JPH0547501A - Thick film resistor - Google Patents

Abstract

PURPOSE:To trim multilayered resistors simultaneously by a small laser output, without using a large laser output. CONSTITUTION:A pair of conductor patterns 3 and 4 are provided on a substrate 2. A cylindrical resistor 5 of multilayer structure is provided between both conductor patterns 3 and 4 in such a manner that an insulator is enveloped by the upper layer resistor and the lower layer resistor. Also, a groove part 6 is obliquely formed on the whole width of the upper surface side of the cylindrical resistor 5 ranging from the conductor pattern 3 to the other conductor pattern 4. The groove part 6 is formed penetrating the upper layer resistor and the insulator, and the bottom of the groove part 6 is used as the lower layer resistor. Accordingly, in view of the fact that the cylindrical resistor 5 is one resistor of the multilayer structure, the rated power against its mounting area can be made larger. Also, by laser-trimming the lower layer resistor only along the groove part 6, it is adjusted to the necessary resistance value by a small laser output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a thick film resistor used in hybrid integrated circuits and the like.

[0002]

2. Description of the Related Art Conventionally, a thick film resistor of this type has been adjusted to a required resistance value by trimming with a laser beam or the like after being formed on an insulating substrate by printing and drying.

For example, in the technique of "printing resistor" disclosed in Japanese Patent Application Laid-Open No. 1-302801, as shown in FIG. 10, two resistors 21, 22 are superposed with an insulating layer 23 interposed therebetween. It was arranged in multiple layers. In addition, each resistor 21,2
The two opposing ends were connected to each other and the electrode conductors 24 and 25 were connected to the other ends, respectively. Then, the resistance values are adjusted by trimming the resistors 21, 22 and the insulating layer 23 at once.

In this way, by arranging the two resistors 21 and 22 in multiple layers to form one long resistor, the mounting area as a thick film resistor is reduced and high density mounting is performed. I was trying. Further, since the same effect as the formation of a plurality of trimming grooves can be obtained by forming one trimming groove 26, the trimming time is shortened and the trimming software is simplified.

[0005]

However, in the above-mentioned prior art, since the resistors 21, 22 and the insulating layer 23 are trimmed at once, a high laser output is required when trimming with laser light. Was there. In addition, when trimming is performed with a high laser output, thermal influence on other parts of the substrate becomes large, and there is a problem in reliability.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is a thick film resistor capable of being trimmed at one time regardless of a high laser output, by arranging resistors in multiple layers. To provide the body.

[0007]

In order to achieve the above object, in the present invention, a pair of electrodes provided on a substrate so as to face each other and a lower layer resistor provided between the electrodes. A body, an insulator provided on the upper part of the lower layer resistor in a layered manner, and provided between both electrodes so as to cover the upper part of the insulator and the side parts of the insulator and the lower layer resistor. In a thick film resistor composed of an upper layer resistor provided in an overlapping manner, from one side of the upper layer resistor to the other side of the opposite side thereof, from one electrode vicinity to the other electrode vicinity, A groove is formed through the upper resistor and the insulator, and the bottom of the groove serves as the lower resistor.

[0008]

According to the above construction, one resistor having a multi-layered structure in which the lower layer resistor and the upper layer resistor wrap the insulator inside is formed. Further, since it is a single resistor having a multilayer structure, the rated power for its mounting area is large.

Further, by performing continuous trimming with laser light from one end side to the other end side along the groove,
It is possible to adjust to the required resistance value. In this case, since the bottom of the groove is a single layer of the lower layer resistor, high laser output is not required.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the thick film resistor according to the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a perspective view showing the appearance of the thick film resistor 1 of this embodiment, and FIG. 2 is a plan view thereof. On a substrate 2 made of an insulating material, a pair of conductor patterns 3 and 4 made of Ag-Pd paste as electrodes are provided to face each other with a predetermined interval. Both conductor patterns 3,
Between the four, a cylindrical resistor 5 having a substantially cylindrical shape is provided,
Both ends thereof are connected to both conductor patterns 3 and 4.
In addition, on the upper surface side of the cylindrical resistor 5, from one side portion in the width direction to the other side portion on the opposite side, from the tip position of one conductor pattern 3 to the tip of the other conductor pattern 4. The groove portion 6 reaching the position is formed obliquely. Here, the film thickness of the cylindrical resistor 5 is set to about “0.01 mm”. Further, the groove portion 6 is used for trimming for adjusting the resistance value, and the width thereof is "0.2 to.
It is set to about 0.4 mm ".

FIG. 3 is a sectional view taken along line AA of FIG.
3 is a cross-sectional view taken along the line BB of FIG. 2, showing the structure of the thick film resistor 1. The cylindrical resistor 5 is composed of a lower layer resistor 7 and an upper layer resistor 8, and an insulator 9 is interposed between the two resistors 7. The lower layer resistor 7 is provided so as to extend between both conductor patterns 3 and 4, and both ends thereof are respectively formed into the conductor patterns 3 and 4.
It is connected to the. The insulator 9 is provided on the upper surface of the lower layer resistor 7 in a layered manner. Furthermore, the upper layer resistor 8 is provided across both conductor patterns 3 and 4,
The upper portion of the insulator 9 and the side portions of the insulator 9 and the lower layer resistor 7 are provided so as to be overlapped with each other. In this way, one cylindrical resistor 5 having a multi-layer structure in which the insulator 9 is wrapped inside by the lower layer resistor 7 and the upper layer resistor 8 is formed.
Is configured. Then, the groove portion 6 of the tubular resistor 5
From the one side portion of the upper layer resistor 8 to the other side portion on the opposite side thereof, from the tip position of the one conductor pattern 3 to the tip position of the other conductor pattern 4, the upper layer resistor 8 and the insulation It is formed so as to penetrate the body 9, and the bottom of the groove portion 6 serves as the lower layer resistor 7.

Next, the manufacturing process of the thick film resistor 1 will be described with reference to FIG.
~ It demonstrates according to FIG. First, in the first step, as shown in FIG.
As shown in (A) and (B), both conductor patterns 3 and 4 are formed by screen-printing a conductor paste on the substrate 2 and drying it.

Next, in the second step, as shown in FIGS.
As shown in, the lower layer resistor 7 is formed by printing a resistance paste between both the conductor patterns 3 and 4 and drying it.

In the third step, as shown in FIGS. 7A and 7B, the insulating paste is printed and dried on the upper surface of the lower resistor 7 with the gap 9a provided obliquely. The insulator 9 is formed.

Then, in the fourth step, as shown in FIG.
As shown in (B), the insulator 9 and the lower-layer resistor 7 are covered with the gap 8a provided between the conductor patterns 3 and 4 on the upper surface of the insulator 9 so as to match the gap 9a. The upper resistance 8 is formed by printing the resistance paste and drying it. At this time, the upper layer resistor 8 is formed so as to overlap the periphery of the lower layer resistor 7 formed in the second step.

Thereafter, in a fifth step, the dried conductor patterns 3 and 4, the lower layer resistor 7, the upper layer resistor 8 and the insulator 9 are simultaneously fired, as shown in FIGS. The manufacture of the thick film resistor 1 is completed.

The manufacturing process of the thick film resistor 1 in this embodiment and the equipment therefor are basically the same as those of a general thick film resistor. Next, the operation of the thick film resistor 1 configured as described above will be described.

According to the thick film resistor 1, the lower layer resistor 7
And the upper layer resistor 8 constitute one cylindrical resistor 5 having a multilayer structure in which the insulator 9 is wrapped inside. Therefore, the resistance characteristic of the tubular resistor 5 is substantially proportional to the length between the conductor patterns 3 and 4.

The thick film resistor 1 is adjusted to a desired resistance value by irradiating the groove portion 6 with laser light using a predetermined laser trimmer and trimming. At the time of this trimming, as shown by the chain double-dashed line in FIG. 2, laser light is continuously irradiated along the groove portion 6 from one end side to the other end side for an appropriate length, and the trimming groove 10 is formed. To form. At this time, the laser light is applied only to the lower layer resistor 7 at the bottom of the groove 6 to perform trimming. Moreover, the required resistance value can be adjusted only by trimming once with an appropriate length.

Therefore, the laser output required for trimming need only be sufficient to trim only the lower layer resistor 7, and a high laser output is not required. In other words, 1 with a relatively small normal laser output
You can trim every time. Thereby, at the time of trimming, it is possible to reduce the thermal influence on other portions on the substrate 2 and to simplify the trimming.

Further, since the entire width of the cylindrical resistor 5 can be trimmed along the groove 6 for adjusting the resistance value, the resistance value can be adjusted in a wide range of "0 to 100%". it can. Moreover, since the trimming can be performed diagonally over the entire width of the tubular resistor 5, the accuracy of adjusting the resistance value by trimming can be improved. Therefore, in designing a hybrid integrated circuit using this thick film resistor 1, the circuit constant can be changed in a wide range with high accuracy, and the degree of freedom in design can be increased. Moreover, by trimming over the entire area of the groove portion 6,
The resistance of the thick film resistor 1 can be easily deleted.

Further, in this thick film resistor 1, since the cylindrical resistor 5 has a multi-layer structure, the rated power for its mounting area is large. That is, the projected shape and area of the cylindrical resistor 5 in the unfolded state are as shown by the solid line in FIG. On the other hand, the actual projection shape and area of the cylindrical resistor 5 are as shown by the two-dot chain line and the solid line in FIG. That is, in order to obtain the required rated power, the actual projected area of the cylindrical resistor 5 can be halved. Therefore, high density mounting of the thick film resistor 1 can be realized in the hybrid integrated circuit. Further, since the rated power can be changed depending on the size of the tubular resistor 5, it is not necessary to increase the film thickness of the tubular resistor 5 more than necessary to change the rated power. Therefore, the deterioration of the temperature coefficient of resistance can be prevented and the quality of the thick film resistor 1 can be secured.

The present invention is not limited to the above-described embodiments, but may be implemented by appropriately modifying a part of the configuration without departing from the spirit of the invention. For example, in the above-described embodiment, the groove portion 6 is formed obliquely over the entire width of the tubular resistor 5 so as to extend from the tip position of one conductor pattern 3 to the tip position of the other conductor pattern 4.
The positions of both ends of the groove may be appropriately brought close to or apart from each conductor pattern.

[0025]

As described in detail above, according to the present invention,
An insulator is provided in a layered manner on the upper part of the lower layer resistor provided between both electrodes on the substrate, and the upper layer resistor is provided so as to cover the upper part of the insulator and the sides of the insulator and the lower layer resistor. In a thick film resistor that is provided by stacking the above, from one side of the upper layer resistor to the other side of the opposite side, from the vicinity of one electrode to the vicinity of the other electrode, the upper layer resistor and insulation Since the groove portion that penetrates the body is formed and the bottom of the groove portion is the lower layer resistor, as a resistor arranged in multiple layers, it is possible to perform trimming at a time along the groove portion regardless of the high laser output, As a result, the thermal effect on other parts of the substrate can be reduced, and the trimming can be simplified, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a thick film resistor in one embodiment embodying the present invention.

FIG. 2 is a plan view showing the appearance of a thick film resistor in one example.

FIG. 3 is a diagram showing the structure of a thick film resistor in one embodiment.
2 is a cross-sectional view taken along line AA of FIG.

FIG. 4 is a diagram showing the structure of a thick film resistor in one embodiment.
FIG. 6 is a sectional view taken along line BB of FIG.

FIG. 5 is a diagram illustrating a first example of manufacturing a thick film resistor according to an embodiment.
The process is shown, (A) is a sectional view in the length direction,
(B) is a cross-sectional view in the width direction.

FIG. 6 shows a second example of manufacturing a thick film resistor in one embodiment.
The process is shown, (A) is a sectional view in the length direction,
(B) is a cross-sectional view in the width direction.

FIG. 7 shows a third example of manufacturing a thick film resistor in one embodiment.
The process is shown, (A) is a sectional view in the length direction,
(B) is a cross-sectional view in the width direction.

FIG. 8 is a fourth view for manufacturing a thick film resistor according to an embodiment.
The process is shown, (A) is a sectional view in the length direction,
(B) is a cross-sectional view in the width direction.

FIG. 9 is a diagram illustrating a projected shape and an area of a developed state of a cylindrical resistor according to an embodiment.

FIG. 10 is an exploded perspective view showing a “printed resistor” in a conventional example.

[Explanation of symbols]

2 ... Substrate, 3, 4 ... Conductor pattern as electrode, 5 ... Cylindrical resistor, 6 ... Groove part, 7 ... Lower layer resistor, 8 ... Upper layer resistor, 9 ... Insulator.

Claims (1)

[Claims] 1. A pair of electrodes provided on a substrate so as to be opposed to each other, a lower layer resistor provided between the electrodes, and a layered upper layer provided on the lower layer resistor. A thick film composed of an insulator and an upper layer resistor provided between the electrodes and overlappingly provided so as to cover the upper part of the insulator and the side parts of the insulator and the lower layer resistor. In the resistor, a groove portion that extends from one side of the upper layer resistor to the other side of the opposite side thereof from the vicinity of the one electrode to the vicinity of the other electrode and penetrates the upper layer resistor and the insulator. And the bottom of the groove is the lower layer resistor.