JPH0716970A - Manufacture of laminated plate - Google Patents

Abstract

PURPOSE:To obtain a laminated plate whose warp is little, by a method wherein a plurality of short-sized prepregs belonging to a high-ranking group at the time of division of a thickness of a pressed body evenly into the upper and lower sides are loaded by uniting to either one side of the surface or the rear and a plurality of short-sized prepregs belonging to a low-ranking group are loaded by uniting to either the other side of the surface or the rear. CONSTITUTION:Out of prepregs 4 of a laminated plate, the prepreg 4 coming into contact with a circuit forming copper foil 1 brings a rear side where a quantity of resin is much into contact with the surface of the copper foil 1. In the case where at least three sheets of the prepregs are used, a plurality of the short-sized prepregs belonging to a high-ranking group at the time of division of a thickness of a pressed body evenly into the upper and lower sides are loaded by uniting to either one side of the surface or the rear and a plurality of short-sized prepregs belonging to a low-ranking group are loaded by uniting to either the other side of the surface or the rear. Namely, the prepregs are loaded symmetrically to the upper and lower sides. Consequently, since the more the laminated plate contains the quantity of the resin, the larger contraction in the laminated plate by heating and cooling becomes, this works so as to project a warp of the laminated plate to a surface side, equal forces are applied to both the surfaces in the opposite directions from each other and the warp is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated board, and more particularly to a method for manufacturing a laminated board for a printed wiring board used in electronic equipment and electric equipment.

[0002]

2. Description of the Related Art In the production of a laminated board, for example, a base material is impregnated with an epoxy resin, a plurality of semi-cured prepregs are stacked, and a copper foil is laminated on the outermost prepreg outer surfaces of these prepregs. Then, the pressed body is sandwiched between molding plates and thermocompression-molded. The copper foil-clad laminate thus obtained has a warp that is concave on the copper foil surface side after the completion of molding. It is speculated that the above-mentioned warpage occurs because the difference in the resin amount between the front side and the back side of this prepreg greatly differs as the resin amount of the prepreg increases. Sometimes there is a problem of lacking in dimensional accuracy.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a method for manufacturing a laminated board having a small warpage.

[0004]

According to the method for manufacturing a laminated sheet of the present invention, the width of the sheet is the direction perpendicular to the longitudinal direction, and one end of the width direction is the left end and the other is the right end. Impregnation step of impregnating varnish on the back side, drying step of drying the wet sheet impregnated with the resin obtained in this impregnation step, cutting step of cutting the long prepreg obtained in this drying step, obtained in this cutting step In a method for manufacturing a laminated plate, which includes a stacking step of stacking a plurality of quadrilateral short prepregs and a molding step of thermocompressing the compressed body obtained in this stacking step, the thickness of the compressed body is equalized vertically. When divided, a plurality of short length prepregs belonging to the upper group are uniformly loaded on either the front or back side, and a plurality of short length prepregs belonging to the lower group are loaded on either the front side or the other side uniformly .

[0005]

According to the method for producing a laminated sheet of the present invention, the width in the direction orthogonal to the longitudinal direction is set as the width, and the front and back surfaces of a long sheet whose one end is the left end and the other end is the right end are impregnated with varnish. Impregnating step, drying step of drying the wet sheet impregnated with the resin obtained in this impregnating step, cutting step of cutting the long prepreg obtained in this drying step, quadrangular short piece obtained in this cutting step In a method for manufacturing a laminated plate, which includes a stacking step of stacking a plurality of prepregs and a molding step of thermocompressing the pressed body obtained in this stacking step, an upper layer when the thickness of the pressed body is equally divided vertically Since multiple short prepregs belonging to a group are uniformly loaded on either the front or back, and multiple short prepregs belonging to a lower group are loaded on either the front or the other, the heating and cooling of the molding process The plate shrinks more when the amount of resin is larger, so it functions to make the warp of the laminated plate convex to the side with the larger amount of resin, and since multiple short prepregs are stacked vertically symmetrically, the same size on both sides. Forces are applied in opposite directions, thus reducing the warpage.

The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing separately the constituent materials of a laminated plate having copper foils on both sides according to an embodiment of the present invention.

In the method for producing a laminated plate of the present invention, the width is set in the direction orthogonal to the longitudinal direction, and the front and back surfaces of a long sheet having one end at the left end and the other end at the right end are impregnated with varnish. , A wet sheet impregnation step, a resin-impregnated wet sheet obtained in this impregnation step is dried to obtain a long prepreg, a long prepreg obtained in this drying step is cut, and a quadrilateral is cut. Cutting process to obtain a short prepreg, stacking a plurality of quadrilateral short prepregs obtained in this cutting process to obtain a pressed body, sandwiching the pressed body obtained in this loading process with a molding plate, heat A molding step of hardening the varnish in the prepreg by pressure molding is included.

Examples of the varnish include epoxy resin and polyimide. The long sheet, for example, glass, woven fabric made of inorganic fibers such as asbestos and polyester, polyamide, polyvinyl alcohol, organic synthetic fibers such as acrylic and natural fibers such as cotton,
A non-woven fabric, a mat, a paper, or a base material in which these are combined is used.

Further, in the present invention, the copper foil (1) for forming a circuit may be provided on both surfaces of the prepreg, and when provided, the copper foil (1) for forming a circuit is particularly limited. There is no.

As shown in FIG. 1, among the prepregs (4) used for manufacturing a laminated board, the prepreg (4) in contact with the copper foil (1) for forming a circuit has a large amount of resin on the back side of the copper foil (1) surface. Is in contact with. When three or more prepregs (4) are used, a plurality of short length prepregs belonging to the upper group when the thickness of the body to be pressured is evenly divided into the upper and lower groups are uniformly loaded on one of the front and back sides, and the lower group is A plurality of short prepregs belonging to the front and back are unified and stacked on the other side. That is, the prepreg (4) is vertically symmetrically stacked. With this configuration, the shrinkage of the laminate due to heating and cooling increases as the amount of resin increases, so it acts to make the warp of the laminate convex to the copper foil side with respect to the heat applied to the laminate, and the same size on both sides. Forces are applied in opposite directions, thus reducing the warpage. Furthermore, when the prepregs (4) are stacked in an alternating arrangement on the left and right with respect to the line direction in which the prepregs (4) are obtained, they are biased to the left and right in the width direction in the process of impregnating the front and back surfaces of a long sheet with varnish. It can cover the point where the varnish is impregnated, making the above warpage even smaller.

After the pressure-sensitive body, in which the varnish in the short prepreg has been hardened by the thermocompression molding, is taken out of the molding plate, a double-sided copper-clad laminate is obtained.

[0012]

【Example】

Example 1 As a copper foil (1) for forming a circuit, a foil having a thickness of 35 μm (manufactured by Furukawa Circuit Foil Co., Ltd., trade name TSTO) was used. As the prepreg (4), a prepreg having a resin amount of 50%, which was obtained by impregnating a glass cloth having a thickness of 180 μm (Nitto Boseki, trade name WE-116) with an epoxy resin and semi-curing the resin, was used. At this time, when the cross section of the prepreg (4) was observed, 35% of the resin was attached to the front side and 65% of the resin was attached to the back side. Next, as shown in FIG. 1, from the bottom, the copper foil (1), the above prepreg (4), three with the front side facing up, three with the back side facing up, and the copper foil (1) are stacked in this order. Then, the pressure target is sandwiched between molding plates, and the temperature is adjusted to 170
After heating at 40 ° C. and a pressure of 40 kg / cm ² for 60 minutes, a double-sided copper-clad laminate was obtained.

Example 2 As the prepreg (4), there was used a prepreg having a resin content of 60%, which was obtained by impregnating a 180 μm-thick glass cloth (Nitto Boseki, trade name WE-116) with an epoxy resin and semi-curing. At this time, when observing the cross section of the prepreg (4),
30% of the resin was attached to the front side and 70% of the resin was attached to the back side. A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except for the above.

Example 3 The front and back surfaces of a long sheet were impregnated with varnish and dried,
A double-sided copper-clad laminate was prepared in the same manner as in Example 1 except that the left-right direction of the prepreg was determined with respect to the width direction of the step of cutting to obtain the prepreg and the prepregs (4) were stacked in an alternating left-right array. Obtained.

COMPARATIVE EXAMPLE 1 Six copper foils (1), six prepregs (4) used in Example 1 with the front side facing upward, and the copper foil (1) were stacked in this order from the bottom, and this pressure-sensitive body was placed. Sandwiched between molding plates, temperature 170 ℃,
A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that heating was performed at a pressure of 40 kg / cm ² for 60 minutes.

Comparative Example 2 Six pieces of the copper foil (1) and the prepreg (4) used in Example 2 with the front side facing up were stacked in order from the bottom, and the copper foil (1) was loaded from below. Sandwiched between molding plates, temperature 170 ℃,
A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that heating was performed at a pressure of 40 kg / cm ² for 60 minutes.

Next, the warpage of the double-sided copper-clad laminates obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was evaluated by the following method.

A double-sided copper-clad laminate cut into a vertical length of 300 mm and a horizontal length of 300 mm was placed on a smooth surface plate, and the maximum amount of lifting was measured with a JIS class 1 metal gauge.

The double-sided copper-clad laminate cut into the above vertical 300 mm × horizontal 300 mm was etched to reduce the residual copper rate to 0%, and then placed on a smooth surface plate, and the maximum amount of lifting was measured with a JIS class 1 metal gauge. It was measured.

The above-mentioned double-sided copper-clad laminate, which was cut into a vertical length of 300 mm × horizontal length of 300 mm and etched, was heated at
After heating at 0 ° C. for 30 minutes, the plate was placed on a smooth surface plate, and the maximum lifting amount was measured with a JIS class 1 metal gauge.

The results of warpage in the normal state, after etching, and after heating were as shown in Table 1. In Examples 1 to 3, as compared with Comparative Examples 1 and 2, the normal state, the warpage after etching and after heating were all good.

[0022]

[Table 1]

[0023]

According to the method for manufacturing a laminated board of the present invention, a laminated board having a small warpage can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing separately the constituent materials of a laminated plate having copper foils on both sides according to an embodiment of the present invention.

[Explanation of symbols]

 1 Copper foil 4 Prepreg

Claims (2)

[Claims] 1. An impregnation step of impregnating varnish on the front and back surfaces of a long sheet having a width in a direction orthogonal to the longitudinal direction and having one end at the left end and the other end at the right end in the width direction. A drying step of drying the wet sheet impregnated with the resin, a cutting step of cutting the long prepreg obtained in this drying step, a loading step of loading a plurality of quadrilateral short prepregs obtained in this cutting step, In the method for manufacturing a laminated plate including a molding step of thermocompressing the pressed bodies obtained in this stacking step, a plurality of short prepregs belonging to a superordinate group when the thickness of the pressed bodies is equally divided into upper and lower sides are provided. A method for manufacturing a laminated board, characterized in that a plurality of short length prepregs belonging to a lower group are uniformly loaded on either one of the front and back sides. 2. The method for manufacturing a laminated board according to claim 1, wherein a plurality of short prepregs belonging to the upper group and the lower group are stacked alternately on the left and right.