JP5157178B2 - Square chip resistor - Google Patents

Description

  The present invention relates to a rectangular chip resistor used in various electronic devices, and more particularly to a rectangular chip resistor having a resistor on both sides and having a low resistance value.

  As shown in FIG. 5, a conventional square chip resistor of this type is formed with a pair of upper surface electrodes 2a and a pair of rear surface electrodes 2b on the upper surface and the back surface of an insulating substrate 1 made of alumina or the like, and the pair of upper surface electrodes. An upper surface resistor 3a and a back surface resistor 3b are formed between the electrodes 2a and between the pair of back surface electrodes 2b, respectively, and thereafter, an upper surface trimming groove 4a and a back surface trimming groove 4b are formed in the upper surface resistor 3a and the back surface resistor 3b, respectively. After that, the upper surface resistor 3a and the back surface resistor 3b are covered with the upper surface protection layer 5a and the back surface protection layer 5b, respectively, and then the upper surface electrode 2a and the back surface electrode 2b are electrically connected to both ends of the insulating substrate 1. The side electrode 6 is formed, and then the plating layer 7 is formed on the surface of the side electrode 6.

For example, Patent Document 1 and Patent Document 2 are known as prior art document information relating to the invention of this application.
Japanese Patent Laid-Open No. 11-191502 Japanese Utility Model Publication No.59-107102

  As shown in FIG. 5, the conventional rectangular chip resistor disclosed in Patent Document 1 is provided with an upper surface resistor 3a and a back surface resistor 3b on the upper surface and the back surface of the insulating substrate 1, respectively. A square chip resistor having a low variation and a small variation can be obtained.

  However, in the above conventional technique, as shown in FIGS. 6 and 7 which are plan views immediately after the formation of the top surface trimming groove 4a and the back surface trimming groove 4b, the top surface trimming groove 4a and the back surface trimming groove 4b are formed on the top surface of the insulating substrate 1. Since the upper surface resistor 3a is trimmed to form the upper surface trimming groove 4a and then the rear surface resistor 3b is trimmed to form the rear surface trimming groove 4b, the rear surface trimming is performed. Due to the heat generated when the groove 4b is formed, the insulating property of the upper surface trimming groove 4a is deteriorated, which causes a problem that the TCR of the square chip resistor is deteriorated.

  On the other hand, Patent Document 2 discloses that local heat generation points formed by trimming are dispersed on the front and back sides, but a specific method and configuration for dispersing heat generation points associated with the formation of trimming grooves are not disclosed. Is.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a rectangular chip resistor having a good TCR and a stable resistance value.

  In order to achieve the above object, the present invention has the following configuration.

According to the first aspect of the present invention, there is provided an insulating substrate, a pair of upper surface electrodes and a pair of back electrodes provided on both ends of the upper surface and the back surface of the insulating substrate, the pair of upper surface electrodes and the pair of upper surfaces. A top surface resistor and a back surface resistor provided so as to be electrically connected to the back surface electrode; and a top surface trimming groove and a back surface trimming groove respectively provided in the top surface resistor and the back surface resistor. forming the back surface trimming groove and trimming groove so as not to overlap each other in the upper surface and the back surface of the insulating substrate, and a position which is a substantially point-symmetric with respect to the center of the upper surface trimming groove and the insulating substrate to the back surface trimming groove And the upper surface trimming groove and the rear surface trimming groove are formed in opposite directions when viewed from the upper surface of the insulating substrate, and The length of the top surface trimming groove and the length of the back surface trimming groove are configured to be less than half the width of the top surface resistor and the width of the back surface resistor, respectively, and the top surface trimming groove is the length of the top surface resistor. Extending from the side of the direction in the width direction of the upper surface resistor, and extending from the end point in a direction away from the rear surface trimming groove in the length direction of the upper surface resistor, and the rear surface trimming groove of the rear surface resistor The upper surface resistance of the upper surface trimming groove is a shape extending from the side in the length direction in the width direction of the back surface resistor and extending from the end point in a direction away from the upper surface trimming groove in the length direction of the back surface resistor. a portion extending a portion extending in the width direction of the body width direction of the back resistor of the back trimming groove than those located on a straight line different from a top view, the shape later Since the heat generated in the process of forming the trimming groove does not affect the insulating property of the trimming groove formed first, a rectangular chip resistor with a stable resistance value can be obtained while suppressing the deterioration of TCR. . In addition, since the heat generating parts where current flows through the top resistor and back resistor are formed at positions where they do not overlap each other when viewed from the top surface of the insulating substrate, the locations where heat is generated when current flows in the square chip resistors are dispersed. As a result, it is possible to obtain a square chip resistor that is small in size and can handle high power. In addition, since the upper surface trimming groove and the rear surface trimming groove are formed at positions that are substantially point-symmetric with respect to the center of the insulating substrate, the heat generated in the trimming process affects the upper, lower, left, and right sides of the insulating substrate equally. Thus, there is an effect that the problem that heat is concentrated on a part of the insulating substrate and distortion is generated and the shape becomes unstable can be suppressed.

  As described above, in the rectangular chip resistor according to the present invention, the upper surface trimming groove and the rear surface trimming groove are formed at positions where they do not overlap each other on the upper surface and the back surface of the insulating substrate. As a result, the heat generated in the process of forming the trimming groove to be formed later does not deteriorate the insulation by affecting the trimming groove formed first, so that the TCR deterioration is suppressed and the resistance value is reduced. An excellent effect is obtained in that a stable rectangular chip resistor can be obtained.

  Hereinafter, a rectangular chip resistor according to an embodiment of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view of a rectangular chip resistor according to an embodiment of the present invention, FIG. 2 is a plan view of a work piece of the rectangular chip resistor, FIGS. 3 (a) to 3 (d) and FIG. 4 (a). (E) is a manufacturing process figure which shows the manufacturing method of a equiangular chip resistor.

  As shown in FIGS. 1 and 2, the rectangular chip resistor according to one embodiment of the present invention includes a pair of upper surface electrodes 12a and a pair of rear surfaces on an upper surface and a rear surface of an insulating substrate 11 made of alumina having a purity of about 96%. Forming an electrode 12b, and forming an upper surface resistor 13a and a back surface resistor 13b between the pair of upper surface electrodes 12a and between the pair of back surface electrodes 12b, respectively, at positions overlapping each other when viewed from the upper surface of the insulating substrate 11, An upper surface trimming groove 14a and a back surface trimming groove 14b are formed in the upper surface resistor 13a and the back surface resistor 13b, respectively, and then the upper surface resistor 13a and the back surface resistor 13b are covered with the upper surface protection layer 15a and the back surface protection layer 15b, respectively. Then, the end which electrically connects the upper surface electrode 12a and the back surface electrode 12b to the both ends of the insulating substrate 11 The electrode 16 is formed, Thereafter, those that are prepared by forming a plating layer 17 on the surface of the end face electrodes 16. Here, as shown in FIG. 2, the upper surface trimming groove 14 a and the rear surface trimming groove 14 b are opposite to each other when viewed from the upper surface of the insulating substrate 11 at positions that are substantially point-symmetric with respect to the center of the insulating substrate 11. Further, the length of the top surface trimming groove 14a and the length of the back surface trimming groove 14b are configured to be less than half the width of the top surface resistor 13a and the back surface resistor 13b, respectively. As shown in FIGS. 1 and 2, the shortest distance d between the upper surface trimming groove 14a and the rear surface trimming groove 14b is configured to be 0.55 mm or more. Further, the plating layer 17 is usually constituted by a two-layer structure of a nickel plating layer and a solder or tin plating layer.

  Next, based on FIGS. 3A to 3D and FIGS. 4A to 4E, a method of manufacturing a rectangular chip resistor in one embodiment of the present invention will be described.

  First, as shown in FIG. 3A, a sheet-like insulating substrate 11c made of alumina having a purity of about 96% having a primary division groove 11a and a secondary division groove 11b is prepared, and straddling the primary division groove 11a. A plurality of upper surface electrodes 12a made of a conductive paste mainly composed of silver or copper are formed on the upper surface of the sheet-like insulating substrate 11c by a screen printing method, and are fired with a profile having a peak temperature of 850 ° C. Is a stable membrane. Although not shown, a plurality of back surface electrodes 12b are formed on the back surface of the sheet-like insulating substrate 11c in the same manner as the top surface electrode 12a. The back electrode 12b may be formed before the top electrode 12a.

  Next, as shown in FIG. 3B, the upper surface of the sheet-like insulating substrate 11c is made of ruthenium oxide, a silver palladium alloy, a copper nickel alloy or the like so as to be electrically connected to the plurality of upper surface electrodes 12a. The upper surface resistor 13a is formed by a screen printing method and baked with a profile having a peak temperature of 850 ° C. to 900 ° C., thereby making the upper surface resistor 13a a stable film. Although not shown, a back surface resistor 13b is formed on the back surface of the sheet-like insulating substrate 11c in the same manner as the top surface resistor 13a, and the top surface resistor 13a and the back surface resistor 13b are formed on the insulating substrate 11. They are formed so that they do not overlap each other when viewed from above. The back surface resistor 13b may be formed before the top surface resistor 13a.

  Next, as shown in FIG. 3C, after forming pre-coated glass (not shown) so as to cover the entire upper surface resistor 13a, the resistance value of the upper surface resistor 13a is adjusted to a desired value. Then, the upper surface trimming groove 14a is formed in the upper surface resistor 13a using a laser.

  Next, as shown in FIG.3 (d), after forming precoat glass (not shown) so that the whole back surface resistor 13b may be covered, in order to adjust the resistance value of the back surface resistor 13b to a desired value. In addition, the back surface trimming groove 14b is formed in the back surface resistor 13b using a laser. Here, the back surface trimming groove 14b is formed at a position where the top surface and the back surface of the sheet-like insulating substrate 11c do not overlap with the top surface trimming groove 14a, and preferably the top surface trimming groove 14a and the back surface trimming groove 14b are the center of the insulating substrate 11. The upper surface trimming groove 14a and the back surface trimming groove 14b are formed at positions opposite to each other when viewed from the upper surface of the insulating substrate 11, and the upper surface trimming is further performed. The length of the groove 14a and the length of the back surface trimming groove 14b are formed to be less than half of the width of the top surface resistor 13a and the back surface resistor 13b, respectively. The shortest distance d between them is formed to be 0.55 mm or more. The top surface trimming groove 14a and the back surface trimming groove 14b may be formed in reverse order.

  Next, as shown in FIG. 4A, an upper surface protective layer 15a made of resin is formed so as to cover all of the upper surface resistor 13a and the upper surface trimming groove 14a, and cured with a profile having a peak temperature of 200 ° C. Thus, the upper surface protective layer 15a is made a stable film. Although not shown, the back surface protective layer 15b is formed on the back surface of the sheet-like insulating substrate 11c in the same manner as the upper surface protective layer 15a. The back surface protective layer 15b may be formed before the upper surface protective layer 15a.

  Next, as shown in FIG. 4B, a strip-shaped substrate 11d is obtained by dividing the sheet-like insulating substrate 11c along the primary dividing groove 11a.

  Next, as shown in FIG. 4C, the end face electrode 16 is formed by applying a conductive paste or sputtering so as to electrically connect the top electrode 12a and the back electrode (not shown).

  Next, as shown in FIG. 4D, the strip-shaped substrate 11d is divided along the secondary dividing grooves 11b to obtain the individual substrate 11e.

  Finally, as shown in FIG. 4 (e), a two-layered plating layer 17 made of nickel and solder or tin is formed on the surface of the end face electrode 16 by using barrel plating, thereby implementing one embodiment of the present invention. A rectangular chip resistor in the form of is obtained.

  Table 1 shows the TCR test results of the rectangular chip resistor and the conventional rectangular chip resistor according to the embodiment of the present invention manufactured by the above manufacturing method. The defect rate is as follows: 1,000 square chip resistors each having a resistance value of 75 mΩ were manufactured for each of the conventional product and the present invention product, and TCR was measured for all of these square chip resistors, and this TCR was 250 ppm / ° C. The above items were determined as defective products, and the ratio of defective products was calculated for each of the conventional product and the present invention product.

  As apparent from Table 1, in the conventional rectangular chip resistor in which the shortest distance d between the upper surface trimming groove 14a and the rear surface trimming groove 14b is 0.50 mm or less, the defect rate is 0.5% to 1%. In the rectangular chip resistor according to the embodiment of the present invention in which the shortest distance d between the upper surface trimming groove 14a and the rear surface trimming groove 14b is 0.55 mm or more, the defect rate is 0%. Met. That is, in a relatively large size square chip resistor manufactured using an insulating substrate having a thickness of 0.55 mm or more, the upper surface trimming groove 14a and the back surface trimming groove 14b overlap each other on the upper surface and the back surface of the insulating substrate 11. Even if it is formed at the position, the heat generated in the process of forming the trimming groove to be formed later does not affect the insulating property of the trimming groove that was formed first, and no defective TCR occurred. Since the thickness of the insulating substrate 11 is 0.35 mm, the top surface trimming groove 14a and the back surface trimming groove 14b are formed at positions where they overlap each other on the top surface and the back surface of the insulating substrate 11. In this case, the shortest distance between the two trimming grooves is 0.35 mm. % Are those with higher. Therefore, even in a rectangular chip resistor of 1005 size or less manufactured using an insulating substrate having a thickness of 0.35 mm, the upper surface trimming groove 14a and the rear surface trimming groove 14b are formed at positions where the upper surface and the rear surface of the insulating substrate 11 do not overlap each other. If the shortest distance between the two trimming grooves is 0.55 mm or more, heat generated in the process of forming the trimming groove to be formed later does not affect the insulating property of the trimming groove formed first. Deterioration is suppressed and the defect rate becomes zero. In addition, since the heat generating portions where current flows through the upper surface resistor 13a and the back surface resistor 13b are formed at positions where they do not overlap each other when viewed from the upper surface of the insulating substrate 11, the portion where the current flows in the rectangular chip resistor generates heat. Thus, a rectangular chip resistor that is small in size and can handle high power can be obtained.

  From the above results, in the rectangular chip resistor according to the embodiment of the present invention, the top surface trimming groove 14a and the back surface trimming groove 14b are formed at positions where they do not overlap each other on the top surface and the back surface of the insulating substrate 11, Since the grooves 14a and 14b are kept away from each other, the heat generated in the process of forming a trimming groove to be formed later does not affect the insulating property of the trimming groove formed first, thereby causing deterioration in TCR. It can be seen that a square chip resistor that is suppressed and has a stable resistance value can be obtained.

  In the rectangular chip resistor according to the embodiment of the present invention, the top surface trimming groove 14a and the back surface trimming groove 14b are formed at positions that are substantially point-symmetric with respect to the center of the insulating substrate 11. The heat generated in the process uniformly affects the upper, lower, left and right sides of the insulating substrate 11, thereby suppressing the problem that the heat is concentrated on a part of the insulating substrate 11 to cause distortion and the shape becomes unstable. In addition, since the heat generating portions where the current flows through the top resistor 13a and the back resistor 13b are formed at positions where they do not overlap each other when viewed from the top surface of the insulating substrate, the current flows in the rectangular chip resistor. The locations that generate heat will be formed in a dispersed manner, which makes it possible to obtain a square chip resistor that is small and can handle high power. It is those having the effect that.

  In addition, in the rectangular chip resistor according to the embodiment of the present invention, the top surface resistor 13a and the back surface resistor 13b are formed at positions overlapping each other when viewed from the top surface of the insulating substrate 11, so that the space-saving resistor is provided. This has the effect that a square chip resistor having a low value can be obtained.

  Furthermore, in the rectangular chip resistor according to the embodiment of the present invention, the upper surface trimming groove 14a and the rear surface trimming groove 14b are formed in opposite directions when viewed from the upper surface of the insulating substrate 11, and the length of the upper surface trimming groove 14a is increased. And the length of the back surface trimming groove 14b are less than half the width of the upper surface resistor 13a and the width of the back surface resistor 13b, respectively, so that the trimming grooves 14a and 14b of both are close to each other. Thus, since the heat generated in the process of forming the trimming groove to be formed later does not affect the insulating property of the trimming groove that is formed first, the square shape whose resistance value is stable while suppressing the deterioration of the TCR is suppressed. It has the effect that a chip resistor can be obtained.

  Furthermore, in the rectangular chip resistor according to the embodiment of the present invention, the shortest distance between the upper surface trimming groove 14a and the rear surface trimming groove 14b is 0.55 mm or more. Since the trimming grooves 14a and 14b do not approach each other, heat generated in the process of forming a trimming groove to be formed later does not affect the insulating property of the trimming groove that is formed first. Therefore, a square chip resistor having a stable resistance value can be obtained.

  In the rectangular chip resistor according to the present invention, the upper surface trimming groove and the rear surface trimming groove are formed at positions where they do not overlap each other on the upper surface and the back surface of the insulating substrate, so that heat generated in the process of forming the trimming groove to be formed later is first generated. The TCR is prevented from deteriorating so as not to affect the insulating properties of the formed trimming groove, and is particularly useful when applied to a rectangular chip resistor that requires high accuracy with a low resistance value. .

Sectional drawing of the square chip resistor in one embodiment of this invention Plan view of work-in-progress of equiangular chip resistors (A)-(d) Manufacturing process figure which shows the manufacturing method of a equiangular chip resistor (A)-(e) Manufacturing process figure which shows the manufacturing method of a equiangular chip resistor Cross-sectional view of a conventional square chip resistor Plan view of work-in-progress of equiangular chip resistors Plan view of work-in-progress of equiangular chip resistors

Explanation of symbols

11 Insulating substrate 12a Top surface electrode 12b Back surface electrode 13a Top surface resistor 13b Back surface resistor 14a Top surface trimming groove 14b Back surface trimming groove

Claims (1)

An insulating substrate, a pair of upper surface electrodes and a pair of back electrodes provided on both ends of the upper surface and the back surface of the insulating substrate, and the pair of upper surface electrodes and the pair of back electrodes, respectively, are electrically connected a top resistor and backside resistive body provided, and a said top resistor and the back resistors on the upper surface trimming grooves and the back surface trimming grooves provided respectively, the rear surface trimming groove and the upper surface trimming groove of the insulating substrate Forming the upper surface trimming groove and the rear surface trimming groove at positions that are substantially point-symmetric with respect to the center of the insulating substrate; and forming the upper surface trimming groove and the rear surface. Trimming grooves are formed in opposite directions when viewed from the top surface of the insulating substrate, and the length of the top surface trimming groove and the back surface are formed. The length of the trimming groove is configured to be less than half of the width of the upper surface resistor and the width of the back surface resistor, and the upper surface trimming groove extends from the side in the length direction of the upper surface resistor. Extending in the width direction of the upper surface resistor and extending in the direction away from the back surface trimming groove in the length direction of the upper surface resistor, the back surface trimming groove extending from the side in the length direction of the back surface resistor to the back surface It extends in the width direction of the upper surface trimming groove in the upper surface trimming groove, extending in the width direction of the resistor, extending from the end point in a direction away from the upper surface trimming groove in the length direction of the back surface resistor. A square chip resistor in which the portion and the portion of the back surface trimming groove extending in the width direction of the back surface resistor are located on different straight lines when viewed from above .

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