JPS58210652A - Resistance adjustment of thick film hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To obtain high precision resistance value with less aging fluctuation without lowering working efficiency by intermittently executing the laser beam irradiation process and setting an angle between the slit for coarse adjustment and the slit for fine adjustment to an obtuse angle in the fine adjustment processes for resistance value. CONSTITUTION:A slit 3 is provided for coarse adjustment of desired resistance value, while a plurality of intermittent slits 4' provided on a thick film resistor for fine adjustment of resistance value. Working efficiency can be improved by setting an angle 5 formed by the slit 3 and slit 4' to an obtuse angle, namely by making large a changing rate of resistance by gradually narrowing the width of main current path 6 of thick film resistor body 1 and by making short the total length of the slit 4'. As described above, a resistor body receives less concentration of heat as compared with the conventional element because the laser beam is irradiated intermittently and thereby less crack is generated in the periphery of slit. Accordingly, a stable resistance value having less aging fluctuation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting the resistance of a thick film hybrid integrated circuit, and more particularly to a method for trimming a resistive element using a laser beam.

Resistance elements used in thick film hybrid integrated circuits are those in which a thick film resistance film made of ruthenium oxide or the like is printed between the conductors of a circuit pattern printed on a ceramic substrate, and a low resistance value is required for the resistance element. In some cases, the conductor itself of the circuit pattern may be used.

A trimming method using a laser beam is used to process the resistive element to a desired resistance value with a predetermined precision.

The conventional trimming method using this type of laser beam is the first method.
This will be explained using figures.

Reference numeral 1 denotes a rectangular thick film resistor printed on a ceramic substrate, and both longitudinal ends of the resistor 1 are partially covered by circuit pattern conductors 2° 2' printed on the ceramic substrate. The L-shaped slits 3.4 of the thick film resistor 1 are removed by laser beam irradiation. That is, the slit 3 in the width direction of the thick film resistor 1 is for coarse adjustment, and the slit 4 in the longitudinal direction is for fine adjustment. This resistance adjustment method by laser beam irradiation is a method of adjusting by melting and vaporizing a part of the thick film resistor 1, so a part of the resistor is heated intensively and the area around the cut slit is heated. Cracks occur, and this is one of the causes of deterioration over time. Furthermore, since the speed at which the resistor is trimmed by the laser beam is fast, it is difficult to obtain a highly accurate resistance value.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a method for laser trimming a resistor element of a thick film hybrid integrated circuit, which can obtain a highly accurate resistance value with little change over time without reducing work efficiency. .

An embodiment of the present invention will be described with reference to FIG. Corresponding to FIG. 1, 1 is a thick film resistor printed on a ceramic substrate, and 2.2' is a part of a circuit pattern conductor also printed on a ceramic substrate. Reference numeral 3 denotes a slit which is removed by irradiating the thick film resistor 1 with a laser beam. As described above, this slit 3 is used for coarse adjustment of the desired resistance value, and the length of the slit 3 is determined so that the resistance value is somewhat smaller than the desired resistance value. A plurality of intermittent slits 4' on the thick film resistor are for fine adjustment of the resistance value, and these are also processed by laser beam irradiation. The number of slits to be machined is continued until the resistor reaches a desired resistance value, and the adjustment is finely performed. Also, if the spacing between the slits is too narrow, the current density between the slits will be high, which will cause the problem that the thick film resistor will be locally heated, so the spacing between the slits must be set appropriately. desirable. The length of the slit 4' may be determined by sequentially shortening the irradiation time of the laser beam to make it easier to obtain resistance accuracy by processing shorter slits as in this embodiment, or by intermittent slits of the same minute length. Of course.

Furthermore, in the present invention, the decrease in work efficiency due to the intermittent use of the slits for fine adjustment of the resistance value can be avoided by using slits 3 and 4.
This is compensated for by making the angle 5 formed by the angle 5 obtuse. That is, by sequentially narrowing the width of the main current path portion 6 of the thick film resistor 1, the rate of change in resistance is increased, and the overall length of the slit 4' is shortened, thereby improving workability. I can do it.

As described above, according to the present invention, since the laser beam irradiated to the resistor is intermittent, it is less exposed to excessive thermal radiation than in the past, and the cracks that occur around the slit are also reduced. , it is possible to obtain a stable resistance value with little change over time.

Furthermore, since the intermittent irradiation period of the laser beam is changed and the resistance value is finally adjusted while opening extremely short slits, a highly accurate resistance value can be obtained. moreover,
By making the angle between the coarse adjustment slit and the fine adjustment slit obtuse, a laser beam trimming method for thick film integrated circuits with good workability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional laser trimming method, and FIG. 2 is a diagram showing a laser trimming method according to the present invention. 1...Thick film resistor, 2.2'...Circuit pattern conductor, $1/Kaya 2

Claims (1)

[Claims] L. Roughly adjusting the resistance value by processing a slit in the width direction of the thick film resistive film preprinted on the substrate of the thick film hybrid integrated circuit by irradiating it with a laser beam;
In the process of finely adjusting the resistance value by machining slits in the longitudinal direction, the process of finely adjusting the resistance value is performed intermittently with the process of laser beam irradiation, and the slits for coarse adjustment are performed intermittently. A method for adjusting the resistance of a thick film hybrid integrated circuit, characterized in that the angle formed by the fine adjustment slit is an obtuse angle.