JPS63141387A - Manufacture of thick film circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a thick film circuit board, and in particular to a thick film circuit with an improved connection process between a resistor and a second layer conductor. It is related to the manufacturing method of the substrate.

(Prior art) Recent electronic devices are becoming smaller and thinner.
In order to meet this demand, thick film circuit boards having resistors, conductors, etc. formed by, for example, thick film technology are often used. Further, conductors are becoming more multi-layered in order to increase the density of circuit boards.

Conventionally, such a thick film circuit board has a third layer as described below.
It is manufactured by the steps shown in Figures (a) to (d).

First, as shown in FIG. 3(a), for example, a ruthenium oxide (RuO2>-based resistance paste) is printed on, for example, an alumina plate 1 as an insulating plate by a screen printing method, and after drying, the paste is dried in an air atmosphere at about 850°C. A resistor 2 having a film thickness of 12 μm and 12 μm is formed by firing in the interior.Continuously, a conductive paste containing, for example, copper (CU) is printed by a screen printing method, and after drying, the resistor 2 is heated at about 600°C. Baked in a non-oxidizing atmosphere, such as a nitrogen atmosphere, to a film thickness of 17 μm.
The first layer conductors 3 to 6 are formed respectively (as shown in FIG. 2(b)).
. Subsequently, for example, ZnO is applied on the conductor 4 between the conductors 3.5.
A glass insulating paste of this type is printed by a screen printing method, dried, and then fired in a non-oxidizing atmosphere, such as a nitrogen atmosphere, at about 600°C to form an insulating layer 7 with a thickness of 40 μm (see FIG. C) As shown). Next, a conductive paste containing copper (Cu) is printed by a screen printing method, dried, and then fired at about 600° C. in a non-oxidizing atmosphere, such as a nitrogen atmosphere, so that it is placed on the insulating layer 1. , a second layer conductor 8 having a thickness of 17 μm is formed to connect the conductors 3.5, and a second layer conductor 8 having a thickness of 17 μm is formed to connect both ends of the resistor 2 and the conductor 4.6 located near both ends thereof. A thick film circuit board is manufactured by forming second layer conductors 9 and 10 with a thickness of 17 μm (as shown in FIG. 4D).

However, in the conventional method described above, the resistor 2 and the first
When printing the conductive paste for forming the second layer conductor 9.10 that connects to the layer conductor 4.6, a step of approximately 12 μm corresponding to the film thickness of the resistor 2 is present in the etched portion of the resistor 2. As a result, the conductor paste in the etched portion of the resistor 2 bleeds. Specifically, when a conductor paste for forming the second layer conductor 9.10 is printed, dried, and fired, as shown in FIG. Extending portions 111 to 114 are generated due to bleeding of the conductor paste toward the center of the resistor 2 at four edge portions around the resistor 2 where the sides of the layer conductor 4.6 intersect. The length of these extensions 111 to 114 is approximately 60 μm.
It may be m. As a result, the extension portions 111-1
Depending on the length of 14, the printed resistance value (initial resistance value) of resistor 2 will vary by ±10% to ±30% of the average value.
What kind of problem was there?

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and it is possible to easily manufacture a thick film circuit board having a resistor with little variation in initial resistance value. It is intended to provide a method.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes the steps of: forming at least a resistor and a first layer conductor disposed close to both ends of the resistor on an insulating plate; In the method for manufacturing a thick film circuit board, the method includes the step of connecting both ends of the resistor and a first layer conductor adjacent to the both ends with a second layer conductor, wherein a side orthogonal to both ends of the resistor and a first layer conductor adjacent to the ends At the four corners around the resistor where the sides of the first layer conductor intersect, apply a coating layer such that the side of the coating layer opposite to the first layer conductor matches or has a resistance higher than the side of the second layer conductor on the resistor side. This is a method of manufacturing a thick film circuit board, characterized in that the thick film circuit board is formed so as to be located on the center side of the body.

The win may be formed at any time before the step of forming the second layer conductor. Specifically, the coating layer can be formed in the process of forming a resistor, the process of forming a first layer conductor, and the process of forming an insulator layer for insulating between the first and second layer conductors. Such a coating layer is made of a resistive material when it is formed in a resistor forming process, and a conductive material when it is formed in a conductor forming process. There is no difference in forming the shape. Also, number 1! If the coating layer is formed simultaneously with the formation of the I conductor, it may be integrated with the first layer conductor.

(Function) According to the present invention, a coating layer is placed at the four corners around the resistor where the sides perpendicular to both ends of the resistor intersect with the sides of the first layer conductor, on the opposite side of the coating layer from the first layer conductor. By forming the second layer conductor so that its side coincides with the resistor side side of the second layer conductor to be formed or is located closer to the center of the resistor than the side of the second layer conductor to be formed,
When printing a conductor paste for a layered conductor, the step difference in the etched portion of the resistor where the sides of the conductor paste intersect can be alleviated or eliminated by the coating layer. As a result, it is possible to significantly suppress the extension of the resistor towards the center of the resistor due to bleeding of the conductor paste due to the step difference in the resistor, and the influence of resistance value fluctuation due to the extension can be reduced. Variations in initial resistance values can be reduced.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1(a) to (d).

First, as shown in FIG. 1(a), for example, ruthenium oxide (RuO2) is placed on an alumina plate 21 as an insulating plate.
A resistance paste of Ω/hole was printed on System 1 by screen printing, dried, and then fired in an air atmosphere at about 850° C. to form a resistor 22 with a film thickness of 12 μm. Next, a conductor paste containing, for example, copper (Cu) is printed using a screen printing method, and after drying, approximately 600
C. in a non-oxidizing atmosphere, such as a nitrogen atmosphere, to form first layer conductors 23 to 26 each having a film thickness of 17 .mu.m.

At this time, the conductor 24.2 is attached to the four corners around the resistor 22.
A conductor film layer 27.6 with a thickness of 17 μm is integrated with the conductor film layer 27.6. ~2
74 (as shown in (1) in the same figure). These conductor films 1!271-274 are arranged so that the side opposite to the conductor 24.26 coincides with the side of the second WII conductor located on the center side of the resistor 22, which will be formed in a step to be described later. It was placed in Subsequently, a ZnO-based glass insulating paste, for example, is printed on the conductor 24 between the conductors 23 and 25 by screen printing, dried, and then baked in a non-oxidizing atmosphere, for example, a nitrogen atmosphere at about 600° C. to increase the film thickness. Target 4
An insulator layer 28 having a thickness of 0 μm was formed (as shown in FIG. 3C).

Next, a conductive paste containing copper (Cu) is printed on the insulating layer 28 by a screen printing method, and at the same time,
Both ends of the resistor 22, conductors 2 located near both ends of the resistor 22
4.26 and the conductor 111 layer 27. A second layer conductor 29 with a film thickness of 17 μm that connects the conductors 23.25 by printing on the conductors 23. and conductors 24 and 26 located at both ends of the resistor 22 and near both ends.
A second layer conductor 30. with a film thickness of 17 μm for connecting with.
31 was formed respectively to manufacture a thick film circuit board (see figure (d)
).

According to the present invention, FIG. 1(d) and the resistor 2
As shown in FIG. 2, which is an enlarged view of the area around 2, conductors [1
By providing m271 to m274, the second W! When printing a conductor paste for the J conductor, the step of the etched portion of the resistor 22 where the sides of the conductor paste intersect is
71 to 274 to relax or eliminate the second layer conductor 30.
The second layer conductor 30.31 can reduce bleeding on the resistor 22, and the side located on the resistor 22 side is formed linearly.
I was able to connect to. When the initial resistance value of the resistor connected in this way was measured for 20 samples, it was ±7% of the average value.
It fit in. Furthermore, even when a resistor paste other than No. 07 was used in Example 1, a resistor with a smaller variation in initial resistance value than the conventional one could be formed, as in the example.

Note that in the above embodiment, the conductor n layers 271 to 274 are
Although the arrangement is such that the side opposite to 4.26 coincides with the side located on the center side of the resistor 22 of the second layer conductor to be formed, the present invention is not limited thereto. For example, the conductor film layer is
The second layer conductor may be formed so that the side opposite to the layer conductor is located closer to the center of the resistor than the side of the second layer conductor that is located closer to the center of the resistor.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a method for manufacturing a thick film circuit board that has a resistor with little variation in initial resistance value and can easily manage the formation of the resistor.

[Brief explanation of the drawing]

Figures 1 (a) to (d) are plan views showing the manufacturing process of a thick film circuit board in an embodiment of the present invention, and Figure 2 is Figure 1 (d).
2(a) to (d) are plan views showing the manufacturing process of a thick film circuit board by the conventional method. FIG. 4 is an enlarged plan view of the vicinity of the resistor in FIG. 3(d). FIG. 21...Alumina plate, 22...Resistor, 23-26
...First layer conductor, 271-214...Conductor film layer, 2
9-31...Second layer conductor. Applicant's agent Patent attorney Takehiko Suzue (a) (d) Figure 1 (a) (d) (C) Figure 3 procedural amendment (flag) 62, 3.10 Showa year Mon/Japan Commissioner of the Japan Patent Office Black 1) Yu Akira 1, Indication of the case Patent Application No. 1988-288101 2, Name of the invention Method for manufacturing thick film circuit board 3, Person making the amendment Relationship with the case Patent applicant (307) Toshiba Corporation 4, Agent 7. Contents of amendment (1) [
Figure 2 (a) - (d) J is replaced with "Figure 3 (a) -
(d) Correct it to -1.

Claims (2)

[Claims] (1) forming at least a resistor and a first layer conductor disposed close to both ends of the resistor on an insulating plate; In the method for manufacturing a thick film circuit board, which includes the step of connecting a conductor with a second layer conductor, the resistor is connected to the resistor at four corners around the resistor where sides orthogonal to both ends of the resistor intersect with sides of the first layer conductor. , the coating layer is formed such that the side of the coating layer opposite to the first layer conductor is aligned with the side of the second layer conductor on the resistor side or is located closer to the center of the resistor than the side of the second layer conductor on the resistor side. A method for manufacturing a thick film circuit board. (2) The method for manufacturing a thick film circuit board according to claim 1, characterized in that the coating layer is formed integrally with the first layer conductor.