JP6756534B2 - Chip resistor and trimming method of chip resistor - Google Patents

Description

The present invention relates to a chip resistor whose resistance value is adjusted by forming a trimming groove in a resistor provided on an insulating substrate, and a method for trimming such a chip resistor.

The chip resistors are a rectangular body-shaped insulating substrate, a pair of front electrodes arranged to face each other on the front surface of the insulating substrate at a predetermined interval, and a pair of front electrodes arranged to face each other on the back surface of the insulating substrate at a predetermined interval. It is mainly composed of a back electrode, an end face electrode that bridges the front electrode and the back electrode, a resistor that bridges the paired front electrodes, a protective film that covers the resistor, and the like.

Generally, when manufacturing such a chip resistor, a large number of electrodes, resistors, protective films, etc. are collectively formed on a large-sized assembly substrate, and then the assembly substrate is divided into a grid pattern. A large number of chip resistors are taken by dividing along a line (for example, a dividing groove). In the manufacturing process of such a chip resistor, a large number of resistors are formed by printing and firing a resistance paste on one side of the assembly substrate, but misalignment and bleeding during printing, temperature unevenness in the firing furnace, etc. Since it is inevitable that the size and film thickness of each resistor will vary slightly due to the influence of the above, resistance value adjustment is performed by forming a trimming groove on each resistor in the state of the assembled substrate and setting it to the desired resistance value. Work is done.

The trimming groove is a notch (slit) formed by irradiation with laser light, but fine cracks called microcracks are generated at the tip of the notch, and the cracks grow over time or a protective film that covers the resistor. There is a problem that the resistance value deviates from the desired resistance value (so-called resistance value drift) when the laser enters the crack, and there is also a problem that the reliability such as noise characteristics and overload characteristics is lowered due to the microcracks.

Therefore, conventionally, as described in Patent Document 1, a plurality of highly conductive portions made of a substance having a higher conductivity than the conductivity of the resistor are formed between the pair of electrodes, and these highly conductive portions are resisted. A trimming method has been proposed that reduces the adverse effect on the resistance value caused by microcracks by setting the position so that it overlaps with the side part of the body and ending the tip of the trimming groove in the highly conductive part. Has been done.

In such a resistor trimming method, when the resistance value is adjusted with high accuracy, the resistance value of the resistor is set as the target resistance by forming one or more trimming grooves extending to the highly conductive portion in the resistor. After raising the resistance value until it approaches the value, a trimming groove that does not reach the highly conductive portion is formed to finely adjust the resistance value. At that time, since the high conductivity portion is formed in advance on the side surface portion of the resistor, even if a microcrack occurs at the tip portion of the trimming groove, the resistance value is greatly affected because the vicinity thereof has high conductivity. Will not give.

Japanese Unexamined Patent Publication No. 62-154601

In the prior art described in Patent Document 1, since a highly conductive portion is formed on the side surface portion of the resistor, even if a microcrack occurs at the tip portion of the trimming groove reaching the highly conductive portion, the micro The adverse effect on the resistance value due to the crack does not occur. However, since the tip of the trimming groove formed last for fine adjustment to the desired resistance value does not reach the highly conductive portion, the resistance value drift and the like are caused by the microcracks generated at the tip of the final trimming groove. It was impossible to prevent it from being affected by microcracks at all.

The present invention has been made in view of the actual situation of the prior art, and the first object thereof is to provide a chip resistor which is not affected by microcracks and can adjust the resistance value with high accuracy. In providing, a second purpose is to provide a method of trimming such chip resistors.

In order to achieve the first object, the chip resistor of the present invention bridges between an insulating substrate, a pair of electrodes arranged to face each other at a predetermined interval on the insulating substrate, and these electrodes. In a chip resistor provided with a resistor and whose resistance value is adjusted by forming a trimming groove in the resistor, a conductor made of a material having a conductivity higher than that of the resistor between the pair of electrodes. The pattern is formed so as to overlap with the resistor, and the trimming groove is formed with a groove width wider than that of the conductor pattern from one side of the resistor along the extending direction of the conductor pattern. I made it.

In the chip resistor configured in this way, a conductor pattern is formed between the pair of electrodes so as to overlap with the resistor, and the trimming groove has a groove width wider than this conductor pattern and the trimming groove is a conductor pattern from one side of the resistor. Since it is formed along the extending direction of the trimming groove, the conductor pattern made of a highly conductive material is surely positioned at the tip of the trimming groove regardless of the depth of cut of the trimming groove, and the tip of the trimming groove is formed. It will not be affected by microcracks generated in the part. Moreover, the groove width of the trimming groove is wider than that of the conductor pattern, and the trimming groove removes the resistor together with the conductor pattern, so that the resistance value changes per the depth of cut of the trimming groove, and the resistance is low. Not only the value but also the resistance value of high resistance can be easily adjusted.

In the above chip resistor, if the end of the conductor pattern protrudes to the outside of the resistor, the conductor pattern that protrudes from the resistor when irradiating laser light from one side of the resistor to form a trimming groove. By recognizing, it becomes easy to align the relative positions of the trimming groove and the conductor pattern, which is preferable.

Further, in the above-mentioned chip resistor, the conductor pattern may be formed under the resistor, but if the conductor pattern is formed on the upper surface of the resistor, the position of the conductor pattern is only easily recognized. However, when the conductor pattern and the resistor are vaporized and removed with laser light, the conductor pattern can be removed together with the resistor without remaining because there is a resistor under the conductor pattern that tends to remain. Is preferable.

Further, in the above-mentioned chip resistor, when the conductor pattern and the electrode are made of the same material, it is preferable that the pair of electrodes and the conductor pattern can be formed at the same time.

In order to achieve the second object, the method of trimming a chip resistor according to the present invention is to use an insulating substrate, a pair of electrodes arranged to face each other at a predetermined interval on the insulating substrate, and between these electrodes. In a method of trimming a chip resistor provided with a cross-linking resistor and the resistance value is adjusted by irradiating the resistor with laser light to form a trimming groove, the resistor of the resistor is provided between the pair of electrodes. By forming a conductor pattern made of a material having a conductivity higher than the conductivity so as to overlap the resistor, and then irradiating the laser beam from one side of the resistor along the extending direction of the conductor pattern. , The trimming groove having a groove width wider than that of the conductor pattern is formed.

In this way, a conductor pattern is formed in advance between the pair of electrodes so as to overlap with the resistor, and when a trimming groove is formed by irradiating laser light from one side of the resistor, a groove wider than the conductor pattern is formed. When a notch is formed in the width along the extending direction of the conductor pattern, the conductor pattern made of a highly conductive material is surely located at the tip of the trimming groove regardless of the cutting depth of the trimming groove. It is no longer affected by microcracks generated at the tip of the. Moreover, the groove width of the trimming groove is wider than that of the conductor pattern, and the trimming groove removes the resistor together with the conductor pattern, so that the resistance value changes per the depth of cut of the trimming groove, and the resistance is low. Not only the value but also the resistance value of high resistance can be easily adjusted.

In the above trimming method, the conductor pattern is formed so as to protrude outward from both opposite sides of the resistor, and the laser beam is irradiated from one end of the conductor pattern toward the inside of the resistor. By doing so, when the trimming groove is formed by irradiating the laser beam from one side of the resistor, the relative position of the trimming groove and the conductor pattern can be easily aligned by recognizing the conductor pattern protruding from the resistor. preferable.

The chip resistor according to the present invention is not affected by microcracks and can adjust the resistance value with high accuracy. Further, in the method of trimming a chip resistor according to the present invention, it is possible to prevent the influence of microcracks and to easily adjust the resistance value regardless of the resistance value of low resistance or high resistance.

It is a top view of the chip resistor which concerns on 1st Embodiment of this invention. It is explanatory drawing which shows the trimming method of the chip resistor which concerns on 1st Embodiment example. It is a top view of the chip resistor which concerns on 2nd Embodiment of this invention. It is a top view of the chip resistor which concerns on 3rd Embodiment of this invention. It is a top view of the chip resistor which concerns on 4th Embodiment of this invention. It is a top view of the chip resistor which concerns on 5th Embodiment of this invention. It is a top view of the chip resistor which concerns on 6th Embodiment of this invention. It is explanatory drawing which shows the trimming method of the chip resistor which concerns on 6th Embodiment example. It is a top view of the chip resistor which concerns on 7th Embodiment of this invention. It is explanatory drawing which shows the trimming method of the chip resistor which concerns on 7th Embodiment example.

Explaining the embodiment of the invention with reference to the drawings, as shown in FIG. 1, the chip resistor according to the first embodiment has a rectangular body-shaped insulating substrate 1 made of ceramic or the like and the surface of the insulating substrate 1. A pair of surface electrodes 2 and 3 provided at both ends in the longitudinal direction of the above, a resistor 4 connected to the pair of surface electrodes 2 and 3, and a resistor 4 overlapped between the pair of surface electrodes 2 and 3. It is mainly composed of a conductor pattern 5 formed in the above and a protective film (not shown) covering the resistor 4, and a trimming groove 6 for adjusting the resistance value is formed in the resistor 4. Although not shown, a pair of back electrodes are provided on the back surface of the insulating substrate so as to correspond to the front electrodes 2 and 3, and the corresponding front electrodes are provided on both end faces in the longitudinal direction of the insulating substrate. An end face electrode that bridges the back electrode is provided.

The insulating substrate 1 is made of ceramic or the like, and the insulating substrate 1 is obtained by dividing a large-sized collective substrate along vertical and horizontal dividing grooves and taking a large number of them. The pair of surface electrodes 2 and 3 are made by screen-printing Ag paste and drying / baking, and the resistor 4 is made by screen-printing a resistor paste such as ruthenium oxide and drying / baking.

The conductor pattern 5 is made of a material having a higher conductivity than that of the resistor 4, and in the case of this embodiment, the conductor pattern 5 and the pair of surface electrodes 2 and 3 are screen-printed with the same material, that is, Ag paste. It is dried and baked. The conductor pattern 5 extends in a strip shape so as to vertically traverse the central portion of the resistor 4 in the vertical direction in the drawing, and a part of the conductor pattern 5 projects upward from the upper side 4a of the resistor 4.

The trimming groove 6 is a slit extending linearly upward from the lower side 4b of the resistor 4 along the extending direction of the conductor pattern 5, and the groove width of the trimming groove 6 is set wider than the pattern width of the conductor pattern 5. ing. Although the details will be described later, the trimming groove 6 irradiates the surface of the insulating substrate (aggregate substrate) 1 with a laser beam while bringing a probe (not shown) into contact with the pair of surface electrodes 2 and 3, and resists the laser beam. It is formed by scanning in the internal direction of the body 4.

Next, a trimming method for the chip resistor configured as described above will be described with reference to FIG. Although FIG. 2 shows only the insulating substrate 1 equivalent to one chip, in reality, since a large number of chip resistors are manufactured at once, a large number of chips are used for a large number of collective substrates. The chip forming region of is provided.

First, as shown in FIG. 2A, Ag paste is screen-printed on the surface of the insulating substrate 1, and then dried and fired to obtain a pair of surface electrodes 2 and 3 and a conductor pattern 5 on the insulating substrate 1. At the same time. Here, the conductor pattern 5 is formed in a band shape at an intermediate position between the pair of surface electrodes 2 and 3, and the pattern width thereof is set to W1.

Next, a resistor paste such as ruthenium oxide was screen-printed from above the conductor pattern 5, and then dried and fired to form both ends on the surface electrodes 2 and 3 as shown in FIG. 2 (b). The superposed resistors 4 are formed. At this time, most of the conductor pattern 5 is covered with the black resistor 4 to make it difficult to see, but both ends of the conductor pattern 5 project visibly from the upper side 4a and the lower side 4b of the resistor 4. There is.

After that, a probe (not shown) is brought into contact with the pair of surface electrodes 2 and 3 to measure the resistance value of the resistor 4, and a laser beam is applied to a portion (start point) away from the resistor 4 on the insulating substrate 1. Irradiate. At that time, since both ends of the conductor pattern 5 project outward from the resistor 4, the position of the conductor pattern 5 can be easily recognized, and the start point of the laser beam can be aligned to an appropriate position. Then, the irradiation position of the laser beam is scanned from the start point toward the lower side 4b of the resistor 4 directly above in the drawing, and then extended upward along the extending direction of the conductor pattern 5 as it is in FIG. 2. As shown in (c), a trimming groove 6 extending linearly inward from the lower side 4b of the resistor 4 is formed.

The groove width W2 of the trimming groove 6 is wider than the pattern width W1 of the conductor pattern 5, and the conductor pattern 5 and the resistor 4 are removed together in the width dimension of W2 by irradiation with laser light, so that the trimming groove is formed. By extending the depth of cut in 6, the resistance value of the resistor 4 gradually increases. Then, when the irradiation of the laser beam is stopped when the resistance value is increased until it matches the target resistance value, a linear trimming groove 6 is formed in the resistor 4, and the trimming step is completed. Although not shown, the resistor 4 is covered with an undercoat layer (protective film), and a trimming groove 6 is formed by irradiating the undercoat layer with a laser beam.

As described above, in the chip resistor according to the first embodiment, the conductor pattern 5 is formed so as to overlap the resistor 4 between the pair of surface electrodes 2 and 3, and the pattern of the conductor pattern 5 is formed. Since the trimming groove 6 is formed from one side of the resistor 4 along the extending direction of the conductor pattern 5 with a groove width W2 wider than the width W1, no matter how the depth of cut of the trimming groove 6 changes. The conductor pattern 5 made of a highly conductive material is surely positioned at the tip of the trimming groove 6. Therefore, even if microcracks occur at the tip of the trimming groove 6, the influence of the microcracks can be reduced because the vicinity thereof is a highly conductive portion having a very small resistance value. Moreover, the groove width W2 of the trimming groove 6 is wider than the pattern width W1 of the conductor pattern 5, and the resistor 4 is removed together with the conductor pattern 5 by forming the trimming groove 6, so that the trimming groove 6 is cut. The resistance value changes per quantity, and the resistance value can be easily adjusted not only for the low resistance value but also for the high resistance value.

Further, since both ends of the conductor pattern 5 project outward from the upper side 4a and the lower side 4b of the resistor 4, the conductor protruding from the resistor 4 when the laser beam is aligned with the start point away from the resistor 4. By recognizing the pattern 5, the start point of the laser beam can be easily aligned to an appropriate position.

Further, since the conductor pattern 5 and the pair of surface electrodes 2 and 3 are made of the same material, the conductor pattern 5 and the surface electrodes 2 and 3 can be formed at the same time. However, if the conductor pattern 5 is a material having a higher conductivity than the conductivity of the resistor 4, the conductor pattern 5 may be formed of a material different from the surface electrodes 2 and 3.

In the first embodiment, the case where the resistor 4 is formed on the conductor pattern 5 has been described, but conversely, the conductor pattern 5 may be formed on the resistor 4. .. When the conductor pattern 5 is formed on the upper surface of the black resistor 4 in this way, not only the position of the conductor pattern 5 can be easily confirmed when the laser beam is irradiated, but also the conductor pattern 5 and the resistor 4 are evaporated by the laser beam. Since there is a resistor 4 under the conductor pattern 5 that tends to remain when the conductor pattern 5 is removed, the conductor pattern 5 can be removed together with the resistor 4 without remaining.

Further, the number of trimming grooves 6 and the overall shape of the resistor 4 are not limited to the first embodiment, and various modified examples can be adopted. For example, the conductor pattern 5 does not necessarily have to protrude outward from the resistor 4, and the conductor pattern 5 is formed up to a position before reaching the upper side 4a of the resistor 4 as in the second embodiment shown in FIG. You may do so.

In the third embodiment shown in FIG. 4, in order to increase the distance between the electrodes and improve the surge resistance characteristics, the resistor 4 has a meandering shape (serpentaine) meandering for 4 turns, and is formed in the central portion of the resistor 4. Along the formed conductor pattern 5, a trimming groove 6 wider than the conductor pattern 5 is provided.

In the fourth embodiment shown in FIG. 5, two conductor patterns 5a and 5b parallel to each other are formed so as to overlap with the resistor 4, and the upper side 4a of the resistor 4 is wider than one conductor pattern 5a. The resistor 4 has a meandering shape by providing the trimming groove 6a and the trimming groove 6b wider than the other conductor pattern 5b from the lower side 4b of the resistor 4.

In the fifth embodiment shown in FIG. 6, in order to enable highly accurate resistance value adjustment, two conductor patterns 5a and 5b parallel to each other are formed so as to overlap with the resistor 4, and one conductor is used. After the first trimming groove 6a wider than the pattern 5a is applied to raise the resistance value to near the target value (coarse adjustment of the resistance value), the second trimming groove 6b wider than the other conductor pattern 5b is formed. By applying the resistance value, the resistance value of the resistor 4 is adjusted to the target resistance value by one trimming groove (fine adjustment of the resistance value).

In the sixth embodiment shown in FIG. 7, the conductor pattern 5 is formed at a position deviated from the central portion of the resistor 4, and the resistor 4 has a trimming groove 6a wider than the conductor pattern 5 and the trimming groove. By providing the trimming groove 6b having a cut amount smaller than that of 6a, highly accurate resistance value adjustment is possible.

When forming such double-cut shaped trimming grooves 6a and 6b, as shown in FIG. 8A, the conductor pattern 5 is formed so as to overlap the resistor 4 at a position closer to one of the surface electrodes 2. After that, as shown in FIG. 8B, a first trimming groove 6a wider than the conductor pattern 5 is provided from the lower side 4b of the resistor 4 to raise the resistance value to the vicinity of the target value (coarse adjustment of the resistance value). ). Next, as shown in FIG. 7, a second trimming groove 6b is provided from the lower side 4b of the resistor 4 at a position closer to the other surface electrode 3, and the depth of cut of the trimming groove 6b is set to the first trimming groove 6a. The resistance value of the resistor 4 may be matched with the target resistance value (fine adjustment of the resistance value) by not exceeding the above. In this case, a microcrack is generated at the tip of the second trimming groove 6b, but the portion where the trimming groove 6b is formed is a region where the resistance value hardly changes (current hardly flows), so that the microcrack occurs. The influence of can be reduced.

In the seventh embodiment shown in FIG. 9, a trimming groove 6c wider than the conductor pattern 5 is provided by forming a U-shaped continuous slit in the resistor 4. When forming the trimming groove 6c having such a shape, as shown in FIG. 10A, after forming the conductor pattern 5 having a width W1 so as to overlap with the resistor 4, as shown in FIG. 10B. By folding back the narrow trimming groove 6c cut inward from the lower side 4b of the resistor 4 in a U-shape, a notch is made to separate a part of the conductor pattern 5 from the resistor 4 into the island-shaped separating portion 5c. The width dimension W2 of this notch may be wider than the pattern width W1 of the conductor pattern 5.

1 Insulated substrate 2, 3 Table electrode 4 Resistor 5, 5a, 5b Conductor pattern 6, 6a, 6b Trimming groove

Claims (6)

A resistance value is provided by providing an insulating substrate, a pair of electrodes arranged to face each other on the insulating substrate at predetermined intervals, and a resistor that bridges between these electrodes, and forming a trimming groove in the resistor. Is adjusted in the chip resistor
A conductor pattern made of a material having a conductivity higher than that of the resistor is formed between the pair of electrodes so as to overlap the resistor, and the trimming groove has a groove width wider than that of the conductor pattern. A chip resistor characterized in that it is formed from one side of the resistor along the extending direction of the conductor pattern. The chip resistor according to claim 1, wherein the end portion of the conductor pattern protrudes outward from the resistor. The chip resistor according to claim 1, wherein the conductor pattern is formed on the upper surface of the resistor. The chip resistor according to claim 1, wherein the conductor pattern and the electrode are made of the same material. It is provided with an insulating substrate, a pair of electrodes arranged to face each other on the insulating substrate at predetermined intervals, and a resistor that bridges between these electrodes, and the resistor is irradiated with laser light to form a trimming groove. In the trimming method of a chip resistor whose resistance value is adjusted by forming
A conductor pattern made of a material having a conductivity higher than that of the resistor is formed between the pair of electrodes so as to be superimposed on the resistor, and then the laser beam is emitted from one side of the resistor to the conductor pattern. A method for trimming a chip resistor, which comprises forming the trimming groove having a groove width wider than that of the conductor pattern by irradiating along the extending direction. In the fifth aspect of the present invention, after the conductor pattern is formed so as to project outward from both opposite sides of the resistor, the laser beam is emitted from one end of the conductor pattern to the inside of the resistor. A method of trimming a chip resistor, which is characterized by irradiating toward.