JPS627531A - Contact bonding of planar printed-circuit board - Google Patents

Abstract

PURPOSE:To prevent a rejected part due to defective bonding force by a method wherein the printed-circuit portions of a planar printed-circuit board, onto which a plurality of printed-circuits are neatly arranged, are pressurized more positively than other portions so as to suppress bubbles generating in an adhesive layer. CONSTITUTION:Firstly, a pair of planar printed-circuit boards, onto which printed-circuit patterns 4 are formed, are prepared, coated with adhesive 5 and pasted together with each other. Secondly, the resultant pasted board assembly is placed on the jig planes 1 of a hot press in the state that spacers 2 are located so as to completely cover the respective printed-circuits 4 individually in order to contact-bond the assembly under heat. The thickness of the spacer 2 is preferably 5mum or more so as to develop enough pressure difference between the printed-circuit portion and the remaining portion such as the portion between the printed-circuit portions and the like. A matter, which is easily shaped into a flat surface body with uniform thickness and at the same time stands against pressure and heat, such as Teflon, silicone rubber, copper or the like is employed as the material for the spacer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for crimping substrates having planar conductor parts, such as printed circuits.

In the present invention, a printed circuit refers to one electronic component circuit formed using printing technology. In addition, a planar printed circuit board is a board with one printed circuit on a flat surface, or several printed circuits arranged in an orderly manner. First, a planar double-sided printed circuit board is a board made by bonding a pair of planar printed circuit boards with an insulating layer in between. Further, the term "between printed circuits" refers to a portion between adjacent printed circuits among a plurality of printed circuits on a planar printed circuit board.

(Conventional technology and its problems) In recent years, conductor patterns have been placed on both sides of the insulating layer.
□Many printed circuits with high wiring density have been produced.

In particular, the insulating layer needs to be as thin as 500 μm or less, and the wiring density needs to be as fine as 2 wires/dragon or more.

The method for manufacturing such thin printed circuits with high density wiring is to form a resist pattern of the desired circuit on a thin metal plate, then plate it on top to obtain a fine conductor pattern. The most preferred method is to bond the two sheets with an insulating layer in between so that the conductor patterns face each other, and then remove the thin metal plates on both surfaces to obtain a planar double-sided printed circuit board with conductor patterns arranged on both sides of the insulating layer. In this method, the insulating layer is formed with an adhesive, and the adhesive that forms the insulating layer has a thin and uniform thickness between the two facing conductor patterns, and is cured without the inclusion of air bubbles. For this purpose, an excess amount of adhesive is applied between the two planar printed circuit boards that are to be bonded together, and the material is placed between the pressure section of a pressure machine and pressurized to remove excess air bubbles. It is desirable to manufacture by extrusion and pressure bonding. Generally, electronic components having printed circuits on both sides of an insulating layer are preferably manufactured in multiple pieces at a time in consideration of workability and cost. A plurality of printed circuit resist patterns are arranged in an orderly manner.

Therefore, the pair of planar printed circuit boards immediately before being bonded together with the adhesive layer in between is in a state as shown in FIG. 3, for example. If you apply an excessive amount of adhesive to such planar printed circuit boards as described above, sandwich it between the pressing flat parts of a pressure machine, and apply pressure uniformly, the pressure will be applied to the entire board, causing the printed circuits and printing Since it is applied without distinction between circuits,
In particular, when bonding a printed circuit with a fine pattern of 2 lines/dragon or more on both sides with an insulating layer thickness of 500 μm or less, it is difficult for air bubbles to escape from the printed circuit near the center of the board, causing air bubbles to accumulate and reducing adhesive strength. A problem arises.

(Structure and operation of the invention) The present invention provides a method for bonding planar printed circuit boards on which a plurality of printed circuits are arranged at appropriate intervals using a pressurizing machine. The above-mentioned problem is solved by positively applying pressure only to the printed circuit area by making a difference in the pressure applied to the area.

There are no particular limitations on the specific means for applying more pressure to the printed circuit portion of a planar printed circuit board on which a plurality of printed circuits are arranged in an orderly manner than to other portions, but it is possible to A method in which an interlayer is inserted only between the printed circuit board and the printed circuit board is preferable. The interlayer referred to here is a planar body that has a necessary and sufficient area to cover the printed circuit part on a planar printed circuit board, and is large enough that adjacent interlayers do not come into contact with each other. As shown in Fig. 1(a), the printed circuit part is sandwiched between the pressurizing flat part of the pressure machine and the flat printed circuit board so as to cover the printed circuit part, and the pressure is applied by making a difference in distance from the pressurizing flat part. Crimp with a difference. The thickness of the interlayer is appropriately selected to be 5 μm or more so that a sufficient pressure difference is created between the printed circuit portion and other portions such as between the printed circuits. The interlayer may be made of any material as long as it can be easily shaped into a planar body with uniform thickness and can withstand pressure and heat, such as Teflon, silicone rubber, and copper. It is preferable to provide these inserts between the two pressure flat parts and the flat printed circuit board as shown in Figure 1, but only between one of the pressure flat parts and the printed circuit board. may be provided. In addition, it is possible to save a plurality of interlayers to be applied to a plurality of printed circuit parts by connecting them with a thin bridging band as shown in FIG. 2, without the trouble of laying each interlayer one by one.

Furthermore, as shown in FIG. 1 fb), these inserts can be fixed to the pressing flat part of the pressing machine in accordance with the arrangement of the printed circuit pattern. Alternatively, as shown in FIG. 1(C), the pressurizing plane portion itself may be formed into an uneven shape in accordance with the arrangement of the printed circuit pattern. In this case, the area and thickness of the convex portion are determined in the same manner as for the interlayer. Note that in addition to making the pressurizing plane part itself uneven, it is also possible to provide a thin cushioning material on the convex part.

Furthermore, if possible, as shown in FIG. 1(d), the pressure applied to each part may be adjusted by changing the pressurizer between the printed circuit part and other parts of the planar printed circuit board.

Furthermore, as shown in an example in Fig. 1(e), a recess or hole is provided on one or both sides of a flat printed circuit board, avoiding the printed circuit, and this is sandwiched between the pressurizing flat part of the pressurizer. It is also possible to apply even pressure. By providing these recesses and holes, the uniform pressure applied from the pressing plane is concentrated on the printed circuit area.

In this case, it is preferable to provide at least one recess or hole for each printed circuit, and the size of the recess or hole is 0.5% or more of the area of the printed circuit, and it is located very close to the printed circuit without touching it. It is preferable to provide one. Also, not only holes but also grooves may be cut.

If planar printed circuit boards on which a plurality of printed circuits of the same shape are arranged in an orderly manner are pressed together using the above-mentioned specific method, the excessive amount of adhesive applied between the facing individual printed circuits and The air bubbles are pushed out to the area around the printed circuit section where the degree of pressure is lower, and as a result, the individual printed circuits are strongly adhered to each other through a bubble-free adhesive layer of uniform thickness.

Next, examples of the crimping method of the present invention will be described, but the present invention is not limited thereto.

(Example 1) Individually 8011 vertical and 8C11 horizontal on a flat printed circuit board
Prepare a pair of square printed circuit patterns with 6 pieces vertically and 6 pieces horizontally, spaced at 2 cm intervals, and apply adhesive (Oy-1〇-liquid type, manufactured by Asahi Kasei Corporation). was coated on one of the flat printed circuit boards to a thickness of 1'50 μm using the blade neat method, and placed on the flat surface of the jig of the zero-order pressure heating machine, which was bonded to the other board, to form individual printed circuits on each board. 9cm long and 9cm wide so that it is completely covered.
A 500 μm thick Teflon interlayer was installed at am.
Heating was carried out at 100° C. and pressure bonding was performed at 2.0 kg/ajL for 30 minutes.

The resulting planar double-sided printed circuit board has an insulating layer of 1
The insulation layer had a uniform thickness of 00±5 μm, and there were no air bubbles in the insulating layer.When the shear bond strength of the flat double-sided printed circuit board obtained through this pressure bonding process was measured, the tensile speed was 5. 140K at a temperature of 25°C
g/-.

(Example 2) Individually 8all vertically and 8a11 horizontally on a flat printed circuit board
Prepare a pair of square printed circuit patterns with 6 pieces vertically and 6 pieces horizontally, spaced at 2 cm intervals, and apply adhesive (Oy-10-liquid type, manufactured by Asahi Kasei Corporation). It was coated on one of the planar printed circuit boards to a thickness of 150 μm using a blade coating method, and then bonded to the other board. Next, we prepared an aluminum press that had a square pressure surface measuring 9 cm long x 9 cm wide, which is a size that completely covers each printed circuit, and had a pattern with a 500 μm difference in distance between the pressed flat part and the groove that was not pressed. Using a pressure plate, it was installed in a pressure heating machine, and heated at 100° C. and crimped at 2.0 kg/crA for 30 minutes.

The resulting planar double-sided printed circuit board has an insulating layer of 1
The insulating layer has a reasonable thickness of 00±5 μm, and there are no air bubbles in the insulating layer. When the shear bond strength of the flat double-sided printed circuit board obtained through this pressure bonding process was measured, the tensile speed was 5 n/min. min., 137Kg at a temperature of 25℃
/ctl.

(Example 3) A pair of square printed circuit patterns of 13Cs Two φ2.5 holes per printed circuit pattern were drilled between the printed circuit patterns on the board. An adhesive (manufactured by Asahi Kasei Industries, Ltd., 0Y-10-liquid epoxy adhesive) was applied to one side of the planar printed circuit board to a thickness of 150 μm by a blade coating method. Next, the pair of substrates were pasted together, placed on the plane of a jig of a press-type heating machine, and heated and pressed at 100° C. and 20 g/− for 30 minutes. As a result, the insulating layer of the printed circuit pattern part of the obtained planar double-sided printed circuit board had a thickness of 100 μm±5 μm.
The thickness of the insulating layer is uniform, and there are no air bubbles in the insulating layer (and when the shear bond strength of the flat double-sided printed circuit board obtained through this crimping process was measured, it was found that the tensile speed was 5 mm/ The value was 135 Kg/cj at a temperature of 25°C.

(Example 4) On a planar printed circuit board, there were printed circuit patterns each having a square shape of 8 clll in the vertical direction and 81 cm in the horizontal direction, 6 in the vertical direction and 6 in the horizontal direction.
Prepare a pair of those formed with a spacing of 21 mm, and apply adhesive (manufactured by Asahi Kasei Corporation, 0Y-10'-liquid type).
was coated on one of the planar printed circuit boards to a thickness of 150 μm by blade coating, and then attached to the other board.

Next, the length Q c is large enough to completely cover each individual printed circuit.
Using the same number of pressure machines as the number of printed circuits, which have a pressure flat part of s
00° C., pressure bonding was performed at 2.0 Kg/aJ for 30 minutes. The insulation layer of the resulting planar double-sided printed circuit board was 100%
It has a uniform thickness of ±5 μm, and there are no bubbles in the insulating layer.The shear adhesive strength of the flat double-sided printed circuit board obtained through this pressure bonding process was measured at a tensile speed of 5 m/min. 135Kg/1 at a temperature of 25℃
It was the value of ffl.

(Comparative example) On a flat printed circuit board, there were 6 square printed circuit patterns vertically, 6 squares horizontally,
Prepare a pair of those formed at 2 cm intervals, and apply adhesive (manufactured by Asahi Kasei Corporation, 0Y-10-liquid type).
was coated on one of the planar printed circuit boards to a thickness of 150 μm by a blade coating method, and then attached to the other board. Next, place it on the plane of the jig of the press type heating machine and heat it for 100 minutes.
℃, crimping was carried out at 2.0 kg/aJ for 30 minutes. As a result, the two planar printed circuits formed an insulating layer with a thickness of about 100 μm, but small and large air bubbles were generated here and there, especially in the printed circuit in the center of the board, there were many large air bubbles. I pouted. The shear adhesive strength was 85 kg/aJ under the following conditions: a tensile rate of 5 fins/min, and a temperature of 25°C.

(Effects of the Invention) By employing the pressure bonding method of the present invention, a large number of printed circuits formed on the same planar printed circuit board are all evenly and closely bonded to opposing printed circuits. As a result, air bubbles that occur in the adhesive layer are suppressed, eliminating defects that previously occurred due to poor adhesive strength, and making it possible to produce large quantities of high-precision double-sided printed circuits with a single press. .

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the crimping method of the present invention. (a) shows the case where the insert is sandwiched, and (b) shows the case where the insert is fixed to the pressurizing flat part of the pressurizer. C1 is a case in which a concave-convex pattern is provided on the pressurizing tool of a pressurizing machine, (d) is a case in which the pressurizing plane part of a pressurizing machine is divided into small parts, and (e) is a case in which a concave pattern is provided on the flat printed circuit board itself which is the object to be pressed. In addition, Fig. 2 is a perspective view showing an embodiment of interlays that are cross-linked with each other by a bridging band, and Fig. 3 is a planar printing to which the crimping method of the present invention is applied. 1 is a plan view showing an example of a circuit board. 1... Pressure plane part of a pressure machine 2... Interlayer 3... Metal thin plate 4... Printed circuit 5... Adhesive layer 6 ・-・ Bridge band 7 --- Concavity 8 -- Hole Patent applicant Asahi Kasei Kogyo Co., Ltd. Figure 1 (d) Figure 1 (e) - ■ Figure 1 (e) - ■ Figure 1 (e) - ■

Claims (5)

[Claims] (1) When two or more planar printed circuit boards, each of which has a plurality of printed circuits of the same shape arranged in an orderly manner at appropriate intervals, are crimped together using a pressure machine, substantially the same and uniform application is applied only to the printed circuit parts. A method for crimping a planar printed circuit board, characterized by applying pressure. (2) The crimping method according to claim 1, wherein an interlayer is inserted between the pressing plane part of the pressing machine and the printed circuit part of the planar printed circuit board to apply pressure. (3) The crimping method according to claim 1, in which pressure is applied using a pressurizer in which a portion of the pressurizing flat portion corresponding to the printed circuit portion of the planar printed circuit board is made convex and the other portions are concave. (4) The crimping method according to claim 1, wherein recesses or holes are provided in a portion of the planar printed circuit board other than the printed circuit portion, and pressure is applied. (5) The crimping method according to claim 1, wherein pressure is applied using different pressure machines between the printed circuit portion and other portions of the planar printed circuit board.