JPH0548263A - Manufacture of copper-clad laminated board for printed wiring - Google Patents

Abstract

PURPOSE:To omit a polishing work by so superposing a polishing film on a surface of a copper foil that a polishing particle layer is brought into contact with the surface of the foil when the foil is extended on a prepreg resin laminated board, pressurized and hot pressed, and pressuring, and heat treating it. CONSTITUTION:A copper foil is superposed on one or both sides of a prepreg resin laminated board. Further, one side of an extrafine heat resistant film 3 made of polyester, polyimide film, etc., is coated with a high hardness polishing particle single layer or plural layers of heat resistant binder 2. The film 3 formed with predetermined uneven part on the surface is so superposed that the particle coating surface is brought into contact with the surface of the foil. After it is pressurized and heated through a mold by a press, the resin is cured, and then the film is peeled. Thus, the uneven part of the particle coating surface is transferred to the surface of the foil, and a fine and dense point-like uneven part having 1.0-10mum of Rmax is generated. Accordingly, a polishing work can be omitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a copper clad laminate for printed wiring used in electronic equipment and the like.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process of a copper clad laminate for printed wiring, a predetermined number of prepreg resin plates are combined according to the thickness of the laminate, and copper foil is superposed on one side or both sides of the prepreg resin board, and the prepreg resin board is used for molding There is a step of sandwiching between the substrates and simultaneously pressing and heating a plurality of substrates with a high-pressure multi-stage press machine to cure the resin and firmly bond the copper foil to the surface.

As a post-process of this step, the copper-clad surface is polished with a non-woven cloth polishing roll or the like to smooth the copper-clad laminate, adhere to resist, improve adhesion in through-hole plating or soldering. The foil surface is polished in a certain direction, and the surface roughness is adjusted to Rmax 1.0 to 10 μm.

[0004]

The above-mentioned polishing work includes rough polishing and finish polishing steps using a dedicated polishing machine, and since it is wet polishing, there are many steps such as washing and drying after polishing,
The cost of the series of polishing operations was enormous.
In addition, there is a defect that the grain is directional, and the surface roughness is remarkably different between the direction parallel to the grain and the direction perpendicular to the grain, and sometimes deep scratches are generated in the grain. This has been a factor that hinders the precision of printed wiring. The present invention aims to achieve the purpose of polishing by omitting this polishing operation and using new means.

[0005]

In order to achieve the above object, in the method for producing a copper clad laminate for printed wiring according to the present invention, a copper foil is superposed on one side or both sides of a prepreg resin laminate, and further on it. A single layer or multiple layers of ultra-thin heat-resistant film such as polyester or polyimide film is coated with a high-hardness abrasive particle with a heat-resistant binder to form a predetermined unevenness on the surface, and a flexible abrasive film is coated with abrasive particles. The surface is in contact with the copper foil surface, pressed and heated with a press machine through a mold to cure the resin, and then the polishing film is peeled off to provide the abrasive particle coated surface on the copper foil surface. It is intended to transfer the unevenness of (3) to generate fine and dense dot-like unevenness of Rmax 1.0 to 10 μm.

The polishing film laminated on the copper foil surface is
By sticking it as it is after the pressing step, it serves as a protective film until the film is peeled off in the subsequent step.

The polishing film as used herein is called a lapping film or polishing film which is currently used for polishing magnetic heads, magnetic disks, precision rolls, etc., and the base film is generally polyester. Target. If the temperature at the time of pressing is about 170 ° C, polyester has sufficient heat resistance, but at higher temperatures, a polyimide film or aluminum foil film is suitable for the purpose.

As the abrasive particles, high hardness abrasive particles having a Mohs hardness of 7 or more such as aluminum oxide and silicon carbide are used. The size of the abrasive particles is selected according to the required surface roughness of the copper foil surface, but in order to obtain a copper foil surface roughness of 1 to 10 μm, the particle size of # 600 to # 4000 is used. Select and use.

Further, in order for the irregularities on the surface coated with the abrasive particles to make a predetermined impression on the surface of the copper foil, the abrasive particle layer needs to be rigid, and the abrasive particles are packed most densely to give the thickness of the abrasive particle layer. Is 25
At least μm is required.

As a binder for applying abrasive particles to a base film and firmly adhering the abrasive particles without dropping off during use, both flexibility and heat resistance are required, so a thermosetting resin is required. Is desirable. Examples thereof include urethane resin and epoxy resin.

[0011]

[Function] As described above, the polishing films are laminated so that the surface of the polishing particles is in contact with the surface of the copper foil, and pressure and heat are applied through the mold, so that the sharp tips of the high-hardness polishing particles have the copper foil surface. An indentation is made on the surface, and fine and dense dot-like irregularities with Rmax of 1.0 to 10 μm occur. This myriad of relatively uniform irregularities is similar to the surface condition created by sandblasting.

[0012]

EXAMPLE An example will be described with reference to the drawings. FIG. 1 shows a grain size on a polyester film having a thickness of 25 μm.
FIG. 7 is a cross-sectional view of a polishing film obtained by coating # 1000 white fused alumina abrasive with a urethane resin. The thickness of the abrasive particle layer is about 30 μm. FIG. 2 shows the surface roughness of this polishing film, which was Rmax of 15 μm.

A predetermined number of epoxy resin prepregs based on glass cloth are combined, and the thickness is 18
Overlay the copper foil of μm, and then on the copper foil on both sides,
Lay the # 1000 polishing film so that the surface coated with the polishing particles is in contact with the copper foil surface, sandwich it between two flat molds, and press at a pressure of 30 kg / cm2, 170 ° C for 90 minutes. -Heated. When the polishing film was peeled off and the surface roughness was measured, it was as shown in FIG. 3, and Rmax was 5.0 μm.

Non-woven cloth polishing roll # 8 which is a conventional polishing method
The surface roughness of the copper foil surface finished by polishing with 00 in the direction perpendicular to the polishing eyes was as shown in FIG. 4, and Rmax was 5.3 μm.
The surface roughness was almost the same. The above-mentioned copper clad laminate having irregularities formed with a polishing film had no difference from the conventional polished finish, and had good adhesiveness with resist, through-hole plating and solder.

[0015]

According to the present invention, it can be carried out in the conventional manufacturing process without using any new equipment or device, and it requires a great deal of cost in terms of labor, equipment and materials for polishing work. The work can be omitted, and the economic effect is great. In addition, there are no scratches on the surface of the copper foil, which are sometimes seen when polished, and point-like fine and dense irregularities are created without any directivity, so the reliability of pattern formation of printed wiring is also improved. ..

[0016]

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a polishing film.

FIG. 2 is a surface roughness curve of a polishing film.

FIG. 3 is a surface roughness curve of a copper clad laminate obtained by the present invention.

FIG. 4 is a surface roughness curve of a copper clad laminate obtained by conventional polishing.

[Explanation of symbols]

 1 Abrasive particles 2 Binder 3 Polyester film

Claims (1)

[Claims] 1. A process for producing a copper clad laminate for printed wiring by laminating a copper foil on one or both sides of a prepreg resin laminate of a paper or glass cloth base material and pressurizing and heating with a press machine to produce polyester or polyimide. An ultra-thin heat-resistant film such as a film is coated with a high-hardness abrasive particle in a single layer or multiple layers with a heat-resistant binder to form a predetermined unevenness on the surface. Layered so that they touch the surface, pressurize and heat with a press through a mold to cure the resin, and then peel off the polishing film to transfer the unevenness of the surface coated with abrasive particles to the copper foil surface. A method for producing a copper-clad laminate for printed wiring, characterized in that fine and minute dot-like concavities and convexities of Rmax 1.0 to 10 μm are produced.