JPS59232845A - Manufacture of metallic foil lined metallic substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a metal foil-covered metal substrate with uniform heat dissipation properties.

Conventionally, the production of resin-based copper-clad laminates such as phenolic resin/paper-based copper-clad laminates and epoxy resin/glass cloth-based @clad laminates has been carried out using pre-7' IJ semi-cured to the B stage.
This was done by assembling a large number of copper foils and inserting them into a multi-throw press, heating and pressurizing them to harden the resin. The advantage of this method is that a large number of laminated substrates can be manufactured at one time, but the disadvantages are: ■ Long time required for preliminary operations, temperature rise, etc.
3-73 seconds; (1) It was difficult to control the process such as heating and cooling to reduce uneven heating of the substrate; (2) It required a large investment in equipment.

By the way, in recent years, aluminum-based copper-clad substrates with thermal conductivity and electrical insulation properties have appeared as substrates for hybrid ICs on which semiconductor elements that generate a lot of heat, such as power transistors and power ICs, are mounted. It has come to be used exclusively. These aluminum substrates can be made by hot-compressing copper foil coated with adhesive onto an aluminum substrate using a multi-stage press (7111), or by placing semi-cured Derederig in a B-stage shape on the aluminum substrate, and then bonding the copper foil to the aluminum substrate. It is manufactured by a thermocompression bonding method using 1-4 foils in a multi-stage press. However, since the thickness of the insulating adhesive layer existing between the aluminum substrate and the copper foil is as thin as -1050 mm in the case of the resin-based copper clad laminate described above, it is difficult to completely degas during pressing. Since the process is extremely volatile and air bubbles may remain, the reliability of the adhesive strength and withstand voltage of the copper foil may be affected.

The inventors of the present invention have conducted extensive research into a method for producing metal foil-covered metal substrates that does not use a multi-stage press, which is extremely difficult to operate and requires a large amount of capital investment. We have invented a method for manufacturing metal foil-clad metal substrates that is easy to operate and has reliable adhesive strength.

That is, the present invention provides a method for manufacturing a metal foil-covered metal board in which an insulating layer and a metal foil are sequentially laminated on a metal plate, and at least two layers of hardening and hardening are applied on at least one lower surface. At the same time, heating and melting the surface of the insulating layer on the provided metal plate under pressure using a laminator,
The present invention is characterized by comprising the steps of adhering the metal foil-covered metal substrate by pasting and temporarily bonding the metal foil together, and further heating and curing the metal foil-covered metal substrate.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a schematic sectional view of a laminating apparatus of the present invention, and FIG. 2 is a schematic sectional view of a laminating apparatus in which a metal foil-covered metal substrate is inserted. FIG. 1 shows a typical laminator that can be used in the present invention, and reference numerals 1 and 6 indicate stands (support stands) for supporting materials to be laminated during transport. 2.3
．． 4 and 5 are rolls, and the rolls 2, 3, 4 and 5 have a structure in which pressure can be applied using hydraulic pressure or the like.

Among the rolls, at least roll 2 contains a heater, and its surface is made of heat-resistant rubber such as silicone rubber to facilitate degassing during lamination. Rolls 3.4 and 5 can have exactly the same specifications as roll 2, but they can also be metal rolls.

When manufacturing a metal foil-covered metal substrate (hereinafter referred to as a substrate), an insulating layer 8 is first formed on a metal substrate 9, a metal foil 7 is placed on the insulating layer 8, and then passed through a laminator as shown in Fig. fJ1. As a result, as shown in FIG. 2, the surface layer of the insulating layer 8 is melted by the heat generated by the heater of the roll 2, and
The metal foils 7 are crimped one after another in the direction of the arrow with the pressure of . The substrates are further pressed again by rolls 4 and 5 and heated or cooled to temporarily bond them. This temporarily bonded substrate is further heated and post-cured. For this post-curing, an ordinary blow dryer or far-infrared drying method may be used, but hot pressing may also be used.

As the metal substrate of the present invention, aluminum and its alloys, iron, iron-nisokel cladding, stainless steel, etc. are used, but an aluminum plate treated with alumite may be used without any problem.

Next, as the metal foil, copper foil, aluminum foil, fixed foil made by cladding aluminum foil and copper foil, foil in which copper foil is plated with different metals, etc. can be used. The thickness of the metal foil is 5μ~
200μ is appropriate).

In the present invention: J: The metal foil used for manufacturing the stone substrate may be either sheet-shaped or rolled, and in particular, in the latter case, continuous production is possible.

Next, the insulating layer on the metal substrate used in the present invention is preferably made of 70 resoleg or filler-filled epoxy resin, which is melted by heating and applied in at least two steps. It is preferable in terms of withstand voltage. Furthermore, it is preferable that the insulating layers have different degrees of hardening from the viewpoint of withstand voltage.

In addition, the laminating conditions of the present invention vary depending on the dissolution of the absolute pop layer and the state of temporary adhesion, but the roll sensitivity is 50 to 200 °C, the roll speed is 0.5 to 10 m/min,
The roll pressure force is preferably in the range of 1-10 kg/CTL2; outside this range, the temporary adhesion of the metal foil to the metal substrate, yoke, and productivity will deteriorate.

Further, for the subsequent post-curing of the metal foil and the long metal substrate, generally in a dryer at 2D'C to 200'C! , it is necessary to select the curing time from 24 hours to 10 minutes depending on the temperature and the condition of the insulating layer curing agent.

Hereinafter, the present invention will be explained in detail by way of examples.

Example 1 A filler-filled epoxy resin containing a curing agent was coated onto an i, 5+im aluminum plate to a thickness of about 40 μm using a spray gun. This was then cured with an aluminum plate at 80 DEG C. for 190 minutes, and then an additional 40 .mu.m thick edge layer was applied in the same manner.

This aluminum substrate with an insulating layer was cured at 80°C for 160 minutes, and a roll diameter of 15C was obtained to obtain the structure shown in Figure 1.
Using a TL laminator, laminate a 65μ sheet-shaped sheet of 11 layers. Rolls 2 and 3 were heated to 150°C, and rolls 4 and 5 were not heated. The aluminum plate feeding speed is 1.07 n/min, and a pressure of 2 kg/an2 is applied to rolls 2 and 4 at 7
:l) Being kicked.

Next, after this operation, one piece of copper foil-covered aluminum plate (the sheet is cured in a dryer at 140°C for 16 hours).
. The peel strength of the copper foil-covered aluminum board was 2.0 kg/Cm, and even in the solder bath 600°C, 60-minute immersion test, the peel strength was 4+ll1l. This steel foil-covered aluminum substrate after this treatment is as follows:
Example 2 Similar to Example 1, a filler-filled epoxy resin insulating layer with two different degrees of hardening was formed on the aluminum foil, and a 60μ absolute 1VFI layer was further applied thereon. form, 80
After curing by °Cl2O, heat all the rolls in 2.3.4.5 in Figure 1 to 100°'C, and in the single state, feed the substrate at a speed of 1.5 L/min to form a sheet of 35 μm. '1lil/
i13 was laminated. However, the substrates to which rolls 4 and 5 were applied were cooled by cold air and reached room temperature within 10 minutes.

The copper foil-covered aluminum substrate produced by this operation was subjected to post-aging under the same conditions as Example 1. The peeling strength of the resulting copper foil-covered aluminum substrate was 2.2 kg/cr.
rt, and as in Example 1, no bulging of the steel foil occurred in the solder bath immersion test at 30 °C for 160 minutes. After this heat treatment, the copper foil-covered aluminum substrate
The withstand voltage was determined as follows: 6 I × 0 or higher Example 2 Same as Example 2, but with different degrees of hardening 6) (To)
An aluminum plate having a pentagonal size of 60α was coated with a coating layer consisting of the following, and laminated with a roll of 65μ 11J foil under the same lamination and tar conditions as in Example 2. Cooling was carried out in the same manner as in Example 2, and after cutting the lining, post-curing was carried out under the same conditions as in Example 1. The peel strength of the obtained steel foil-clad aluminum substrate was 1.9 kg/cm, and the peel strength was 600°C.
Even in a 60-minute solder pass immersion test, no blistering of the copper foil occurred. This IIJ? After the treatment, the steel foil-clad aluminum substrate has a withstand voltage of d1]1,
There were two cases over 3KV.

Comparative Example 1 35μ4 was placed on the same fastened aluminum plate as in Example 1.
The 11-piece foil was heated to 150°, placed in a foilless machine heated to 1000°C, left under pressure for 60 minutes, and then heated to 150°.
C. and heated for 2 hours to produce a copper-clad substrate. When we measured the peel strength of a copper foil-covered aluminum board, we found that the thickness was 2-Okg/cm $) and partially 1.4! 17'/(when indicating rll),
There was a possibility that air bubbles were mixed in between the steel foil and the insulating layer. This copper foil-covered aluminum board was subjected to a solder pass immersion test at 300°C for 30 minutes. Foil blistering was observed.The steel foil-covered aluminum substrate, which was not subjected to heat treatment, was measured for 11iI voltage and found to be less than 5KV.

Comparative Example 2 An 80μ insulating layer was made into a 1.5+ layer by the same operation as in Example 1.
It was painted on a temporary aluminum plate. This aluminum substrate with an insulating layer was cured at 80° C. for 60 minutes, and the same lamination and curing conditions as in Example 1 were used to produce a foil-covered aluminum substrate. The peel strength of the obtained same flattened aluminum substrate is 1-9K! / / cra, and some blistering occurred when immersed in a solder bath at 300°C for 160 minutes. After this heat treatment, the steel foil-clad aluminum substrate had a dielectric strength of 1. It was below OK V. When the substrate before heat treatment was etched and the copper foil was removed,
There were some defects in the absolute +t+=.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of the laminating apparatus of the present invention, and FIG. 2 is a schematic cross-sectional view in which a metal foil-covered metal substrate is inserted. Code 1.6...Support stand, 2,3.4.5...Roll 7.
...Metal foil, 8...Insulating layer, 9...Metal substrate Patent applicant Denki Kagaku Kogyo Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] Insulating layer and metal foil on metal plate? In the method of manufacturing a metal foil-covered metal substrate that is sequentially laminated, 1) A metal plate having a small number of insulating layers (both two layers D) with different degrees of hardening on the main surface is laminated under pressure using a laminator. At the same time, the upper surface of the insulating layer is heated and melted, and at the same time, the metal foil is laminated and temporarily bonded to the metal foil-covered metal substrate, and 2) the metal foil-covered metal substrate is further heated to post-cure. A unique method for manufacturing metal foil-covered metal substrates.