JPH03190102A - Thick film resistor - Google Patents

Abstract

PURPOSE:To remove the harmful influence of microcracks, and to obtain a highly reliable thick film by a method wherein the resistance value of the thick film is adjusted by the trimming of the pectinated auxiliary electrode which is integrally provided on an outlet electrode. CONSTITUTION:A plurality of pectinated electrodes 13a, having the same line width and length, are arranged at the same interval pitch of 200mum, for example, for use as auxiliary electrodes 13, and the length against the intended resistance value is worked out from a formula of calculation. In the case where the above-mentioned length is set in the distance from the point A of an electrode 11 and the point B of the auxiliary electrodes 13, three each of the pectinated electrodes 13a are arranged on both sides of the point B in such a manner that they are connected to a resistance film 14, and its resistance value is adjusted by the trimming of each pectinated electrode 13a. The length of the resistance film 14 is made longer by 200mum by cutting one by one the pectinated electrodes 13a of the auxiliary electrodes 13 from the side of the electrode 11, and as the resistance value changes by about 20OMEGA, the adjustment of about 940 to 1100OMEGA against the resistance value of the intended resistance value of 1kOMEGA can be possible, if the entire six pectinated electrodes 13a are trimmed using a trimming device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to thick film resistors printed on insulating substrates.

Conventional technology Traditionally, this type of thick film resistor used in hybrid integrated circuits is
As shown in FIG. 3, a resistive film 3 having a planar rectangular shape corresponding to the desired resistance value is placed between two lead-out electrodes 1 and 2 which are preprinted on a ceramic substrate (not shown) using a mask or a screen. It is formed by drawing and printing.

The resistance film 3 formed on the ceramic substrate is formed in advance to have a resistance value lower than a required value.

Then, in order to correct for variations in the resistance value during the manufacturing process of a single thick film resistor or variations in other circuit components mounted in a hybrid integrated circuit, the resistor film 3 is trimmed while observing the resistance value. The resistance value is increased and adjusted to the required resistance value.

Trimming methods include a laser method in which the resistive film 3 is evaporated until it reaches a predetermined resistance value using a laser beam of Nd, YAG, CO2, Xe, etc. focused to a diameter of about 50 to 250 am, and a laser method in which the resistive film 3 is evaporated until a predetermined resistance value is reached. There is a sandblasting method in which aluminum powder with a diameter of 30 to 60 μm is sprayed onto the resistive film 3 together with compressed air and mechanically scraped off.Recently, a laser method with a fast trimming speed has become mainstream.

4 and 5 show different aspects of the trimming performed by the above method. Trimming 4 in FIG. 4 shows an L-shape in which the trimming 4 enters from one side of the resistive film 3, and when the target resistance value is approached to a certain extent, the direction is turned 90 degrees to perform fine adjustment. The trimming 5 shows an S type that enters from both sides of the resistive film 3.

Problems to be Solved by the Invention However, in the conventional trimming method described above, microcracks 6 are generated in the resistive film 3 at the trimming end point due to the resolution of the laser device, the temperature difference between the laser beam and the printed resistive film 3, etc. There were times when I was forced to do so. These microcracks 6 tend to extend along the trimming direction, and when trimming is performed in a direction transverse to the direction of current flowing through the resistive film 3, the generated microcracks 6
There is a problem in that the thick film resistor crosses the current path and deteriorates the drift characteristics, causing a major problem in circuits using this thick film resistor.

The present invention solves these conventional problems, and aims to provide an excellent thick film resistor whose resistance value can be adjusted without causing microcracks in the resistive film.

Means for Solving the Problems In order to achieve the above object, the present invention has a structure in which the interval between two extraction electrodes can be effectively adjusted, so that the length of the resistive film can be adjusted without trimming the resistive film itself. The resistance value can be adjusted by changing .

Therefore, according to the present invention, the resistance value can be adjusted by effectively changing the distance between the extraction electrodes, which is one of the other factors that determine the resistance value, without trimming the resistance film. Therefore, the harmful effects of microcracks caused by trimming the resistive film can be removed, and a highly reliable thick film resistor can be realized.

Example FIG. 1 shows an embodiment of the present invention.

In FIG. 1, reference numerals 11 and 12 are two separate extraction electrodes preprinted on an insulating ceramic substrate (not shown). One extraction electrode 12 has, in addition to an electrode part 12a facing the other extraction electrode 11, an extension part 12b that bends at a right angle toward the other extraction electrode 11, and a plurality of comb teeth that bend further inward from this at a right angle. It is integrally provided with an auxiliary electrode 13 having a shaped electrode 13a. 14
is each comb-shaped electrode 1 between two extraction electrodes 11 and 12.
It is a planar rectangular resistive film that is screen-printed or drawn-printed using a mask so that the tip of 3a is covered. In the auxiliary electrode 13, the larger the number of comb-shaped electrodes 13a, the wider the adjustment range, and the smaller the pitch interval of each comb-shaped electrode 13a, the more fine adjustment can be made.

Next, the operation of the above embodiment will be explained. In the above embodiment, comb-like electrodes 13a of the same length and line width of 100 μm are arranged as the auxiliary electrodes 13 at a pitch interval of 200 μm, and the length corresponding to the target resistance value derived from the calculation formula is extracted from point A of the electrode 11. When the electrode 13 is up to point B, three comb-like electrodes 13a are placed on both sides of point B, and the resistive film 14 is
The resistance value is adjusted by trimming each comb-shaped electrode 13a. For example, if all six of the comb-shaped electrodes 13a are trimmed by a trimming device, the resistance value of the target resistance value IKΩ can be adjusted to about 940Ω to 1100Ω.

The second session shows a second embodiment of the present invention. In the first embodiment, the auxiliary electrode 13 was arranged only on one side of the resistive film 14, but in the embodiment shown in FIG. The tip of each comb-shaped electrode 13a is connected to the resistive film 14.

Line widths 101 facing each other on both sides of the resistive film 14
The comb-shaped electrodes 13a with a 00u pitch interval of 200 μm are formed by shifting the pitch by 1100t1, and the actual pitch interval of the entire comb-shaped electrode is 100 μm.
It is μm.

In the first embodiment, the comb-shaped electrode 1 of the auxiliary electrode 13
By cutting 3a one by one from the extraction electrode 11 side, the length of the resistive film 14 increases by 200 μm, and the resistance value changes by about 20Ω. On the other hand, in the second embodiment,
By alternately cutting the comb-shaped electrodes 13a of the auxiliary electrodes 13 arranged on both sides of the resistive film 14, the length of the resistive film 13 can be increased by 1100u, making the resistance value even finer. can be adjusted to In this embodiment, by cutting one comb-shaped electrode 13a, approximately 4
Ω can be adjusted.

Since the pitch interval of the comb-shaped electrodes 13a cannot be made very fine due to manufacturing technology problems, the pitch interval of each comb-shaped electrode 13a is shifted from each other on both sides of the resistive film 14 as described above. Substantial narrowing is extremely useful.

Effects of the Invention As is clear from the above embodiments, the present invention adjusts the resistance value of the thick film resistor by trimming the comb-shaped auxiliary electrode integrally provided with one of the extraction electrodes. By trimming the resistive film, the harmful effects of microcracks that occur can be removed, and a highly reliable thick film resistor can be realized.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a thick film resistor according to an embodiment of the present invention, FIG. 2 is a schematic plan view of a thick film resistor according to another embodiment of the present invention, and FIG. 3 is a schematic plan view of a conventional thick film resistor. Floor plan, 4th
This figure and FIG. 5 are schematic plan views showing the trimming state of a conventional thick film resistor. 11.12... Extraction electrode, 12a... Facing electrode part, 12b... Extension part, 13... Auxiliary electrode, 13a
... comb-shaped electrode, 14 ... resistance film, 15 ...
·trimming.

Claims (2)

[Claims] (1) A resistive film connecting two separated extraction electrodes printed on an insulating substrate, and a plurality of comb-shaped electrodes connected to at least one side surface along the longitudinal direction of the resistive film. A thick film resistor comprising an auxiliary electrode integrally provided on one of the extraction electrodes. (2) A resistive film is provided to connect two separated extraction electrodes printed on an insulating substrate, and a plurality of resistive electrodes are connected to each other on both sides along the longitudinal direction of the resistive film. A thick film resistor, in which an auxiliary electrode having a comb-shaped electrode is integrally provided on one of the extraction electrodes, and the pitches of the mutually opposing comb-shaped electrodes are shifted from each other.