JPS59215299A - Hot press - Google Patents

Abstract

PURPOSE:To apply an optimum pressure distribution on objects to be adhered and to form an adhered material having less dimensional change and no remaining foam by providing means for preventing deformation of the object and control means for said means on the heat insulating plate side of a bolster. CONSTITUTION:Objects 15 to be adhered of multi-layered printed wiring boards, etc. are inserted between a lower hot plate 6 and an intermediate hot plate 8 as well as between the plate 8 and an upper hot plate 10 of a hot press. Forming heat energy is applied on the plates 6, 8, 10 and an oil pressure is supplied to a main ram cylinder 2 to press the plates 6, 8, 10. A control oil pressure is supplied to a counter cylinder 9 and the control oil pressure to an auxiliary ram cylinder 26 in this stage, then a deformation of a smooth projecting shape is generated on the upper heat insulating plate 11 side of a cushion plate 29 by the thrust of a ram 27, by which the recessed deformation arising on the object 15 side is prevented. The resin of a fluid medium flows toward the outside circumferential direction while the adhering sheets of the objects 15 flows and at the same time the internal foam which is the factor for defective insulation is removed to the outside.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a combination? - This article relates to a multi-stage hot press suitable for bonding multilayer printed wiring boards for various electronic devices.

[Background of the invention]

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

Conventionally, as a hot press for heating and pressurizing a plurality of multilayer printed wiring boards, as shown in Fig. 1,
A lower bolster 4 is placed on the ram 3 of the main ram cylinder 2 fixed to the lower press frame 1.
4, a lower heat plate 6 is attached to the tightening bolt 7 via a lower heat insulating plate 5.
An intermediate heating plate 8 is fixed at the upper part, which is further provided with an opening for carrying in and out of the adherend, and supported by a counter cylinder 9, and an upper heating plate 10 is thermally insulated by an upper heating plate 11 at the top. It is fixed with a tightening bolt 14 to an upper bolster 13 which is connected to the lower mount 1 by a column 12.

In this hot press, objects 15 such as multilayer printed wiring boards are inserted between the lower hot plate 6 and the intermediate hot plate 8, and between the intermediate hot plate 8 and the upper hot plate 10, and At the same time, a heating/cooling control device 17 consisting of a switching valve 16 for controlling temperature and switching a heating/cooling medium applies molding heat energy, and at the same time, an oil pump 18 and a pressure pump are applied to the main ram cylinder 2 and counter cylinder 9. A device consisting of a control valve 19, an oil cooler 20, etc. is supplied, and the object to be bonded 15 is pressurized and bonded.

By the way, the upper and lower bolsters 13, 4 and the upper and lower hot plates 10
, 6 are inserted between the upper and lower bolsters 13.4, and, like the hot plates 10, 6, from the viewpoint of dimensional accuracy, the upper and lower heat insulating plates 11, 5 thermally insulate the upper and lower bolsters 13.4. Parallelism of less than a millimeter and min. OX
A compression modulus of about 1 0'K9/α2 is required. When bonding the adhered object 15, due to the softening and melting of the Gripreg to which the multilayer printed wiring board is bonded, the inner part (2) has a higher pressure distribution (squeeze effect) than the outer part (2), like a second crystal. Since the pressure P generated on the adhered object 15 and the heat insulating plates 11 and 5 have a smaller compressive elastic modulus than the hot plates 10 and 5, the hot plate and the heat insulating plate have a concave shape as shown in the second b and c. The bonded object 15 after bonding is deformed into a convex shape as shown by D.

As a countermeasure against deformation of these hot plates and heat insulating plates, depending on the bonding pressure conditions, shims corresponding to the rotation of the hot plates and heat insulating plates are placed on the lower bolster 4, the lower heat insulating plate 5, and the upper bolster 1 in advance.
3 and the heat insulating board 11. When using shims to prevent deformation, the amount of shim insertion must be changed each time the bonding conditions change, which leads to longer work setup times and lower reliability.

In addition, deformation of the hot plate and the heat insulating plate can be prevented by increasing the thickness and increasing the bending rigidity;
The heat capacity for cooling is enormous, and the hot press itself becomes larger.

Furthermore, in order to obtain the adherend 15 with less variation in dimensional changes, it is desirable to perform the pressure bonding under conditions of low pressure.

That is, even if the hot plate 6.10 is processed with high precision, there is a limit to the processing and perfect flatness cannot be obtained.

If the pressing force is high, the influence of imperfect flatness will be exerted on the adhered object 15, but if the pressing force is low, the influence of imperfect flatness can be reduced by the fluid in which Gripreg is melted. .

However, when crimping is performed under low pressure conditions, it may be impossible to completely extrude the air bubbles generated when the Gripreg melts during bonding to the outside of the molded object 15 if pressure is applied with a parallel plate. Since it is necessary to increase the pressure at the outer circumference compared to the outer circumference, measures are required to increase the internal pressure by adjusting the shim.

[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 dimensional change and no residual bubbles. .

[Summary of the invention]

It is believed that it is necessary to manufacture a pot press with high static precision in order to mold objects to be bonded such as multilayer printed wiring boards with high precision, and we have been pursuing measures to improve mechanical precision. However, according to experimental results, in order to mold a molded product with little dimensional change and no residual air bubbles, the true optimum pressure must be taken into consideration, such as the compressive elastic modulus of the heat insulating board and the pressure distribution during melting of Gripreg, an adhesive sheet. It turned out that no distribution could be obtained.

As a solution to this problem, the present invention provides a means for preventing deformation of the adhered object by providing an optimal pressure distribution on the adhered object, which is provided on the heat insulating plate side of the bolster; It is equipped with means for controlling.

[Embodiments of the invention]

Examples of the hot press of the present invention are shown below in Figures 3 and 4.
This will be explained using figures. In Figures 3 and 4, the first
The same reference numerals as in the figures and FIG. 2 indicate the same parts.

The hot press of the present invention mainly includes the heating and cooling device 1.
7. Hydraulic device 21, press body 22 and control device 3
It is composed of 2 etc.

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

The hydraulic system 21 also includes a hydraulic pump 18 and a pressure control valve 19.
, an oil cooler 20, a counter cylinder pressure regulating valve 30, an auxiliary ram pressure regulating valve 31, etc.

Further, the press main body 22 includes an auxiliary ram cylinder 26 serving as a deformation prevention means, an oil passage 35 communicating with the auxiliary ram cylinder 26, and an upper bolster incorporating a ram 27 that is fitted into the auxiliary ram cylinder 26 so as to be movable in the vertical direction. -'28, a buffer plate 29 that receives the thrust of the ram 27 using the outer periphery of the upper bolster 28 as a fulcrum and imparts a smooth pressure distribution to the hot plate 11; a main ram cylinder 2 and a ram 3 are built in the lower part; Lower frame 1, pillars 1 that support each
2, nuts 36, 37, etc. The upper heating plate 10 that pressurizes and heats the object to be formed 15 is thermally insulated via the upper heating plate 11 and is supported by an upper bolster 28 by a tightening bolt 14. The hot plate 6 is thermally insulated via the lower heat insulating plate 5 and supported by the lower bolster 4 by tightening bolts 7, and the intermediate hot plate is connected to the upper and lower bolsters 4 by a counter cylinder 9.
, 28.

First, between the lower hot plate 6 and the intermediate hot plate 8 and between the intermediate hot plate 8 and the upper hot plate 10, an object 15 such as a multilayer printed wiring board
The heating and cooling control device 17 applies molding heat energy to these hot plates 6, 8.10', and at the same time, the hydraulic system 21 supplies hydraulic pressure 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 correct the dead weight of the hot plate itself, control hydraulic pressure is supplied to the counter cylinder 9, and at the same time, the auxiliary ram pressure regulating valve 31 is supplied to the auxiliary ram cylinder 26 in order to correct the deformation of the heat insulating plate 11 due to the bonding pressure conditions. Supplies control hydraulic pressure. At this time, the thrust of the ram 27 deforms the buffer plate 28 into a smooth convex shape on the side of the hot plate 11 using the nut 36 as a fulcrum, so the hot plate 11 undergoes this deformation, which occurs on the side of the adhered object 15. Concave deformation can be prevented. Note that the control hydraulic pressure of the auxiliary ram cylinder is
In order to provide the optimum pressure distribution and parallelism to the main ram 3, the pressure conditions of the main ram 3, the bending rigidity of the buffer plate 28, the compressive elastic modulus of the heat insulating plate, etc. are determined in advance through experiments.

Furthermore, if the buffer plate 28 is deformed into a convex shape when the prep V-g, which is the adhesive sheet for the adhered object 15, flows, it will flow in the -direction, and at the same time, internal air bubbles that may cause insulation defects can be removed to the outside. can.

According to this embodiment, the concave deformation of the heat insulating plate can be absorbed by the convex deformation of the buffer plate 28 by the four auxiliary rams 27, so a heat insulating plate with a small compressive elastic modulus but a good heat insulation rate can be used. In addition, since the flatness between the hot plates can be adjusted arbitrarily, it is possible to eliminate residual air bubbles when bonding multilayer printed wiring boards, produce wiring boards with high flatness accuracy, and reduce variations in dimensional changes of wiring boards. have an effect.

FIG. 4 shows another embodiment of the hot press of the present invention, in which the auxiliary ram 26 of the deformation prevention means, which was previously operated in reverse by control hydraulic pressure, is mechanically operated.

In FIG. 4, numeral 38 is an upper bolster, and inside this upper polster 38 there is a threaded auxiliary ram cylinder 39 with a threaded portion on the inner periphery, and an auxiliary ram cylinder 39 that engages with the screw provided on the outer periphery to provide an auxiliary ram cylinder. A ram 40 that moves vertically within the cylinder 39 is built in. This auxiliary ram 40 is driven by an electric motor 43 and is moved vertically via a transmission shaft 41 and a transmission 42.

〔Effect of the invention〕

According to the hot press of the present invention, it is possible to arbitrarily change the pressure distribution during pressurization and heating of the adherend.
It becomes possible to mold a bonded object with little dimensional deformation and no residual bubbles.

Therefore, when the object to be adhered is used, for example, in the work of adhering multilayer printed wiring boards, a great effect is exhibited.

[Brief explanation of drawings]

Figure 1 is a front view showing the structure of a conventional hot press, and a control system diagram for hydraulic pressure and heating/cooling. Figure 2 shows the pressure distribution during pressurization of the object to be formed, the heat insulating plate for the object to be bonded, and the deformation of the hot plate. 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; FIG. 4 is a front view showing another embodiment of the deformation prevention means of the present invention. be. 1... lower hunmu, 2... ramshi leader, 3...
・Ram, 4...Lower bolster-15...Lower insulation board, 6
...Lower hot plate, 8...Intermediate hot plate, lO...Upper hot plate,
DESCRIPTION OF SYMBOLS 11... Appeal hot plate, 12... Strut, 13... Upper bolster 115... Bonded object, 17... Heating/cooling control device, 21... Hydraulic device, 22... Press Main body, 26...Auxiliary cylinder, 27...■ 1
Figure 2 ρ Figure 4 Δ3 Inside Hitachi, Ltd. Production Technology Laboratory, 292 Yoshida-cho, Totsuka-ku, Yokohama

Claims (1)

[Claims] 1. In a hot press in which an object to be bonded is heated and pressurized between upper and lower bolsters, and a heat insulating plate is inserted between the bolster and a hot plate, the heat insulating plate side of the bolster is 1. A hot press, comprising means for preventing deformation of an object to be adhered by applying an optimum pressure distribution to the object to be adhered, and means for controlling the deformation prevention means. 2. The means for preventing deformation of the adhered object includes a hydraulic auxiliary ram cylinder formed in the bolster, and an auxiliary ram fitted into the ram cylinder so as to be movable in the pressing direction of the adhered object. A hot press according to claim 1, characterized in that the hot press is configured as follows. 3. The means for preventing deformation of the adhered object includes a screw type auxiliary ram cylinder formed in the bolster and having a threaded part on the inner periphery, and a threaded part that engages with the threaded part in the ram cylinder on the outer periphery. and a screw-type auxiliary ram that is fitted and inserted so as to be movable in the pressurizing direction of the adherend due to the meshing of both threaded portions. hot press.