Chip resistor

Abstract

The invention provides a chip resistor with excellent corrosion resistance. This chip resistor (1) is provided with: a rectangular parallelepiped-shaped insulating substrate (2); a pair of surface electrodes (3) provided on both end portions of the surface of the insulating substrate (2); a pair of rear surface electrodes (4) formed on both end portions of the rear surface of the insulating substrate (2); a resistor (5) that bridges the pair of surface electrodes (3); a second insulating layer (protective film 7) which is formed of a resin material and covers the resistor (5); a third insulating layer (auxiliary film 8) formed of a resin material and laminated on the second insulating layer 7; a pair of auxiliary electrode layers (9) that are formed from a resin material containing conductive particles and that are laminated on the surface electrode (3); a pair of end surface electrodes (10) extending on both end surfaces of the insulating substrate (2) and conducting between the corresponding auxiliary electrode layers (9) and the back surface electrodes (4); and a pair of external plating layers (11) provided so as to cover the surfaces of the auxiliary electrode layer (9) and the end surface electrode (10), the auxiliary electrode layer (9) being formed to a position covering the end surface of the third insulating layer (8), and the second insulating layer (7) containing more inorganic filler than the third insulating layer (8).

Description

Technical Field

[0001] The present invention relates to a surface mounting type chip resistor. Background Art

[0002] Typically, a chip resistor is mainly composed of the following components: an insulating substrate in the shape of a rectangular parallelepiped; a pair of surface electrodes, which are arranged opposite to each other at a specified interval on the surface of the insulating substrate; a resistor body, which bridges the paired surface electrodes to each other; an insulating protective film, which covers the resistor body; a pair of back electrodes, which are arranged opposite to each other at a specified interval on the back side of the insulating substrate; a pair of end electrodes, which conduct the surface electrode and the back electrode; and a pair of external plating layers covering these electrodes.

[0003] In this type of chip resistor, a metal material of the Ag (silver) series with low resistivity is usually used in the surface electrode, and an external plating layer is formed in a manner covering the surface electrode. However, highly corrosive sulfide gases and the like can easily invade from the gap at the boundary between the external plating layer and the protective film. Therefore, there is a risk that the surface electrode portion at the boundary between the surface electrode and the protective film is corroded by sulfide gases and the like, resulting in adverse conditions such as changes in resistance value and disconnection.

[0004] In the past, as disclosed in Patent Document 1, a chip resistor with improved sulfurization resistance was proposed, in which a protective electrode formed of a conductive resin material is formed by connecting to both a surface electrode and a protective film, an end face electrode is formed on the surface electrode and the protective electrode in a manner not in contact with the protective film, and an external plating layer is formed in a manner exceeding the boundary position between the protective electrode and the end face electrode and covering the end of the protective film.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent document 1: International Publication No. 2018 / 123419. Summary of the invention

[0008] Problem that the invention aims to solve

[0009] In the chip resistor disclosed in Patent Document 1, a protective film formed of an insulating resin material covers the resistor body, and a protective electrode is formed in contact with the upper surface of the end of the protective film, so that the protective electrode and the protective film are closely fitted. However, in general, in order to ensure heat resistance and mechanical strength to the heat generated by the resistor body, the resin material of the protective film contains inorganic fillers such as SiO2, and on the other hand, in order to ensure conductivity, the resin material of the protective electrode contains metal particles, so these inorganic fillers and metal particles impair the close fit between the protective electrode and the protective film. As a result, thermal stress generated by thermal cycles, etc., causes a gap to form at the interface between the protective electrode and the protective film, and there is a risk of sulfide gas entering from this portion.

[0010] The present invention has been made in view of the above-mentioned actual situation of the prior art, and an object of the present invention is to provide a chip resistor having excellent corrosion resistance.

[0011] Solutions for solving problems

[0012] In order to achieve the above-mentioned purpose, the chip resistor of the present invention is characterized in that it has: an insulating substrate of a rectangular shape; a pair of surface electrodes, which are arranged at both ends of the main surface of the insulating substrate; a resistor, which is arranged in a manner that its two ends overlap with the pair of surface electrodes; a protective film, which is formed of a resin material and is arranged in a manner to cover the resistor; an auxiliary film, which is formed of a resin material and is stacked on the protective film; a pair of auxiliary electrode layers, which are formed of a resin material containing conductive particles and are stacked on the surface electrodes; a pair of end face electrodes, which extend at least to the two end faces of the insulating substrate and are conductive to the auxiliary electrode layer; and an external plating layer, which covers the auxiliary electrode layer and the end face electrodes, the auxiliary electrode layer is formed to a position covering the end surface of the auxiliary film, and the protective film contains more inorganic filler than the auxiliary film.

[0013] In the chip resistor thus constructed, the auxiliary electrode layer formed of a resin material containing conductive particles is laminated on the surface electrode, and the auxiliary electrode layer is in contact with the upper surface of the end of the auxiliary film laminated on the protective film. The protective film formed of the resin material contains more inorganic fillers than the auxiliary film, so the resin component of the auxiliary film is relatively increased, and the close adhesion between the auxiliary electrode layer and the auxiliary film is improved. Therefore, even if thermal stress is generated due to thermal cycles, the auxiliary electrode layer is prevented from peeling off from the auxiliary film due to the thermal stress, so that the sulfide gas is difficult to penetrate into the interior from the interface between the auxiliary electrode layer and the auxiliary film, and the surface electrode can be prevented from being corroded by the sulfide gas.

[0014] In the above structure, when the resistor is provided with an adjustment groove for adjusting the resistance value, it is preferable to further include a glass layer covering the entire resistor including the connection portion between the surface electrode and the resistor, and to laminate a protective film on the glass layer.

[0015] In addition, in the above structure, the inorganic filler contained in the resin material of the auxiliary film only needs to be less than that in the protective film. However, when the content of inorganic filler contained in the resin material of the auxiliary film is zero or less than 10wt%, the resin component of the auxiliary film is greatly increased, thereby effectively improving the close adhesion between the auxiliary electrode layer and the auxiliary film.

[0016] Furthermore, in the above structure, the protective film and the auxiliary film may be made of different types of resin materials. However, when the protective film and the auxiliary film are made of the same type of resin material, the close contact between the auxiliary electrode layer and the auxiliary film is further improved.

[0017] Furthermore, in the above-mentioned structure, when the length along the short side direction of the insulating substrate is set as the width dimension, the width dimension of the auxiliary electrode layer is set to be wider than the width dimension of the surface electrode and narrower than the width dimension of the auxiliary film, the auxiliary electrode layer on which the plating material is easily formed is arranged in the area further inside than the long side end surface of the insulating substrate, so the plating material is also formed on the long side end surface of the insulating substrate to have the same film thickness as other parts. As a result, the local increase in film thickness, which is the main cause of the peeling of the external plating layer, does not occur, so the peeling of the external plating layer can be prevented.

[0018] In addition, in the above structure, the auxiliary film does not have to cover the entire surface of the protective film, but the shape of the auxiliary film is preferably set to be larger than the shape of the protective film. When the auxiliary film is formed in a manner covering the entire surface of the protective film, the close adhesion between the auxiliary electrode layer and the auxiliary film is improved.

[0019] Effects of the Invention

[0020] According to the present invention, it is possible to provide a chip resistor which prevents the auxiliary electrode layer from peeling off and has excellent corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a top view of a chip resistor according to an embodiment of the present invention.

[0022] Figure 2 For along Figure 1 Cross-sectional view along line II-II.

[0023] Figure 3 The figure is a top view showing the manufacturing process of the chip resistor.

[0024] Figure 4 The figure is a top view showing the manufacturing process of the chip resistor.

[0025] Figure 5 A cross-sectional view showing the manufacturing process of the chip resistor.

[0026] Figure 6 A cross-sectional view showing the manufacturing process of the chip resistor.

[0027] Figure 7 The following is a flow chart showing the manufacturing process of the chip resistor.

[0028] Figure 8 It is a cross-sectional view showing the mounted state of the chip resistor. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0030] Figure 1 is a cross-sectional view of a chip resistor according to an embodiment of the present invention, Figure 2 For along Figure 1 Cross-sectional view along line II-II.

[0031] like Figure 1 and Figure 2 As shown, the chip resistor 1 of this embodiment mainly includes: a rectangular insulating substrate 2; a pair of surface electrodes 3, which are arranged at the two ends of the long side direction of the upper surface of the insulating substrate 2; a pair of back electrodes 4, which are arranged at the two ends of the long side direction of the lower surface of the insulating substrate 2; a rectangular resistor 5, which is arranged in a manner that the two ends overlap with the pair of surface electrodes 3; a first insulating layer (glass layer) 6, which covers the entire resistor 5 including the connection part between the surface electrode 3 and the resistor 5; a second insulating layer (protective film) 7, which is stacked on the first insulating layer 6; a third insulating layer (auxiliary film) 8, which is stacked on the second insulating layer 7; a pair of auxiliary electrode layers 9, which are stacked on the surface electrode 3; a pair of end surface electrodes 10, which extend on the two end surfaces of the insulating substrate 2 to conduct between the corresponding surface electrodes 3 (and the auxiliary electrode layer 9) and the back surface electrode 4; and a pair of external plating layers 11, which are arranged in a manner that covers the surfaces of the auxiliary electrode layer 9 and the end surface electrodes 10.

[0032] The insulating substrate 2 is made of ceramic or the like, and is obtained by dividing a large sheet-like substrate described later along primary dividing grooves and secondary dividing grooves extending vertically and horizontally into a plurality of substrates.

[0033] The pair of surface electrodes 3 are formed by screen printing an Ag-based paste containing Pd, drying it, and firing it. These surface electrodes 3 are formed in a rectangular shape in a plan view at both ends of the long side direction of the upper surface of the insulating substrate 2. Figure 1 When the vertical direction (the vertical direction) is set as the width direction, the two ends of the surface electrode 3 in the width direction do not contact the long sides of the insulating substrate 2, and the width dimension of the surface electrode 3 is shorter than the width dimension of the insulating substrate 2.

[0034] A pair of back electrodes 4 are formed by screen printing Ag silver paste, drying it, and firing it. These back electrodes 4 are formed into a rectangular shape in a top view at both ends of the long side direction of the lower surface of the insulating substrate 2, and the width dimension of the back electrodes 4 is also shorter than the width dimension of the insulating substrate 2.

[0035] The resistor 5 is formed by screen-printing a resistor paste of ruthenium oxide or the like, drying it, and firing it, and both ends of the resistor 5 in the longitudinal direction overlap with the surface electrode 3. The resistor 5 is formed with an adjustment groove 5a for adjusting the resistance value.

[0036] The first insulating layer 6 is formed by screen-printing a glass paste, drying it, and firing it. The first insulating layer 6 is formed so as to cover the entire resistor 5 before forming the adjustment groove 5a.

[0037] The second insulating layer 7 is formed by screen printing a resin paste such as epoxy resin or phenolic resin and then heating and curing. The second insulating layer 7 is formed in a manner that covers the entire first insulating layer 6 after the adjustment groove 5a is formed, and both ends of the second insulating layer 7 in the width direction are in contact with the long sides of the insulating substrate 2. In addition, in order to ensure heat resistance and mechanical strength, the resin material of the second insulating layer 7 contains inorganic fillers such as SiO2 and Al2O3. The inorganic filler contained in the resin material of the second insulating layer 7 preferably has a high content. In the present embodiment, the content of the inorganic filler is set to a range of 20 to 40wt%, and the content of the inorganic filler can also be 40wt% or more.

[0038] The third insulating layer 8 is formed by screen printing a resin paste such as epoxy resin or phenolic resin and then heating and curing. The third insulating layer 8 is formed in a manner that covers the entire second insulating layer 7, and both ends of the third insulating layer 8 in the width direction are also connected to the long sides of the insulating substrate 2. That is, the dimension of the third insulating layer 8 in the long side direction is set to be longer than the dimension of the second insulating layer 7 in the long side direction, and the third insulating layer 8 covers the entire surface of the second insulating layer 7 including the connection portion with the surface electrode 3. The resin material of the third insulating layer 8 contains less inorganic filler than the second insulating layer 7, or does not contain inorganic filler at all (content = 0%). The content of inorganic filler contained in the resin material of the third insulating layer 8 is preferably in the range of 10wt% or less. In the present embodiment, the content of inorganic filler is set to a more preferred range of 5wt% or less.

[0039] In addition, the third insulating layer 8 does not need to cover the entire surface of the second insulating layer 7, and can also be formed on the surface of the second insulating layer 7 except for the connection portion with the surface electrode 3. In this case, the third insulating layer 8 is not in contact with the surface electrode 3, and the second insulating layer 7 is exposed between the two ends of the third insulating layer 8 and the surface electrode, but it is sufficient as long as the auxiliary electrode layer 9 covers the two ends of the third insulating layer 8 and is tightly attached.

[0040] The auxiliary electrode layer 9 is formed by screen printing and heat curing a resin paste such as epoxy resin or phenolic resin filled with conductive particles such as Ag, Cu, and Ni. The auxiliary electrode layer 9 is formed in a range from the upper surface of the surface electrode 3 to the middle of the upper surface of the third insulating layer 8, and the curved parts of the two ends of the third insulating layer 8 are covered by the auxiliary electrode layer 9. The resin materials of the auxiliary electrode layer 9 and the third insulating layer 8 can be different materials, but the auxiliary electrode layer 9 and the third insulating layer 8 are preferably formed of the same type of resin material. In addition, the auxiliary electrode layer 9 may not cover the entire upper surface of the surface electrode 3, and the auxiliary electrode layer 9 may be formed at an inner position separated from the end face of the insulating substrate 2 so that a part of the surface electrode 3 is exposed from between the end face of the insulating substrate 2 and the auxiliary electrode layer 9.

[0041] Here, the linear expansion coefficient of the third insulating layer 8 sandwiched between the second insulating layer 7 and the auxiliary electrode layer 9 is preferably a value between the linear expansion coefficient of the second insulating layer 7 and the linear expansion coefficient of the auxiliary electrode layer 9. In the present embodiment, the magnitude of the linear expansion coefficient is in the relationship of second insulating layer 7> third insulating layer 8> auxiliary electrode layer 9, or may be in the relationship of auxiliary electrode layer 9> third insulating layer 8> second insulating layer 7. In addition, from the perspective of the glass transition temperatures of the second insulating layer 7, the third insulating layer 8, and the auxiliary electrode layer 9, it is preferred that the glass transition temperatures of the second insulating layer 7 and the auxiliary electrode layer 9 are within the range of ±10% of the glass transition temperature of the third insulating layer 8.

[0042] The end surface electrode 10 is an electrode formed by sputtering Ni—Cr or the like, and the surface electrode 3 and the auxiliary electrode layer 9 separated from each other by the end surface of the insulating substrate 2 are connected to the back electrode 4. In addition, the upper surface of the auxiliary electrode layer 9 close to the third insulating layer 8 is not covered by the end surface electrode 10, and the inner part of the end surface of the back electrode 4 away from the insulating substrate 2 is not covered by the end surface electrode 10.

[0043] The external plating layer 11 is composed of a two-layer structure of an inner barrier layer 12 and an outer external connection layer 13. The barrier layer 12 is a Ni plating layer formed by electroplating, and the barrier layer 12 covers the entire surface of the end surface electrode 10 and the auxiliary electrode layer 9 and the back electrode 4 exposed from the end surface electrode 10. The external connection layer 13 is a Sn plating layer formed by electroplating, and the external connection layer 13 covers the entire surface of the barrier layer 12.

[0044] Next, refer to Figure 3 to Figure 7 , a method for manufacturing the chip resistor 1 constructed as described above is described. Figure 3 and Figure 4 FIG. 2 is a top view showing the manufacturing process of the chip resistor 1. Figure 5 and Figure 6 2 is a cross-sectional view showing a manufacturing process of the chip resistor 1. Figure 7 1 is a flowchart showing a manufacturing process of the chip resistor 1 .

[0045] First, if Figure 7 As shown in step S1, a large-sized substrate 2A is prepared that can be used to make a plurality of insulating substrates 2. The large-sized substrate 2A is provided with primary dividing grooves and secondary dividing grooves extending in a grid shape, and each grid divided by the two dividing grooves is used as a sheet forming area. Figure 3 to Figure 6 Although one sheet body forming region is representatively shown in the figure, in reality, there are a plurality of such sheet body forming regions arranged in a grid.

[0046] Then, after screen printing the Ag paste on the back side of the large-size substrate 2A, it is dried and then fired at 850°C, thereby forming a pair of opposite back electrodes 4 ( Figure 7 Then, after screen printing the Ag-Pd paste on the surface of the large-size substrate 2A, the Ag-Pd paste is dried and then fired at 850°C, so that Figure 3 (a) and Figure 5 As shown in (a), a pair of surface electrodes 3 ( Figure 7 In addition, the order of forming the surface electrode 3 and the back electrode 4 may be opposite to that described above, or the surface electrode 3 and the back electrode 4 may be formed simultaneously.

[0047] Next, a resistor paste containing ruthenium oxide or the like is screen-printed on the surface of the large-size substrate 2A, dried, and then fired at 850° C. Figure 3 (b) and Figure 5 As shown in (b), a rectangular resistor 5 is formed so that both ends overlap with the surface electrode 3 ( Figure 7 Step S4).

[0048] Next, after screen printing the glass paste on the area covering the resistor 5, the glass paste is dried and then fired at 600°C. Figure 3 (c) and Figure 5 As shown in (c), a first insulating layer 6 ( Figure 7 Then, by irradiating the first insulating layer 6 with laser light from above, an adjustment groove 5a is formed in the resistor 5 to adjust the resistance value.

[0049] Next, after the epoxy resin (or phenolic resin) paste is screen-printed from above the first insulating layer 6, it is heated and cured (sintered) at 200°C, so that Figure 3 (d) and Figure 5 As shown in (d), a second insulating layer 7 ( Figure 7 Step S6). In order to ensure heat resistance and mechanical strength, the resin material of the second insulating layer 7 contains an inorganic filler such as SiO2 and Al2O3 at a content of 20 to 40 wt%.

[0050] Next, after the epoxy resin (or phenolic resin) paste is screen-printed from above the second insulating layer 7, it is heated and cured at 200°C, so that Figure 4 (e) and Figure 6 As shown in (e), a third insulating layer 8 is formed to cover the entire second insulating layer 7 ( Figure 7 Step S7). The resin material of the third insulating layer 8 contains less inorganic filler than that of the second insulating layer 7, or contains no inorganic filler at all, and the content of the inorganic filler contained in the third insulating layer 8 is 10wt% or less (including zero).

[0051] Next, after screen printing a resin paste such as epoxy resin or phenolic resin filled with conductive particles (Ag-based, Cu-based, Ni-based, etc.), the paste is heated and cured at 200°C, thereby forming a conductive film. Figure 4 (f) and Figure 6 As shown in (f), auxiliary electrode layers 9 ( Figure 7 The auxiliary electrode layer 9 is formed in a range from the upper surface of the cover surface electrode 3 to the middle of the upper surface of the third insulating layer 8, and the curved portions at both ends of the third insulating layer 8 are covered by the auxiliary electrode layer 9.

[0052] The process so far is a batch process for large-size substrates 2A. In the next process, Figure 7 As shown in step S9, the large-size substrate 2A is broken once along the primary dividing groove (primary dividing) to obtain the strip substrate 2B.

[0053] Then, Ni-Cr is sputtered onto the split surfaces of the strip-shaped substrate 2B, thereby Figure 4 (g) and Figure 6 As shown in (g), a pair of end surface electrodes 10 ( Figure 7At this time, the end surface electrode 10 is formed into a U-shaped cross section in a manner of covering the auxiliary electrode layer 9 and the surface of the back electrode 4 close to the outer end, and the upper surface of the auxiliary electrode layer 9 close to the third insulating layer 8 is not covered by the end surface electrode 10, and the surface of the back electrode 4 close to the inner end is not covered by the end surface electrode 10.

[0054] Then, if Figure 7 As shown in step S11 , the strip substrate 2B is secondarily broken along the secondary dividing grooves (secondary dividing) to obtain a chip unit 2C having the same size as the chip resistor 1 .

[0055] Then, the individualized sheet-like monomer 2C is subjected to Ni electroplating to form a barrier layer 12 covering the end surface electrode 10. Next, the sheet-like monomer 2C is subjected to Sn electroplating to form an external connection layer 13 covering the barrier layer 12. Figure 4 (h) and Figure 6 As shown in (h), an external plating layer 11 ( Figure 7 Step S12), complete Figure 1 and Figure 2 The chip resistor 1 is shown.

[0056] like Figure 8 As shown, the chip resistor 1 manufactured in this way is mounted on the pads 101 of the circuit substrate 100 with the back surface of the insulating substrate 2 facing downward, and a pair of outer plating layers 11 are respectively bonded to the corresponding pads 101 via solder 102, thereby performing surface mounting.

[0057] As described above, in the chip resistor 1 of this embodiment, the auxiliary electrode layer 9 formed of a resin material containing conductive particles is stacked on the surface electrode 3, and the auxiliary electrode layer 9 is in contact with the upper surface of the end of the third insulating layer (auxiliary film) 8 stacked on the second insulating layer (protective film) 7. The second insulating layer 7 contains more inorganic fillers than the third insulating layer 8. Therefore, the heat resistance and mechanical strength can be ensured by the second insulating layer 7. At the same time, the resin component of the third insulating layer 8 is relatively increased, thereby improving the close adhesion between the auxiliary electrode layer 9 and the third insulating layer 8. As a result, Figure 8 In the installation state of the chip resistor 1 shown, even if thermal stress is generated due to thermal cycles, the peeling of the auxiliary electrode layer 9 from the third insulating layer 8 caused by the thermal stress is suppressed. Therefore, it is difficult for sulfide gas to penetrate into the interior from the interface between the auxiliary electrode layer 9 and the third insulating layer 8, and the surface electrode 3 can be prevented from being corroded by the sulfide gas.

[0058] Furthermore, in the chip resistor 1 of the present embodiment, when the length along the short side direction of the insulating substrate 2 is set as the width dimension, the width dimension of the auxiliary electrode layer 9 is set to be wider than the width dimension of the surface electrode 3 and narrower than the width dimension of the third insulating layer 8. As a result, the auxiliary electrode layer 9 on which the plating material is easily formed is arranged in a region further inside than the long side end face of the insulating substrate 2, so when electroplating is performed to form the barrier layer 12 and the external connection layer 13, the plating material can also form the same film thickness on the long side end face of the insulating substrate 2 as other parts. As a result, the local increase in the film thickness, which is the main cause of the peeling of the external plating layer 11, does not occur, so the peeling of the external plating layer 11 can be prevented.

[0059] In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the main purpose of the present invention, and all technical matters included in the technical ideas recorded in the claims are the objects of the present invention. The above-mentioned embodiments are only preferred examples, and those skilled in the art can realize various alternative examples, modified examples, variant examples or improved examples based on the contents disclosed in this specification, which are included in the technical scope recorded in the scope of the attached claims.

[0060] For example, in the case of a chip resistor that does not require adjustment of the resistance value of the resistor 5 , the first insulating layer (glass layer) 6 may be omitted, and the resistor 5 may be covered with two layers of the second insulating layer (protective film) 7 and the third insulating layer (auxiliary film) 8 .

[0061] In the above embodiment, the chip resistor 1 is described in which the back electrode 4 conductively connected to the front electrode 3 and the auxiliary electrode layer 9 is provided on the back surface of the insulating substrate 2. However, the present invention is also applicable to a chip resistor of a type not having such a back electrode.

[0062] Description of Reference Numerals

[0063] 1: Chip resistor;

[0064] 2: Insulating substrate;

[0065] 2A: Large size substrate;

[0066] 2B: strip substrate;

[0067] 2C: sheet monomer;

[0068] 3: Surface electrode;

[0069] 4: back electrode;

[0070] 5: resistor;

[0071] 5a: adjustment slot;

[0072] 6: first insulating layer (glass layer);

[0073] 7: Second insulating layer (protective film);

[0074] 8: the third insulating layer (auxiliary film);

[0075] 9: auxiliary electrode layer;

[0076] 10: end surface electrode;

[0077] 11: External plating;

[0078] 12: barrier layer;

[0079] 13: External connection layer.

Claims

1. A chip resistor, It is characterized in that have: An insulating substrate in the shape of a rectangular parallelepiped; a pair of surface electrodes disposed at both ends of the main surface of the insulating substrate; A resistor, which is arranged in such a way that both ends overlap with the pair of surface electrodes; A protective film, which is formed of a resin material and is provided in a manner of covering the resistor; an auxiliary film formed of a resin material and laminated on the protective film; a pair of auxiliary electrode layers, formed of a resin material containing conductive particles, and laminated on the surface electrode; a pair of end surface electrodes extending at least on both end surfaces of the insulating substrate and being electrically connected to the auxiliary electrode layer; and an external plating layer covering the auxiliary electrode layer and the end surface electrode, The auxiliary electrode layer is formed to a position covering an end surface of the auxiliary film, The protective film contains more inorganic filler than the auxiliary film.

2. The chip resistor according to claim 1, It is characterized in that The device further comprises a glass layer covering the entire resistor including a connection portion between the surface electrode and the resistor, wherein the protective film is stacked on the glass layer.

3. The chip resistor according to claim 1, It is characterized in that The content of the inorganic filler contained in the resin material of the auxiliary film is zero or less than 10 wt %.

4. The chip resistor according to claim 1, It is characterized in that The protection film and the auxiliary film are formed of the same type of resin material.

5. The chip resistor according to claim 1, It is characterized in that When the length along the short side direction of the insulating substrate is defined as the width dimension, the width dimension of the auxiliary electrode layer is set to be wider than the width dimension of the surface electrode and narrower than the width dimension of the auxiliary film.

6. The chip resistor according to claim 1, It is characterized in that The outer shape of the auxiliary film is set to be larger than the outer shape of the protective film, and the auxiliary film is formed to cover the entire surface of the protective film.

7. The chip resistor according to claim 1, It is characterized in that The device further comprises a back electrode provided on the back surface of the insulating substrate, wherein the end surface electrode is electrically connected to the back surface electrode.

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