JPH0760771A - Manufacture of laminated sheet with one side clad with metallic foil - Google Patents

Abstract

PURPOSE:To provide a manufacture of a laminated sheet wherein it is useful for a high density printed circuit board from a view point of mitigation of a warp of the laminated sheet and its one side is clad with a metallic foil. CONSTITUTION:In a manufacture of a laminated sheet whose one side is clad clad with a metallic foil, a pressed body 4 obtained by laminating a number of necessary sheets of prepregs 1 obtained by impregnating bases with resin varnish, on outside of one of which metallic foil 2 is piled further is put between metallic plates 3, 3, and a plurality of sets of the pressed bodies 4 are put between hot plates 7 for heating and press molding, the laminated sheet wherein a metallic plate 3a which is on the side coming into contact with the prepreg 1 has the higher coefficient of thermal expansion as compared with that of a metallic plate 3b which is on the side coming into contact with the metallic foil 2 is used.

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 single-sided metal foil-clad laminate used as a printed wiring board.

[0002]

2. Description of the Related Art In recent years, electronic devices have been improved in performance and frequency,
Along with downsizing, there is an increasing demand for higher density in printed wiring boards used for this purpose.

As shown in FIG. 2, the single-sided metal foil-clad laminate used in the manufacture of this printed wiring board has a prepreg (1) obtained by impregnating a base material with a resin varnish between a pair of hot plates.
A desired number of layers are laminated, and a pressure-sensitive body (4) having a metal foil (2) stacked on one outer side is sandwiched between metal plates (3), and a plurality of sets of the pressure-sensitive bodies (4) are heated and pressed. It can be obtained by molding, but if the warpage of the laminate obtained by such a manufacturing method is large, poor adhesion and etching of the film during circuit pattern formation, misalignment of surface printing during outer layer processing, and holes The dawn accuracy cannot be secured, and as a result, the demand for higher density cannot be met.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and an object thereof is to reduce warpage of a laminated board, which is useful for a high-density printed wiring board. It is to provide a method for manufacturing a metal foil-clad laminate.

[0005]

A method for manufacturing a single-sided metal foil-clad laminate according to the present invention comprises laminating a required number of prepregs (1) obtained by impregnating a base material with a resin varnish, and further laminating the outside of one of the prepregs. The pressed body (4) having the metal foil (2) superposed on it is sandwiched between the metal plates (3), and a plurality of sets of the compressed bodies (4) are sandwiched in the hot platen (7) to be heated and pressed. In the method for producing a single-sided metal foil-clad laminate, a metal plate (3) on the side that contacts the prepreg (1) has a larger coefficient of thermal expansion than the metal plate (3) on the side that contacts the metal foil (2). It is characterized by using.

[0006]

According to the method for producing a single-sided metal foil-clad laminate according to the present invention, a required number of prepregs (1) obtained by impregnating a resin varnish into a base material are laminated, and a metal foil (2 ) Is sandwiched between a pair of metal plates (3) and (3), and a plurality of sets of the bodies to be pressured (4) are sandwiched in a hot platen (7) for heating and pressure molding. In the method for producing a single-sided metal foil-clad laminate, the metal plate (3a) contacting the prepreg (1) has a larger coefficient of thermal expansion than the metal plate (3b) contacting the metal foil (2). As a result, the metal plate (3a) that comes into contact with the prepreg (1) at the time of heating and pressing thermally expands more than the metal plate (3b) that comes into contact with the metal foil (2). Distracting power works.

The present invention will be described in detail below. FIG. 1 is a structural diagram of the inside of the upper and lower heating plates when a laminated plate is formed by the method for producing a single-sided metal foil-clad laminated plate of the present invention.

In the present invention, as shown in FIG. 1, the upper and lower heating plates (7) and (7) have a structure in which a single-sided metal foil-clad laminate is formed. A required number of prepregs (1) obtained by impregnating the same are laminated, and a metal foil (2) is further laminated on one outer side of the prepreg (1). The resin varnish used here is epoxy resin, phenol resin,
A resin varnish made of a thermosetting resin such as a melamine resin or a polyimide resin, to which a flame retardant such as antimony oxide is added if necessary. As the base material to be impregnated with this resin varnish, natural fibers such as pulp paper and cotton, organic synthetic fibers such as polyamide, polyvinyl alcohol, polyester, polyacrylic and glass, and woven fabrics and non-woven fabrics and mats of inorganic fibers such as asbestos are used. Used. The metal foil (2) is not particularly limited, but generally 12 μm to 70 μm used for a laminated plate.
Of copper foil is preferable, and an adhesive layer provided on the back surface of the metal foil (2) is suitable. As the metal plate (3) sandwiching the body to be pressed (4), a plate whose surface is chromium-plated with a mirror plate of an iron plate or a stainless steel plate having a thickness of 2 to 3 mm,
A mirror surface plate having a thickness of 2 to 3 mm, which is made of copper, bronze, brass, aluminum, duralumin, or the like, and whose surface is plated with chrome, is used. In the present invention, two types of metal plates (3) having different coefficients of thermal expansion are used. That is, the metal plate (3a) having a high coefficient of thermal expansion is placed on the prepreg (1) side, and the metal plate (3) having a coefficient of thermal expansion lower than that of the metal plate (3a).
When b) is used on the metal foil (2) side, the prepreg (1) is elongated compared to the metal foil (2) due to the difference in thermal expansion between the metal plates (3a) and (3b) during heating and pressing. That is, since the thermal expansion of the metal foil (2) is larger than the thermal expansion of the prepreg (1), the stretching balance of the front and back sides is lost, and a convex warp occurs with the metal foil (2) side facing up.
In order to maintain the balance of the distraction on the front and back, a metal plate (3
The difference in thermal expansion between (a) and (3b) is used to extend the prepreg (1) as compared with the metal foil (2). Coefficient of thermal expansion of these metal plates (3a) (3b), the resin of the pressure-receiving member (4) to be molded, the metal foil (2), the substrate, with those selected by the thickness difference 10 × 10 ^{- 6 to} 25 × 10 ^-6 is preferable, and a metal plate (3b) having a coefficient of thermal expansion equivalent to that of this metal is used on the metal foil (2) side so that wrinkles do not occur in this metal foil (2). Difference in coefficient of thermal expansion is 5 × 10 ^-6
The above is more preferable.

[0009]

EXAMPLES Examples of the present invention will be given below.

Example 1 As a resin varnish, a resol type phenolic resin varnish having a resin content of 50% by weight was impregnated into kraft paper having a thickness of 0.1 mm as a paper substrate and dried, and a prepreg (1) having a resin content of 45% by weight was obtained. 8 sheets are laminated, and metal foil (2) is further on the lower side.
As a result, a pressure-sensitive body (4) was obtained by stacking a copper foil having a thickness of 35 μm. The pressure-increased body has an upper side with a thickness of 2 mm and a coefficient of thermal expansion of 17.3.
A metal plate (3a) of × 10 ⁻⁶ is arranged, and a metal plate (3 mm) having a thickness of 2 mm and a coefficient of thermal expansion of 11.6 × 10 ⁻⁶ is provided on the lower side.
b) is arranged, and below the body (4) to be pressed.
Was placed so that the copper foil was on the upper side, and further, the metal plate (3a) having a thermal expansion coefficient of 17.3 × 10 ⁻⁶ was placed on the lower side. That is, the metal plate (3a) having a coefficient of thermal expansion of 17.3 × 10 ⁻⁶ always has a coefficient of thermal expansion of 1 on the prepreg side.
The pressure plate (4) is placed on the 1.6 × 10 ⁻⁶ metal plate (3b) so that the copper foil side always faces, and the hot plate (7) and the metal plate (3a closest to the hot plate (7) are placed. Between 5), 5 sheets of kraft paper with a thickness of 0.2 mm as a cushioning material (6) and a contact plate (6) of a phenol resin laminated plate with a thickness of 2 mm are inserted between the pair of heating plates at 170 ° C. and 50 kg. / Cm ² , 1
Heat-press molding was carried out for 20 minutes to obtain a single-sided metal foil-clad laminate having a thickness of 1.6 mm.

In order to evaluate the warp of this one-sided metal foil-clad laminate, the above-mentioned one-sided metal foil-clad laminate was subjected to 1020 × 10.
When it was cut into a size of 20 mm, placed on a flat surface plate, and the value of the warp on the end face was measured, the value was 10 mm.

Comparative Example 1 As the metal plate (3), a metal plate (3) having a thickness of 2 mm and a coefficient of thermal expansion of 17.3 × 10 ⁻⁶ was used. Was heat-pressed to obtain a single-sided metal foil-clad laminate having a thickness of 1.6 mm. When the warp was evaluated by placing it on a flat surface plate in the same manner as in Example 1,
The warp value at the end surface of 1020 × 1020 mm size is 3
It was 0 mm.

[0013]

According to the method for producing a single-sided metal foil-clad laminate according to the present invention, the difference in elongation between the front and back surfaces caused by the difference in thermal expansion between the metal foil and the prepreg is reduced by the thermal expansion of the metal plates having different thermal expansion coefficients. The difference is buffered to reduce the warpage of the single-sided metal foil-clad laminate. By reducing the warpage, it is possible to perform highly accurate processing work useful for high-density printed wiring boards and the like.

[Brief description of drawings]

FIG. 1 is a configuration diagram of upper and lower heating plates when a single-sided metal foil-clad laminate according to the present invention is formed.

FIG. 2 is a configuration diagram of the inside of the upper and lower heating plates when a conventional single-sided metal foil-clad laminate is formed.

[Explanation of symbols]

 1 prepreg 2 copper foil 3 plate 4 pressure body 5 current plate 6 action material 7 hot platen

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29K 105: 06

Claims (1)

[Claims] 1. A pressure-sensitive body (4) is formed by laminating a required number of prepregs (1) obtained by impregnating a base material with a resin varnish, and further laminating a metal foil (2) on one side of the prepregs. In a method for producing a single-sided metal foil-clad laminate, which comprises sandwiching between a plurality of sets of the pressed bodies (4) in a hot platen (7) by sandwiching them between metal plates (3) and (3), a prepreg ( A one-sided metal foil-clad laminate characterized in that the metal plate (3) on the side contacting with (1) has a coefficient of thermal expansion larger than that of the metal plate (3) on the side contacting with the metal foil (2). Production method.