Chip resistor and its manufacturing method

Abstract

To provide a chip resistor that prevents flow into a dividing groove of a glass protective film.SOLUTION: A rectangular glass protective film 4 is formed such that the boundary between surface electrodes 3a and 3b does not exist under the corner portions of the rectangular glass protective film 4, thereby eliminating a step caused by the thickness of an electrodes. This configuration solves a problem in which the corners of the glass protective film bleed and spread outside the substrate (dividing groove) when glass paste is individually printed on individual chip resistor chips on a multi-piece large-sized substrate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chip resistor used, for example, for current detection and a method for manufacturing the same. [Background technology]

[0002] Many chip components such as chip resistors are used in electronic devices, and there is an increasing demand for the components themselves to be more compact and more reliable. For example, low-resistance chip resistors used for current detection and the like are required to have smaller sizes and lower resistances to improve current detection accuracy.

[0003] A typical chip resistor has a resistor formed on the upper surface of an insulating substrate, electrodes electrically connected to both ends of the resistor, and the surface of the resistor and part of the surface of the electrodes are covered with a glass protective film. The glass protective film is further covered with a resin protective film, and end electrodes and plating layers overlapping the end electrodes are formed on the surfaces of the electrodes and the end faces of the insulating substrate.

[0004] The glass protective film is formed for the purpose of protecting the resistor from the laser used in the process of adjusting the resistance value of the chip resistor. When manufacturing chip resistors using a large-sized substrate for multiple pieces, for example, as described in Patent Document 1, there is a method of forming a band-shaped glass protective film so as to collectively cover multiple resistors on the large-sized substrate.

[0005] However, if a glass protective film is formed on multiple resistors at once, the paste-like glass material printed as the glass protective film will get into the slits (division grooves) provided to divide the large-format substrate into individual pieces, which may result in the substrate not breaking along the division grooves during the process of dividing the large-format substrate, or the broken substrate may have a defective shape.

[0006] In order to avoid such problems, a method has been used in which, rather than covering multiple resistors on a large-format substrate for multiple pieces with a glass protective film in a band-like shape, a glass protective film is formed in an island shape so as to cover the multiple resistors individually (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2005-191406 A [Patent Document 2] Patent No. 5115968 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0008] The glass protective film that individually covers multiple resistors on the large-format substrate for multiple pieces as described above is formed in a rectangular shape, for example, glass protective film 94 shown in Figure 12(a), and there is a problem that the corners of the rectangular glass protective film will seep when the glass paste is extruded during screen printing, and flow into the slits (division grooves) provided in the large-format substrate.

[0009] This problem becomes more pronounced as chip resistors become smaller. That is, as chip resistors become smaller, the proportion of the surface of the insulating substrate where resistors and electrodes are formed increases, and the electrodes and resistors are formed up to positions close to the slits (division grooves). As a result, the glass protective film that covers the surfaces of the electrodes and resistors is also inevitably formed up to positions close to the slits (division grooves).

[0010] 12(a), if there is a boundary between electrodes 93a, 93b (the boundary between the part where the electrodes are formed and the part where they are not formed) on the substrate at corners G1-G4 of rectangular glass protective film 94, a slight step occurs due to the thickness of the electrodes. This step affects the printing of the glass paste, causing the corners G1-G4 of glass protective film 94 to bleed and spread to slits (division grooves) 1a that form the longitudinal side edges of each insulating substrate, which is an individual chip area, as shown by the white arrow in FIG.

[0011] Such bleeding at the corners of the glass protective film not only causes cracking defects when dividing a large-sized substrate into individual pieces, but also causes the glass of the protective film to be exposed from the side surface in the long side direction of the insulating substrate, which may damage the glass in the plating process and affect the acid resistance. In addition, the glass that has bled from the rectangular corners is exposed in a scattered manner from the long side direction of the insulating substrate, which may have a negative effect on the shape of the chip resistor.

[0012] On the other hand, in the case of the above-mentioned low-resistance chip resistor for current detection, it is conceivable to further reduce the resistance by, for example, reducing the distance between the electrodes formed on the insulating substrate to reduce the area (formation area) of the resistor. However, because the external dimensions of chip resistors are standardized, if the area of ​​the resistor is reduced, the area of ​​the electrodes on the insulating substrate will increase accordingly.

[0013] Normally, the electrodes of a chip resistor are formed in a rectangular shape on the surface of an insulating substrate, but by reducing the area of ​​the resistor as described above, forming rectangular electrodes over a wide area (formation region) requires a large amount of electrode material. In this case, the cost of the chip resistor increases due to the influence of Ag and Pd contained in the electrode material.

[0014] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to prevent a glass protective film from flowing into slits (division grooves) during the process of forming elements for multiple chip resistors on a large-format substrate for multiple units. [Means for solving the problem]

[0015] As a means for achieving the above object and solving the above-mentioned problems, for example, the following configuration is provided. That is, the present invention is a low resistance chip resistor with standardized external dimensions, comprising a rectangular parallelepiped insulating substrate, a pair of surface electrodes arranged facing each other at a predetermined distance apart on both ends of the surface of the insulating substrate in the longitudinal direction, a resistor formed between the pair of surface electrodes, and a rectangular-shaped Glass protective film the glass protective film having a trimming groove formed in association with the formation of a trimming groove for adjusting a resistance value of the resistor; The resistor and the pair of surface electrodes are disposed in a short direction of the insulating substrate. Glass the pair of surface electrodes are formed up to positions close to both longitudinal edges of the insulating substrate within a range not exceeding the boundary of the protective film, the pair of surface electrodes being composed of an extension portion having a width dimension wider than the width dimension of the resistor in the short-side direction of the insulating substrate at a connection portion between the pair of surface electrodes and the resistor, and a portion having a width dimension substantially the same as the width dimension of the resistor and extending from the extension portion to the longitudinal end portion of the insulating substrate, Glass The protective film is formed on the entire surface of the resistor and the Extension In the predetermined region including the Glass The protective film is characterized in that the four corners of the protective film do not overlap the pair of surface electrodes and are formed to avoid both longitudinal edges of the surface of the insulating substrate.

[0016] For example, the width of the extension portion gradually changes toward both ends of the insulating substrate in the longitudinal direction so as to approach the width of the resistor. 。

[0017] The present invention also relates to Low resistance with standardized external dimensions A method for manufacturing a chip resistor includes a step of forming a lattice-like primary division groove and a secondary division groove perpendicular to each other on a surface of a large insulating substrate for producing a large number of chip resistors, and a step of forming a plurality of partitions on the surface of the large insulating substrate by the primary and secondary division grooves. Territoryforming a plurality of electrodes facing each other at a predetermined interval in the region; forming a plurality of resistors so as to straddle the plurality of electrodes arranged facing each other; and each and a connection portion between each of the plurality of electrodes. Prescribed forming a rectangular glass protective film that covers each of the regions individually; forming trimming grooves in each of the plurality of resistors after forming the glass protective film to adjust the resistance value; dividing the large insulating substrate along the primary division groove to obtain rectangular substrates; forming end electrodes on the divided surfaces of the rectangular substrates; and dividing the rectangular substrates with the end electrodes formed thereon along the secondary division groove to obtain individual chip resistors. Each of the plurality of electrodes and each of the plurality of resistors are formed in the primary division groove direction up to a position close to the secondary division groove within a range not exceeding the boundary of the glass protective film, and each of the plurality of electrodes comprises an extension portion having a width dimension wider than the width dimension of the resistor in the primary division groove direction at the connection portion, and a portion having a width dimension substantially the same as the width dimension of the resistor and extending from the extension portion to an end of the single chip resistor in the secondary division groove direction, The glass protective film is In the predetermined region, When viewed from above, the four corners of the glass protective film do not overlap with any of the electrodes and are formed to avoid the secondary division grooves. attitude It is characterized by the above.

[0018] example For example, the method further comprises the step of forming a plurality of resin protective films extending in strip shapes along the primary dividing grooves. Effect of the Invention

[0019] According to the present invention, it is possible to provide a chip resistor and a manufacturing method thereof that solves the problem of the corners of the rectangular glass protective film formed on the upper surface, etc. of the resistor element bleeding and spreading outward (to the dividing grooves). [Brief description of the drawings]

[0020] [Figure 1] 1 is an external perspective view of a chip resistor according to an embodiment of the present invention. [Diagram 2] 2 is a plan view of the chip resistor shown in FIG. 1 as viewed from the z direction. [Diagram 3] 4 is a flowchart showing a time sequence of a manufacturing process for a chip resistor according to an embodiment. [Figure 4]FIG. 2 is a diagram showing a rear electrode formed on a large insulating substrate. [Diagram 5] FIG. 2 is a diagram showing a surface electrode formed on a large insulating substrate. [Figure 6] FIG. 1 is a diagram showing a resistor formed between surface electrodes of a large insulating substrate. [Figure 7] FIG. 13 is a diagram showing a glass protective film formed so as to cover the entire surface of a resistor element and part of a surface electrode of a large insulating substrate. [Figure 8] FIG. 13 is a diagram showing a notch (trimming groove) for adjusting the resistance value of a resistor in a large insulating substrate. [Figure 9] FIG. 1 is a diagram showing a resin protective film formed on a large insulating substrate so as to cover a glass protective film and the like. [Figure 10] 13A and 13B are diagrams showing modified shapes of the extension portion of the surface electrode. [Figure 11] 11A and 11B are diagrams showing modified examples of the shape of the resistor; [Figure 12] FIG. 1 is a diagram showing a problem with the conventional technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is an external perspective view of a chip resistor according to the embodiment, and Fig. 2 is a plan view of the chip resistor shown in Fig. 1 as viewed from the z direction.

[0022] The insulating substrate 1 of the chip resistor 10 shown in FIG. 1 etc. is an electrically insulating substrate made of, for example, alumina (Al2O3) having a predetermined thickness and shape (rectangular parallelepiped shape), and is a large number of individual substrates obtained by dividing a large-sized substrate described later along vertical and horizontal dividing grooves (slits).

[0023] A resistor 2 is formed on the upper surface (front surface) of the insulating substrate 1. The resistor 2 is a thick-film resistor formed by screen-printing a resistive paste made of a resistive material such as ruthenium oxide (RuO2), copper (Cu), or silver-palladium (Ag-Pd) in a rectangular shape on the surface of the insulating substrate 1, and then firing it. The resistor 2 has a notch (trimming groove) 8 for adjusting the resistance value.

[0024] The size of the chip resistor 10 is a standard size, for example, 1.6 mm × 0.8 mm. When the chip resistor 10 is to be made low-resistance for use in current detection or other applications, a resistor material with low electrical resistance is preferable, but a thin-film resistor such as a metal film can also be used as the resistor 2 depending on the required characteristics.

[0025] Low resistance chip resistors are used, for example, in protection circuits for batteries and current detection circuits, and their resistance value is, for example, 100 Ω or less.

[0026] A pair of surface electrodes (upper electrodes) 3a, 3b electrically connected to the resistor 2 are formed on both ends in the longitudinal direction (y direction) of the upper surface of the insulating substrate 1. In addition, a back electrode (lower electrode) (not shown) is formed on the end of the lower surface of the insulating substrate 1 at a position corresponding to the surface electrodes with the insulating substrate 1 in between.

[0027] Although not shown in the figure, end electrodes that electrically connect the front and back electrodes are formed on each end side surface in the longitudinal direction of the insulating substrate 1. Furthermore, the chip resistor 10 has external electrodes (plating) (not shown) formed so as to cover each of the back electrodes, each of the end electrodes, and a part of the resin protective film (not shown).

[0028] The entire surface of the resistor 2 and at least a part of the surfaces of the surface electrodes 3a and 3b are covered with a glass protective film 4 formed by screen printing, for example, a borosilicate glass paste. Furthermore, on the glass protective film 4, a resin protective film (not shown) is formed which functions as an insulating film and corresponds to the outermost layer.

[0029] As described later, glass protective film 4 is a protective film formed in an island shape so as to cover a plurality of resistors individually on a large-sized substrate for multiple pieces. Since glass protective film 4 is made of transparent or semi-transparent glass, it is indicated by a dotted line in Fig. 1 etc.

[0030] As shown in FIG. 2, in the chip resistor 10 according to this embodiment, the surface electrodes 3a, 3b have a width dimension (dimension in the x-direction) W1 of the connection portion with the resistor 2 (the portion overlapping with the resistor 2, also called the extension portion A1, A2) that is formed wider than the width dimension W2 of the other portion that is continuous with the extension portion A1, A2, and the width dimension W2 of the portion other than the extension portion A1, A2 is formed to be approximately the same width as the width dimension W3 of the resistor 2.

[0031] One of the reasons for providing the surface electrodes 3a, 3b with the extensions A1, A2 formed wider than the resistor 2 is to allow for misalignment of the printing position of the resistor 2, which has approximately the same width as the surface electrodes 3a, 3b. In addition, the extensions A1, A2 can prevent the corners (four corners) C1-C4 of the glass protective film 4 from overlapping with the boundaries of the surface electrodes 3a, 3b on the insulating substrate.

[0032] On the other hand, by forming the width dimension of the resistor 2 and the width dimension of the surface electrodes 3a, 3b excluding the extension parts A1, A2 to be approximately the same, a current path is secured and the current density is constant, so that heat generation due to current concentration in a specific location can be suppressed. Also, a sufficient area can be secured for contacting a probe for measuring resistance value other than the wide parts (extension parts A1, A2) of the surface electrodes 3a, 3b.

[0033] Furthermore, by making the width dimensions of the resistor 2 and the surface electrodes 3a, 3b approximately the same, the current path from the surface electrodes to the resistor is less likely to be biased, which contributes to reducing the area of ​​the resistor, i.e., lowering the resistance of the chip resistor.

[0034] 2, the glass protective film 4 is substantially rectangular, and as described above, is disposed such that the boundaries of the surface electrodes 3a, 3b do not exist beneath the corners C1-C4. In other words, the glass protective film 4 is formed in such a position that the corners C1-C4 do not overlap with the surface electrodes 3a, 3b when viewed in a plan view (when viewed from the z direction).

[0035] This arrangement eliminates the occurrence of steps due to the thickness of the surface electrodes 3a, 3b at the corners C1 to C4 of the glass protective film 4, preventing the spread of the printed glass paste. Compared to the insulating substrate surface, these steps are on the order of several μm to several tens of μm, but are a significant step in a small chip resistor.

[0036] Furthermore, by arranging glass protective film 4 as described above, it is possible to prevent the glass protective film from flowing into the division grooves formed in a large-sized substrate for multiple production, which will be described later, and thus to reduce the occurrence of division defects and the like.

[0037] Furthermore, the prevention of the glass protective film from flowing in improves the freedom of design. For example, the width dimensions of the surface electrodes 3a, 3b and the resistor 2 can be made wider, and the surface electrodes can be made relatively thick (for example, 10 μm or more) or can be formed in two or more layers. As a result, the increased volume allows for a higher power chip resistor (a shunt resistor for large current applications such as current detection).

[0038] In addition, as shown in Figures 1 and 2, by completely covering the extensions A1 and A2 of the surface electrodes 3a and 3b with the glass protective film 4, electrical insulation between the electrodes in adjacent regions separated by the dividing grooves can be ensured in the manufacturing process to prevent leakage current, improving measurement accuracy when adjusting the resistance value. As a result, it is possible to narrow the resistance value tolerance and obtain, for example, a low-resistance chip resistor with a high-precision low resistance value.

[0039] Next, a method for manufacturing the chip resistor according to the present embodiment will be described with reference to Fig. 3, which is a flow chart showing the manufacturing process of the chip resistor according to the present embodiment in chronological order.

[0040] First, in step S11 of Fig. 3, an insulating substrate is prepared. Here, for example, a large insulating substrate for multiple pieces formed of an alumina (Al2O3) substrate, a ceramic substrate, or the like is prepared. In the following step S13, a primary dividing groove is formed in one direction of the substrate as a dividing groove (slit) on the surface of the insulating substrate, and a secondary dividing groove is further formed in a direction perpendicular to the first direction. Note that these dividing grooves may be formed not only on the surface but also on the back surface of the insulating substrate.

[0041] In step S15, a back electrode is formed in each of the regions divided by the dividing grooves. For example, as partially shown in FIG. 4, an electrode material (back electrode) 33 made of a silver (Ag)-based paste is screen-printed. The electrode material 33 straddles the primary dividing groove 31 on the back surface of the insulating substrate, extends in a direction along the primary dividing groove 31, and has a predetermined width in the direction in which the secondary dividing groove 41 extends. The back electrode may be formed by screen-printing the electrode material 33 in a strip shape as shown in FIG. 4, or may be formed by screen-printing the electrode material 33 in an island shape independently in each of the regions divided by the dividing grooves. The printed electrode material 33 is dried and then fired, for example, at 850°C.

[0042] In step S17, a surface electrode is formed. For example, as shown in Fig. 5, an electrode material (surface electrode) 35 made of a silver (Ag)-based paste is screen-printed on the upper surface (surface) of the insulating substrate, straddling the primary dividing groove 31 and sandwiched between two adjacent secondary dividing grooves 41, facing each other at a predetermined interval in the direction along the secondary dividing grooves 41. After drying, the electrode material 35 is fired at, for example, 850°C.

[0043] The printed electrode material (surface electrode) 35 is an individual insulating substrate obtained by dividing a large insulating substrate, and has a wide extension portion at the center and a shape that is narrower at the end sides compared to the extension portion and has the same width as the resistor element to be printed in the next process.

[0044] The electrodes formed in steps S15 and S17 above form a pair of back electrodes on the lower surface side of the insulating substrate of each individual chip resistor, and a pair of front electrodes on the upper surface side of the insulating substrate.

[0045] The back electrode and the front electrode may be formed of the same electrode material as described above, or different electrode materials may be used. The order of forming the back electrode and the front electrode is not limited to the above, and the back electrode may be formed after the front electrode is formed. Alternatively, the back electrode and the front electrode may be formed in the same process.

[0046] In step S19, a resistor is formed between the surface electrodes. Here, for example, as shown in Fig. 6, resistor 37 is formed between a pair of opposing surface electrodes 35 in an individual region (an individual region surrounded by the primary division groove and the secondary division groove) on the surface of the insulating substrate, with a part of resistor 37 overlapping and electrically connected to the surface electrodes 35. Resistor 37 is formed by screen printing a resistance paste made of, for example, ruthenium oxide (RuO2) or the like, dried, and then fired at, for example, 850°C.

[0047] As described above, resistor 37 is formed so that a part of it overlaps with surface electrode 35, but the positional relationship of the overlapping part in the vertical direction (z direction) is arbitrary. That is, as shown in Fig. 1 etc., the ends of resistor 2 may be located above surface electrodes 3a and 3b, or after forming a resistor on an insulating substrate, the ends of the surface electrodes may be formed to be located above both ends of the resistor.

[0048] In step S21, for example, as shown in FIG. 7, a substantially rectangular glass protective film 39 is individually formed to cover the entire surface of the resistor 37 formed in step S19 above, the entire extended portion of the surface electrode 35 (see FIG. 5), and part of the other portions.

[0049] In this case, as described above, the corners (four corners) of glass protective film 39 are positioned so that they do not overlap surface electrodes 35 when viewed in a plan view, and glass protective film 39 is formed at a position that avoids both edges of the individual region on the insulating substrate surface, i.e., secondary division grooves 41, as shown in Figure 7.

[0050] The glass protective film 39 is formed for the purposes of protecting the resistor 37 from a laser used in a process of adjusting the resistance value of a chip resistor, which will be described later, and improving trimming accuracy.

[0051] The glass protective film 39 is formed by screen printing a protective film paste made of lead borosilicate glass at the above-mentioned positions, and then drying and firing the protective film paste. The protective film paste is fired at 600° C., for example, to form the glass protective film.

[0052] In step S23, for example, as shown in FIG. 8, a cut (trimming groove) 43 is made in the resistor from above the glass protective film 39 formed in step S21 above by a laser beam, thereby adjusting (trimming) the resistance value of the resistor.

[0053] The resistance value of a resistor can be adjusted to a desired value by, for example, changing the distance (width) between the electrodes, the thickness of the resistor, forming trimming grooves in part of the resistor, etc. Here, the resistance value between the surface electrodes is based on the resistance value, and a cut is made in the resistor with a laser beam to adjust it to the target resistance value. The number and shape of the trimming grooves are changed depending on the target resistance value.

[0054] As described above, by performing the trimming process in step S23 after the glass protective film forming process in step S21, the glass protective film functions as a protective film for the resistor, and the occurrence of microcracks in the resistor due to the laser in the trimming process can be suppressed.

[0055] Furthermore, when the trimming step in step S23 is performed, the entire extension of the surface electrode is already covered with the glass protective film in the glass protective film forming step in step S21, so that the insulation between adjacent surface electrodes is improved through the slits (division grooves). This makes it possible to prevent the measurement current from leaking to the adjacent surface electrodes when adjusting the resistance value by laser trimming, and allows the resistance value to be measured and adjusted with high accuracy.

[0056] In step S25, a resin protective film is formed. Here, as shown in Fig. 9, a continuous strip of resin paste is screen-printed in the direction along the primary division groove so as to cover the entire surface of the glass protective film 39 and all or part of the surface electrode 35. After drying, the resin protective film is heated and cured at, for example, 200°C to form the resin protective film 45.

[0057] The resin protective film 45 is made of, for example, a thermosetting resin paste in which a filler is added to an epoxy resin, which is a thermosetting resin. Since the resin protective film is flexible, even if it is printed on the slits (division grooves) of the substrate, it does not interfere with the subsequent division of the substrate.

[0058] In step S27, the large insulating substrate is divided into rectangular pieces (primary division) along the primary division grooves 31 provided in the large insulating substrate in step S13. In the following step S29, the substrates divided into rectangular pieces in step S27 are stacked, and an end surface electrode is formed on one of the fractured surfaces (both side surfaces) by depositing, for example, a NiCr-based alloy material by sputtering.

[0059] Instead of the above sputtering, for example, a resin silver (Ag) paste may be applied, dried, and fired to form the end electrodes.

[0060] In step S31, the substrate divided into rectangular shapes and having end surface electrodes formed thereon as described above is further divided into chips along the secondary division grooves 41 provided in the large insulating substrate in step S13. This results in single chips (individual pieces) having the same size as the chip resistor 10 shown in FIG. 1 etc.

[0061] In step S33, a plating layer (external electrode) is formed using, for example, nickel (Ni), tin (Sn), gold (Au), copper (Cu), etc. so as to cover the entire end face electrodes and back face electrodes, and part of the front face electrodes and resin protective film.

[0062] The plating layer may have a laminated structure by applying an undercoat plating of nickel or the like and then performing solder plating, etc. Note that the plating layer may be formed after dividing the substrate into strips and before dividing it into individual pieces.

[0063] <Modification> The chip resistor according to the present embodiment is not limited to the above-mentioned configuration, and various modifications are possible. For example, the shape of the extensions (overlapping portions with the resistor) of the surface electrodes is not limited to the example shown in Fig. 1, etc. For example, as shown by dotted circles E1 to E4 in Fig. 10, the extensions B1 and B2 of the surface electrodes 23a and 23b may have a shape that gradually changes in width so that the width approaches the width of the resistor 2 toward both ends in the longitudinal direction (y direction) of the surface of the insulating substrate 1.

[0064] This eliminates bias in the current path between the surface electrodes 23a, 23b and the resistor 2, making it possible to suppress heat generation due to current concentration during current flow.

[0065] On the other hand, the shape of the resistor is not limited to the example shown in Fig. 1 etc. For example, the resistor 22 may have a meandering pattern as shown in Fig. 11. This allows the electrodes to be formed closer to the dividing grooves (the above-mentioned primary dividing grooves) and the resistor 22 to be routed long between the electrodes, which is particularly advantageous for chip resistors in the medium and high resistance ranges.

[0066] As described above, the chip resistor of this embodiment can solve a problem that does not occur with a resin protective film made of resin paste, but is specific to forming a glass protective film by extruding glass paste individually into the areas separated by the dividing grooves after forming the dividing grooves.

[0067] In other words, by forming the glass protective film so that there is no electrode boundary on the base at the corners of the rectangular glass protective film (so that the edges of the electrode do not overlap the corners of the protective film), thereby eliminating the step caused by the thickness of the electrode, it is possible to eliminate the problem of the corners of the glass protective film bleeding and spreading outside the substrate during the process of printing glass paste individually onto individual chips of chip resistors on a large-format substrate for multiple units.

[0068] Furthermore, in the surface electrodes formed on the multi-piece substrate, the connection portion with the resistor is shaped to have an extension wider than the resistor, and the resistor and the extension are covered with a glass protective film, after which trimming is performed to adjust the resistance value. This prevents the measurement current for trimming from leaking to the adjacent electrodes, enabling high-precision resistance value measurement and narrowing the resistance value tolerance.

[0069] In addition, by adopting the above configuration, even when reducing the area of ​​the resistor body to lower resistance in a small chip resistor having standardized external dimensions, the area of ​​the electrodes is prevented from increasing, thereby providing cost benefits. [Explanation of symbols]

[0070] 1. Insulating substrate 2,22,37 Resistor 3a,3b,23a,23b,35,53a,53b Surface electrode 4,39 Glass protection film 8,43 Resistance adjustment notch (trimming groove) 10 Chip resistors 31 Primary dividing groove 33 Back electrode 41 Secondary dividing groove 45 Resin protective film A1, A2, B1, B2 extension C1~C4 Corners of the glass protective film (four corners)

Claims

1. A low resistance chip resistor with standardized external dimensions, A rectangular insulating substrate; a pair of surface electrodes disposed opposite each other at both ends in the longitudinal direction of the surface of the insulating substrate and spaced apart by a predetermined distance; a resistor formed between the pair of surface electrodes; a rectangular glass protective film covering a predetermined region of the insulating substrate, the glass protective film having a trimming groove formed in association with the formation of a trimming groove for adjusting a resistance value of the resistor; Equipped with the resistor and the pair of surface electrodes are formed in a short-side direction of the insulating substrate up to positions close to both longitudinal edges of the insulating substrate within a range not exceeding a boundary of the glass protective film, the pair of surface electrodes each include an extension portion having a width dimension wider than a width dimension of the resistor in the short-side direction of the insulating substrate at a connection portion between the pair of surface electrodes and the resistor, and a portion having a width dimension substantially the same as the width dimension of the resistor and extending from the extension portion to an end portion in the long-side direction of the insulating substrate; the glass protective film is formed in the predetermined region including the entire surface of the resistor and the extension portion such that, in a plan view, four corners of the glass protective film do not overlap the pair of surface electrodes and avoid both longitudinal edges of the surface of the insulating substrate; A low resistance chip resistor.

2. 2. The low resistance chip resistor according to claim 1, wherein the width of the extension portion gradually changes toward both ends of the insulating substrate in the longitudinal direction so as to approach the width of the resistor element.

3. A step of forming a lattice-like primary division groove and a secondary division groove perpendicular to each other on a surface of a large-sized insulating substrate for producing a large number of low-resistance chip resistors having standardized outer dimensions; forming a plurality of electrodes facing each other at a predetermined interval in a plurality of regions partitioned by the primary and secondary dividing grooves on the surface of the large-sized insulating substrate; forming a plurality of resistors so as to straddle the respective spaces between the plurality of electrodes disposed opposite to each other; forming a rectangular glass protective film that individually covers the entire surface of each of the plurality of resistors and a predetermined area including a connection portion between each of the plurality of resistors and each of the plurality of electrodes; forming a trimming groove in each of the plurality of resistors to adjust a resistance value after forming the glass protective film; dividing the large-sized insulating substrate along the primary dividing grooves to obtain rectangular substrates; forming end surface electrodes on the divided surfaces of the rectangular substrate; dividing the rectangular substrate on which the end surface electrodes are formed along the secondary division grooves to obtain individual chip resistors; Equipped with each of the plurality of electrodes and each of the plurality of resistors are formed in a direction of the primary division groove up to a position close to the secondary division groove within a range not exceeding a boundary of the glass protective film, Each of the plurality of electrodes includes an extension portion having a width dimension wider than the width dimension of the resistor body in the primary division groove direction at the connection portion, and a portion having a width dimension substantially the same as the width dimension of the resistor body and extending from the extension portion to an end portion of the single chip resistor in the secondary division groove direction, A manufacturing method for a low-resistance chip resistor, characterized in that in the specified region, the glass protective film is formed so that, when viewed in a plane, the four corners of the glass protective film do not overlap with each of the multiple electrodes and so as to avoid the secondary division grooves.

4. 4. The method for manufacturing a low resistance chip resistor according to claim 3, further comprising the step of forming a plurality of resin protective films extending in strip shapes along the primary division grooves.

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