JPH01304706A - Trimming of film resistor - Google Patents

Abstract

PURPOSE:To assure high accuracy trimming and improve pulse resistance by locating starting and end points of the trimming outside a resistor film and hence providing a kerf of a shape without any pointed portion. CONSTITUTION:A kerf 4 of a shape without any pointed portion is formed in a resistor film provided between a pair of terminal electrodes 1, 2 such that starting and end points of trimming are located outside the resistor film 3. Hereby, an electrically independent part 5 is formed. A shape of the kerf 4 at portions opposite to the terminal electrodes 1, 2 on the side of at least the trimming end point side is of an arcuate one protruding toward the terminal electrodes 1, 2. This prevents any microcrack as well as a large change in resistance from being produced. Further, a portion near the end point of the trimming is far away from a current path flowing through between the pair of the terminal electrodes, and hence a rate of a change in the resistance to a given amount of the trimming is reduced than that at other portions. Hereby, a film resistor excellent in pulse resistance is realizable without producing a large change in the resistance even if a large surge current flows, thereby assuring high accuracy trimming.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for trimming a film resistor in which a resistive film is provided between a pair of terminal electrodes provided on an insulating substrate.

(Prior Art) A typical conventional trimming method for a film resistor is as shown in FIGS. 2 and 3. That is, what is shown in FIG. 2 is obtained by trimming the resistive film 13 provided between the pair of terminal electrodes 11 and 12 with a linear cut groove I4. Further, in the case shown in FIG. 3, the resistive film 13 is
It is trimmed with a cut groove 15 in the shape. That is, in both cases, the starting point of trimming is located outside the resistive film 13, but the ending point is located inside the resistive film 13.

(Problems to be Solved by the Invention) In the conventional trimming method as described above, since the end point of trimming is located inside the resistive film I3, microcracks are likely to occur in that part. Therefore, when a large surge current due to induced lightning or the like flows between the terminal electrodes 11 and 12, local heat generation occurs due to current concentration at the terminal point, and microcracks that occur during trimming progress and expand, resulting in large surges. There is a problem in that resistance changes occur. Furthermore, since the shape of the trimming groove is monotonous, the change in resistance for a given amount of trimming is approximately constant, which makes it difficult to trim with high precision.

The present invention has been made in view of the above problems, and includes:
The purpose of this invention is to realize a membrane resistor with excellent pulse resistance that does not cause a large change in resistance even when a large surge current flows, and to provide a method for trimming a membrane resistor that enables highly accurate trimming.

(Means for Solving the Problems) In order to achieve such an object, the present invention provides a method in which a trimming start point and an end point of a resistive film provided between a pair of terminal electrodes are both located outside the resistive film. A cut groove with no sharp edges is provided to form an electrically independent part.
The cutting groove is characterized in that the shape of the cut groove at least in the portion facing the terminal electrode on the end point side of the trimming is formed into an arc shape projecting with respect to the terminal electrode.

(Function) According to the method for trimming a film resistor of the present invention, the trimming start point and the end point of the trimming are both located outside the resistive film, and the resistive film portion is trimmed to be electrically independent. is formed, there are no areas where microcracks occur, and no large resistance changes occur.

In addition, since the shape of the cut groove in the part facing the terminal electrode on the end point side of trimming has an arc shape that protrudes from the terminal electrode, the part near the end point of trimming flows between the pair of terminal electrodes. It is located far away from the current path, and the ratio of resistance change to a certain amount of trimming is smaller than that of other parts, allowing highly accurate trimming.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view of a membrane resistor according to an embodiment of the present invention. In FIG. 1, reference numerals 1.2 denote a pair of terminal electrodes provided facing each other on an insulating substrate made of alumina or the like (not shown).

This terminal electrode 1.2 is made by printing and baking Ag-Pd paste, for example. This pair of terminal electrodes 1.
A resistive film 3 is provided between the two. This resistive film 3 is made by printing and baking a resistive material paste such as ruthenium oxide. A film resistor having such a structure can be formed on a chip-shaped insulating substrate to form a chip resistor, or it can be formed on an insulating substrate on which other chip-shaped electronic components are mounted to form a hybrid integrated circuit. It can be used for various purposes such as configuring.

Trimming of a film resistor having such a configuration is performed by the following procedure. First, a starting point A for trimming is provided outside the resistive film 3, and a cut groove is provided in which the portion facing the terminal electrode 1 has an arc shape that projects with respect to the terminal electrode and has no sharp edges. Let this area be B. Next, a pair of terminal electrodes 1.2 are continuously placed in this area B.
A cut groove is provided parallel to the axis connecting the two. Let this area be C. Continuing from this region C, a cut groove is provided in which the portion facing the terminal electrode 2 has an arcuate shape and does not have a sharp part and projects with respect to the terminal electrode. Let this area be D. The kerf in this area is trimmed following the kerf in area C, and is formed such that the trimming end point E is located outside the resistive film 3. The method of trimming a film resistor of the present invention is carried out by forming the electrically independent portion 5 in the resistive film 3 by forming the kerf 4 having the regions B, C, and D as described above. . Note that the kerf in region B, which is the starting point side of trimming, does not necessarily have to have an arc shape protruding from the terminal electrode 1 as in the above embodiment, and may have another shape as long as there is no sharp part. Good too.

According to this method of trimming a film resistor, both the starting point and the ending point of trimming are located outside the resistive film 3, and the electrically independent resistive film portion 5 is formed by the cut groove having no sharp part. Because of this, microcracks do not occur. Further, since the shape of the cut groove in the portion facing the terminal electrode 2 on the side of the end point of trimming has an arc shape that projects with respect to the terminal electrode, the portion near the end point of trimming is located between the pair of terminal electrodes 1. 2, and the ratio of resistance change to a certain amount of trimming is smaller than that of other parts.

(Effects) As is clear from the above explanation, according to the method for trimming a membrane resistor of the present invention, since the trimming method is performed using the above-mentioned cut grooves, there is no large change in resistance even when a large surge current flows. It is possible to realize a film resistor with excellent pulse resistance that does not cause pulse generation, and has the excellent effect of enabling highly accurate trimming.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a membrane resistor according to an embodiment of the present invention. FIGS. 2 and 3 are plan views of a film resistor for explaining a conventional trimming method. 1.2... Terminal electrode, 3... Resistive film, 4... Cut groove, 5... Electrically independent resistive film portion.

Claims (1)

[Claims] (1) By providing a cut groove with no sharp edges in the resistive film provided between a pair of terminal electrodes so that both the start and end points of trimming are located outside the resistive film, the resistive film is A method for trimming a membrane resistor in which electrically independent parts are formed, wherein the shape of the cut groove at least in the part facing the terminal electrode on the end point side of the trimming has an arc shape projecting with respect to the terminal electrode. A method for trimming a membrane resistor, characterized in that: