Chip resistor

Abstract

The present invention makes peel-off of an insulating film from an insulating substrate in a chip resistor less likely. A chip resistor (10) comprises an insulating substrate (1), a first upper surface electrode (411) and a second upper surface electrode (421), a resistance body (2), an insulating film (3), a first rear surface electrode (412) and a second rear surface electrode (422), a first end surface electrode (413), a second end surface electrode (423), a first plating film (414), and a second plating film (424). The first upper surface electrode (411) and the second upper surface electrode (421) are each disposed on a first main surface (81) of the insulating substrate (1). The insulating film (3) is disposed on a second main surface (82), of the insulating substrate (1), on the side opposite of that of the first main surface (81). The insulating film (3) contains a cured product of a hydroxyphenyl epoxy resin (A).

Description

Chip resistor

[0001] This disclosure relates to chip resistors used in various electronic devices.

[0002] Patent Document 1 discloses a chip-shaped electronic component comprising a substrate and an end-face electrode layer disposed on the end face of the substrate. Here, the end-face electrode layer is composed of a mixed material containing a conductive substance (a'), whisker-like particles (b) coated with the conductive substance (a'), conductive flake-like particles (c), and a tetrafunctional hydroxyphenyl type epoxy resin (d) having a molecular weight of 450 or more and less than 800, wherein the mass ratio of the flake-like particles (c) to the whisker-like particles (b) is 3 / 7 or more and 9 or less.

[0003] International Publication No. 2019 / 131352

[0004] In some cases, an insulating film is fabricated on the substrate of a chip-shaped electronic component as described above, and the insulating film is interposed between the substrate and the electrode. In this case, it is desirable that the insulating film be less likely to peel off from the substrate.

[0005] The object of this disclosure is to provide a chip resistor in which the insulating film is less likely to peel off from the insulating substrate.

[0006] A chip resistor according to one aspect of the present disclosure comprises an insulating substrate, a first upper electrode, a second upper electrode, a resistor, an insulating film, a first back electrode, a second back electrode, a first end electrode, a second end electrode, a first plating film, and a second plating film. The first upper electrode and the second upper electrode are each disposed on the first main surface of the insulating substrate. The resistor electrically connects the first upper electrode and the second upper electrode. The insulating film is disposed on the second main surface of the insulating substrate opposite to the first main surface. The first back electrode and the second back electrode are each disposed on the insulating film. The first end electrode is electrically connected to the first upper electrode and the first back electrode. The second end electrode is electrically connected to the second upper electrode and the second back electrode. The first plating film covers the first upper electrode, the first back electrode, and the first end electrode. The second plating film covers the second upper electrode, the second back electrode, and the second end electrode. The insulating film contains a cured product of a hydroxyphenyl-type epoxy resin (A).

[0007] According to this disclosure, it is possible to provide a chip resistor in which the insulating film is less likely to peel off from the insulating substrate.

[0008] Figure 1 is a cross-sectional view of a chip resistor according to an embodiment.

[0009] 1. Overview Embodiments of this disclosure will be described with reference to the figures. Note that the embodiments described below are only a part of the various embodiments of this disclosure. Furthermore, the embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. The figures referred to below are schematic diagrams, and the dimensional ratios of the components in the figures do not necessarily reflect the actual dimensional ratios. The arrows indicating direction in the drawings are not intended to define the direction in which the chip resistor 10 is used, but are merely included to make the explanation easier to understand and do not have any actual meaning. In this disclosure, the vertical direction is also called the thickness direction, and viewing along the thickness direction is called a plan view.

[0010] Figure 1 is a cross-sectional view of a chip resistor 10 according to an embodiment. The chip resistor 10 according to the embodiment comprises an insulating substrate 1, a first upper electrode 411, a second upper electrode 421, a resistor 2, an insulating film 3, a first back electrode 412, a second back electrode 422, a first end electrode 413, a second end electrode 423, a first plating film 414, and a second plating film 424. The first upper electrode 411 and the second upper electrode 421 are each arranged on the first main surface 81 of the insulating substrate 1. The resistor 2 electrically connects the first upper electrode 411 and the second upper electrode 421. The insulating film 3 is arranged on the second main surface 82 of the insulating substrate 1, opposite to the first main surface 81. The first back electrode 412 and the second back electrode 422 are each arranged on the insulating film 3. The first end electrode 413 is electrically connected to the first upper electrode 411 and the first back electrode 412. The second end electrode 423 is electrically connected to the second top electrode 421 and the second back electrode 422. The first plating film 414 covers the first top electrode 411, the first back electrode 412, and the first end electrode 413. The second plating film 424 covers the second top electrode 421, the second back electrode 422, and the second end electrode 423. The insulating film 3 contains a cured product of hydroxyphenyl type epoxy resin (A). Because the chip resistor 10 according to the embodiment has the above configuration, the insulating film 3 is less likely to peel off from the insulating substrate 1. The reason why the chip resistor 10 according to the embodiment can exhibit the above effect has not been precisely revealed, but it is presumed to be due to the following reasons.

[0011] When the temperature of the cured hydroxyphenyl epoxy resin (A) is lowered, the storage modulus of the cured hydroxyphenyl epoxy resin (A) does not tend to become excessively high. Therefore, even if the ambient temperature in which the chip resistor 10 is placed becomes lower, the insulating film 3 can easily follow the deformation of the insulating substrate 1 due to temperature changes.

[0012] Furthermore, when the temperature of the cured hydroxyphenyl epoxy resin (A) is increased, the storage modulus of the cured hydroxyphenyl epoxy resin (A) does not change significantly. Therefore, even if the ambient temperature in which the chip resistor 10 is placed becomes higher, the difference in thermal expansion between the insulating substrate 1 and the insulating film 3 is easily mitigated.

[0013] Thus, even if the ambient temperature in which the chip resistor 10 is placed changes, the chip resistor 10 can exhibit the above-mentioned effect due to the cured product of the hydroxyphenyl-type epoxy resin (A). Therefore, in this embodiment, it is presumed that the insulating film 3 is less likely to peel off from the insulating substrate 1. A chip resistor 10 equipped with such an insulating film 3 can have high reliability even under harsh conditions. For example, even if the chip resistor 10 according to this embodiment is placed in an environment where the temperature repeatedly changes from relatively low temperatures (e.g., -55°C) to relatively high temperatures (e.g., 200°C), peeling of the insulating film 3 from the insulating substrate 1 is suppressed, and the performance of the chip resistor 10 can be maintained.

[0014] 2. A chip resistor 10 according to a detailed embodiment will be described with reference to the drawings.

[0015] 2.1 Configuration of Chip Resistors The specific components of the chip resistor 10 according to the embodiment will be described below.

[0016] (Insulating Substrate) The chip resistor 10 includes an insulating substrate 1. The insulating substrate 1 has a rectangular shape when viewed from above. Therefore, the insulating substrate 1 has two opposing surfaces in the thickness direction, namely a first main surface 81 and a second main surface 82 on the opposite side of the first main surface 81. The distance between the first main surface 81 and the second main surface 82 is the thickness of the insulating substrate 1. For example, the thickness of the insulating substrate 1 is 100 μm or more and 600 μm or less.

[0017] In this embodiment, the insulating substrate 1 is made of alumina (Al ２ O ３ The insulating substrate 1 contains a sintered body. In addition, the insulating substrate 1 may contain components other than the alumina sintered body. The content of the alumina sintered body in the insulating substrate 1 is preferably 96% by mass or more, more preferably 99% by mass or more, and even more preferably 100% by mass.

[0018] (Electrodes) In this embodiment, the chip resistor 10 includes a first upper electrode 411 and a second upper electrode 421. Each of the first upper electrode 411 and the second upper electrode 421 is arranged on the first main surface 81 of the insulating substrate 1. For example, each of the first upper electrode 411 and the second upper electrode 421 is electrically connected to each of the left and right ends of the resistor 2. Each of the first upper electrode 411 and the second upper electrode 421 also contains a metal. For example, the metal includes at least one selected from the group consisting of silver, copper, gold, nickel, tin, and palladium. Each of the first upper electrode 411 and the second upper electrode 421 can be formed (film-formed) by sputtering the metal material. Alternatively, they may be formed from a conductive paste containing the metals mentioned above. In this case, the conductive paste includes at least one selected from the group consisting of a resin component and a glass component, in addition to the metal.

[0019] In this embodiment, the chip resistor 10 includes a first back electrode 412 and a second back electrode 422. Each of the first back electrode 412 and the second back electrode 422 is arranged on the second main surface 82 of the insulating substrate 1. Note that each of the first back electrode 412 and the second back electrode 422 does not have to be in direct contact with the second main surface 82. In this embodiment, each of the first back electrode 412 and the second back electrode 422 is arranged on the second main surface 82 of the insulating substrate 1 so as to be in direct contact with the insulating film 3 arranged on the second main surface 82.

[0020] In this embodiment, the chip resistor 10 includes a first end electrode 413 electrically connected to a first top electrode 411 and a first back electrode 412, and a second end electrode 423 electrically connected to a second top electrode 421 and a second back electrode 422. Each of the first end electrode 413 and the second end electrode 423 is positioned to cover the left-right edges of the insulating substrate 1. Each of the first end electrode 413 and the second end electrode 423 is formed from a conductive paste containing a resin component, carbon particles, and silver powder. The resin component includes at least one selected from the group consisting of phenoxy resin and epoxy resin, etc. The carbon particles can increase the conductivity of the first end electrode 413 and the second end electrode 423. The silver powder includes at least one selected from the group consisting of, for example, whisker-shaped silver powder, flake-shaped silver powder, etc., whose surfaces are coated with a silver conductive film. The whisker-shaped silver powder can increase the deflection strength of the first end electrode 413 and the second end electrode 423. The flake-shaped silver powder can improve the adhesion between the first end electrode 413 and the first plating film 414, which will be described later. The flake-shaped silver powder can also improve the adhesion between the second end electrode 423 and the second plating film 424, which will be described later.

[0021] In this embodiment, the chip resistor 10 comprises a first plating film 414 covering a first top electrode 411, a first back electrode 412, and a first end electrode 413, and a second plating film 424 covering a second top electrode 421, a second back electrode 422, and a second end electrode 423.

[0022] For example, the first plating film 414 includes a first intermediate electrode and a first external electrode covering the first intermediate electrode. The first intermediate electrode is manufactured by Ni plating. The first intermediate electrode covers the first upper electrode 411, the first back electrode 412, and the first end electrode 413. The first external electrode is manufactured by Sn plating. The first external electrode covers the first upper electrode 411, the first back electrode 412, and the first end electrode 413 via the first intermediate electrode. The second plating film 424 includes a second intermediate electrode and a second external electrode covering the second intermediate electrode. The second intermediate electrode is manufactured by Ni plating. The second intermediate electrode covers the second upper electrode 421, the second back electrode 422, and the second end electrode 423. The second external electrode is manufactured by Sn plating. The second external electrode covers the second upper electrode 421, the second back electrode 422, and the second end electrode 423 via the second intermediate electrode.

[0023] (Resistor) The chip resistor 10 comprises a resistor 2. The resistor 2 is electrically connected to the first upper electrode 411 and the second upper electrode 421. The resistor 2 is placed on the first main surface 81 of the insulating substrate 1. The shape of the resistor 2 in plan view is, for example, rectangular. The resistor 2 is made of, for example, RuO ２ It is composed of AgPd, CuNi, etc.

[0024] In this embodiment, for example, the resistor 2 can be formed from a thin-film conductor obtained by a thin-film process. In other words, the chip resistor 10 according to this embodiment is a thin-film chip resistor. For example, the thickness of the resistor 2 is, for example, 10 nm or more and 1000 nm or less. In this case, the effects of the embodiment are particularly easily demonstrated.

[0025] (Insulating Film) The chip resistor 10 is provided with an insulating film 3 on its second main surface 82. The insulating film 3 contains a cured product of hydroxyphenyl type epoxy resin (A).

[0026] The thickness of the insulating film 3 is preferably 10 μm or more and 100 μm or less. In this case, the insulating film 3 is less likely to peel off from the insulating substrate 1. A thickness of 20 μm or more is more preferable. Furthermore, a thickness of 40 μm or less is even more preferable.

[0027] The number average molecular weight of the hydroxyphenyl-type epoxy resin (A) is preferably 450 or more and 800 or less. In this case, both the rigidity and flexibility of the cured product of the hydroxyphenyl-type epoxy resin (A) are enhanced. As a result, fatigue fracture of the insulating film 3 becomes less likely.

[0028] The hydroxyphenyl-type epoxy resin (A) preferably has two or more epoxy groups in one molecule, more preferably three or more, and even more preferably four or more. In other words, the hydroxyphenyl-type epoxy resin (A) preferably contains a tetrafunctional hydroxyphenyl-type epoxy resin (A1). For example, the tetrafunctional hydroxyphenyl-type epoxy resin (A1) contains a compound represented by formula (1).

[0029]

[0030] In the embodiment, it is preferable that the storage modulus of the cured product of the hydroxyphenyl-type epoxy resin (A) satisfies a specific range. Specifically, in a temperature range of 25°C or higher and 200°C or lower, the storage modulus of the cured product of the hydroxyphenyl-type epoxy resin (A) is 1.0 × 10⁻⁶. ７ Pa or higher and 1.5 × 10 ８ It is preferable that the pressure be Pa or less. In this case, the insulating film 3 becomes less likely to peel off from the insulating substrate 1.

[0031] Furthermore, from the viewpoint of suppressing the peeling of the insulating film 3 from the insulating substrate 1, it is preferable that the storage modulus of the cured hydroxyphenyl epoxy resin (A) does not change significantly even when there is a change in the temperature at which the cured hydroxyphenyl epoxy resin (A) is placed. In the embodiment, as the temperature at which the cured hydroxyphenyl epoxy resin (A) is placed increases, the storage modulus of the cured hydroxyphenyl epoxy resin (A) may decrease gradually. In this case, it is preferable that the difference between the storage modulus of the cured hydroxyphenyl epoxy resin (A) at 50°C and the storage modulus of the cured hydroxyphenyl epoxy resin (A) at 200°C is 50 MPa or less. In this case, the insulating film 3 becomes even less likely to peel off from the insulating substrate 1.

[0032] For example, the insulating film 3 is produced from a resin composition containing a hydroxyphenyl-type epoxy resin (A) (hereinafter, also referred to as composition (M)). For example, the composition (M) contains an inorganic filler (B) in addition to the hydroxyphenyl-type epoxy resin (A). In other words, the insulating film 3 may contain the inorganic filler (B) in addition to a cured product of the hydroxyphenyl-type epoxy resin (A).

[0033] For example, the inorganic filler (B) contains at least one selected from the group consisting of titanium oxide, talc, Aerosil, kaolin, calcium carbonate, barium sulfate, mica, and potassium titanate. It is preferable that the inorganic filler (B) contains at least one selected from the group consisting of titanium oxide, talc, and Aerosil.

[0034] Further, when the inorganic filler (B) contains at least one selected from the group consisting of titanium oxide, talc, and Aerosil, the content of these components is preferably adjusted within a specific range. The content of titanium oxide relative to 100 parts by mass of the hydroxyphenyl-type epoxy resin (A) is preferably 38 parts by mass or more and 76 parts by mass or less. The content of talc relative to 100 parts by mass of the hydroxyphenyl-type epoxy resin (A) is preferably 50 parts by mass or more and 86 parts by mass or less. The content of Aerosil relative to 100 parts by mass of the hydroxyphenyl-type epoxy resin (A) is preferably 4 parts by mass or more and 14 parts by mass or less. In this case, the insulating film 3 becomes more difficult to peel from the insulating substrate 1.

[0035] In addition, the composition (M) may contain at least one selected from the group consisting of a curing agent (C), a solvent (D), a curing catalyst (E), and an antifoaming agent (F), in addition to the hydroxyphenyl-type epoxy resin (A), or the hydroxyphenyl-type epoxy resin (A) and the inorganic filler (B).

[0036] For example, the curing agent (C) comprises at least one selected from the group consisting of imidazole-based curing agents such as phenylimidazole and cyanoimidazole, and dicyandiamide. When the curing agent (C) contains both an imidazole-based curing agent and dicyandiamide at the same time, curing of the composition (M) can be promoted. The content of the curing agent (C) is not particularly limited, but is 1 part by mass or more and 10 parts by mass or less relative to 100 parts by mass of the hydroxyphenyl-type epoxy resin (A).

[0037] For example, the solvent (D) is not particularly limited, but comprises at least one selected from the group consisting of ether solvents such as ethyl carbitol and butyl carbitol acetate, and alcohol solvents such as benzyl alcohol.

[0038] For example, the curing catalyst (E) comprises at least one selected from the group consisting of tin-based curing catalysts typified by dioctyltin dilaurate and stannous 2-ethylhexanoate, and phosphorus-based curing catalysts typified by triphenylphosphine and tri-p-tolylphosphine.

[0039] For example, the composition (M) is produced by forming a mixed material containing the above-listed components into a uniform paste using a kneading apparatus. Examples of the kneading apparatus include a kneader mixer, a planetary mixer, and a three-roll mill.

[0040] (Protective Film) For example, the chip resistor 10 includes a protective film 6. In the embodiment, the protective film 6 comprises an inorganic protective layer 62 and a resin layer 63 disposed on the inorganic protective layer 62.

[0041] The inorganic protective layer 62 is disposed so as to cover a part of the resistor 2. The inorganic protective layer 62 is in direct contact with the resistor 2. Further, the inorganic protective layer 62 is disposed so as to cover a part of the first upper surface electrode 411 and a part of the second upper surface electrode 421. That is, when viewed in plan, the inorganic protective layer 62 covers the connection portions between the resistor 2 and each of the first upper surface electrode 411 and the second upper surface electrode 421. In this case, fluctuations in the resistance value of the resistor 2 can be suppressed.

[0042] The inorganic protective layer 62 is formed of an inorganic material. Examples of inorganic materials include glass materials, metal oxides, and metal nitrides. Examples of glass materials include crystal glass and quartz glass. Examples of metal oxides include Al ２ O ３ Examples include alumina.

[0043] The resin layer 63 can protect the resistor 2 and the inorganic protective layer 62. For example, the resin layer 63 is arranged to cover the entire inorganic protective layer 62, in which case fluctuations in the resistance value of the resistor 2 can be suppressed.

[0044] The resin layer 63 is formed from a resin composition containing a resin component such as epoxy resin. In addition to the resin component, the resin composition may also contain at least one selected from the group consisting of silica particles and silicone rubber particles. In this case, the stress generated in the resin layer 63 due to heat, etc., can be relieved compared to the case where the resin layer 63 is formed from resin components alone. As a result, the resin layer 63 becomes less likely to peel off from the inorganic protective layer 62.

[0045] 2.2 Method for Manufacturing Chip Resistors A brief description will be given of the method for manufacturing the chip resistor 10 according to the embodiment.

[0046] First, a thin film conductor is formed on the first main surface 81 of the insulating substrate 1 by a thin-film process such as sputtering. Then, a resistor 2 is formed by removing the unnecessary portion of the thin film conductor by a photolithography process.

[0047] Next, the first upper electrode 411 and the second upper electrode 421 are formed on the resistor 2 by sputtering a CuNi alloy layer.

[0048] Next, a protective film 6 is formed. First, an inorganic protective layer 62 is formed by sputtering an inorganic material to cover the resistor 2. Subsequently, an epoxy resin composition is applied to the inorganic protective layer 62, and the epoxy resin composition is heated and cured. This forms a resin layer 63 that covers the inorganic protective layer 62.

[0049] Subsequently, the composition (M) is applied onto the second main surface 82 of the insulating substrate 1, and is heated and cured to form the insulating film 3 on the second main surface 82. When the composition (M) contains a solvent, the solvent can be removed by heating the composition (M).

[0050] Next, a first back electrode 412 and a second back electrode 422 are respectively formed on the insulating film 3. Subsequently, a first end face electrode 413 and a second end face electrode 423 are respectively formed on each of the left and right side surfaces of the insulating substrate 1. The first back electrode 412, the second back electrode 422, the first end face electrode 413, and the second end face electrode 423 are all formed by sputtering a CuNi alloy.

[0051] Then, a first plating film 414 covering the first upper surface electrode 411, the first back electrode 412, and the first end face electrode 413, and a second plating film 424 covering the second upper surface electrode 421, the second back electrode 422, and the second end face electrode 423 are formed. In the present embodiment, Ni plating is performed so as to cover each of the first end face electrode 413 and the second end face electrode 423, thereby forming a first intermediate electrode and a second intermediate electrode, respectively. Further, Sn plating is performed so as to cover each of the first intermediate electrode and the second intermediate electrode, thereby forming a first external electrode and a second external electrode, respectively.

[0052] According to such a procedure, the chip resistor 10 according to the embodiment can be manufactured. Note that the above method is merely an example of a method for manufacturing the chip resistor 10 according to the embodiment.

[0053] 2.3 Modified Example A modified example of the chip resistor 10 will be described. Note that the modified example is an example of a variation in which the configuration of the embodiment is partially changed, added, or deleted. Also, with regard to the modified example, descriptions of configurations that are the same as those of the chip resistor 10 of the embodiment will be omitted.

[0054] In the embodiment, the insulating substrate 1 contains alumina (Al ２ O ３ ) sintered body, but is not limited thereto. For example, the insulating substrate 1 contains alumina (Al ２ O ３It may also contain a sintered body of a different metal oxide than alumina (Al). ２ O ３ In addition to sintered bodies, aluminum nitride (AlN), zirconia (ZrO ２ ) and silicon nitride (Si ３ Ni ４ It contains at least one sintered body selected from the group consisting of the following:

[0055] In this embodiment, the first intermediate electrode and the second intermediate electrode are each made by Ni plating, and the first external electrode and the second external electrode are each made by Sn plating, but the invention is not limited to this. That is, each of the first plating film 414 and the second plating film 424 may contain, in addition to nickel (Ni) and tin (Sn), at least one element selected from the group consisting of copper (Cu), chromium (Cr), lead (Pb), zinc (Zn), indium (In), bismuth (Bi), gold (Au), silver (Ag), palladium (Pd), and platinum (Pt).

[0056] In the embodiment, composition (M) contained a hydroxyphenyl-type epoxy resin (A), but for example, composition (M) may contain a resin different from the hydroxyphenyl-type epoxy resin (A), as long as it does not impair the effects of the embodiment. In this case, the insulating film 3 contains a cured product of a resin different from the hydroxyphenyl-type epoxy resin (A) in addition to the cured product of the hydroxyphenyl-type epoxy resin (A).

[0057] The present disclosure will be described in detail below with reference to examples. However, the present disclosure is not limited to the following examples.

[0058] 1. Method for Preparing Evaluation Samples Gold paste was applied to the first main surface of an insulating substrate (alumina sintered substrate), and this was fired at 850°C for 5 minutes to form the first upper electrode. Subsequently, a thin film conductor was formed by a thin-film process such as sputtering, covering the first main surface and the first upper electrode of the insulating substrate. Then, a resistor with a thickness of 12 nm was formed by removing the unnecessary parts of the thin film conductor using a photolithography process. Next, an inorganic protective layer was formed by sputtering an inorganic material (alumina) onto the resistor. Then, a conductive paste containing silver was applied onto the resistor and fired to form the second upper electrode. Subsequently, a resin composition was applied to the second main surface of the insulating substrate 1 (the surface opposite to the surface on which the resistor was placed), and this was heated at 200°C for 1 hour to produce an insulating film. Evaluation samples were prepared according to this method.

[0059] Table 1 shows the composition of the resin compositions used to fabricate the insulating film. Fifteen identical evaluation samples were prepared for each type of resin composition, and these were evaluated.

[0060] The details of the components contained in the resin composition are shown below.

[0061] (Hydroxyphenyl-type epoxy resin) Hydroxyphenyl-type epoxy resin #1: A tetrafunctional hydroxyphenyl-type epoxy resin with a number average molecular weight of approximately 620.

[0062] (A resin different from hydroxyphenyl-type epoxy) Epoxy / bismaleimide / triazine resin #1.

[0063] (Inorganic filler) Titanium oxide #1.

[0064] Talc #1.

[0065] Aerosil #1.

[0066] (Hardening agent) Hardening agent #1: Imidazole.

[0067] (Solvent) Solvent #1: Ethyl carbitol.

[0068] 2. Evaluation (Heat Cycle Test) A heat cycle test was performed on the evaluation samples. First, the evaluation samples were placed in a liquid-bath type heat cycle tester (ESPEC Corporation, liquid-bath thermal shock device, model TSB-51) and subjected to 3000 cycles of repeated temperature history between a low temperature state (-55°C x 30 minutes) and a high temperature state (155°C x 30 minutes). After that, the number of evaluation samples in which the insulating film had peeled off from the insulating substrate was checked, and evaluation samples in which the insulating film had peeled off from the insulating substrate were deemed unacceptable. This evaluation was performed similarly on 15 samples. The evaluation was performed according to the following criteria, and the results are shown in Table 1.

[0069] A: 0 unsuccessful samples B: Less than 20% of samples were unsuccessful C: More than 20% of samples were unsuccessful Table 1 shows the number of unsuccessful samples relative to the number of samples evaluated.

[0070]

[0071] (Aspects) As is clear from the embodiments described above, this disclosure includes the following aspects. Hereafter, reference numerals are enclosed in parentheses solely to indicate their correspondence with the embodiments.

[0072] A chip resistor (10) according to a first aspect of the present disclosure comprises an insulating substrate (1), a first upper electrode (411), a second upper electrode (421), a resistor (2), an insulating film (3), a first back electrode (412), a second back electrode (422), a first end electrode (413), a second end electrode (423), a first plating film (414), and a second plating film (424). The first upper electrode (411) and the second upper electrode (421) are each arranged on the first main surface (81) of the insulating substrate (1). The resistor (2) electrically connects the first upper electrode (411) and the second upper electrode (421). The insulating film (3) is arranged on the second main surface (82) of the insulating substrate (1) opposite to the first main surface (81). The first back electrode (412) and the second back electrode (422) are each placed on the insulating film (3). The first end electrode (413) is electrically connected to the first top electrode (411) and the first back electrode (412). The second end electrode (423) is electrically connected to the second top electrode (421) and the second back electrode (422). The first plating film (414) covers the first top electrode (411), the first back electrode (412), and the first end electrode (413). The second plating film (424) covers the second top electrode (421), the second back electrode (422), and the second end electrode (423). The insulating film (3) contains a cured product of hydroxyphenyl type epoxy resin (A).

[0073] According to this embodiment, a chip resistor (10) is provided in which peeling between the insulating substrate (1) and the insulating film (3) is less likely to occur.

[0074] In the first embodiment, the chip resistor (10) according to a second aspect of the present disclosure has a storage modulus of 5.0 × 10⁻¹⁰ of the cured hydroxyphenyl epoxy resin (A) in a temperature range of 25°C to 200°C. ７ Pa or higher and 1.5 × 10 ８ It is less than or equal to Pa.

[0075] A chip resistor (10) according to a third aspect of the present disclosure, in the first or second aspect, further comprises an inorganic filler (B) in which the insulating film (3) includes at least one selected from the group consisting of titanium oxide, talc, and aerosil.

[0076] In the fourth aspect of the present disclosure, the chip resistor (10) has, in the third aspect, a titanium oxide content of 38 parts by mass or more and 76 parts by mass or less per 100 parts by mass of hydroxyphenyl type epoxy resin (A).

[0077] In the fifth aspect of the present disclosure, the chip resistor (10) has, in the third aspect, a talc content of 50 parts by mass or more and 86 parts by mass or less per 100 parts by mass of hydroxyphenyl type epoxy resin (A).

[0078] In the sixth aspect of the present disclosure, the chip resistor (10) has, in the third aspect, an aerosil content of 4 parts by mass or more and 14 parts by mass or less per 100 parts by mass of hydroxyphenyl-type epoxy resin (A).

[0079] The chip resistor of this disclosure makes it difficult for the insulating film to peel off from the insulating substrate. Therefore, the chip resistor of this disclosure has improved durability and can be used under harsh temperature conditions. Thus, the chip resistor of this disclosure is industrially useful.

[0080] 1 Insulating substrate 2 Resistor 3 Insulating film 10 Chip resistor 411 First top electrode 412 First back electrode 413 First end electrode 414 First plating film 421 Second top electrode 422 Second back electrode 423 Second end electrode 424 Second plating film 81 First main surface 82 Second main surface

Claims

1. A chip resistor comprising: an insulating substrate; a first upper electrode and a second upper electrode disposed on a first main surface of the insulating substrate; a resistor electrically connecting the first upper electrode and the second upper electrode; an insulating film disposed on a second main surface of the insulating substrate opposite to the first main surface; a first back electrode and a second back electrode disposed on the insulating film; a first end electrode electrically connected to the first upper electrode and the first back electrode; a second end electrode electrically connected to the second upper electrode and the second back electrode; a first plating film covering the first upper electrode, the first back electrode, and the first end electrode; and a second plating film covering the second upper electrode, the second back electrode, and the second end electrode, wherein the insulating film contains a cured product of hydroxyphenyl type epoxy resin (A).

2. In a temperature range of 25°C or higher and 200°C or lower, the storage modulus of the cured product of the hydroxyphenyl-type epoxy resin (A) is 5.0 × 10⁻⁶. ７ Pa or higher and 1.5 × 10 ８ A chip resistor according to claim 1, wherein the current is Pa or less.

3. The chip resistor according to claim 1, wherein the insulating film further contains an inorganic filler (B) comprising at least one selected from the group consisting of titanium oxide, talc, and aerosil.

4. The chip resistor according to claim 3, wherein the content of titanium oxide per 100 parts by mass of the hydroxyphenyl type epoxy resin (A) is 38 parts by mass or more and 76 parts by mass or less.

5. The chip resistor according to claim 3, wherein the content of talc per 100 parts by mass of the hydroxyphenyl type epoxy resin (A) is 50 parts by mass or more and 86 parts by mass or less.

6. The chip resistor according to claim 3, wherein the content of Aerosil per 100 parts by mass of the hydroxyphenyl type epoxy resin (A) is 4 parts by mass or more and 14 parts by mass or less.

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