JP2000216543A - Manufacture of multilayered printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce warpage of a multilayered printed wiring board using an one-side printed wiring board as an inner printed wiring board 1 at the time of manufacturing the wiring board. SOLUTION: On the surface of an inner printed wiring board 1 carrying no wiring pattern, a frame body 6 of metallic foil is formed so as to surround the area 5 of a wiring pattern formed on the opposite surface of the wiring board 1 at the position where the frame body 6 does not overlap the area 5. A multilayered printed wiring board is manufactured through a step of arranging metallic foil on both surfaces of the wiring board 1 through adhesive prepreg, and forming the board 1 and metallic foil integrally by heating and pressuring the laminated body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a multilayer printed wiring board in which an inner printed wiring board is prepared in advance, metal foils are arranged on both sides of the printed wiring board via an adhesive prepreg, and heat and pressure is formed. The present invention relates to a method for manufacturing a multilayer printed wiring board using a single-sided printed wiring board provided with a wiring pattern on only one side as an inner layer printed wiring board.

[0002]

2. Description of the Related Art As a technique for manufacturing a multilayer printed wiring board using a single-sided printed wiring board provided with a wiring pattern on only one side as an inner layer printed wiring board, there is a technique shown in FIG. FIG. 4 shows an example of manufacturing a three-layer printed wiring board. A metal foil 3 (copper foil) is disposed on the outermost layer via a predetermined number of adhesive prepregs 2 on both sides of the inner printed wiring board 1,
These are sandwiched between metal mirror plates 4 and formed by heating and pressing to be integrated. Thereafter, the metal foil 3 on the surface is etched to form a printed wiring. A single-sided printed wiring board used as the inner-layer printed wiring board 1 may be either a double-sided metal foil-clad laminate, or a printed circuit board formed on one side by etching to remove all the metal foil on the opposite side, or a single-sided metal-foiled laminate. It is manufactured by forming a printed wiring by etching.

[0003]

When a printed wiring is formed only on one side of a double-sided metal foil-clad laminate and all the metal foil on the other side is removed, the surface of the resin layer from which the metal foil has been removed is covered by the metal foil. Since the suppressed force of the suppressed resin layer to be released is released, the manufactured inner printed wiring board is warped. Also, in the method of manufacturing an inner printed wiring board from a single-sided metal foil-clad laminate, the warpage occurs from an initial stage due to the asymmetric material composition in the thickness direction, and the warpage is caused by the formation of the printed wiring. It gets even bigger. Therefore, such a single-sided printed wiring board is used as an inner printed wiring board, and the multilayer printed wiring board produced by the above-mentioned heat and pressure molding reflects the warpage of the inner printed wiring board, and warpage is easily generated. Has become. Such a problem of the warpage of the multilayer printed wiring board becomes more remarkable as the thickness of the adhesive prepreg and the inner printed wiring board is reduced with the demand for thinner multilayer printed wiring boards.

[0004] An object of the present invention is to reduce the warpage generated in a manufactured multilayer printed wiring board in manufacturing a multilayer printed wiring board using a single-sided printed wiring board as an inner layer printed wiring board.

[0005]

In order to solve the above-mentioned problems, a method according to the present invention uses a single-sided printed wiring board having a wiring pattern provided only on one side as an inner-layer printed wiring board, and an adhesive prepreg on both sides thereof. In manufacturing a multilayer printed wiring board through a process of arranging metal foils and integrating them by heat and pressure molding, on the surface where the wiring pattern of the inner layer printed wiring board is not provided, it is provided on the opposite surface. A metal foil frame is formed so as to surround the wiring pattern area at a position that does not overlap with the wiring pattern area. The warping force of the inner-layer printed wiring board (single-sided printed wiring board) is suppressed by the metal foil frame formed on the surface on which the wiring pattern is not provided. , The amount of warpage is reduced.

When a multilayer printed wiring board is manufactured by laminating a plurality of inner printed wiring boards, an adhesive prepreg is interposed between the inner printed wiring boards, and a metal foil is disposed on both sides via the adhesive prepreg. Then, they pass through a step of integrating them by heating and pressing. Even when a single-sided printed wiring board is used for at least one of the plurality of inner-layer printed wiring boards, the amount of warpage is increased by using the single-sided printed wiring board on which the metal foil frame is formed. Is reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS For producing a single-sided printed wiring board used as an inner-layer printed wiring board, for example, a glass woven fabric substrate double-sided copper-clad epoxy resin laminate is used. A predetermined printed wiring is provided on one side by etching. At this time,
The copper foil on the opposite surface is removed by etching, but the copper foil frame is left at a position that does not overlap the position of the wiring pattern. It is preferable to leave the frame as wide as possible without overlapping the position of the wiring pattern, and it is more effective to reduce the amount of warpage. Also, since the smaller the copper foil left on the surface of the single-sided printed wiring board on which the printed wiring is provided, the smaller the warpage becomes, it is better not to leave the copper foil other than the wiring pattern.

In some cases, a copper foil frame is left around the wiring pattern area on the surface of the single-sided printed wiring board used as the inner printed wiring board on which the printed wiring is provided. In such a case, in order to allow the thermosetting resin flowing from the adhesive prepreg to flow out of the copper foil frame during the heat and pressure molding of the multilayer printed wiring board, the copper foil is notched in the frame. May be provided. The cutouts are provided in the frame on both sides, but are preferably arranged so that the cutouts on both sides do not overlap each other. If the positions of the cutouts on both sides overlap,
This is because only that portion becomes the resin layer of the laminated board, and as a result, when the thickness of the inner printed wiring board is thin, the strength is weakened and there is a fear of breakage.

[0009]

EXAMPLES Example 1 (see FIG. 1) The size of the inner printed wiring board 1 was 340 × 510 m.
A single-sided printed wiring board prepared by etching a glass woven fabric substrate double-sided copper-clad epoxy resin laminate (using 18 μm thick copper foil) having a thickness of 0.1 mm and a thickness of 0.1 mm was prepared. On the surface of the single-sided printed wiring board on which the printed wiring was provided, the size of the wiring pattern area 5 was 290 × 460 mm, and all the copper foil other than the wiring pattern area 5 was removed by etching. On the other hand, on the surface without printed wiring,
The copper foil frame 6 was left in a width, and the other portions of the copper foil were removed by etching. On both sides of the inner printed wiring board 1 thus prepared, a size of 340 × 510 mm and a thickness of 0.1
mm adhesive prepreg 2 (glass woven fabric base epoxy resin prepreg, resin amount 52% by weight) was laminated one by one, and a metal foil 3 (copper foil having a thickness of 18 μm) was disposed on the outermost layer. These were sandwiched between 1.2 mm-thick mirror-finished plates 4 (made of SUS301), and heated and pressed at a pressure of 40 kgf / mm ² and a temperature of 175 ° C. for 85 minutes to integrate them as a whole. Molding is performed in one stage between press hot plates.
Four sets of materials were charged and performed. Then, the metal foils on both surfaces were etched to provide printed wiring, and a three-layer printed wiring board was obtained.

Second Embodiment In the first embodiment, as the inner layer printed wiring board 1, a copper foil frame having a width of 20 mm is formed on the periphery of the wiring pattern region on the surface on which the printed wiring is provided, similarly to the surface on which the printed wiring is not provided. A single-sided printed wiring board with the remaining was prepared. other than that,
A three-layer printed wiring board was obtained in the same manner as in Example 1.

Example 3 In Example 2, the width of the copper foil frame on both sides of the single-sided printed wiring board prepared as the inner-layer inner-layer printed wiring board was 10 mm. Otherwise, in the same manner as in Example 2, a three-layer printed wiring board was obtained.

Example 4 (see FIG. 2) In Example 2, the copper foil frames 6 on both sides of the single-sided printed wiring board prepared as the inner-layer printed wiring board 1 each have
A notch 7 having a width of 0 mm was formed. The cutouts 7 were arranged at four locations on the long side and three locations on the short side at 100 mm intervals. The cutouts 7 on both sides are arranged so that their positions do not overlap each other. Otherwise, in the same manner as in Example 2, a three-layer printed wiring board was obtained. The notch 7 is an escape route provided to allow the epoxy resin flowing from the adhesive prepreg to flow out of the frame at the time of heat and pressure molding.

Fifth Embodiment (See FIG. 3) In the second embodiment, the wiring pattern area 5 of the inner printed wiring board 1 is formed into two surfaces of about 200.times.290 mm so as to separate the two wiring pattern areas by 20 mm.
A frame 6 'of width has been added. The addition of the frame 6 ′ was performed on both sides of the inner printed wiring board 1. Otherwise, in the same manner as in Example 2, a three-layer printed wiring board was obtained.

COMPARATIVE EXAMPLE 1 In Example 2, a single-sided printed wiring board from which a frame on which no printed wiring was provided was removed was used as the inner-layer printed wiring board 1, and the other three layers were the same as in Example 2. A printed wiring board was obtained.

The maximum amount of warpage was measured for each of the 14 three-layer printed wiring boards manufactured in the above Examples and Comparative Examples. Table 1 shows the results.

[0016]

[Table 1]

[0017]

As is clear from Table 1, according to the method of the present invention, when manufacturing a multilayer printed wiring board using a single-sided printed wiring board as an inner printed wiring board,
Warpage generated in the multilayer printed wiring board can be reduced.

[Brief description of the drawings]

FIG. 1 shows a single-sided printed wiring board used as an inner-layer printed wiring board in an example according to the present invention, and is an explanatory plan view seen from a surface where no printed wiring is provided.

FIG. 2 is a plan view showing a single-sided printed wiring board used as an inner-layer printed wiring board in another embodiment according to the present invention, viewed from a surface where no printed wiring is provided.

FIG. 3 is a plan view showing a single-sided printed wiring board used as an inner-layer printed wiring board in still another embodiment according to the present invention, viewed from a surface where no printed wiring is provided.

FIG. 4 is an explanatory view showing an example of manufacturing a multilayer printed wiring board using a single-sided printed wiring board as an inner-layer printed wiring board.

[Explanation of symbols]

 1 is an inner printed wiring board 2 is an adhesive prepreg 3 is a metal foil 4 is a mirror plate 5 is a wiring pattern area 6 and 6 'is a frame 7 is a cutout

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E346 AA05 AA11 AA12 AA15 BB01 EE02 EE06 EE09 EE14 GG28 HH11

Claims (4)

[Claims] 1. A step of using a single-sided printed wiring board having a wiring pattern provided only on one side as an inner-layer printed wiring board, arranging metal foils on both sides thereof via an adhesive prepreg, and integrating them by heating and pressing. In the manufacturing of the multilayer printed wiring board, the surface of the single-sided printed wiring board on which the wiring pattern is not provided is formed so as to surround the wiring pattern area at a position not overlapping with the area of the wiring pattern provided on the opposite surface. A method for producing a multilayer printed wiring board, characterized in that a metal foil frame is formed in advance. 2. A process in which an adhesive prepreg is interposed between a plurality of superposed inner-layer printed wiring boards, and metal foils are arranged on both surfaces via the adhesive prepreg, and these are integrated by heating and pressing. In the production of a multilayer printed wiring board, at least one of the inner-layer printed wiring boards is a single-sided printed wiring board provided with a wiring pattern on only one side, and the surface of the single-sided printed wiring board on which the wiring pattern is not provided is provided. A method of manufacturing a multilayer printed wiring board, wherein a metal foil frame is formed so as to surround the wiring pattern area at a position not overlapping with a wiring pattern area provided on the opposite surface. 3. The multilayer printed circuit according to claim 1, wherein all the metal foils other than the metal foil forming the wiring pattern are removed from the surface of the single-sided printed wiring board on which the wiring pattern is provided. Manufacturing method of wiring board. 4. A metal foil frame is formed around a surface of a single-sided printed wiring board on which a wiring pattern is provided, and a cutout is formed in the frame and the frame on the opposite surface. 3. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the positions of the cutouts on each surface are not overlapped with each other.