JPH04245695A - Thick film circuit substrate and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the generation of wiring line separation from a glass insulation film attributable to differential potential produced by the difference between the main components of each paste material during burning between a first line and a second line which are cross-laid out with a glass insulation film between the two lines on a board. CONSTITUTION:A branch wiring line which connects a first wiring line 2 with a second wiring line 5 is pulled out in the shape of a branch from each wiring line so that both the lines may be short-circuited, thereby eliminating differential potential prevailing between both of the lines during the burning of the second wiring line. After the burning, a first branch wiring line 3 or a second branch wiring line 6 is partly cut down, thereby insulating the spot between & both & wiring lines.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] On the surface, the present invention comprises:
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 each other with an insulating film in between, and a method for forming the same.

0002

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

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

0004

[Problems to be Solved by the Invention] However, when the first wiring line is formed using Ag-based paste and the second wiring line is formed using Au paste as in the above-mentioned conventional technology, the main component of each paste material is Since the standard electrode potentials of the two wiring lines are significantly different from each other, when firing the second wiring line that is screen printed to intersect with the first wiring line,
A potential difference occurs between the two wiring lines that are present via the softened glass insulating film. When a potential difference occurs 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, generating 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 conventional technology and prevents peeling of the glass insulating film by eliminating the potential difference caused by the significant difference in standard electrode potential of the paste materials forming the two wiring lines. However, it is an object of the present invention to provide a thick film circuit board and a method for manufacturing the same, which can be expected to improve yield.

[0006]

[Means for Solving the Problem] As a result of intensive research in order to achieve the above object, the present inventors have discovered that before firing a second wiring line formed on a glass insulating film so as to intersect with a first wiring line. First, by short-circuiting both wiring lines so that no potential is generated between both wiring lines when firing the second wiring line, and insulating between both wiring lines after firing the second wiring line, the wiring line The present invention was achieved by discovering that it is possible to prevent the generation of bubbles at the boundary between the glass insulating film and the glass insulating film.

That is, the present invention provides a thick film circuit board having a structure in which wiring lines formed by two thick film conductors intersect with each other with an insulating film interposed on the surface of the board. Branch wiring lines using similar thick film conductors are
Branches are drawn out from each wiring line in such a manner as to short-circuit the two wiring lines, and further, a dividing portion is provided in at least a part of the branch-like portion consisting of the branch wiring line to insulate the branch-like portion. A thick film circuit board characterized in that one of the two wiring lines is made of a paste material containing Au as a main component, and the other is made of a paste material containing Ag, Cu, Ni, or Z.
The above thick film circuit board is formed from a paste material whose main component is one metal selected from the group consisting of n, Al, or Sn; and one of the two wiring lines is made mainly of Ag. paste material as a component, the other is Ni,
The thick film circuit board described above is formed from a paste material whose main component is one metal selected from the group consisting of Zn, Al, or Sn; In a method for manufacturing a thick film circuit board having a structure in which a main wiring line exists, first, when forming a first wiring line, a branch wiring line is drawn out from this line in a branch shape, and a branch wiring line is drawn out from the first wiring line. An insulating film is formed covering the upper surface of a predetermined portion, and then a second insulating film is formed on this insulating film.
When forming the 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 branch wiring line, and after firing the second wiring line, a part of the branch-like part consisting of these branch wiring lines is separated, and both the short-circuited wirings are removed. The present invention provides a method for manufacturing a thick film circuit board characterized by insulating lines.

[0008]

[Operation] In the thick film circuit board of the present invention, the second wiring line is formed by short-circuiting both wiring lines before firing the second wiring line, which is formed by intersecting the first wiring line with a glass insulating film in between. The potential difference that occurs between both wiring lines when firing the wiring lines disappears. Therefore, even if the standard electrode potentials of the main components of the paste materials 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.

Further, the thick film circuit board of the present invention is particularly effective when the standard electrode potential difference of the main components of the paste material forming the first wiring line and the second wiring line is 0.7 V or more. It is.

[0010] The present invention will now be explained in more detail with reference to Examples. However, the scope of the present invention is not limited to the following examples.

[0011]

[Example] The manufacturing process of the thick film circuit board of the present invention is shown in FIG.
This will be explained using 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 this substrate using Au paste.
It was formed by firing in air at 850°C for 10 minutes (Figure 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 is baked in air at 850°C for 10 minutes to form a glass insulator. A film 4 was formed (FIG. 3). continue,
A second wiring line 5 was screen printed using Ag/Pt paste so as to be perpendicular to the first wiring line 2 and to pass over the glass insulating film 4 . At the same time, a second branch wiring line 6 was screen printed from this second wiring line 5 to the end of the first branch wiring line 3 to short-circuit both wiring lines, and the temperature was increased to 850°C in air. , 10
It was baked for a minute (Figure 4).

After baking, a part of the second branch wiring line 6 was cut with a YAG laser to insulate the first wiring line 2 and the second wiring line 5, and a thick film circuit board was manufactured. (Figure 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 no peeling of the glass insulating film occurred.

[0016]

[Effects of the Invention] With the advent of the present invention, bubbles are no longer 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 manufacturing thick film circuit boards has been significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing step-by-step an example of the manufacturing process of the thick film circuit board of the present invention, showing a part of the second branch wiring line on the board in FIG. 4, which is the final step. FIG. 3 is a plan view showing the thick film circuit board after being divided.

FIG. 2 is a diagram showing step-by-step an example of the manufacturing process of the 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 board. FIG.

3 is a plan view showing a state in which a glass insulating film is formed on the substrate of FIG. 2, which is one of the diagrams showing step-by-step an example of the manufacturing process of the thick film circuit board of the present invention; FIG.

4 is one of the diagrams showing step-by-step an example of the 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; FIG. FIG.

FIG. 5 is a diagram illustrating step-by-step an example of a conventional thick film circuit board manufacturing process, and is a plan view showing a state in which a first wiring line is formed on a substrate.

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

7 is a diagram showing step-by-step an example of the manufacturing process of a conventional thick film circuit board, the thick film after the final step of forming a second wiring line on the substrate of FIG. FIG. 3 is a plan view showing the circuit board.

[Explanation of symbols]

１‥‥Substrate 2..First wiring line 3..First branch wiring line ４‥‥Glass insulation film 5. Second wiring line 6. Second branch wiring line 7‥‥Divided part

Claims (4)

[Claims] 1. A thick film circuit board having a structure in which wiring lines made of two thick film conductors intersect with each other with an insulating film on the surface of the board, the wiring line being a thick film similar to the two wiring lines. A branch wiring line made of a conductor is drawn out in a branch shape from each wiring line in such a manner as to short-circuit the two wiring lines, and further, the branch wiring line is drawn out in a branch shape from each wiring line in such a manner as to short-circuit the two wiring lines, and further, the branch wiring line is connected to at least a part of the branch portion formed by the branch wiring line. 1. A thick film circuit board characterized by having a dividing part that insulates a shaped part. 2. One of the two wiring lines is made of a paste material mainly composed of Au, and the other is made of a paste material containing Ag, Cu, Ni, etc.
2. The thick film circuit board according to claim 1, wherein the thick film circuit board is made of a paste material whose main component is one metal selected from the group consisting of Zn, Al, or Sn. 3. One of the two wiring lines is made of a paste material whose main component is Ag, and the other is made of a paste material whose main component is one metal selected from the group consisting of Ni, Zn, Al, or Sn. The thick film circuit board according to claim 1, wherein the thick film circuit board is formed by forming a thick film circuit board. 4. In a method for manufacturing a thick film circuit board having a structure in which two wiring lines intersect with each other with an insulating film on the surface of the substrate, first, when forming a first wiring line, A branch wiring line is drawn out in a branch shape from the first wiring line, an insulating film is formed covering the upper surface of a predetermined portion of this first wiring line, and then when a second wiring line is formed on this insulating film, the branch wiring line is A branch wiring line connecting the first wiring line and the second 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 the second wiring line, these branches are connected. A method for manufacturing a thick film circuit board, which comprises dividing a part of a branch portion consisting of a wiring line to insulate a short-circuited wiring line.