JPH01146740A - Manufacture of copper-plated laminated sheet - Google Patents

Abstract

PURPOSE:To reduce remarkably the pressurizing condition of a double belt press and to improve the dimension stability of the laminated sheet backed with copper by using the laminate in which the base material impregnated with resin and a copper foil are preliminarily heat-welded continuously under reduced pressure. CONSTITUTION:For example light long base materials 1 impregnated with resin and wound into a roll, and e.g. two copper foils 2 are introduced into the chamber 4 kept under reduced pressure by a vacuum pump 7, and between a pair of vacuum sealing rolls 41, and then after they have been heated under reduced pressure from this both surfaces by a far infrared ray heater 43, and made into one body by two pairs of heating and pressurizing rolls 42, it exits from the reduced pressure-chamber through a pair of vacuum sealing rolls 41, and is introduced into a double belt press 5. The resin is cured by heating and pressurizing, and after it has been made into one body with the copper foil, it is discharged, and is cut by a cutting tool 6. Thus the laminated sheet 3 backed with copper is obtained. In this manufacture, by using the laminated material preliminarily heat bonded under reduced pressure, a high pressure is not required in the double belt press, and the copper-plated laminated sheet having no bubbles and no defects is obtained. When the laminated sheet is worked into a printed wiring board, the rate of dimension change is small, and its warp is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a continuous manufacturing method for copper-clad laminates used for printed wiring boards for electrical and electronic equipment.

[Conventional technology and its problems]

As one of the manufacturing methods for copper-clad laminates, a laminate consisting of a desired number of long resin-impregnated base materials and a long copper foil layered on one or both of the outermost surfaces is placed between a pair of belts. A method for producing a continuous copper-clad laminate using a double belt press method using heat and pressure is known (Japanese Patent Application Laid-open No. 10456/1983, etc.).

In order to produce a laminate with no defects such as air bubbles in the laminate using this method, the pressure of the double belt press must be 50 kg/co?
It is essential to use a high pressure.

However, there are various problems with the pressurization method due to the use of high pressure in the double belt press. For example, when fluids such as air or oil are used as pressurizing media, it is necessary to devise seals to prevent leakage of these media, resulting in large-scale equipment, or it is impossible to completely prevent leakage. It was difficult to do so. In addition, in the method of using rolls (rollers) for pressurizing, it is necessary to use many small diameter ones from the point of view of press smoothness, but when trying to generate high pressure, the load on the rollers becomes large. It becomes too strong compared to its strength, causing problems such as easy damage to the rollers, so it is essential to devise a buffer/tube mechanism.

In addition, as a method to improve the shortcomings of the above methods, there is a proposal to use molten metal as a pressurizing medium and pressurize it as a solid cooled below the melting point. This will cause some problems.

[Problems to be Solved by the Invention] The present invention has been developed as a result of intensive studies on a method that significantly reduces the pressure applied in the double belt press method compared to the conventional method and does not generate bubbles. The present invention was completed by discovering a method of using a laminated material that has been heat-fused in advance.

That is, the present invention heats and presses between a pair of belts a laminated material composed of one or more long resin-impregnated base materials and a long copper foil layered on one or both of the outermost surfaces thereof. A method for manufacturing a continuous copper-clad laminate using a double belt press method, characterized in that a laminate is used in which a resin-impregnated base material and a copper foil are continuously heat-fused under reduced pressure in advance. In a preferred embodiment, the pressure during continuous heat-sealing is 500 mmHg or less, particularly 200 mmHg or less, and the resin-impregnated base material and the copper foil are placed in a continuous heat-sealing device. The cleanliness of the parts where the product is introduced and taken out is below class 100.000, especially class 1.
The purpose is to keep it below 0.000.

According to the manufacturing method of the present invention, the pressure conditions of the double belt press can be significantly reduced to lθ ~ 30 kg/cJ, and the dimensional stability (dimensional change rate, warpage) of the manufactured copper clad laminate is also excellent. It is something that

The configuration of the present invention will be explained below.

The resin-impregnated base material of the present invention usually refers to a varnish such as a phenol resin, an epoxy resin, an unsaturated polyester resin, or a thermosetting resin composition in a solvent-free liquid state, such as kraft paper, linter paper, glass woven fabric, or glass. It is obtained by continuously impregnating a long reinforcing base material such as a nonwoven fabric, and drying it appropriately to remove the solvent.

In addition, copper foils include long electrolytic copper foils, rolled copper foils, etc., as well as those whose back surfaces (adhesive side) have been treated for adhesion, and those with adhesive layers formed on the back surfaces. It is also possible to use the resin, and it is selected depending on the type of resin of the resin-impregnated base material described above.

Further, the double belt press of the present invention may be manufactured by using air, oil, etc. as a pressurizing medium, using small diameter rollers, using a pressurizing medium and small diameter rollers together, or any other method. 10 to 30 kg/cffl is sufficient, and the temperature and residence time should be selected appropriately depending on the type of resin-impregnated base material used, but from the viewpoint of productivity, the temperature is It is preferable to set the temperature high to shorten the residence time.

The above method of heat-sealing the resin-impregnated base material and copper foil under reduced pressure involves introducing the desired resin-impregnated base material and copper foil into a reduced-pressure chamber that has a heating means inside, and heating the resin-impregnated base material and copper foil under reduced pressure. After melting the impregnated resin and removing air and residual volatile matter within the impregnated resin base material, between the resin-impregnated base materials, and between the resin-impregnated base material and the copper foil, press fusion is performed.

Here, in order to maintain the inside of the reduced pressure chamber at reduced pressure, the introduction and removal parts of the resin-impregnated base material and copper foil into the reduced pressure channel XJ- are sealed using one or more pairs of rolls. However, it is difficult to completely prevent air from flowing into the decompression chamber from the seal, and if there is dust in the air near the inlet/outlet, the dust in the air will seal as the air flows in. Dust that adheres to the resin-impregnated base material surface, copper foil surface, etc., which corresponds to the part, and in particular, dust that adheres to the copper foil surface tends to cause unevenness on the copper foil surface by pressure pressing. Therefore, in order to avoid this problem, it is necessary to add measures such as installing the device in a clean room or blowing clean air out from near the entrance and exit of the decompression chamber so that the cleanliness class is 100.000 or less. In particular, it is preferable to maintain the temperature at class 10°000 or less.

In addition, various methods can be used as the heating means, and examples include radiant heating using far infrared rays, conduction heating using a heating roll, etc., but radiant heating using a non-contact type far infrared heater, lamp, etc. is preferable. .

Furthermore, in the decompression chamber, the internal process is not only to remove the air between the resin-impregnated base materials or between the resin-impregnated base material and the copper foil as described above, but also to fuse the resin-impregnated base materials and the copper foil. It is preferable to also remove air bubbles in the resin-impregnated base material that inevitably occur during the manufacturing process.
It is especially important to separate the resin-impregnated base materials introduced into the vacuum chamber or between the resin-impregnated base material and the copper foil and heat them under reduced pressure to sufficiently remove volatile components and then press-fuse them. This is preferable.

Next, an example of the manufacturing method of the present invention will be explained with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the continuous copper-clad laminate manufacturing apparatus of the present invention, in which a long resin-impregnated base material [1] is wound into a roll.
8 sheets and two sheets of copper foil [2] are introduced through a pair of vacuum seal rolls [41] into a vacuum chamber [4] maintained at a reduced pressure by a vacuum pump [7], where they are sealed from both sides under reduced pressure. After being heated by a far-infrared heater [43] and integrated by two pairs of heating pressure rolls [42], it passes through a pair of vacuum seal rolls [41], exits the vacuum chamber, and is transferred to a double belt press [5]. The resin is heated and pressurized to harden the resin and become a copper-clad laminate integrated with the copper foil, which is then discharged and cut by a cutting machine [6] to form a copper-clad laminate [3]. In the drawing, a simple enclosure is attached to the front of the seal roll [41] that introduces the resin-impregnated base material 1 and the copper foil 2 into the reduced pressure chamber while vacuum-sealing it, and the rear part of the exit. Cleaned air outlet [
44] to maintain the cleanliness of this area in particular, to prevent defects from occurring in the copper clad laminate due to "dust".

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 A glass woven fabric having a thickness of 0.2 mm was impregnated with an epoxy resin varnish and dried to obtain a long prepreg with a resin content of 40%.

As shown in the attached Figure 1, 8 sheets of the prepreg obtained above,
Furthermore, it has a structure in which copper foil with a thickness of 35ρ is layered on both sides, which is introduced into a reduced pressure chamber, heated and pressurized to fuse and integrate, and then introduced into a double belt press and heated and pressurized to form a copper-clad laminate. A copper-clad laminate was manufactured by manufacturing a copper-clad laminate and cutting it into a predetermined size upon exiting the double belt press.

The entire apparatus was installed in a room with a cleanliness class of 100,000 or less, and dry air with a cleanliness class of 10,000 or less was blown out from the entrance and exit of the vacuum chamber. Also, the residence time in the vacuum chamber is 0.3
The pressure was 100 mmHg, the surface temperature of the prepreg at the time of fusion was 100° C., the residence time in the double press was 1.0 minutes, the temperature was 200° C., and the pressure was 25 kg/cITI.

Table 1 shows the properties of the obtained copper-clad laminate.

Comparative Example 1 Using the same prepreg and copper foil as in Example 1, without heat fusing under reduced pressure, double belt press conditions were 200 ° C.
A copper-clad laminate was produced in the same manner except that the weight was 50 kg/cnf.

Table 1 shows the properties of the obtained copper-clad laminate.

[Operation and effects of the invention]

As is clear from the detailed description of the invention, Examples, and Comparative Examples, the method for manufacturing copper-clad laminates using double perdoube of the present invention uses laminates that have been pre-fused under reduced pressure in advance. A defect-free copper clad laminate with bubbles removed can be obtained without the need for high pressure in a double belt press, and the pressure mechanism and other parts used in the double belt press can be manufactured extremely easily, making it economical as well. It is excellent.

Furthermore, since continuous lamination molding can be performed at low pressure, the resulting copper-clad laminates are not only free from defects such as remaining bubbles, but are also superior to conventional methods that do not undergo vacuum pre-fusing treatment in advance. The dimensional change rate, which is the biggest problem when processing copper-clad laminates into printed wiring boards, is small, and warping has been greatly improved, making it extremely practical in terms of improved performance. It's a good process and something is understood.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a method for manufacturing a copper-clad laminate using a double belt press according to the present invention, and the numbers in the figure are 1: resin-impregnated base material, 2: copper foil, 3: copper-clad laminate. Board, 4:
Decompression chamber, 5: double belt press, 6: cutting machine, 7: vacuum pump, 41: vacuum seal roll, 42: heating pressure roll, 43: far infrared heater, 44: clean air outlet.

Claims (1)

[Claims] 1. A laminate consisting of one or more long resin-impregnated substrates and a long copper foil layered on one or both of the outermost surfaces is heated between a pair of belts. A method for producing a continuous copper-clad laminate using a double-belt pressing method, characterized in that a laminate is used in which a resin-impregnated base material and a copper foil are continuously heat-fused under reduced pressure in advance. Method of manufacturing boards. 2 The degree of vacuum during continuous heat fusion is 500mmH
The manufacturing method according to claim 1, wherein the pressure is less than g. 3. Claims 1 or 2 in which the air cleanliness near the entrance and exit where the resin-impregnated base material and copper foil are introduced into and taken out of the decompression device for continuous heat-fusion is class 100,000 or less Manufacturing method described in section.