JPH0684621A - Trimming method for resistor - Google Patents

Abstract

PURPOSE:To realize highly accurate trimming method for resistor in which surge resistance is enhanced remarkably by projecting laser beam through a resistor from one electrode to the other electrode thereof repeatedly until a specific resistance is achieved thereby eliminating concentration of current density. CONSTITUTION:A pair of electrodes 12 are printed on a ceramic substrate 11 and then they are fired. A resistor 13 is printed between the electrodes 12 and subsequently fired. A thick film resistor element 14 thus produced is then trimmed by means of laser beam. A linear laser beam is projected repeatedly from a starting point (point a) on the outside of one electrode through the electrode 12 located immediately thereabove, a resistor 13, and the other electrode 12 to an ending point (point b) on the outside of the electrode 12 until a specific resistance is achieved. This method eliminates concentration of current density and realizes remarkably high surge resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of trimming a resistor such as a thick film resistor formed by printing and firing a resistive material on a substrate by using a laser beam.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional thick film resistance element, in which a pair of electrodes 2 made of silver, palladium or the like is printed on a ceramic substrate 1 and baked, and a resistor 3 made of ruthenium oxide or the like is provided therebetween. Is printed and fixed by firing.

A laser beam is used to make a single cut 4 at a right angle from the side of the resistor 3 as shown in FIG.
Trimming is performed by making two notches 4 and 5 as shown in FIG. 5 or making an L-shaped notch 6 as shown in FIG.

[0004]

Among the conventional trimming methods as described above, the one shown in FIGS.
Alternatively, there are problems that a current density concentration portion is generated at the tip of No. 5, microcracks are generated in the trimming direction to reduce surge resistance, and resistance value drift after trimming occurs.

Further, the method of FIG. 6 has less concentration of the current density as compared with the methods of FIGS. 4 and 5, but has a problem that the surge resistance is not significantly improved.

In view of the problems of the prior art as described above, an object of the present invention is to provide a trimming method which does not generate a current density concentration portion, is excellent in surge resistance and can perform highly accurate trimming. Is.

[0007]

In order to solve the above-mentioned problems, the present invention irradiates a laser beam from one electrode of the resistor to the other electrode so that the laser beam goes straight through the resistor, and the laser beam is irradiated at a predetermined level. The method of repeating until the resistance value is reached is adopted.

[0008]

In the present invention, since the laser beam is made to penetrate straight through the resistor as described above, the current density of the resistor becomes uniform and the end portion of the cut groove formed by the laser beam is It is not formed in the resistor. Therefore, the surge resistance is improved and highly accurate trimming is possible.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1 and FIG. 2, reference numeral 11 denotes a ceramic substrate (only a main part is shown) which constitutes a hybrid IC or the like.
Then, a pair of electrodes 12 made of silver, palladium, or the like is printed on the upper surface of each and baked.

Then, a resistor 13 made of ruthenium oxide or the like is printed between the both electrodes 12 and connected to the both electrodes 12, followed by firing.

The thick film resistance element 14 manufactured as described above is trimmed by a laser beam, but in the embodiment, as shown by the arrow in FIG. 1, it is straight from the outer starting point (point a) of one electrode 12. Through the electrode 12, the resistor 13, the other electrode 12, and the end point (point b) outside the electrode 12.

By repeating the irradiation of such a linear laser beam several times until a predetermined resistance value is obtained, as shown in FIG.
As described above, the resistor 13 is formed by irradiating the required number of laser beams. In order to prevent the resistor from remaining in the cut portion 15, it is preferable that the laser beam interval be slightly smaller (about 0.03 mm) than the laser beam width (about 0.04 mm). In this embodiment, the starting point (point a) and the ending point (point b) of the laser beam may be located on the electrodes 12 on both sides, and the point is that they are outside the resistor 13.

Further, as shown in FIG. 3, it is also possible to first widen the intervals of the laser beams and then narrow the intervals of the laser beams for trimming. In this case, trimming speed can be increased.

[0015]

Since the method of the present invention irradiates the laser beam from the electrode at one end to the electrode at the other end in a straight line as described above, it is formed by the laser beam as in the conventional trimming method. The end of the cut groove is not formed in the resistor.

Therefore, unlike the conventional product, there is no portion where the current density is concentrated, and a large surge resistance can be obtained. In addition, the laser beam is simply passed straight from the electrode on one end to the electrode on the other end, so trimming is easy and, for example, 0.5 mm × 0.5 m
There is an effect that it is easy to trim a small-sized resistor of m, 0.3 mm × 0.3 mm or less.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the method of the present invention.

FIG. 2 is a plan view of a resistance element trimmed by the method of FIG.

FIG. 3 is a plan view showing another embodiment of the method of the present invention.

FIG. 4 is a plan view showing a conventional example.

FIG. 5 is a plan view showing another conventional example.

FIG. 6 is a plan view showing still another conventional example.

[Explanation of symbols]

 12 electrode 13 resistor 14 thick film resistance element 15 cut portion

Claims (1)

[Claims] 1. A method of trimming a resistor with a laser beam, wherein a laser beam is applied from one electrode of the resistor to the other electrode so that the laser beam goes straight through the resistor, and a predetermined resistance value is applied. The trimming method of the resistor is characterized in that it is repeated until the following.