JPH07131136A - Manufacture of thick film wiring substrate - Google Patents

Abstract

PURPOSE:To provide a thick film wiring substrate which can be simply separated without die stamping to obtain a large number of boards. CONSTITUTION:A photoresist pattern 21 is formed on the surface of an aluminum substrate 20, and a copper plating layer 22 is formed thereon by electroplating. A coating film 23 of epoxy resin is formed on the copper plating layer by electrodeposition coating, and is heated and cured. The aluminum substrate is dissolved and removed to obtain a pattern plating formation A. Another copper plating layer 22a is formed on the copper plating layer, and a coating film 24 is formed thereon by electrodeposition coating. Two pattern plating formations A are heated and cure in such a way that the coating films 24 are superposed, and to obtain a pattern plating laminate B. Through holes are formed in specified points on the copper plating layers, and a copper plating layer is formed within the through holes to provide continuity between the upper and lower copper plating layers. The coating film is removed by excimer laser processing in the positions of electrode terminals to expose them.

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 thick film wiring board, and more particularly to a method for manufacturing a thick film wiring board suitable for forming a fine pattern.

[0002]

2. Description of the Related Art Thick film wiring boards having thick conductor circuits formed by plating or etching are used in electronic parts such as small coils, high density connectors, and high density wiring boards with large operating current. In particular, with the recent miniaturization of electronic devices, there is a great demand for further miniaturization of these electronic components. For this reason, the pitch of the conductor pattern of the thick film wiring board is required to be very fine, that is, 10 lines / mm or more. Conventionally, this kind of thick film wiring substrate has been manufactured as disclosed in, for example, Japanese Patent Publication No. 2-19992. The outline of the manufacturing process will be described below with reference to FIGS. 4 and 5. First, a desired photoresist pattern 2 is formed on a thin plate 1 made of aluminum or the like.
(See FIG. 4 (a)), and then a copper conductor pattern 3 having a wiring density of 5 wires / mm or more and a film thickness of 15 to 200 μm is formed by an electroplating method using a copper pyrophosphate plating solution at a current density of 5 A / dm ^2. Are formed (see FIG. 4B). An adhesive 5 is applied to both surfaces of the insulating substrate 4, and two thin plates 1 provided with copper conductor patterns sandwiching the insulating substrate 4 are fixed by adhering the conductor patterns to the adhesive 5 (FIG. 4).
(See (c)). The thin plates 1 and the insulating substrate 4 are firmly fixed by thermocompression bonding the thin plates 1 to the insulating substrate 4 (see FIG. 4D).

Subsequently, both thin plates 1 are dissolved and removed in a hot alkaline solution to obtain a thick film conductor substrate F (see FIG. 4 (e)). This thick film conductor board F is provided with through holes 6 in the board in order to connect predetermined conductors in the copper conductor patterns 3 on both sides (see FIG. 5F), and the inside of the through holes 6 is electroplated. Conduction is made and both conductors are connected (see FIG. 5 (g)). At this time, the copper conductor pattern 3 is also plated, so that the film thickness becomes thicker and the conductor resistance can be reduced. Further, a cover coat film 7 for protecting the conductive film is provided on both surfaces of the thick film conductor substrate F except for the input terminal portion (not shown) (see FIG. 5 (h)). Then, the multi-cavity thick-film conductor board F is punched out using a die to divide it into individual thick-film conductor boards (see FIG. 5 (i)).

[0004]

However, in the above-mentioned method for manufacturing a thick film wiring board, it is necessary to use a thick and hard insulating substrate to provide two layers of conductive wiring films and integrate them. There is a problem that it is very difficult to reliably punch out the insulating substrate and the cover coat film at the time of the final substrate division in the multi-cavity substrate so as not to destroy them. The present invention is intended to solve the above problems, and an object of the present invention is to provide a method for manufacturing a thick film wiring board that can obtain a thick film wiring board that is easy to divide and has excellent reliability.

[0005]

In order to achieve the above object, the structural features of the invention according to claim 1 are a photolithography step of providing a predetermined resist pattern on the surface side of a metal thin plate, and a metal thin plate. A plating step of providing a conductive film on a portion other than the resist pattern on the surface side of the metal by a plating method, a first insulating film forming step of covering and fixing the first insulating film centering on the conductive film on the surface side of the thin metal plate, A metal thin plate removing step of removing the thin plate to provide a wiring pattern molded product; a second insulating film forming process of providing a second insulating film having adhesiveness on the metal thin plate removing side of the wiring pattern molded product; and a second insulating film. A stacking step of stacking and fixing the two wiring pattern molded products provided by stacking the second insulating film on each other;
Through-hole forming step of providing a through-hole in a predetermined portion of the upper and lower conductive films of the laminated wiring pattern molded product, and a through-hole conducting step of providing a conductor layer in the through-hole to electrically connect the upper and lower conductive films. And an electrode forming step of exposing a conductive film at an electrode position by removing a part of the insulating film.

[0006] Further, the structural feature of the invention according to claim 2 is that in the method for manufacturing a thick film wiring board according to claim 1, the first insulating film and the second insulating film are formed by an electrodeposition coating method. The first insulating film and the second insulating film are formed and fixed by heating.

[0007]

In the invention according to claim 1 configured as described above, after the conductive film is provided on the surface side of the thin metal plate, the first insulating film is covered around the conductive film to bond and fix it. By doing so, the conductive film after the thin metal plate is removed is supported by the first insulating film. A laminated insulating substrate is obtained by providing a second insulating film having adhesiveness on the side of the wiring pattern molded product from which the thin metal plate is removed, and stacking and fixing two wiring pattern molded products by the second insulating film. Then, the upper and lower predetermined conductive films of the laminated substrate are electrically connected through the through holes, and the first insulating film in the electrode terminal portion is removed to provide the electrode terminal. As a result, since the first and second insulating films are scarcely provided in the divided portions of the multi-cavity substrate where the conductive film is scarcely provided, a punching operation using a die is performed to divide the multi-cavity substrate. It is not necessary and can be performed by a simple operation of only separating the conductive film and the like. Further, since the substrate is not damaged by the separation, the reliability of the thick film wiring substrate is improved. The first insulating film and the second insulating film are
Since it serves both as a conductive film supporting material and as a conductive film protecting material and an adhesive, it is not necessary to separately provide a protective film and an adhesive layer.

Further, in the invention according to claim 2 configured as described above, since the first insulating film and the second insulating film are formed by the electrodeposition coating method, the electrodeposition coating is conductive. Since it deposits only on the film and not on the insulating part, the paint does not deposit at the dividing positions on the multi-cavity substrate, and the effect that the substrate can be easily separated is obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a stator component of a flat plate type motor to which the present invention is applied. This stator component 1
0 is outer diameter 35 mmφ x inner diameter 6 mmφ x thickness 0.5 mm
This is an annular thick film wiring substrate of No. 1, in which an electrode terminal portion 11 is provided on a part of the outer peripheral side, and nine equally divided coil portions 12 are provided in a central 30 mmφ range. Is provided with an outer frame portion 13. The coil portion 12 is an A pole portion 12a in which three sets are provided with two adjacent coils separated by 40 °.
And the B pole portion 12b, which is provided with three pieces each separated by 80 °. The A pole portion 12a is connected to the outer terminal 11a of the electrode terminal portion 11, and the B pole portion 12b is connected to the inner terminal 11b of the electrode terminal portion 11. The flat plate type motor is formed by facing a stator component 10 with a rotor component (not shown) in which twelve magnets are alternately arranged with north and south poles.

Next, the coil portion 12 and the electrode terminal portion 1
A manufacturing process of the thick film wiring board including the above-mentioned No. 1 will be described. First, an aluminum plate 20 having a thickness of 0.1 mm is prepared, and a photoresist film 21 having a predetermined pattern is provided on one surface side of the aluminum plate 20 by a photolithography technique (see FIG. 2A). The photoresist may be either a positive type or a negative type, and may be either a liquid or a film, but it should have good adhesiveness with the aluminum plate 20 and have the property of not peeling in the plating solution. is necessary.

Next, after a surface treatment such as zinc substitution is performed on the photoresist forming surface of the aluminum plate 20, a copper plating layer 22 is formed by electroplating (see FIG. 2B). Copper sulphate solution is used as the plating solution and the current density is 2
By plating at 0 A / dm ² for about 15 minutes, the film thickness is 6
A plating layer of 0 μm is obtained. Next, a coating film 23 having a thickness of 20 to 40 μm is provided on the copper plating forming surface of the aluminum plate 20 by an electrodeposition coating method using an epoxy resin,
Further, the paint film 23 is heat-treated at 180 ° C. to be baked and hardened to strengthen the adhesion with the copper plating layer 22 (see FIG. 2C). Here, since the paint film 23 formed by electrodeposition coating grows around the copper plating layer 22, the paint film is formed only on the part where the copper plating lead wire is provided at the dividing line position on the multi-piece substrate. To be done. Further, the supporting aluminum plate 20 is removed with an alkaline etching solution to obtain a pattern-plated molded product A (see FIG. 2 (d)). At this time, since the copper plating layer 22 is fixed to the paint film 23 and the paint film 23 is hardened by baking, the pattern-plated molded product A maintains a flat plate shape.

A copper plating layer 22a is provided on the exposed portion of the copper plating layer 22 of this pattern-plated molded product A by the electroplating method under the same conditions as described above (see FIG. 2 (e)) to reduce the resistance of the copper plating layer. Let Then, the copper plating layer 22
The paint film 24 is provided on the exposed surface under the same conditions as above by the electrodeposition coating method (see FIG. 2 (f)). Then, the two pattern-plated molded products A provided with the paint film 24 are adhered to each other on the surfaces on which the paint film 24 is formed (see FIG. 3 (g)), and the paint is baked in this state to form both pattern-plated molded products. Are laminated and integrated to form a pattern-plated laminated product B (see FIG. 3 (h)).

Of the two copper plating layers 22 of the pattern plating laminate B, a through hole 25 is provided by drilling with a drill or the like in order to electrically connect the upper and lower copper plating layers 22 at predetermined portions (see FIG. 3). (See (i)), and further, the copper plating layer 25a is provided in the through hole 25 by the electroplating method to electrically connect the upper and lower copper plating layers 22 (see FIG. 3 (j)). Further, the paint film 23 at the position of the input terminal portion of the pattern-plated laminate B is removed by excimer laser processing, the copper plating layer 22 is exposed and the electrode terminals 26 are formed, whereby a thick film wiring board is obtained (FIG. 3). (See (k)). Then, the thick film wiring board is divided into individual thick film wiring boards by separating the lead wire portion for electroplating.

As described above, in the thick film wiring board, the support for supporting the conductive film is constituted by the paint film by the electrodeposition coating method, so that the paint film functions as an adhesive and copper plating is performed. It also acts as a cover coat to protect the layers. Therefore, the adhesive agent and the cover coating agent are not required, so that the material cost can be reduced, and the labor for applying the adhesive agent and the cover coating agent can be saved to reduce the manufacturing cost. In addition, since the paint film is formed centering on the copper plating layer, the paint hardly deposits on the separated part of the multi-piece board connected by the lead wire for electroplating,
Therefore, cutting into individual wiring boards can be easily performed with scissors or the like without using a mold or the like. As a result, the reliability of the wiring board is improved without damaging the board due to the separation.

In each of the above embodiments, the epoxy-based paint film formed by the electrodeposition coating method is used, but the invention is not limited to the electrodeposition coating method, and a photoresist film formed by the photolithography method may be used. In addition to the epoxy-based paint film, a film of an organic material such as a polyimide film may be used. Further, the conductor layer is not limited to the copper plating layer, and another metal plating layer or vapor deposition film may be used. Furthermore, although the present invention is applied to the manufacture of the stator portion of the flat plate type motor in each of the above embodiments, it may be applied to other small coils, high density connectors, high density wiring boards and the like.

[Brief description of drawings]

FIG. 1 is a plan view showing a stator portion of a planar motor to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a part of the manufacturing process of the thick film wiring substrate according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a part of a manufacturing process for the same thick film wiring board.

FIG. 4 is a cross-sectional view showing a part of a manufacturing process of a thick film wiring board according to a conventional example.

FIG. 5 is a cross-sectional view showing a part of a manufacturing process for the same thick film wiring board.

[Explanation of symbols]

10; Stator component, 11; Electrode terminal part, 12; Coil part, 12a; A pole part, 12b; B pole part, 20; Aluminum substrate, 21; Photoresist film, 22, 22a; Copper plating layer, 23, 24; Paint film, 25; through hole, 2
5a: Copper plating layer, 26: Electrode terminal, A: Pattern plating molded product, B: Pattern plating laminated product.

Claims (2)

[Claims] 1. A photolithography step of providing a predetermined resist pattern on the front surface side of the metal thin plate, a plating step of providing a conductive film on a portion other than the resist pattern on the front surface side of the metal thin plate by a plating method, and a photolithography step of the metal thin plate. A first insulating film forming step of covering and fixing a first insulating film centering on the conductive film on the front surface side, a metal thin plate removing step of removing the metal thin plate to provide a wiring pattern molded product, the wiring pattern molded product And a second insulating film forming step of providing a second insulating film having adhesiveness on the metal thin plate removal side, and superimposing the two second insulating films on the two wiring pattern molded products provided with the second insulating film. And a through-hole forming step of providing through-holes at predetermined portions in the upper and lower conductive films of the laminated wiring pattern molded article, and A conductive layer is provided in the via hole to form a through-hole conduction step for conducting the upper and lower conductive films, and an electrode forming step for removing a part of the insulating film to expose the conductive film at the electrode position. A method for manufacturing a thick film wiring board characterized by the above. 2. The method for manufacturing a thick film wiring board according to claim 1, wherein the first insulating film and the second insulating film are formed by an electrodeposition coating method, and the first insulating film and the second insulating film are formed. The method for manufacturing a thick film wiring board is characterized in that the fixing is performed by heating and baking.