JPH01220886A - Thick-film circuit substrate - Google Patents

Abstract

PURPOSE:To enable the set value of function trimming to be set easily without being behind the speed of laser beams, etc., by forming structure in which a third resistor is connected in parallel with a second resistor through an electrode in the direction of the notch of a trimming groove. CONSTITUTION:An electronic part, etc., are mounted and a trimming groove 19 is shaped to a first resistor 15, a trimming groove 20 is cut to a second resistor 16 by laser beams, etc., and trimming is adjusted at a set value. Since a third resistor 17 is connected at the nose of the trimming groove 20 through electrodes 18a, 18b at that time, the effect of parallel resistance is displayed with proceeding in the direction of the arrow A of the trimming groove, and the change of a resistance value is made slower than the speed of a laser beams. Since the size of a resistor for function trimming, the third resistor 17, is determined in consideration of a set target value, proceeding in the direction of the arrow A of the trimming groove 20 means approaching the set target value.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a thick film circuit board, and particularly to the improvement of a thick film circuit board equipped with a resistor for trimming a resistor and a resistor for function trimming. Involved.

(Prior Art) As is well known, in hybrid integrated circuits, circuit boards are used in which resistors, etc. are provided using a thick film technology in which a resistor paste is printed and fired on an insulating plate (Japanese Patent Application No. 1983) -2
81728). In such a circuit board, after electronic components and the like are mounted on the circuit board, function trimming is performed on the function trimming resistor to set the resistance value according to the use of the hybrid integrated circuit. Conventionally, a thick film circuit board having the structure shown in FIG. 2, for example, is known as a thick film circuit board provided with the above-mentioned resistor for resistance trimming and resistor for function trimming.

1 in the figure is an insulating plate. On this insulating plate 1, there is a conductor 2 with pads 2a and 2b on the left end, and a pad 2b on the right end.
and a conductor 4 having a pad 4a in the middle.
is formed. A resistor 5 for resistor trimming is provided between the pad 2b of the conductor 2 and the pad 4a of the conductor 4 by thick film technology. Similarly, a function trimming resistor 6 is provided between the conductors 2 and 3. However, the function trimming resistor 6
is set to a value so small that the initial resistance value can be ignored. In a circuit board having such a configuration, electronic parts and the like are mounted and function trimming is performed.

However, during this trimming, as the target value of function trimming is approached, the rate at which the resistance value changes with respect to the speed of the laser beam etc. tends to increase, making it difficult to set the target value.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and provides a thick film circuit board that can easily set the function trimming setting value without slowing down the speed of a laser beam or the like. The purpose is to provide.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention includes a first resistor for resistor trimming, and a function connected in series to the first resistor and whose initial value is negligible. a second resistor for trimming and this second resistor;
The gist is to include a third resistor for trimming connected in parallel to the resistor.

According to the present invention, when the second resistor for function trimming whose initial value is negligibly small is trimmed with a laser beam or the like, the trimming is applied to the third resistor connected in parallel to the second resistor through the electrode. As the direction increases, the parallel effect increases and the change in resistance value becomes more gradual with respect to the speed of the laser beam. Therefore, it is possible to easily approach a preset target value.

(Example) An embodiment of the present invention will be described below with reference to FIG.

11 in the figure is an insulating plate. On this insulating plate 11,
A conductor 12 with pads 12a and 12b on the left end, a conductor 13 with a pad 12b on the right end, and a pad 14 in the middle.
A conductor 14 having a is formed. A resistor trimming resistor (first resistor) 15 is provided between the pad 12b of the conductor 12 and the pad 14a of the conductor 14 by thick film technology. Similarly, between the conductors 12 and 13,
Function trimming resistor (second resistor) 16
is provided. However, the initial resistance value of the second resistor 16 is set to a value so small that it can be ignored.

A trimming resistor (third resistor) 17 is connected in parallel to the second resistor 16 via electrodes 18a and 18b. Here, since the initial resistance value of the second resistor 16 is set to a negligibly small value, the third resistor 16 connected in parallel with the second resistor 16
The initial resistance value of the resistor 17 is also negligibly small.

In a thick film circuit board having such a configuration, after mounting electronic components etc. and forming a trimming groove 19 in the first resistor 15, a trimming groove 20 is formed in the second resistor 16 using a laser beam or the like. Adjust 2J to. At this time, the third
The resistor 17 has electrodes 18a, 1 at the tip of the trimming groove 20.
8b, as the trimming groove advances in the direction of arrow A, the effect of the parallel resistance is enhanced, and the resistance value changes gradually with respect to the speed of the laser beam. However, since the size of the function trimming resistor, that is, the third resistor 17, is determined in consideration of the set target value, the progress of the trimming groove 20 in the direction of arrow A indicates that the trimming groove 20 approaches the set target value. In addition, 21 in the figure
indicates a trimming groove provided in the third resistor 17, which is trimmed for fine adjustment when the second resistor 16 is trimmed too much, and can normally be adjusted without trimming.

In this way, according to the thick film circuit board according to the above embodiment,
Since the third resistor 17 is connected in parallel to the second resistor 16 via the electrodes 18a and 18b in the cutting direction of the trimming groove 20, the function trimming operation can be performed extremely easily. It is possible to improve yield by reducing defects caused by cutting too much or not cutting enough relative to the set target value.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a thick film circuit board in which the setting value of function trimming can be easily set without slowing down the speed of a laser beam or the like.

[Brief explanation of the drawing]

FIG. 1 shows a thick film circuit board according to an embodiment of the present invention.
FIG. 2 is a plan view of a conventional thick film circuit board. 11... Insulating plate, 12.13.14... Conductor, 15
．． 16.17...Resistor, 19,20.21...Trimming groove, 18a, 18b...Electrode. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A first resistor for resistor trimming, a second resistor for function trimming that is connected in series to the first resistor and whose initial value is negligibly small, and a trimmer that is connected in parallel to the second resistor. A thick film circuit board characterized by comprising a third resistor for use in the circuit board.