the tip of the piping of the pressure reducing means G.

It is provided so as to be able to communicate with and shut off from the airtight chamber E.

Incidentally, the surface plate 20 and the pressing member J form a flat plate with good thermal conductivity, whose surface in contact with the material to be formed 1 is flat and whose surface is smoothed.

FIG. 6 shows another embodiment of the airtight chamber E.

The airtight chamber E is provided on the upper surface of the lateral pressure prevention member H and on the outer periphery of the pressing member J with a sealing member K integrated with a rectangular frame presser plate 26 interposed therein so as to be movable up and down.

The molded material 1 is configured to be pressurized by applying pressure from above using high-pressure steam to cause the sealing member and the pressing member J to act downwardly.

As shown in FIGS. 1 and 2, the pressure reducing means G includes a vacuum pump 23 installed outside the container 2, an automatic valve 24, and an automatic valve 2.
5 and is connected to the inside of the container 2 for piping. The tip of the automatic valve 24 is opened inside the container 2, and the tip of the automatic valve 25 is provided with a vacuum coupler 27 as shown in FIGS. is provided so as to be detachable from the coupler 27 of the piping section of the vacuum path 22 of the surface plate 20 in order to reduce the pressure inside the airtight chamber E.

Here, in the present invention, the state in which the materials to be formed are stacked will be described.

As shown in FIG. 7, a ventilation plate 28 provided with a vacuum path is arranged on the surface plate 20, and then a mirror plate 30 to a release film 3 are arranged.
1~Copper foil 32~Prepreg 33~Inner layer circuit board 34~Prepreg 33~Copper foil 32~Release film 31~Front plate 30
-Release film 31 -Copper foil 32 -Prepreg 33 -Inner layer circuit board 34 -Prepreg 33 -Copper foil 32 -Release film 31 -Mirror plate 30 are sequentially stacked, and this stacking is stacked in multiple stages.

Then, the material to be formed 1 is surrounded by a lateral pressure prevention member H and sealed with a sealing member I, furthermore, a suppressing member J is placed on the material to be formed 1, and the material to be formed 1 is sealed with a sealing member K. , check its sealing condition.

In addition, as a means for this sealing, the lateral pressure prevention member H2 is first installed.
The suppressing member J and the sealing member K may be integrally combined and sealed by covering the material to be formed 1 loaded on the surface plate 20, and either of the above-mentioned means may be used for removal after forming. Not limited to means.

Next, its operation will be explained according to the heating and pressurizing program shown in FIG.

The material to be formed 1, which has been prepared by being housed and sealed inside the airtight chamber E, is placed on a shelf of a cart 38 shown in FIGS. 1 and 2 and carried into the pressure vessel 2. Next, the coupler 27 of the surface plate 20 is connected to the coupler 27 of the container internal piping part of the pressure reducing means G, and the door 3
and seal container 2.

Next, the vacuum pump 23, the automatic valve 24, and the automatic valve 25 are operated to reduce the pressure inside the container 2 and the airtight chamber E. When the inside of the container 2 becomes vacuum, the automatic valve 24 is reversely operated to reduce the pressure inside the container 2 and the airtight chamber E. 2 Stop the vacuum inside.

Next, the automatic valve 5 is operated to supply high-pressure steam into the container 2 to pressurize and heat the molded material 1 housed in the airtight chamber E.

At this time, the inside of container 2 is in a vacuum.

The high-pressure steam is uniformly distributed inside the container 2, and due to the hydrostatic characteristics of this high-pressure steam and the function of the airtight chamber E, the material to be formed 1 is pressed by pressure from above and heated from the upper and lower surfaces.

In this way, the material to be formed 1 is heated from above and below, and heat is transferred from the upper and lower surfaces of the material to be formed 1, but the gap 37 in the airtight chamber shown in FIG. 4 is in a high vacuum. Therefore, there is no heat dissipation from the ends (periphery) of the material 1 to be formed, and the upper end (periphery) 35 and center 36 of the prepreg plane of the material 1 to be formed can be heated almost uniformly. There is no temperature difference between the center part 36 on the prepreg plane of the material 1 and the end part (peripheral part) 35, and the center part 3 on the prepreg plane of each stage is reduced.
The melt viscosities of the melt viscosity at the end portion 6 and the end portion (periphery portion) 35 are approximately equal.

Then, heating of the stacked materials 1 to be formed progresses.

When the melt viscosity of the prepreg resin part reaches its minimum, the air bubbles existing in the prepreg resin part float above the resin part, but due to the pressure from above and the vacuum from the side, the prepreg and copper foil It moves to the edge (periphery) of the prepreg and is discharged into vacuum.

Subsequently, the temperature of the material to be formed 1 is further increased, and once it reaches a specified temperature, that temperature is maintained for a while to bond and harden the material to be formed.

Next, the automatic valve 5 is operated in reverse to stop the supply of high pressure steam 2.
Next, the automatic valve 13 is operated to supply high-pressure air into the container 2, and the automatic valve 6 is operated to discharge high-pressure steam, so that the material to be formed 1 is pressurized with high-pressure air instead of high-pressure steam, and is pressurized to a predetermined level. Control to maintain pressure.

Next, the automatic valve 14 is operated to supply cooling water to the heat exchanger 4 to cool the high pressure air (high pressure gas) in the container 2, and the cooled high pressure air is blown by the fan 18 of the circulation means. The material to be formed 1 is circulated in the container 2 and placed in the airtight chamber E.
to cool down.

Next, the automatic valve 9 is operated to gradually reduce the pressure inside the container 2.

When the material to be formed 1 is cooled, all operations are stopped, the door 3 is opened, and the material to be formed 1 is carried out to the outside, completing one process.

Note that during cooling, if a means for introducing air into the airtight chamber E is used, the cooling heat of the cooled gas is transmitted from the airtight chamber to the air to the workpiece 1, thereby cooling the workpiece in a short time. can do.

Here, 1 dimension: 330mm x 500mm prepreg, t
The R foil and the inner layer circuit board are sandwiched between mirror plates as shown in FIG. 7, and stacked one on top of the other to a height of about 60III+. At this time, temperature detectors 40 are appropriately inserted into the ends (periphery), 35, and center 36 of the material to be formed 1. Then, when molding was carried out under the conditions of the heating and pressing program shown in Fig. 8, there was no temperature difference between the central part and the end part (periphery) of the prepreg of each material to be formed 1, as shown in Fig. 9. As a result, a six-layer copper-clad laminate with uniform thickness and no voids could be formed within a predetermined time.

Note that the heating and pressurizing program used in the present invention is No. 1.

Conditions other than those shown in FIG. 8 may be used, such as those shown in FIG. 10, and the conditions are not limited to the embodiments of the present invention.

Effect of the invention According to the present invention, the following effects are achieved.

An openable and closable airtight chamber capable of accommodating a material to be formed with a gap in vacuum heating and pressure forming of a laminate in an autoclave, and capable of pressurizing the material from the top and preventing pressure from the sides. the airtight chamber and an external pressure reducing means are provided so that they can be connected and disconnected, the material to be formed is accommodated in the airtight chamber, sealed and carried into a pressure vessel, and the airtight chamber is used as the pressure reduction means. The connection was made to reduce the pressure inside the airtight chamber, and then apply high pressure steam to the container to pressurize and heat the material to be molded to harden the adhesive and form it. This is prevented by the side pressure prevention member and is evenly pressurized from the upper surface of the material to be formed by hydrostatic pressure.

Furthermore, since the airtight chamber is kept in a vacuum during heating of the material to be formed, heat is not transferred from the side surfaces, and there is no heat dissipation from the ends of the material to be formed, and heat is evenly transferred from the upper and lower surfaces.

As a result, there is no temperature difference between the center and edges of each prepreg of the material to be molded, and the resin becomes uniformly molten, making it easier to flow. Even though there is a small amount of spillage, the air bubbles can be expelled into the vacuum by vacuuming, and a laminate of uniform thickness without voids and without resin loss can be produced within a predetermined time. It can be molded with.

In addition, since the pressure applied to the material to be molded is lower than that of the conventional hot platen press method, there is less shrinkage due to stress, and there is no misalignment of circuit lines on multilayer circuit boards, making it possible to accommodate higher circuit densities. can.

Furthermore, warping and twisting are reduced, and combined with uniform plate thickness, a high-quality laminate with good dimensional stability can be obtained.

Furthermore, since the outflow of resin is reduced and voids can be removed, and there is no loss of resin, it is possible to form multiple layers with almost no change in board thickness, thus meeting the demand for higher multilayers.

Furthermore, it is reusable and the material to be formed can be easily inserted.

Since it has an airtight chamber that can be taken out, there is no need for conventional vacuum bag film that cannot be reused and is expensive.
It is economical, has good workability, and can be expected to be compatible with automation.

Furthermore, since high-pressure steam is used as the pressurized heating means, the material to be molded can be heated by the high thermal energy contained in the steam, so it can be molded in a shorter time than with conventional heating means using heating gas. .

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway schematic side view showing one embodiment of the device according to the present invention. 2 is a schematic vertical sectional view of the apparatus shown in FIG. 1, and FIG. 3 is a schematic vertical sectional view showing another embodiment of the cooling means. FIG. 4 is a schematic longitudinal cross-sectional view of an airtight chamber that accommodates the material to be formed. FIG. 5 is a top view of FIG. 4. FIG. 6 is a schematic vertical sectional view of another embodiment of the airtight chamber. FIG. 7 is a schematic vertical cross-sectional view showing a state in which materials to be formed are stacked and placed in the present invention. FIG. 8 is a diagram showing an embodiment of a heating and pressing program for molding a material to be molded according to the present invention. FIG. 9 shows actual measurement values obtained by molding the material to be molded according to the present invention according to the heating and pressing program set in FIG. 8. FIG. 10 is a diagram showing another embodiment of the heating and pressing program for molding the material to be molded according to the present invention. FIG. 11 is a schematic vertical sectional view showing a conventional method of loading materials to be formed, covering them with a vacuum bag film, and sealing them. FIG. 12 is a diagram showing an example of a prior art heating and pressing program for molding a material to be molded. In these figures, AJI pressure heating means, B: high pressure air supply means, C: cooling means, D: circulation means, E: airtight chamber, F attachment/detachment means, G: pressure reduction means, H: lateral pressure prevention member, J: pressing member , Ni seal member, L: seal member, 1: molded material, 2・pressure vessel, 3
: Door, 4: Heat exchanger. 5.6,9: automatic valve, 7: trap, safety valve at 1, 12
Compressor, 13, 14, 15° 17 = automatic valve,
16. Pressure pump, 18. fan. 19: Motor, 20: Surface plate, 21: Wind shoulder plate, 22: Vacuum path, 23: Vacuum pump, 24, 25: Automatic valve. 26: Presser plate, 27: Cover, 28: Ventilation plate. 30-mirror plate, 31; release film, 32: copper foil. 33 Nibbly preg, 34: Inner layer circuit board, 35: End portion of material to be formed, 36: Center portion of material to be formed, 37: Gap portion, 38
; Trolley, 40: Temperature detector, 41: Breather, 42: Vacuum bag film, 43 Nizi-lant. Figure 3 Figure 5

Claims (1)

[Claims] An openable and closable airtight chamber capable of accommodating a material to be formed with a gap in vacuum heating and pressure forming of a laminate in an autoclave, and capable of pressurizing the material from the top and preventing pressure from the sides. providing the airtight chamber and an external pressure reduction means so that they can be connected and disconnected, and storing the material to be formed in the airtight chamber, sealing it, and transporting it into a pressure vessel;
Forming of a laminate, characterized in that the airtight chamber is connected to a pressure reducing means to reduce the pressure inside the airtight chamber, and then high pressure steam is applied to the container to pressurize and heat the material to be formed to harden the adhesive and form it. Method.