Chip Resistors

Abstract

To provide a chip resistor having excellent corrosion resistance.SOLUTION: A chip resistor 1 of the present invention includes: a rectangular parallelepiped insulating substrate 2; a pair of front electrodes 3 formed on opposite ends of the front surface of the insulating substrate 2; a pair of back electrodes 4 formed on opposite ends of the back surface of the insulating substrate 2; a resistor 5 straddling over the pair of front electrodes; a first insulating layer 6 that is formed from a glass material and that covers the resistor 5; a second insulating layer 7 that is formed from a resin material and that is laminated on the first insulating layer 6; a pair of auxiliary electrode layers 8 that is formed from a highly sulfur-resistant material and that is laminated on the front electrodes 3; a pair of end-face electrodes 9 that extends on opposite end faces of the insulating substrate 2 and that enables electrical conduction between the auxiliary electrode layers 8 and the back electrodes 4; and outer plated layers 10 that cover the auxiliary electrode layers 8, the end-face electrodes 9, and the back electrodes 4. The first insulating layer 6 has projection parts 6a that are not covered with the second insulating layer 7 and that overlap the upper surfaces of the front electrodes 3. The auxiliary electrode layers 8 are formed so as to cover the front electrodes 3 and the projection parts 6a to reach the upper surface of the second insulating layer 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a surface mount type chip resistor. [Background technology]

[0002] Generally, a chip resistor is mainly composed of a rectangular insulating substrate, a pair of front electrodes arranged opposite each other with a predetermined distance on the surface of the insulating substrate, a pair of back electrodes arranged opposite each other with a predetermined distance on the back surface of the insulating substrate, a pair of end electrodes connecting the front electrodes and the back electrodes, a pair of external plating layers covering each of these electrodes, a resistive element bridging the pair of front electrodes, and an insulating protective film covering the resistive element.

[0003] In this type of chip resistor, the front electrode is usually made of a silver (Ag)-based metal material with low resistivity, and an external plating layer is formed to cover this front electrode. However, highly corrosive gases such as sulfuric acid gases can easily enter through the gap at the boundary between the external plating layer and the protective film, and the front electrode portion at the boundary between the front electrode and the protective film may be corroded by the sulfuric acid gases, resulting in problems such as changes in resistance value and breakage.

[0004] Conventionally, as disclosed in Patent Document 1, a chip resistor has been proposed in which a protective electrode is formed that connects to both the front electrode and the protective film, end electrodes are formed on the front electrode and the protective electrode so as not to contact the protective film, and an external plating layer is formed so as to extend beyond the boundary between the protective electrode and the end electrode and cover the end of the protective film, thereby improving the sulfurization resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 123419 Summary of the Invention [Problem to be solved by the invention]

[0006] In the chip resistor disclosed in Patent Document 1, the external plating layer is formed on a conductive protective electrode, which provides better adhesion than an insulating protective film. Moreover, the external plating layer and the protective electrode form a double shielding structure, which makes it possible to suppress the intrusion of sulfur gas into the front electrode.

[0007] However, since the protective electrode is formed along the slope of the end of the protective layer and the external plating layer is formed to cover this protective electrode, if the adhesion between the external plating layer and the protective electrode is reduced due to thermal stress caused by a heat cycle or the like, a gap will be formed at the boundary between the protective layer and the protective electrode, allowing sulfide gas and the like to enter through this part.

[0008] In addition, end electrodes are generally formed using a highly productive sputtering method, but if the sputtered particles during sputtering exceed the protective electrode and reach the top surface of the protective layer, the outer plating layer will be deposited up to that area. In this case, since the outer plating layer has low adhesion to the insulating protective layer, even if the protective electrode is formed inside the outer plating layer, the outer plating layer on the protective electrode is likely to peel off from the protective layer due to stress generated from the tip of the outer plating layer.

[0009] The present invention has been made in consideration of the above-mentioned current state of the prior art, and an object of the present invention is to provide a chip resistor having excellent corrosion resistance. . [Means for solving the problem]

[0010] In order to achieve the above object, the chip resistor of the present invention comprises an insulating substrate having a rectangular parallelepiped shape, a pair of front electrodes provided at both ends of the front surface of the insulating substrate, a pair of back electrodes provided at both ends of the back surface of the insulating substrate, a resistor provided so as to overlap both ends of the pair of front electrodes, a first insulating layer made of a glass material provided so as to cover the entire resistor including the connection portion between the front electrodes and the resistor, a second insulating layer made of a resin material laminated on the first insulating layer, and a pair of auxiliary electrodes laminated on the front electrodes and made of a material having a higher sulfur resistance than the front electrodes. the first insulating layer has a protrusion that is not covered by the second insulating layer and overlaps a portion of the upper surface of the front electrode, the auxiliary electrode layer is formed so as to cover at least the front electrode and the protrusion, and the maximum height position on the surface of the auxiliary electrode layer is set to be higher than the maximum height position on the surface of the second insulating layer.

[0011] In the chip resistor thus configured, the step from the top surface of the front electrode to the top surface of the second insulating layer is divided into a step from the top surface of the front electrode to the top surface of the protruding portion of the first insulating layer and a step from the top surface of the protruding portion of the first insulating layer to the top surface of the second insulating layer, and the height of each step is small, so that the auxiliary electrode layer can be formed in a stable shape in the portion including these steps. Also, by making the maximum height position on the surface of the auxiliary electrode equal to or higher than the maximum position on the surface of the second insulating layer, the shape is stabilized at the end of the auxiliary electrode layer overlapping the second insulating layer, so that stress concentration on the end of the auxiliary electrode layer is reduced, and peeling between the auxiliary electrode layer and the second insulating layer and peeling between the outer plating layer and the auxiliary electrode layer can be prevented.

[0012] In addition, this chip resistor has a structure in which the first insulating layer has a protruding portion that is not covered by the second insulating layer and overlaps the upper surface of the front electrode, and the second insulating layer is not in direct contact with the front electrode, so that even if sulfurizing gas penetrates from the interface between the auxiliary electrode layer and the second insulating layer, the sulfurizing gas is received by the protruding portion of the first insulating layer made of a glass material before it reaches the front electrode, thereby preventing the front electrode from being corroded by the sulfurizing gas. Note that sulfurizing gas tends to penetrate into the second insulating layer made of a resin material in a high humidity atmosphere, but even in that case, the sulfurizing gas that passes through the second insulating layer is received by the first insulating layer made of a glass material before it reaches the front electrode, thereby preventing the front electrode from being corroded by the sulfurizing gas.

[0013] In the above configuration, the auxiliary electrode layer may be formed of a material that is more resistant to sulfurization than the front electrode, and it is particularly preferable that the auxiliary electrode layer is made of a resin material containing conductive particles. Here, the conductive particles contained in the resin material are preferably metal particles such as silver (Ag) or nickel (Ni) or carbon particles, and either one of the metal particles or the carbon particles may be used alone, or both the metal particles and the carbon particles may be used in combination.

[0014] In this case, if the surface of the auxiliary electrode layer is roughened, the adhesive strength of the outer plating layer to the auxiliary electrode layer can be increased. In particular, when the auxiliary electrode layer is made of a carbon-based resin that does not contain metal particles, the adhesiveness of the auxiliary electrode layer to the first insulating layer and the second insulating layer can be increased, and the adhesiveness of the outer plating layer to the auxiliary electrode layer can be increased by the roughening treatment.

[0015] In the above configuration, the second insulating layer may be formed so that both ends overlap both the front electrode and the first insulating layer. However, if the second insulating layer is formed in a position where both ends do not overlap the front electrode, even if the sulfurizing gas penetrates into the second insulating layer made of a resin material, the path that the sulfurizing gas must travel to reach the front electrode is longer, making it possible to more reliably prevent corrosion of the front electrode. Moreover, the step between the first insulating layer and the second insulating layer is smaller, improving printability when forming the auxiliary electrode layer.

[0016] In the above configuration, the auxiliary electrode layer may have a single layer structure, but if the auxiliary electrode layer has a two-layer structure consisting of an upper auxiliary electrode layer and a lower auxiliary electrode layer and the upper auxiliary electrode layer is made of a conductive material having a higher electrical conductivity than the lower auxiliary electrode layer, the adhesive strength of the lower auxiliary electrode layer to the front electrode and the protruding portion of the first insulating layer can be increased, and the adhesive strength of the outer plating layer to the upper auxiliary electrode layer can be increased. In this case, it is preferable that the lower auxiliary electrode layer is made of a carbon-based resin material containing carbon particles, and the upper auxiliary electrode layer is made of a metal-based resin material containing metal particles.

[0017] In this case, if the top surface of the lower auxiliary electrode layer is set at a position lower than the top surface of the second insulating layer, the end shape of the upper auxiliary electrode layer formed from the lower auxiliary electrode layer to the top surface of the second insulating layer is stabilized, thereby reducing stress concentration at the ends between the second insulating layer and the auxiliary electrode layer and between the auxiliary electrode layer and the outer plating layer, and preventing peeling between the layers. Effect of the Invention

[0018] According to the present invention, it is possible to provide a chip resistor having excellent corrosion resistance by preventing peeling of the outer plating layer. [Brief description of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a chip resistor according to a first embodiment of the present invention. [Diagram 2] 5A to 5C are plan views showing a manufacturing process of the chip resistor. [Diagram 3] 3A to 3C are cross-sectional views showing a manufacturing process of the chip resistor. [Figure 4] FIG. 4 is a cross-sectional view of a chip resistor according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view of a chip resistor according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Below, the embodiments of the invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a chip resistor according to a first embodiment, FIG. 2 is a plan view showing a manufacturing process of the chip resistor, and FIG. 3 is a cross-sectional view showing the manufacturing process of the chip resistor.

[0021] As shown in FIG. 1, the chip resistor 1 according to the first embodiment is mainly composed of a rectangular insulating substrate 2, a pair of front electrodes 3 provided at both longitudinal ends of the upper surface of the insulating substrate 2, a pair of back electrodes 4 provided at both longitudinal ends of the lower surface of the insulating substrate 2, a rectangular resistor 5 provided so as to overlap both ends on the pair of front electrodes 3, a first insulating layer 6 covering the entire resistor 5 including the connection portion between the front electrodes 3 and the resistor 5, a second insulating layer 7 laminated on the first insulating layer 6, a pair of auxiliary electrode layers 8 laminated on the front electrodes 3, a pair of end electrodes 9 extending on both end surfaces of the insulating substrate 2 and providing electrical conduction between the corresponding auxiliary electrode layers 8 and the back electrodes 4, and a pair of external plating layers 10 provided so as to cover the auxiliary electrode layer 8, the end electrodes 9, and the back electrodes 4.

[0022] The insulating substrate 2 is made of ceramics or the like, and is obtained by dividing a large sheet-like substrate, which will be described later, along primary dividing grooves and secondary dividing grooves that extend lengthwise and widthwise into a large number of insulating substrates.

[0023] The front electrode 3 was prepared by screen printing an Ag (silver)-based paste containing Pd (palladium), followed by drying and firing.

[0024] The back electrode 4 is formed by screen printing and heat curing (baking) a resin paste filled with metal particles such as silver (Ag) or nickel (Ni) or carbon particles.

[0025] The resistor 5 is formed by screen printing a resistive paste such as ruthenium oxide, followed by drying and baking, and both longitudinal ends of the resistor 5 overlap the front electrodes 3. Although not shown, the resistor 5 has a trimming groove formed therein for adjusting the resistance value.

[0026] The first insulating layer 6 is formed by screen printing a glass paste, followed by drying and firing. The first insulating layer 6 is formed so as to cover the resistor 5 before the trimming groove is formed, and both ends of the first insulating layer 6 exposed from the resistor 5 form protrusions 6a. The protrusions 6a overlap flatly on the upper surface of the inner part of the front electrode 3 away from the end face of the insulating substrate 2.

[0027] The second insulating layer 7 is formed by screen printing an epoxy resin paste and then heat curing it. The second insulating layer 7 is formed so as to cover the first insulating layer 6 except for the protruding portion 6a after the trimming groove is formed.

[0028] The auxiliary electrode layer 8 is made by screen printing and heat-curing a resin paste filled with conductive particles of a material more resistant to sulfuration than the front electrode 3, specifically, silver (Ag), nickel (Ni), carbon, etc. The auxiliary electrode layer 8 covers the front electrode 3 and the protruding portion 6a of the first insulating layer 6 and is formed in an area reaching partway up the upper surface of the second insulating layer 7. The maximum height position on the surface of the auxiliary electrode layer 8 is equal to or higher than the maximum height position on the surface of the second insulating layer 7.

[0029] The end electrode 9 is formed by sputtering nickel (Ni) / chromium (Cr) or the like, and provides electrical continuity between the auxiliary electrode layer 8 and the back electrode 4, which are spaced apart from each other vertically, via the end face of the insulating substrate 2. The upper surface of the auxiliary electrode layer 8 close to the second insulating layer 7 is not covered by the end electrode 9, and the inner portion of the back electrode 4 away from the end face of the insulating substrate 2 is also not covered by the end electrode 9.

[0030] The external plating layer 10 has a two-layer structure consisting of a barrier layer 11 and an external connection layer 12, of which the barrier layer 11 is a Ni plating layer formed by electrolytic plating, and the external connection layer 12 is a Sn plating layer formed by electrolytic plating. The external plating layer 10 covers the entire surface of the end electrode 9 and the auxiliary electrode layer 8 exposed from the end electrode 9, as well as covering the back electrode 4 exposed from the end electrode 9.

[0031] Next, a method for manufacturing the chip resistor 1 configured as above will be described with reference to FIGS.

[0032] First, a large-sized substrate 2A is prepared in which primary and secondary dividing grooves extending in a lattice pattern are formed. These primary and secondary dividing grooves divide the front and back surfaces of the large-sized substrate 2A into numerous chip forming regions, and each of these chip forming regions becomes one insulating substrate 2. Although one chip forming region is representatively shown in Figures 2 and 3, in reality, many such chip forming regions are arranged in a lattice pattern.

[0033] Then, as shown in Figures 2(a) and 3(a), Ag-Pd paste is screen-printed on the surface of the large-sized substrate 2A, and then dried and fired to form a pair of surface electrodes 3 facing each other with a specified gap at both ends of the longitudinal direction of each chip formation area.

[0034] Next, as shown in Figures 2(b) and 3(b), a resistive paste containing ruthenium oxide or the like is screen-printed on the surface of the large-sized substrate 2A, and then dried and fired to form a rectangular resistor 5 with both ends overlapping the front electrodes 3.

[0035] 2(c) and 3(c), a glass paste is screen-printed in the area covering the resistor 5, and then dried and baked to form a first insulating layer 6 that covers the entire resistor 5, including the connection end with the front electrode 3. Then, a laser beam is irradiated from above this first insulating layer 6 to form a trimming groove (not shown) in the resistor 5 to adjust the resistance value.

[0036] 2(d) and 3(d), an epoxy resin paste is screen-printed on the first insulating layer 6 and then heat-cured (baked) to form a second insulating layer 7 covering the first insulating layer 6. At this time, the protrusions 6a formed at both ends of the first insulating layer 6 are exposed from the second insulating layer 7 and overlap flatly with the upper surface of the front electrode 3. Simultaneously or before or after this, a resin paste filled with a carbon-based conductive filler is screen-printed on the back surface of the large-format substrate 2A and then heat-cured to form a pair of opposing back electrodes 4 at a predetermined distance at both ends of the longitudinal direction of each chip formation region.

[0037] 2(e) and 3(e), a resin paste filled with a carbon-based conductive filler is screen-printed and heat-cured to form a pair of auxiliary electrode layers 8 covering the front electrode 3 and the protruding portion 6a of the first insulating layer 6, and then the surfaces of the auxiliary electrode layers 8 are roughened using an organic solvent, blasting, or the like. These auxiliary electrode layers 8 are formed in a range that extends beyond both ends of the second insulating layer 7 to reach the middle of the upper surface, so that the maximum height position on the surface of the auxiliary electrode layers 8 is equal to or higher than the maximum height position on the surface of the second insulating layer 7.

[0038] The steps up to this point have been a one-time process on the large-sized substrate 2A, but in the next step, the large-sized substrate 2A is primarily divided into strips along the primary dividing grooves to obtain strip-shaped substrates 2B whose width dimension is the longitudinal direction of the chip formation area.

[0039] Next, Ni / Cr is sputtered toward the divided surfaces of this rectangular substrate 2B to form a pair of end electrodes 9 that electrically connect the auxiliary electrode layer 8 and the back electrode 4, as shown in Figures 2(f) and 3(f). At this time, the end electrodes 9 are formed in a U-shape in cross section so as to cover the surfaces of the auxiliary electrode layer 8 and the back electrode 4 near the outer ends, but the upper surface of the auxiliary electrode layer 8 near the second insulating layer 7 is not covered by the end electrodes 9, and the surface of the back electrode 4 near the inner end is not covered by the end electrodes 9 either.

[0040] Next, the rectangular substrate 2B is secondarily divided along the secondary dividing grooves into a plurality of chip-like substrates 2C, and then these chip-like substrates 2C are subjected to electrolytic Ni plating to form a barrier layer 11 covering the end surface electrodes 9, as shown in Figures 2(g) and 3(g).

[0041] Thereafter, the chip-shaped substrate 2C is subjected to electrolytic Sn plating to form an external connection layer 12 that covers the barrier layer 11, as shown in Figures 2(h) and 3(h). This forms an external plating layer 10 having a two-layer structure of a Ni plating layer and a Sn plating layer, completing the chip resistor 1 shown in Figure 1.

[0042] As described above, in the chip resistor 1 according to the first embodiment, the step from the upper surface of the front electrode 3 to the upper surface of the second insulating layer 7 is divided into a step from the upper surface of the front electrode 3 to the upper surface of the protruding portion 6a of the first insulating layer 6 (i.e., the thickness of the protruding portion 6a) and a step from the upper surface of the protruding portion 6a of the first insulating layer 6 to the upper surface of the second insulating layer 7 (i.e., the thickness of the second insulating layer 7), and the height of each step is small, so that the auxiliary electrode layer 8 can be formed in a stable shape in the part including these steps. In addition, by setting the maximum height position on the surface of the auxiliary electrode 8 to be equal to or higher than the maximum position on the surface of the second insulating layer 7, the printability of the auxiliary electrode layer 8 is improved, and the shape is stabilized at the end of the auxiliary electrode layer 8 overlapping the second insulating layer 7, so that stress concentration at the end of the auxiliary electrode layer 8 is reduced, and peeling between the auxiliary electrode layer 8 and the second insulating layer 7 and peeling between the outer plating layer 10 and the auxiliary electrode layer 8 can be prevented.

[0043] In addition, in the chip resistor 1 according to the first embodiment, the first insulating layer 6 has a protruding portion 6a that is not covered by the second insulating layer 7 and overlaps the upper surface of the front electrode 3, and the second insulating layer 7 is not in direct contact with the front electrode 3. Therefore, even if sulfur gas enters from the interface between the auxiliary electrode layer 8 and the second insulating layer 7, the sulfur gas is received by the protruding portion 6a of the first insulating layer 6 made of a glass material before it reaches the front electrode 3, and the front electrode 3 can be prevented from being corroded by the sulfur gas. Note that the sulfur gas easily enters the inside of the second insulating layer 7 made of a resin material in a high humidity atmosphere, but even in this case, the sulfur gas that has passed through the inside of the second insulating layer 7 is received by the first insulating layer 6 made of a glass material before it reaches the front electrode 3, and therefore the front electrode 3 can be prevented from being corroded by the sulfur gas.

[0044] Furthermore, in the chip resistor 1 according to the first embodiment, the auxiliary electrode layer 8 is formed of a carbon-based resin material that does not contain metal particles, and the surface of the auxiliary electrode layer 8 covered with the barrier layer 11 is roughened, so that the adhesion of the auxiliary electrode layer 8 to the front electrode 3 and the protruding portion 6a of the first insulating layer 6 can be improved, and the adhesion of the barrier layer 11 (external plating layer 10) to the auxiliary electrode layer 8 can be improved. Note that, as long as the auxiliary electrode layer 8 is formed of a material that is more resistant to sulfurization than the front electrode 3, the auxiliary electrode layer 8 may be formed of a material other than a resin containing only carbon particles, such as a resin containing only metal particles such as silver (Ag) or nickel (Ni) or a resin containing both metal particles and carbon particles.

[0045] Furthermore, in the chip resistor 1 of the first embodiment, the back electrode 4 is formed from a material with high sulfur resistance (for example, a resin material filled with carbon particles), so that the sulfurization of the back electrode 4 is also prevented, resulting in a chip resistor 1 with excellent sulfur resistance.

[0046] FIG. 4 is a cross-sectional view of a chip resistor 20 according to the second embodiment, and parts corresponding to those in FIG. 1 are given the same reference numerals.

[0047] As shown in Figure 4, the chip resistor 20 of the second embodiment is formed in a position where both ends of the second insulating layer 7 do not overlap the front electrode 3, and the other configuration is basically the same as the chip resistor 1 of the first embodiment.

[0048] In the chip resistor 20 according to the second embodiment thus configured, both ends of the second insulating layer 7 are formed at positions that do not overlap the front electrode 3, so that even if sulfurizing gas penetrates into the second insulating layer 7 made of a resin material, the migration path of the sulfurizing gas until it reaches the front electrode 3 is longer, and corrosion of the front electrode 3 can be more reliably prevented. Moreover, the step from the upper surface of the protruding portion 6a of the first insulating layer 6 to the upper surface of the second insulating layer 7 is stepped by the portions of the first insulating layer 6 that overlap both ends of the resistor 5 (portions marked with reference numeral 6b in the figure), so that the step between the first insulating layer 6 and the second insulating layer 7 is smaller, and printability when forming the auxiliary electrode layer 8 can be improved.

[0049] FIG. 5 is a cross-sectional view of a chip resistor 30 according to a third embodiment, and parts corresponding to those in FIG. 1 are given the same reference numerals.

[0050] As shown in FIG. 5, the chip resistor 30 according to the third embodiment has an auxiliary electrode layer 8 having a two-layer structure consisting of a lower auxiliary electrode layer 31 and an upper auxiliary electrode layer 32, and the other configuration is basically the same as that of the chip resistor 1 according to the first embodiment.

[0051] Here, the top surface of the lower auxiliary electrode layer 31 is set at a position lower than the top surface of the second insulating layer 7, and the upper auxiliary electrode layer 32 is formed of a conductive material having higher electrical conductivity than the lower auxiliary electrode layer 31. Specifically, the lower auxiliary electrode layer 31 is formed of a carbon-based resin material containing carbon particles, and the upper auxiliary electrode layer 32 is formed of a metal-based resin material containing metal particles such as Ag and Ni.

[0052] In the chip resistor 30 of the third embodiment configured in this manner, the auxiliary electrode layer 8 has a two-layer structure consisting of a lower auxiliary electrode layer 31 and an upper auxiliary electrode layer 32, and the upper auxiliary electrode layer 32 is made of a conductive material having a higher electrical conductivity than the lower auxiliary electrode layer 31. Therefore, the adhesion strength of the lower auxiliary electrode layer 31 to the surface electrode 3 and the protrusion 6a of the first insulating layer 6 can be increased, and the adhesion strength of the barrier layer 11 (external plating layer 10) to the upper auxiliary electrode layer 32 can be increased.

[0053] Furthermore, in the chip resistor 30 according to the third embodiment, the upper surface of the lower auxiliary electrode layer 31 of the two-layered auxiliary electrode layer 8 is set at a position lower than the upper surface of the second insulating layer 7, so that the shape of the end of the upper auxiliary electrode layer 32 formed from the lower auxiliary electrode layer 31 to the upper surface of the second insulating layer 7 is stabilized. As a result, stress concentration at the end is reduced between the second insulating layer 7 and the auxiliary electrode layer 8 and between the auxiliary electrode layer 8 and the outer plating layer 10, and peeling between the layers can be prevented. [Explanation of symbols]

[0054] 1,20,30 Chip resistors 2. Insulating substrate 2A large board 2B Strip-shaped board 2C Chip-like substrate 3 Surface electrodes 4 Back electrode 5 Resistor 6 First insulating layer 6a Protrusion 7 Second insulating layer 8 Auxiliary electrode layer 9 End electrode 10 External plating layer 11 Barrier Layer 12 External Connection Layer 31 Lower auxiliary electrode layer 32 Upper auxiliary electrode layer

Claims

1. a pair of front electrodes provided on both ends of a front surface of the insulating substrate, a pair of back electrodes provided on both ends of a back surface of the insulating substrate, a resistor provided so as to overlap the pair of front electrodes at both ends, a first insulating layer made of a glass material provided so as to cover the entire resistor including a connection portion between the front electrode and the resistor, a second insulating layer made of a resin material laminated on the first insulating layer, a pair of auxiliary electrode layers laminated on the front electrodes and made of a material having higher resistance to sulfuration than the front electrodes, a pair of end electrodes extending at least on both end surfaces of the insulating substrate and conducting electrical current between the auxiliary electrode layer and the back electrode, and an external plating layer covering the auxiliary electrode layer, the end electrodes, and the back electrode, the first insulating layer has a protruding portion that is not covered by the second insulating layer and overlaps a portion of an upper surface of the front electrode, the auxiliary electrode layer is formed so as to cover at least the front electrode and the protruding portion, and the maximum height position on the surface of the auxiliary electrode layer is set to be equal to or higher than the maximum height position on the surface of the second insulating layer. A chip resistor characterized in that

2. The chip resistor according to claim 1 , wherein the auxiliary electrode layer is made of a resin material containing conductive particles.

3. 3. The chip resistor according to claim 2, wherein the conductive particles are either or both of metal particles and carbon particles.

4. 4. The chip resistor according to claim 2, wherein a surface of the auxiliary electrode layer is subjected to a roughening treatment.

5. The chip resistor according to claim 1 , wherein the second insulating layer is formed at a position such that both ends do not overlap the front electrodes.

6. 2. The chip resistor according to claim 1, wherein the auxiliary electrode layer comprises an upper auxiliary electrode layer and a lower auxiliary electrode layer, the upper auxiliary electrode layer being made of a conductive material having a higher electrical conductivity than the lower auxiliary electrode layer.

7. 7. The chip resistor according to claim 6, wherein the lower auxiliary electrode layer is made of a carbon-based resin material containing carbon particles, and the upper auxiliary electrode layer is made of a metal-based resin material containing metal particles.

8. 8. The chip resistor according to claim 6, wherein an upper surface of the lower auxiliary electrode layer is set at a position lower than an upper surface of the second insulating layer.

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