JPH0546247Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a thick film chip resistor or a resistance network that is provided so that electrical continuity is established between both ends of a resistive film formed on an insulating substrate and an electrode terminal. This relates to the structure of resistors such as.

[Conventional technology]

As shown in FIGS. 2 and 3, this type of resistor is manufactured by applying a conductor paste to both left and right ends of the upper surface of an insulating substrate 1, usually made of ceramic, using a mask, and then firing the electrode terminal 2a. . , 2b is brought into contact with the resistive film 3 to measure the resistance value of the resistive film 3, and the resistive film 3 is trimmed by a laser or the like to adjust the resistance value to a predetermined value.

In this case, conventionally, as shown in FIG. 2, a trimming portion having an L-shape in plan view is provided at a midway point in the longitudinal direction of the resistive film 3 and communicates with one side edge 3a of the resistive film 3 orthogonal to the electrode terminals 2a, 2b. It was normal to form 4.

In this case, the trimming portion 4 includes a horizontal trimming line 4 in the width direction communicating with one side edge 3a of the resistive film 3.
a, and a vertical trimming line 4b extending in the longitudinal direction (direction toward one electrode terminal 2a) from the tip of the horizontal trimming line 4a.

Note that reference numeral 5 is a glass coat that covers the resistive film 3, and it may be coated before trimming and coated again after trimming.

[The problem that the idea aims to solve]

By the way, the resistance value of the resistive film 3 is inversely proportional to the thickness dimension To and width dimension Ho of the resistor element, and proportional to the length dimension Lo. , the resistance value of each part is the sum.

That is, a location A1 with width dimension Ho and length dimensions L1 and L2 adjacent to the pair of electrode terminals 2a and 2b,
The resistance values R1 and R2 of A2 and the length dimension L3 where the width dimension H3 is smaller than the original width dimension Ho at the horizontal trimming line 4a of the trimming part 4.
The sum of the resistance value R3 at point A3 is the total resistance value Ro (=
R1+R2+R3).

Therefore, when there is a trimming part 4 that is L-shaped in plan view, if the length of the vertical trimming line 4a is long, the width dimension H3 of the A3 area adjacent thereto decreases at once, and the resistance value R3 increases. Furthermore, as the vertical trimming line 4b becomes longer, the resistance value R3 increases.

At a location A1 adjacent to the tip of the vertical trimming line 4b, as the length of the vertical trimming line 4b increases, the length L3 of the resistor at the A3 location increases, while the length dimension L3 of the A1 location increases. L1 becomes shorter.

Therefore, when the length dimensions of both the vertical and horizontal trimming lines 4b and 4a in the trimming portion 4 increase, the resistance value Ro of the entire resistive film 3 is adjusted to be larger than in the case where there is no trimming portion. is determined.

Incidentally, there are two methods of trimming: a sandblasting method in which fine alumina powder is blown onto the resistive film 3 together with high-pressure air to mechanically scrape it off, and a laser trimming method in which the resistor is vaporized by irradiation with a laser beam.

Among the trimming parts 4 formed by these trimming methods, stress concentration is likely to occur in the final part of trimming (the tip of the vertical trimming line 4b) (particularly when laser trimming is used, stress concentration is likely to occur). , minute cracks 6 may occur in the resistive film 3, and since these cracks 6 tend to extend from the tip of the vertical trimming line 4b toward one electrode terminal 2a, the length of the trimming line 4b is reduced by the cracks 6. becomes substantially longer, and the relevant part A
There is a large degree of variation in which the area at A1 becomes smaller while the area at A1 becomes larger.

In particular, if the tip of the vertical trimming line 4b is close to one of the electrode terminals 2a, the crack 6 may reach the electrode terminal 2a, and the resistance value at point A1 decreases all at once. Characteristic deterioration occurs.

Therefore, due to the occurrence of the crack 6, it was not possible to improve the accuracy of fine adjustment of the resistance value.

As shown in FIG. 4, as another form of trimming to eliminate this inconvenience, in addition to the L-shaped trimming part 7 in plan view, a vertical trimming line 7 is formed parallel to the horizontal trimming line 7a in the trimming part 7.
It was considered to provide the second horizontal trimming line 8 at a location on the resistive film on the opposite side to the direction in which b extends.

When trimmed in this way, the 5
The sum of the resistance values R1, R2, R3, R4, and R5 of the resistors at the three locations A1, A2, A3, A4, and A5 becomes the overall resistance value Ro.

The second horizontal trimming line 8 is a location where the resistance value is low (a location spanning A2 and A5 in FIG. 4).
Since the resistor extends in a direction perpendicular to the direction in which current flows in the direction of the electrode terminal, the resistor is an extension of the part removed by trimming the width wo and length h1 of the second horizontal trimming line 8. The original purpose is to be able to finely adjust the resistance value R4 at point A4, which is the area of (Ho-h1)×(wo).

However, if the second lateral trimming line 8 is located close to the lateral trimming line 7a in the trimming section 7, even if the second lateral trimming line 8 is short, the crack 9 generated at the tip of the second lateral trimming line 8 will cause the crack 9 to appear on the adjacent trimming section 7. Since the adhesive strength of the resistive film 3 to the insulating substrate 1 by baking is not inherently strong, the resistive film at the portion sandwiched between the horizontal trimming line 7a and the second horizontal trimming line 8 is connected to the horizontal trimming line 7a. Severe peeling may occur.

In this case, the resistance value R5 in the region A5 fluctuates greatly, resulting in a problem that the accuracy of fine adjustment of the resistance value of the entire resistive film cannot be improved.

The present invention aims to solve these problems.

[Means to solve the problem]

To achieve this object, the present invention provides a resistor in which both ends of a resistive film formed on the surface of an insulating substrate are connected to a pair of electrode terminals formed on both ends of the insulating substrate. In the middle part, a horizontal trimming line extending from one side edge of the resistive film extending in the direction of the pair of electrode terminals in a direction intersecting the one side edge, and communicating with the horizontal trimming line and extending in the direction of the one electrode terminal. While forming an L-shaped trimming part in plan view consisting of an extending main vertical trimming line,
A sub-vertical trimming line is formed between the one side edge of the resistive film and the main vertical trimming line, communicating with the horizontal trimming line and being longer than the main vertical trimming line.

〔Example〕

Next, an embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 1 denotes an insulating substrate made of ceramic or glass similar to that used in conventional chip resistors, and 2a and 2b denote the insulating substrate 1. This is an electrode terminal made by printing and firing conductor paste on both the left and right ends.

Further, reference numeral 3 designates a resistive film formed by printing and baking a resistive paste on the upper surface of the insulating substrate 1 so that its ends overlap the electrode terminals 2a and 2b.

Reference numeral 10 denotes a trimming portion having an L-shape in plan view formed by laser trimming in the middle of the resistive film 3 in the longitudinal direction. A horizontal trimming line 10a extending from the side edge 3a in a direction that intersects one side edge 3a at a substantially right angle, and a main vertical trimming line that communicates with the terminal end of the horizontal trimming line 10a and extends in the direction of the one electrode terminal 2a. It consists of a line 10b.

Further, reference numeral 11 denotes a sub-vertical trimming line that is substantially perpendicular to the horizontal trimming line 10a having a length H5 in the L-shaped trimming part 10 in plan view and extends parallel to the main vertical trimming line 10b. The vertical trimming line 11 is separated from the one side edge 3a of the resistive film 3 by a dimension H6 and is connected to the main vertical trimming line 1.
0b, communicates with the horizontal trimming line 10a, and is formed to have a dimension L6 longer than the dimension L5 of the main vertical trimming line 10b.

In order to accurately adjust the resistance value Rx of the resistive film 3, the trimming operation is first performed by trimming the pair of electrode terminals 2.
While touching the probe (probe) to a and 2b and detecting the resistance value of the resistive film between them, the trimming part 10
is formed, and at this time, the length of the main vertical trimming line 10b is shortened and stopped at a value lower than a predetermined resistance value Rx.

Next, while measuring the resistance value in the same way as above,
The secondary vertical trimming line 11 is the main vertical trimming line 1.
0b, and when the resistance value Rx reaches a predetermined value, the laser trimming operation for the sub-vertical trimming line 11 is stopped.

[Operation of the invention] With this configuration, the region of the resistor of the resistive film 3 is as follows from the other electrode terminal 2b to the horizontal trimming line 10.
A rectangular region B1 in plan view up to a, the length L5 of the main vertical trimming line 10b is one side, and the dimension obtained by subtracting the length H5 of the horizontal trimming line from the width Ho of the resistive film 3 (Ho - H5)
A rectangular area B2 whose other side is the length dimension (L6-L5) obtained by subtracting the length dimension L5 of the main vertical trimming line from the length dimension L6 of the secondary vertical trimming line 11, and the dimension ( Ho−H5)
A region B3 having a trapezoidal shape in a plan view with the upper side being the upper side and the lower side having the dimension (Ho-H6), an approximately rectangular region B4 in the plan view adjacent to one electrode terminal 2a and extending to the tip of the sub-vertical trimming line 11, and Therefore, the resistance value Rx of the resistive film 3 after trimming is the same as that of the four regions B1, B2, B3,
Resistance value when B4 resistor is connected in series (=
Rb1+Rb2+Rb3+Rb4).

By forming the sub-vertical trimming line 11 in addition to the trimming portion 10, areas B3 and B
4, and the length L5 of the main vertical trimming line 10b and the length L5 of the sub vertical trimming line 11.
As the difference (L6-L5) from 6 increases, one region B3 becomes larger (the resistance value R of that region
3 becomes larger), while the other region B4 becomes smaller (the resistance value Rb4 of that region becomes smaller).

Therefore, when there is no sub-vertical trimming line 11, that is, when there is only the L-shaped trimming part 4 in plan view, the resistance value of the area A3 due to the increase in the vertical trimming line 4b increases. As shown in FIG.
exists, and there is no increase in the main vertical trimming line 10b in the trimming section 10 (therefore, the area B2
(resistance value is held constant), and region B3 when the sub-vertical trimming line 11 increases,
Comparing the difference increase rate of increase/decrease in B4, since the width dimension (Ho-H6) of area B3 at this time is larger than the width dimension H3 of the area A3, the resistance value is inversely proportional to the width dimension. The resistance value of the region B3 increases sequentially from a state smaller than the resistance value of the region A3, and therefore, the subtractive increase rate of the resistance value when the sub-vertical trimming line 11 is added to the former, that is, the trimming portion 10, is smaller than the resistance value of the region A3. can be made smaller than the subtractive increase rate of the resistance value in the case of only the trimming portion, and it is possible to reliably realize fine adjustment of the resistance value of the entire resistive film by trimming.

Additionally, the trimming section 10 of the present invention
The resistance value of the region B2 adjacent to the main vertical trimming line 10b in the short length main vertical trimming line 1
0b, and then a long sub-vertical trimming line 11 formed substantially parallel to this main vertical trimming line 10b forms regions B3 and B4, thereby finely adjusting the resistance value. Therefore, compared to suddenly adjusting the resistance value just by adjusting the length of the vertical trimming line using one L-shaped trimming section in plan view, the accuracy of the adjustment is much more impressive.

Further, since the length of the main vertical trimming line 10b and the length of the sub-vertical trimming line 11 in the trimming section 10 can be made shorter than when using a single vertical trimming line 4b, even if the tips of these main and sub-vertical trimming lines Even if a crack occurs, it will not reach the electrode terminal unless it is a very long crack.

Furthermore, even if a crack generated from the tip of the main vertical trimming line 10b connects to the adjacent sub-vertical trimming line 11, the position of the crack has no or very little influence on the adjustment of the resistance value. There is no reduction in accuracy.

[Effect of idea]

As a result of the above, by trimming the configuration of the present invention, the resistance value of the resistive film can be adjusted with high precision.

Further, the starting end of the sub-vertical trimming line starts from the middle part of the horizontal trimming line in the L-shaped trimming part in plan view that has already been formed in the previous step, and the resistive film has already been removed by the horizontal trimming line. Since the sub-vertical trimming line starts from this point, the trimming length from one side edge of the resistive film to the starting end of the sub-vertical trimming line can be omitted. The time required to form trimming lines can be reduced,
This has the remarkable effect of improving the precision of the trimming work and allowing it to be done quickly.

It goes without saying that the present invention can be applied not only to thick-film chip resistors but also to resistance networks.Especially, in the case of small resistor films with short length and width dimensions, the effects of cracks caused by laser trimming are significant. However, according to the present invention, the accuracy of adjusting the resistance value is significantly improved, and the stability of the characteristics is also increased.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of the present invention, Fig. 2 is a plan view of a conventional example, Fig. 3 is a cross-sectional view taken from Fig. 2, and Fig. 4 is a plan view showing another conventional example. It is. DESCRIPTION OF SYMBOLS 1...Insulating substrate, 3...Resistive film, 3a...One side edge, 4...Trimming part, 4a...Horizontal trimming line, 4b...Vertical trimming line, 5...Glass coat, 6, 9... crack, 10...trimming section, 10a...horizontal trimming line, 10b...main vertical trimming line, 11...subvertical trimming line.

Claims (1)

[Scope of utility model registration request] In a resistor in which both ends of a resistive film formed on the surface of an insulating substrate are connected to a pair of electrode terminals formed on both ends of the insulating substrate, a resistive film is provided in the middle of the resistive film in the direction of the pair of electrode terminals. A planar view consisting of a horizontal trimming line extending from one side edge of the extending resistive film in a direction intersecting the one side edge, and a main vertical trimming line communicating with the horizontal trimming line and extending in the direction of the one electrode terminal. While forming an L-shaped trimming part, between the one side edge of the resistive film and the main vertical trimming line, communicating with the horizontal trimming line,
A resistor characterized in that a sub vertical trimming line is formed that is longer than the main vertical trimming line.