JPH0322280B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a multistage hot press suitable for bonding multilayer printed wiring boards of various electronic devices such as computers.

[Background of the invention]

In recent years, in order to realize high-density mounting of components onto a molded object such as a printed wiring board, there has been a trend toward multilayering a plurality of printed wiring boards.

Conventionally, as a hot press for layering, heating and pressurizing a plurality of multilayer printed wiring boards, the first
As shown in the figure, a lower bolster 4 is placed on the ram 3 of the main ram cylinder 2 fixed to the lower frame 1, and a lower heating plate 6 is placed on the lower bolster 4 via a lower heat insulating plate 5. It is fixed with bolts 7, and furthermore, an intermediate heating plate 8 is attached to the upper part, and a counter cylinder 9 is attached.
The upper heating plate 10 is supported by the upper heat insulating plate 11 at the top.
The frame 1 is thermally insulated and fixed to an upper bolster 13 connected to the frame 1 by a support 12 with a tightening bolt 14.

In this hot press, a bonded object 15 such as a multilayer printed wiring board is inserted between a lower hot plate 6 and an intermediate hot plate 8, and between an intermediate hot plate 8 and an upper hot plate 10 through an opening.
Molding thermal energy is applied to each of the hot plates 6, 8, and 10 from a heating/cooling control device 17 consisting of a switching valve 16 for temperature control and heating/cooling medium switching, etc., and at the same time, the main ram cylinder 2 and counter cylinder 9 are , hydraulic pump 18, pressure control valve 1
9. Hydraulic pressure is supplied by a hydraulic device 21 comprising an oil cooler 20 and the like, and the object to be bonded 15 is pressurized and bonded.

By the way, since the upper and lower heat insulating plates 11 and 5 are inserted between the upper and lower bolsters 13 and 4 and the upper and lower hot plates 10 and 6, they have a dimensional accuracy of, for example, 500 mm, like the hot plates 10 and 6. Parallelism of 0.03 mm or less and compressive modulus of minimum 1.0×10 ⁴ Kg/cm ² are required. The prepreg for adhering the multilayer printed wiring board of the object to be adhered 15 is softened and melted by heating, and by applying pressure, the inside becomes higher in pressure distribution than the outside, as shown by a in FIG. Since the heat insulating plates 11 and 5 have a smaller compressive elastic modulus than the hot plates 10 and 6, the presence of the adherend 15 deforms the heat plates and the heat insulating plates as shown in b and c in FIG. Glued object 1 after gluing
5 is deformed into a convex shape as shown by D.

To prevent deformation of these hot plates and heat insulating plates,
Shims corresponding to the amount of deformation of the hot plate and the heat insulating plate are inserted in advance between the lower bolster 4 and the lower heat insulating plate 5 and between the upper bolster 13 and the heat insulating plate 11 in accordance with the bonding pressure conditions. This countermeasure against deformation using shims has the problem that the amount of shim insertion must be changed every time the bonding conditions change, resulting in longer work setup time and lower reliability.

Furthermore, the deformation of the hot plate can be prevented by increasing the thickness of the hot plate to increase its bending rigidity, but this increases the heat capacity of the hot plate and requires a large amount of heat medium for heating and cooling. The hot press itself will also become larger.

Furthermore, when forming objects by applying heat and pressure, it is desirable to make the elongation or contraction of each layer of the object uniform, and also to make the thickness of the prepreg uniform. There are variations in material and dimensions, and although the upper and lower hot plates 6 and 10 are processed with high precision, it is difficult to heat the hot plates evenly, so the local flatness of the hot plates may vary. It is difficult to maintain parallelism with high precision, and the pressure applied locally becomes uneven.
Therefore, the bonded object after molding has variations not only in finished external dimensions and parallelism, but also in the amount of expansion and contraction of each layer. This is called dimensional change variation, and in order to reduce this dimensional change variation, it is desirable to reduce the pressure applied.

On the other hand, if the applied pressure is small, the air bubbles generated when the prepreg melts due to heating will be difficult to push out of the adherend due to the poor flow of the prepreg, and the pressure distribution within the prepreg will be limited to the center. It is necessary to increase the pressure at the center compared to the outer periphery, taking into account that the compression rate is high and the compressive elastic modulus of the insulation material is small. Previously, a shim was installed in the center to adjust the pressure.

[Purpose of the invention]

In view of the above points, an object of the present invention is to provide a hot press that can apply an optimal pressure distribution to an object to be adhered, and can form an object to be adhered with little variation in dimensional change and no residual bubbles. do.

[Summary of the invention]

In order to achieve the above object, the present invention provides a hot press that has an upper bolster and a lower bolster to which a hot plate is attached with a heat insulating plate in between, and heats and presses an object to be adhered between the upper bolster and the lower bolster. , a deformation prevention means comprising a hydraulic auxiliary ram cylinder and an auxiliary ram provided on the heat insulation plate side of the upper bolster, a control means for controlling the deformation prevention means, and between the upper bolster and the heat insulation plate. It is equipped with a buffer plate that is inserted and comes into contact with the auxiliary ram.

When hydraulic pressure is supplied to the auxiliary ram cylinder, the auxiliary ram is pushed out and deforms the heat insulating plate into a convex shape, preventing concave deformation of the hot plate. Equalizes the contact between the adherend and the hot plate, which occurs inside the prepreg. By taking advantage of the higher pressure distribution at the center, the fluidized resin is made to flow toward the outer periphery, making it possible to remove internal air bubbles that can cause poor insulation.

[Embodiments of the invention]

Embodiments of the hot press of the present invention will be described below with reference to FIGS. 3 and 4. 3 and 4, the same reference numerals as in FIGS. 1 and 2 indicate the same parts.

The hot press of the present invention mainly includes a press body 22, a heating/cooling device 17, a hydraulic device 21, a control means including a control device 32, and the like.

The heating and cooling control device 17 includes a steam supply source 23,
It is composed of a cooling water supply source 24, a temperature regulator 25, and the like.

Further, the hydraulic system 21 includes a hydraulic pump 18, a pressure control valve 19, an oil cooler 20, a counter cylinder pressure regulation valve 30, an auxiliary ram pressure regulation valve 31, and the like.

Further, the press main body 22 includes an auxiliary ram cylinder 26 and a deformation prevention means consisting of an auxiliary ram 27, and an oil passage 3 communicating with the auxiliary ram cylinder 26.
5 and an upper bolster 28 containing a built-in ram 27.
A buffer plate 29 applies the thrust to the upper heat insulating plate 11 with a smooth pressure distribution, a lower frame 1 containing the main ram cylinder 2 and the ram 3 at the bottom, a strut 12 supporting the upper bolster 28, and nuts 36, 3.
The upper heating plate 10, which pressurizes and heats the adherend 15, is thermally insulated by the upper heat insulating plate 11, and is attached to the upper bolster 28 by tightening bolts 14 with a buffer plate 29 in between. Supported. The buffer plate 29 is fixedly supported around the periphery by the upper bolster 28 and nuts 36. Further, the lower heating plate 6 is thermally insulated by the lower heat insulating plate 5 and is supported by the lower bolster 4 by a tightening bolt 7, and the intermediate heating plate is supported by a counter cylinder 9 between the upper and lower bolsters 4 and 28. .

In the above embodiment, the upper bolster 28 has been described, but the lower bolster 4 may also be provided with a similar deformation prevention means.

The operation of the hot press of the present invention will be explained below.

First, the lower hot plate 6, the intermediate hot plate 8, and the intermediate hot plate 8
A bonded object 15 such as a multilayer printed wiring board is inserted between the upper hot plate 10 and the hot plates 6, 8, 1.
At the same time, the heating and cooling control device 17 applies molding thermal energy to the heating and cooling control device 17, and at the same time, hydraulic pressure is supplied from the hydraulic device 21 to the main ram cylinder 2, and each hot plate 6, 8, 10
This is to propagate the pressurizing force to. At this time, in order to compensate for the weight of the intermediate hot plate 8 itself, control hydraulic pressure is supplied to the counter cylinder 9, and at the same time,
Control hydraulic pressure is supplied from the auxiliary ram pressure regulating valve 31 to the auxiliary ram cylinder 26 in order to correct the deformation of the heat insulating plate 11 due to the bonding pressure conditions. At this time, the upper insulation plate 11 side of the buffer plate 29 undergoes a smooth convex deformation due to the thrust of the ram 27, so the upper insulation plate 11 undergoes this deformation and prevents concave deformation occurring on the adherend 15 side. be able to. The control hydraulic pressure of the auxiliary ram cylinder is determined based on the pressure conditions of the main ram 3, the bending rigidity of the buffer plate 29, the compressive elastic modulus of the heat insulating plate, etc., in order to provide the adhered object 15 with optimal pressure distribution and parallelism. Find it in advance by experiment. Furthermore, when the buffer plate 29 is deformed into a convex shape when the prepreg, which is the adhesive material of the adhered object 15, flows, the resin of the fluid will be Due to the difference, it flows from the center toward the outer periphery, and at the same time, it is possible to remove internal air bubbles that cause insulation defects to the outside.

According to this embodiment, since the concave deformation of the heat insulating plate can be corrected by the convex deformation of the buffer plate 29 by the auxiliary ram 27, it is possible to use a heat insulating plate with a small compressive elastic modulus but a good heat insulation coefficient. In addition, since the flatness between the hot plates can be adjusted arbitrarily, the multilayer printed wiring has the advantage that there are no residual bubbles, the flatness is high, and the variation in dimensional changes can be reduced.

FIG. 4 shows another embodiment of the hot press of the present invention, in which the auxiliary ram 26 of the deformation prevention means is operated by a female thread and a male thread.

In FIG. 4, numeral 38 is an upper bolster, and inside this upper bolster 38, a female threaded portion 39 is provided on the inner periphery, and an auxiliary ram cylinder 4 is provided with a threaded portion on the outer periphery.
The auxiliary ram 40 engages with the female threaded portion 39 and is movable in the vertical direction.
can be moved in the vertical direction via the .

〔Effect of the invention〕

According to the hot press of the present invention, by pushing out the buffer plate with the auxiliary ram, the pressure distribution during pressurization and heating of the adherend can be arbitrarily changed, so the adherend has less variation in dimensional deformation and no residual bubbles. It becomes possible to mold the adhesive, and it is highly effective when used for bonding multilayer printed wiring boards.

[Brief explanation of the drawing]

Figure 1 is a front view showing the structure of a conventional hot press, and a statistical diagram of hydraulic and heating/cooling control. Figure 2 is a diagram showing the structure of a conventional hot press.
FIG. 3 is a front view showing the structure of the hot press of the present invention, and a control system diagram for hydraulic pressure and heating/cooling. The figure is a front view showing another embodiment of the deformation prevention means in the present invention. 1...Lower frame, 2...Ram cylinder, 3...Ram, 4...Lower bolster, 5...Lower heat insulating plate, 6...Lower hot plate, 8...Intermediate hot plate, 10...Upper heat plate, 11...Upper heat insulating plate, 12 ... Strut, 13... Upper bolster, 15... Bonded object, 17... Heating/cooling control device, 21... Hydraulic system, 22... Press body, 26... Auxiliary cylinder, 27... Ram, 28... Upper bolster, 29... Buffer plate .

Claims (1)

[Scope of Claims] 1. A hot press that has an upper bolster and a lower bolster to which a hot plate is attached with a heat insulating plate sandwiched therebetween, and heats and presses an object to be adhered between the upper bolster and the lower bolster. Deformation prevention means consisting of a hydraulic auxiliary ram cylinder and an auxiliary ram provided on the heat insulating plate side of the bolster, a control means for controlling the deformation prevention means, and a control means inserted between the heat insulating plate and the upper bolster, A hot press characterized by being provided with a buffer plate that comes into contact with a ram. 2. In a hot press, which has an upper bolster and a lower bolster to which a hot plate is attached with a heat insulating plate in between, and heats and presses an object to be adhered between the upper bolster and the lower bolster, the upper bolster has a heat plate on the side thereof. a deformation prevention means comprising a female screw provided thereon and a screw type auxiliary ram having a male screw on the outer periphery that engages with the female screw and is movable in a pressurizing direction by rotation; and a control means for controlling the deformation prevention means. ,
A hot press characterized in that a buffer plate is provided which is inserted between the heat insulating plate and the upper bolster and comes into contact with the auxiliary ram.