JP2842699B2 - Thick film circuit board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention
The present invention relates to a thick film circuit board having a structure in which wiring lines formed by two thick film conductors intersect with an insulating film interposed therebetween, and a method for forming the same.

[0002]

2. Description of the Related Art As a thick film circuit board as described above, for example, a board obtained as follows is known. First, a ceramic substrate 1 such as an alumina substrate is prepared, and an Ag-based paste such as an Ag / Pd paste is screen-printed on the surface of the ceramic substrate 1 and baked to form a first wiring line 2 (FIG. 5). ). Next, the first wiring line 2
A glass paste is screen-printed on the upper surface of the predetermined portion to completely cover the wiring line of the portion, and the glass paste is baked to form the glass insulating film 4 (FIG. 6).

Subsequently, the light passes over the glass insulating film 4 and
At this position, an Au paste is screen-printed in a band shape so as to intersect with the first wiring line 2 and fired in air to form a second wiring line 5 (FIG. 7).

[0004]

However, when the first wiring lines are formed of an Ag-based paste and the second wiring lines are formed of an Au paste as in the above-described conventional technique, the main components of each paste material are formed. When the second wiring line screen-printed across the first wiring line is fired because the standard electrode potentials are significantly different from each other,
A potential difference occurs between the two wiring lines existing via the softened glass insulating film. When a potential difference is generated between the two wiring lines, the oxide of the main component metal in the paste material forming these wiring lines is reduced by an electrochemical process to generate a gas such as oxygen. The generated gas appears as bubbles at the boundary between the glass insulating film and the wiring line, causing the glass insulating film to peel off from the wiring line.

The present invention solves the above-mentioned problems of the prior art and eliminates the potential difference caused by the remarkable difference in the standard electrode potential of the paste material forming the two wiring lines, thereby preventing the glass insulating film from peeling. It is another object of the present invention to provide a thick film circuit board which can be expected to improve the yield and a method for manufacturing the same.

[0006]

Means for Solving the Problems The present inventor has conducted intensive studies to achieve the above object, and as a result, before firing a second wiring line formed on a glass insulating film so as to intersect with the first wiring line. By short-circuiting both wiring lines, a potential is not generated between the two wiring lines when the second wiring line is fired, and the wiring lines are insulated after the second wiring line is fired. The present inventors have found that bubbles can be prevented from being generated at the boundary between the glass substrate and the glass insulating film, and have reached the present invention.

That is, the present invention relates to a thick-film circuit board having a structure in which two thick-film conductors intersect with each other with an insulating film interposed therebetween on a substrate surface. A branch wiring line with a similar thick film conductor
The two wiring lines are drawn in a branch shape from each of the wiring lines in a short-circuiting manner, and further, at least a part of the branch portion formed of the branch wiring line is provided with a dividing portion for insulating the branch portion. A thick film circuit board; and one of the two wiring lines is a paste material containing Au as a main component, and the other is Ag, Cu, Ni, Z
the thick film circuit board formed of a paste material containing one metal selected from the group consisting of n, Al, and Sn as a main component; and one of the two wiring lines is mainly composed of Ag. A paste material as a component, the other being Ni,
The above thick film circuit board formed of a paste material containing one metal as a main component selected from the group consisting of Zn, Al or Sn; and 2 intersecting an insulating film on the substrate surface with an insulating film interposed therebetween. In the method of manufacturing a thick film circuit board having a structure in which there are present wiring lines, first, when forming a first wiring line, branch wiring lines are drawn out in a branch shape from this line, and the first wiring line is formed. An insulating film is formed so as to cover a predetermined portion of the upper surface, and then a second insulating film is formed on the insulating film.
When forming the first wiring line, a branch wiring line for connecting the branch wiring line of the first wiring line and the second wiring line is drawn out in a branch shape from the second wiring line, and the first wiring line is formed. And the second wiring line are short-circuited by each of the branch wiring lines, and after firing of the second wiring line, a part of the branch portion formed by these branch wiring lines is cut off to short-circuit the two wiring lines. An object of the present invention is to provide a method for manufacturing a thick-film circuit board characterized by insulating lines.

[0008]

In the thick film circuit board according to the present invention, the two wiring lines are short-circuited before firing the second wiring line formed to intersect the first wiring line with the glass insulating film interposed therebetween. The potential difference between the two wiring lines during firing of the wiring lines disappears. Therefore, even if the standard electrode potentials of the main components of the paste material forming the two wiring lines are significantly different, bubbles can be prevented from being generated at the boundary between the wiring line and the glass insulating film.

The thick-film circuit board of the present invention is particularly effective when the standard electrode potential difference of the main component of the paste material forming the first and second wiring lines is 0.7 V or more. .

Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the present invention is not limited to the following examples.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
This will be described with reference to FIGS. 3, 4, and 1.

First, a 96% alumina substrate 1 is prepared, and a first wiring line 2 and a first branch wiring line 3 are screen-printed on the surface of the substrate using an Au paste. It was formed by firing for minutes (FIG. 2).

Next, an insulating glass paste is screen-printed in a rectangular shape on the first wiring line near the first branch wiring line 3 and baked in air at 850 ° C. for 10 minutes to form a glass insulating film. A film 4 was formed (FIG. 3). Then, Ag ・
Using a Pt paste, it is orthogonal to the first wiring line 2,
The second wiring line 5 was screen-printed so as to pass over the glass insulating film 4. At the same time, a second branch wiring line 6 is screen-printed from the second wiring line 5 to the end of the first branch wiring line 3 to short-circuit both wiring lines. And baked for 10 minutes (FIG. 4).

After firing, a part of the second branch wiring line 6 is cut with a YAG laser to insulate the first wiring line 2 and the second wiring line 5 to produce a thick film circuit board. (FIG. 1).

In the above manufacturing process, no bubbles were generated at the boundary between the first wiring line 2 or the second wiring line 5 and the glass insulating film 4, and the glass insulating film did not peel off.

[0016]

With the advent of the present invention, no bubbles are generated at the boundary between the first wiring line or the second wiring line and the glass insulating film, and peeling of the glass insulating film from the wiring line is prevented. Now you can. Therefore, the yield in the production of the thick film circuit board has been remarkably improved.

[Brief description of the drawings]

FIG. 1 is a view showing stepwise an example of a manufacturing process of a thick film circuit board according to the present invention, in which a part of a second branch wiring line on the board of FIG. FIG. 3 is a plan view showing a thick-film circuit board after division.

FIG. 2 is a view showing stepwise an example of a manufacturing process of a thick film circuit board of the present invention, showing a state in which a first wiring line and a first branch wiring line are formed on the substrate. FIG.

FIG. 3 is a plan view illustrating one example of a step of manufacturing a thick film circuit board according to the present invention, and is a plan view showing a state where a glass insulating film is formed on the substrate of FIG. 2;

FIG. 4 is a view showing stepwise an example of a manufacturing process of the thick film circuit board of the present invention, in which a second wiring line and a second branch wiring line are formed on the substrate of FIG. 3; It is a top view showing the state where it did.

FIG. 5 is a plan view showing one example of a conventional process of manufacturing a thick-film circuit board in a stepwise manner, showing a state where a first wiring line is formed on the board.

FIG. 6 is a plan view illustrating one example of a conventional manufacturing process of a thick film circuit board, and is a plan view showing a state in which a glass insulating film is formed on the substrate of FIG. 5;

FIG. 7 is a view showing stepwise an example of a conventional manufacturing process of a thick film circuit board, and is a thick film after a final step of forming a second wiring line on the substrate of FIG. 6; It is a top view showing a circuit board.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 first wiring line 3 first branch wiring line 4 glass insulating film 5 second wiring line 6 second branch wiring line 7 cutting section

Claims (4)

(57) [Claims] An intersecting insulating film on a substrate surface;
A thick-film circuit board having a structure in which there are wiring lines formed by two thick-film conductors, wherein a branch wiring line formed by a thick-film conductor similar to the two wiring lines short-circuits the two wiring lines. Characterized in that at least a part of the branch portion composed of the branch wiring line has a dividing portion that insulates the branch portion from each wiring line. Circuit board. 2. One of the two wiring lines is a paste material containing Au as a main component, and the other is Ag, Cu, Ni, Z
2. The thick film circuit board according to claim 1, wherein the thick film circuit board is formed from a paste material containing one metal selected from the group consisting of n, Al and Sn as a main component. 3. One of the two wiring lines is made of a paste material mainly composed of Ag, and the other is made of a paste material mainly composed of one metal selected from the group consisting of Ni, Zn, Al and Sn. 2. The thick film circuit board according to claim 1, wherein the circuit board is formed. 4. Intersecting two insulating films on a substrate surface with an insulating film interposed therebetween.
In the method for manufacturing a thick film circuit board having a structure in which there are present wiring lines, first, when forming a first wiring line, branch wiring lines are drawn out in a branch shape from this line,
Forming an insulating film covering a predetermined portion of the upper surface of the first wiring line, and then forming a second wiring line on the insulating film, forming a branch connecting the branch wiring line and the second wiring line; The wiring line is drawn out in a branch shape, the first wiring line and the second wiring line are short-circuited by the branch wiring line, and after firing of the second wiring line, a part of the branch portion composed of these branch wiring lines is formed. And separating the two short-circuited wiring lines from each other by dividing the wiring line.