Chip resistor

Abstract

This chip resistor comprises an insulating substrate and a resistance element. The resistance element includes Cr, Si, N, and O. The resistance element is provided on the insulating substrate. The atomic ratio of Si to Cr in the resistance element is 7.0 / 3.0 to 7.1 / 2.9 at least at the center of the resistance element in the film thickness direction of the resistance element. The atomic percentage of N in the resistance element is 25-33 atom% at least at the center of the resistance element in the film thickness direction. The atomic percentage of O in the resistance element is 10 atom% or less at least at the center of the resistance element in the film thickness direction.

Description

Chip Resistors

[0001] The present disclosure relates generally to chip resistors, and more particularly to chip resistors used in electronic devices.

[0002] A conventional chip resistor of this type includes an insulating substrate and a thin-film resistor provided on the upper surface of the substrate.

[0003] This resistor was made of Cr, Si, Al, and B (Patent Document 1).

[0004] As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

[0005] Japanese Patent Application Laid-Open No. 2001-332402

[0006] In the above-mentioned conventional chip resistors, the thin film resistor has a high resistivity of 4000 μΩ cm or more. However, the difference in temperature coefficient of resistance (TCR), i.e., the difference between the TCR at 155°C and the TCR at -55°C, for example, cannot be reduced.

[0007] A chip resistor according to one aspect of the present disclosure includes an insulating substrate and a resistor. The resistor contains Cr, Si, N, and O and is disposed on the insulating substrate. The atomic ratio of Si to Cr in the resistor is 7.0 / 3.0 or more and 7.1 / 2.9 or less, at least at the center of the resistor in the film thickness direction. The atomic percentage of N in the resistor is 25 atom% or more and 33 atom% or less, at least at the center of the resistor in the film thickness direction. The atomic percentage of O in the resistor is 10 atom% or less, at least at the center of the resistor in the film thickness direction. The resistivity of the resistor is 1200 μΩ·cm or more and 5000 μΩ·cm or less.

[0008] A chip resistor according to one aspect of the present disclosure includes an insulating substrate and a resistor. The resistor contains Cr, Si, N, and O and is disposed on the insulating substrate. The atomic ratio of Si to Cr in the resistor is 7.1 / 2.9 or more and 7.2 / 2.8 or less, at least at the center of the resistor in the film thickness direction. The atomic percentage of N in the resistor is 26 atom% or more and 36 atom% or less, at least at the center of the resistor in the film thickness direction. The atomic percentage of O in the resistor is 10 atom% or less, at least at the center of the resistor in the film thickness direction. The resistivity of the resistor is 1500 μΩ·cm or more and 15000 μΩ·cm or less.

[0009] A chip resistor according to one aspect of the present disclosure includes an insulating substrate and a resistor. The resistor contains Cr, Si, N, and O and is disposed on the insulating substrate. The atomic ratio of Si to Cr in the resistor is 7.2 / 2.8 or more and 7.4 / 2.6 or less, at least at the center of the resistor in the film thickness direction. The atomic percentage of N in the resistor is 26 atom% or more and 37 atom% or less, at least at the center of the resistor in the film thickness direction. The atomic percentage of O in the resistor is 10 atom% or less, at least at the center of the resistor in the film thickness direction. The resistivity of the resistor is 10,000 μΩ·cm or more and 40,000 μΩ·cm or less.

[0010] The chip resistor of the present disclosure can achieve both high resistivity and low temperature coefficient of resistance (TCR) difference.

[0011] Fig. 1 is a cross-sectional view of a chip resistor according to a first embodiment. Fig. 2 is a graph of a resistivity-temperature coefficient of resistance (TCR) difference relationship curve according to the same embodiment. Fig. 3 is a graph of a resistivity-TCR difference relationship curve according to a second embodiment. Fig. 4 is a graph of a resistivity-TCR difference relationship curve according to a third embodiment.

[0012] A chip resistor 10 according to the present disclosure will be described below with reference to FIGS.

[0013] However, the embodiments and modifications described below are merely examples of the present disclosure, and the present disclosure is not limited to the following embodiments and modifications. Various modifications other than the following embodiments and modifications are possible depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure.

[0014] Furthermore, all of the drawings described in the following embodiments are schematic drawings, and the ratios of the sizes and thicknesses of the components in each drawing do not necessarily reflect the actual dimensional ratios.

[0015] (1) First Embodiment (1.1) Overview of Chip Resistor First, an overview of a chip resistor 10 according to a first embodiment will be described with reference to FIG.

[0016] The chip resistor 10 according to the first embodiment is, for example, a surface mount (SMT) chip resistor that is mounted on the surface (mounting surface) of a printed circuit board using a surface mounter. The chip resistor 10 according to the first embodiment is, for example, a thin film chip resistor.

[0017] As shown in FIG. 1 , the chip resistor 10 according to the first embodiment includes an insulating substrate 1 and a resistor 2. In the first embodiment, the resistor 2 contains chromium (Cr), silicon (Si), nitrogen (N), and oxygen (O). The resistor 2 is disposed on the insulating substrate 1. The atomic ratio of Si to Cr in the resistor 2 is 7.0 / 3.0 or more and 7.1 / 2.9 or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic percentage of N in the resistor 2 is 25 atom % or more and 33 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0018] The atomic percentage of O in the resistor 2 is 10 atomic % or less at least at the center of the resistor 2 in the film thickness direction D1.

[0019] The resistivity of the resistor 2 is 1200 μΩ·cm or more and 5000 μΩ·cm or less.

[0020] In the chip resistor 10 according to the first embodiment, the atomic ratio of Si to Cr in the resistor 2 is 7.0 / 3.0 or more and 7.1 / 2.9 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. This makes it possible to reduce the temperature coefficient of resistance (TCR) of the resistor 2.

[0021] In the chip resistor 10 according to the first embodiment, the atomic percentage of N in the resistor 2 is 25 atom % or more and 33 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. In the chip resistor 10 according to the first embodiment, the atomic percentage of O in the resistor 2 is 10 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1. In the chip resistor 10 according to the first embodiment, the resistivity of the resistor 2 is 1200 μΩ cm or more and 5000 μΩ cm or less.

[0022] This makes it possible to increase the resistivity of the resistor 2. That is, the chip resistor 10 according to the first embodiment makes it possible to achieve both high resistivity and low TCR difference.

[0023] (1.2) Configuration of Chip Resistor Next, the configuration of the chip resistor 10 according to the first embodiment will be described with reference to FIG.

[0024] 1 , the chip resistor 10 according to the first embodiment includes an insulating substrate 1 and a resistor element 2. The chip resistor 10 further includes a pair of upper electrodes 3, a first protective film 4, a second protective film 5, a pair of end electrodes 6, a pair of plating layers 7, and a pair of back electrodes 8.

[0025] (1.2.1) Insulating Substrate The insulating substrate 1 is, for example, Al ２ O ３ The insulating substrate 1 is an alumina substrate containing 96% to 99% of alumina. The insulating substrate 1 has a rectangular shape in plan view, for example.

[0026] (1.2.2) Resistor The resistor 2 is provided on the surface 1A of the insulating substrate 1. The resistor 2 has a surface 2B facing and abutting against the surface 1A of the insulating substrate 1, and a surface 2A opposite to the surface 2B. The resistor 2 according to the first embodiment is a thin film provided on one surface (the upper surface in FIG. 1 ) of the insulating substrate 1. The resistor 2 is made of, for example, an alloy of Cr (chromium), Si (silicon), and N (nitrogen). That is, the resistor 2 contains Cr, Si, and N. The atomic ratio of Si to Cr in the resistor 2 is 7.0 / 3.0 or more and 7.1 / 2.9 or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. In other words, the atomic ratio of Cr to Si in the resistor 2 is 3:7 or more and 2.9:7.1 or less. The total atomic amount of N in the total atomic amount of metals constituting the resistor 2 is, for example, 25 atomic % or more and 33 atomic % or less. In other words, the atomic percentage of N in the resistor 2 is 25 atomic % or more and 33 atomic % or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0027] In the first embodiment, the resistor 2 further contains O (oxygen). The atomic percentage of O in the resistor 2 is 10 atomic % or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. By including O (oxygen) in the resistor 2, it is possible to increase the resistivity of the resistor 2.

[0028] The resistor 2 is formed in an approximately rectangular shape by forming a thin-film conductor over almost the entire surface 1A of the insulating substrate 1 using a thin-film process such as sputtering, and then removing unnecessary portions of the thin-film conductor using a photolithography process.

[0029] The atomic composition ratio of the resistor 2 is calculated from the spectral ratio obtained for each of the elements Cr, Si, N, and O on the top surface or cross section of the resistor 2 using, for example, an energy dispersive X-ray spectroscopy (TEM-EDX) or an electron energy loss spectroscopy (TEX-EELS) attached to a transmission electron microscope (TEM). Alternatively, the atomic composition ratio is calculated by correcting each atomic composition ratio evaluated using X-ray photoelectron spectroscopy (XPS) based on a correction factor for each element evaluated using Rutherford backscattering spectroscopy (RBS).

[0030] Furthermore, in the chip resistor 10 according to the first embodiment, a surface oxynitride layer 9 is formed between the resistor 2 and the first protective film 4 in the film thickness direction D1 of the resistor 2. That is, the surface oxynitride layer 9 is provided on the surface 2A (top surface in FIG. 1 ) of the resistor 2 opposite the insulating substrate 1. The surface oxynitride layer 9 is made of an oxynitride film containing at least one of Cr and Al, and Si. As an example in the first embodiment, the surface oxynitride layer 9 is made of an oxynitride film containing Cr and Si. More specifically, the surface oxynitride layer 9 contains Cr oxide and SiON. The surface oxynitride layer 9 is formed by subjecting the resistor 2 to a heat treatment process described below.

[0031] Such a surface oxynitride layer 9 has the advantage of improving oxidation resistance because a passivation film is formed by the Cr oxide contained in the surface oxynitride layer 9. The surface oxynitride layer 9 also has the advantage of improving gas barrier properties by the SiON contained in the surface oxynitride layer 9. That is, by forming such a surface oxynitride layer 9 on the surface 2A of the resistor 2, it is possible to improve the environmental resistance of the resistor 2.

[0032] Furthermore, in the chip resistor 10 according to the first embodiment, the surface oxynitride layer 9 is provided not on the entire surface 2A of the resistor 2 but on a portion of the surface 2A. That is, the surface oxynitride layer 9 is provided only on a portion of the surface 2A of the resistor 2. This allows the resistor 2 and the pair of upper electrodes 3 to abut against each other and be electrically connected to each other in the portions of the surface 2A of the resistor 2 where the surface oxynitride layer 9 is not provided.

[0033] (1.2.3) Top Electrode Each of the pair of top electrodes 3 is made of, for example, Cu. The pair of top electrodes 3 are provided so as to cover a part of the top surface (surface 2A) of the resistor 2 at both ends in the longitudinal direction (left-right direction in FIG. 1 ) of the resistor 2. The pair of top electrodes 3 are formed, for example, by forming a metal film over the entire top surface (surface 2A) of the resistor 2 by sputtering, and then removing the film in the center portion by photolithography and etching.

[0034] (1.2.4) First Protective Film The first protective film (inorganic protective film) 4 is a film for protecting the resistor 2. The first protective film 4 is made of, for example, Al ２ O ３ (alumina). The first protective film 4 is located on the upper surface of the resistor 2. The first protective film 4 also covers a portion of the pair of upper electrodes 3 at both ends in the longitudinal direction (the left-right direction in FIG. 1 ). That is, when viewed in the film thickness direction D1 of the resistor 2 (the thickness direction of the insulating substrate 1), the first protective film 4 covers the boundary between the resistor 2 and the pair of upper electrodes 3, and continuously covers the resistor 2 and at least a portion of the pair of upper electrodes 3. The first protective film 4 is formed, for example, by forming a protective film over the entire resistor 2 by sputtering, and then removing the portions at both ends by photolithography and etching.

[0035] In this way, the provision of the first protective film 4 makes it possible to prevent corrosion of the resistor 2. The first protective film 4 may be made of a metal oxide other than alumina or a metal nitride. The first protective film 4 may also be omitted.

[0036] (1.2.5) Second Protective Film The second protective film (resin protective film) 5 is made of, for example, epoxy resin. The second protective film 5 covers the entire surface of the first protective film 4 and a portion of the pair of upper electrodes 3. That is, when viewed from the film thickness direction D1 of the resistor 2 (the thickness direction of the insulating substrate 1), the second protective film 5 covers the boundary between the first protective film 4 and the pair of upper electrodes 3, and continuously covers from the first protective film 4 to at least a portion of the pair of upper electrodes 3.

[0037] The second protective film 5 is formed, for example, by applying an epoxy resin by screen printing and then curing the epoxy resin by irradiating it with ultraviolet light. Note that the portions of the pair of upper electrodes 3 that are located between both ends (portions covering the pair of upper electrodes 3) of the first protective film 4 in the longitudinal direction (the left-right direction in FIG. 1 ) and the plating layer 7 are directly covered with the second protective film 5.

[0038] (1.2.6) End Electrodes Each of the pair of end electrodes 6 is made of, for example, CuNi. The pair of end electrodes 6 is located at both ends of the insulating substrate 1 in the longitudinal direction (the left-right direction in FIG. 1 ). The pair of end electrodes 6 is formed at both ends of the insulating substrate 1 in the longitudinal direction by, for example, sputtering. The pair of end electrodes 6 is electrically connected to the pair of top electrodes 3.

[0039] (1.2.7) Plating Layer As shown in Fig. 1 , each of the pair of plating layers 7 includes a Ni plating layer 71 and a Sn plating layer 72. Each of the pair of plating layers 7 is connected to a part of the corresponding one of the pair of top electrodes 3, and is in contact with the second protective film 5. In addition, each of the pair of plating layers 7 covers the corresponding one of the pair of end electrodes 6.

[0040] (1.2.8) Rear surface electrodes Each of the pair of rear surface electrodes 8 is made of, for example, epoxy resin containing Ag (silver) as a conductive material. The pair of rear surface electrodes 8 is located at both ends in the longitudinal direction (left and right direction in FIG. 1 ) of the rear surface (lower surface in FIG. 1 ) of the insulating substrate 1. The pair of rear surface electrodes 8 is formed, for example, by applying epoxy resin to both ends in the longitudinal direction of the rear surface of the insulating substrate 1 by screen printing, and then irradiating it with ultraviolet light to harden the epoxy resin. The pair of rear surface electrodes 8 correspond one-to-one to the pair of upper surface electrodes 3. Note that the pair of rear surface electrodes 8 may be omitted.

[0041] (1.3) Method for Manufacturing Chip Resistor Next, a method for manufacturing the chip resistor 10 according to the first embodiment will be described.

[0042] The method for manufacturing the chip resistor 10 according to the first embodiment is a method for manufacturing the chip resistor 10 according to the first embodiment. The method for manufacturing the chip resistor 10 includes a resistor forming step and a pattern forming step.

[0043] The resistor formation step is a step of forming a resistor 2 on an insulating substrate 1. In the first embodiment, in the resistor formation step, the resistor 2 is formed on the insulating substrate 1 by, for example, reactive sputtering in which nitrogen is reacted with the resistor 2, or reactive sputtering in which nitrogen is reacted with oxygen. The sputtering target for reactive sputtering contains, for example, Cr, Si, and O, with an atomic ratio of Cr to Si of 3:7 and an atomic percentage of O of 20 atom %. That is, the sputtering target for reactive sputtering contains 20 atom % or less of oxygen (O).

[0044] The pattern formation step is a step of forming a pattern of the resistor 2 on the insulating substrate 1. In the first embodiment, in the pattern formation step, the resistor 2 is etched by, for example, a photolithography method to form the pattern of the resistor 2. In the pattern formation step, an etching solution containing, for example, hydrofluoric acid is used.

[0045] The manufacturing method of the chip resistor 10 according to the first embodiment further includes a heat treatment process. The heat treatment process is a process of performing heat treatment on the resistor 2 formed (patterned) in the pattern formation process. That is, in the first embodiment, the heat treatment process is performed after the pattern formation process. In the heat treatment process, the heat treatment temperature is 300°C or higher and 800°C or lower. In the first embodiment, as an example, the heat treatment temperature is 520°C. The "heat treatment temperature" here refers to the actual temperature of the resistor 2 in the first embodiment, but may also be the ambient temperature. In the heat treatment process, the oxygen concentration is 1000 ppm or lower.

[0046] In the manufacturing method of the chip resistor 10 according to the first embodiment, as described above, the resistor 2 is formed by reactive sputtering, so the ratio of elements contained in the target of the resistor 2 is approximately the same as the target composition, making it possible to control the chemical composition of the resistor 2.

[0047] Furthermore, in the manufacturing method of the chip resistor 10 according to the first embodiment, as described above, the resistor 2 formed in the resistor formation step is subjected to a heat treatment step, which makes it possible to form a surface oxynitride layer 9 on the surface of the resistor 2.

[0048] (1.4) Characteristics of Chip Resistor Next, the characteristics of the chip resistor 10 according to the first embodiment will be described.

[0049] (1.4.1) Resistivity In the chip resistor 10 according to the first embodiment, the resistor 2 contains Cr, Si, N, and O, but does not contain Al (aluminum). In this case, the atomic ratio of Cr to Si in the resistor 2 changes from 3:2 to 1:4, thereby increasing the resistivity of the resistor 2.

[0050] According to the chip resistor 10 of the first embodiment, the resistivity of the resistor 2 can be adjusted by changing the atomic ratio of Cr to Si in the resistor 2 .

[0051] (1.4.2) TCR If the atomic ratio of Si to Cr in the resistor 2 is 3 / 7, the linearity of the resistance value of the resistor 2 as a function of temperature is good. However, as the atomic ratio of Si to Cr in the resistor 2 approaches (increases to) 4 / 1, the linearity of the above-mentioned function is impaired, making it difficult to control the resistance value of the resistor 2. Therefore, in the first embodiment, the atomic ratio of Si to Cr in the resistor 2 is set to 7.05 / 2.95 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. Note that the atomic ratio of Si to Cr in the resistor 2 may be 7.0 / 3.0 or 7.1 / 2.9 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. That is, as described above, the atomic ratio of Si to Cr in the resistor 2 may be 7.0 / 3.0 or more and 7.1 / 2.9 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0052] (1.4.3) TCR Difference Next, the difference between the TCR at 155°C relative to 25°C and the TCR at -55°C relative to 25°C (hereinafter simply referred to as "TCR difference") in the chip resistor 10 according to the first embodiment will be described with reference to Fig. 2. The horizontal axis of Fig. 2 is resistivity (μΩ cm), the vertical axis of Fig. 2 is TCR difference (ppm / K), and a resistivity-TCR difference relationship curve is drawn using the atomic percentage (atom %) of N in the resistor 2 as a parameter.

[0053] In the resistivity-TCR difference relationship curve, as the resistivity increases, the TCR difference also increases. Also, as the atomic ratio of N in the resistor 2 increases, the resistivity (and TCR difference) increases.

[0054] When the resistivity is 1200 μΩ·cm and the atomic percentage of N in resistor 2 is 25 atom %, the TCR difference is −10 ppm / K. Furthermore, when the resistivity is 5000 μΩ·cm and the atomic percentage of N in resistor 2 is 33 atom %, the TCR difference is 8 ppm / K. That is, as described above, the atomic percentage of N in resistor 2 is 25 atom % or more and 33 atom % or less at least at the center of resistor 2 in the film thickness direction D1. Furthermore, the resistivity of resistor 2 is 1200 μΩ·cm or more and 5000 μΩ·cm or less. As a result, the TCR difference (ppm / K) is −10 ppm or more and 8 ppm or less, which is a preferable value.

[0055] (1.4.4) Effect of Oxygen on Resistivity In the chip resistor 10 according to the first embodiment, as described above, the resistor 2 contains Cr, Si, N, and O. The film thickness of the resistor 2 is 100 nm. Therefore, in this case, the center of the resistor 2 in the film thickness direction D1 of the resistor 2 is 50 nm. At an analysis depth of 50 nm, the atomic percentage (quantitative equivalent value) of O in the resistor 2 is approximately 2 atom %. That is, in the chip resistor 10 according to the first embodiment, the atomic percentage of O in the resistor 2 is 10 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0056] According to the chip resistor 10 of the first embodiment, the resistivity of the resistor 2 can be increased by the resistor 2 containing O (oxygen).

[0057] (1.4.5) Surface Oxynitride Layer As described above, the surface oxynitride layer 9 is formed on the surface of the resistor 2, and the thickness of this surface oxynitride layer 9 is, for example, 10 nm. That is, the surface oxynitride layer 9 covers an analysis depth range of 0 nm to 10 nm. That is, the surface oxynitride layer 9 has a composition gradient from the surface of the surface oxynitride layer 9 to the interior of the surface oxynitride layer 9 in the thickness direction D1 of the resistor 2. This reduces stress in the surface oxynitride layer 9, which has the advantage that the surface oxynitride layer 9 is less likely to peel off from the resistor 2.

[0058] Furthermore, in the surface oxynitride layer 9, the atomic ratio of Si is higher than the sum of the atomic ratios of Cr and Al within a range of 10 nm from the surface of the surface oxynitride layer 9. This has the advantage of forming a very stable passivation state, thereby improving the protection performance of the resistor 2. Furthermore, the atomic ratio of Cr to Si is higher at the surface (outermost surface) of the surface oxynitride layer 9 than at the center of the resistor 2 in the film thickness direction D1.

[0059] The atomic percentage of O in the resistor 2 (quantitative conversion value) is approximately 2 atom %, but it may be 10 atom % or less. Also, the atomic percentage of O in the resistor 2 may be 0 atom % or more. In other words, the atomic percentage of O in the resistor 2 may be 0 atom % or more and 10 atom % or less. More preferably, the atomic percentage of O in the resistor 2 is 0.1 atom % or more and 10 atom % or less.

[0060] (1.5) Summary of First Embodiment In a resistor 2 containing Cr, Si, and N, a larger atomic ratio of Cr to Si increases the TCR. From this perspective, the atomic ratio of Cr to Si is preferably 3 / 7 or less. However, as the atomic ratio of Si to Cr in the resistor 2 increases (as the atomic ratio of Cr to Si decreases), the linearity of the resistance value of the resistor 2 as a function of temperature is impaired. From this perspective, a larger atomic ratio of Cr to Si is preferable. In the first embodiment, the atomic ratio of Si to Cr in the resistor 2 is set to 7.05 / 2.95 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2, thereby achieving a high resistance ratio and suppressing temperature dependence (improving linearity). Note that the atomic ratio of Si to Cr in the resistor 2 may be 7.0 / 3.0 or more and 7.1 / 2.9 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0061] Furthermore, the TCR difference is −10 ppm / K when the resistivity is 1200 μΩ·cm and the atomic percentage of N in resistor 2 is 25 atom %. Furthermore, the TCR difference is 8 ppm / K when the resistivity is 5000 μΩ·cm and the atomic percentage of N in resistor 2 is 33 atom %. As a result, the TCR difference (ppm / K) is −10 ppm or more and 8 ppm or less, achieving a low TCR difference.

[0062] (2) Second Embodiment An overview of the chip resistor 10 according to the second embodiment will be described. The chip resistor 10 according to the second embodiment is mostly the same as the chip resistor 10 according to the first embodiment, and differs from the chip resistor 10 according to the first embodiment only in the composition of the resistor element 2.

[0063] (2.1) Overview of Chip Resistor As shown in FIG. 1 , the chip resistor 10 according to the second embodiment includes an insulating substrate 1 and a resistor 2. In the second embodiment, the resistor 2 contains chromium (Cr), silicon (Si), nitrogen (N), and oxygen (O). The resistor 2 is disposed on the insulating substrate 1. The atomic ratio of Si to Cr in the resistor 2 is 7.1 / 2.9 or more and 7.2 / 2.8 or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic percentage of N in the resistor 2 is 26 atom % or more and 36 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0064] The atomic percentage of O in the resistor 2 is 10 atomic % or less at least at the center of the resistor 2 in the film thickness direction D1.

[0065] The resistivity of the resistor 2 is 1500 μΩ·cm or more and 15000 μΩ·cm or less.

[0066] In the chip resistor 10 according to the second embodiment, the atomic ratio of Si to Cr in the resistor 2 is 7.1 / 2.9 or more and 7.2 / 2.8 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. This makes it possible to reduce the TCR of the resistor 2.

[0067] In the chip resistor 10 according to the second embodiment, the atomic percentage of N in the resistor 2 is 26 atom % or more and 36 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. In the chip resistor 10 according to the second embodiment, the atomic percentage of O in the resistor 2 is 10 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1. In the chip resistor 10 according to the second embodiment, the resistivity of the resistor 2 is 1500 μΩ cm or more and 15000 μΩ cm or less.

[0068] This makes it possible to increase the resistivity of the resistor 2. That is, the chip resistor 10 according to the second embodiment makes it possible to achieve both high resistivity and low TCR difference.

[0069] (2.2) Configuration of Chip Resistor Since the chip resistor 10 according to the second embodiment is largely the same as the chip resistor 10 according to the first embodiment, explanations that overlap with the first embodiment will be omitted and the differences in configuration will be mainly described.

[0070] 1, the chip resistor 10 according to the second embodiment includes an insulating substrate 1 and a resistor 2. The chip resistor 10 also includes a pair of upper electrodes 3, a first protective film 4, a second protective film 5, a pair of end electrodes 6, a pair of plating layers 7, and a pair of back electrodes 8. The explanations of the insulating substrate 1, resistor 2, pair of upper electrodes 3, first protective film 4, second protective film 5, pair of end electrodes 6, pair of plating layers 7, and pair of back electrodes 8 according to the second embodiment are the same as those in (1.2.1) to (1.2.8) of the first embodiment, and therefore will not be repeated. However, the second embodiment differs from the first embodiment in the following respects.

[0071] That is, the atomic ratio of Si to Cr in the resistor 2 is 7.1 / 2.9 or more and 7.2 / 2.8 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic percentage of N in the resistor 2 is 26 atom % or more and 36 atom % or less at least at the center of the resistor 2 in the film thickness direction D1.

[0072] (2.3) Method for Manufacturing Chip Resistor The method for manufacturing the chip resistor 10 according to the second embodiment is similar to that described in (1.3) of the first embodiment (except for the composition of the resistor 2), and therefore will not be described here.

[0073] (2.4) Characteristics of Chip Resistor Next, the characteristics of the chip resistor 10 according to the second embodiment will be described.

[0074] The resistivity is the same as that explained in (1.4.1) of the first embodiment, and therefore will not be explained again.

[0075] (2.4.1) TCR In a resistor 2 containing Cr, Si, and N, the TCR increases as the atomic ratio of Cr to Si increases. The reason for this is as explained in (1.4.2) of the first embodiment, and it is preferable that the atomic ratio of Cr to Si is 3 / 7 or less.

[0076] Furthermore, the larger the atomic ratio of Si to Cr in the resistor 2, the more the linearity of the resistance value of the resistor 2 as a function of temperature is impaired. Therefore, in the second embodiment, the atomic ratio of Si to Cr in the resistor 2 is set to 7.15 / 2.85 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic ratio of Si to Cr in the resistor 2 may be 7.1 / 2.9 or 7.2 / 2.8 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. That is, as described above, the atomic ratio of Si to Cr in the resistor 2 may be 7.1 / 2.9 or more and 7.2 / 2.8 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0077] (2.4.2) TCR Difference Next, the TCR difference in the chip resistor 10 according to the second embodiment will be described with reference to Fig. 3. The horizontal axis of Fig. 3 is resistivity (μΩ cm), and the vertical axis of Fig. 3 is TCR difference (ppm / K). A resistivity-TCR difference relationship curve is plotted using the atomic percentage (atom %) of N in the resistor 2 as a parameter.

[0078] In the resistivity-TCR difference relationship curve, as the resistivity increases, the TCR difference also increases. Also, as the atomic ratio of N in the resistor 2 increases, the resistivity (and TCR difference) increases.

[0079] When the resistivity is 1500 μΩ·cm and the atomic percentage of N in resistor 2 is 26 atom%, the TCR difference is −10 ppm / K. Furthermore, when the resistivity is 15,000 μΩ·cm and the atomic percentage of N in resistor 2 is 36 atom%, the TCR difference is 10 ppm / K. That is, as described above, the atomic percentage of N in resistor 2 is 25 atom% or more and 33 atom% or less at least at the center of resistor 2 in the film thickness direction D1. Furthermore, the resistivity of resistor 2 is 1500 μΩ·cm or more and 15,000 μΩ·cm or less. As a result, the TCR difference (ppm / K) is −10 ppm or more and 10 ppm or less, which is a preferable value.

[0080] The effects of oxygen on resistivity and the surface oxynitride layer 9 are similar to those described in (1.4.4) and (1.4.5) of the first embodiment, and therefore will not be described again.

[0081] (2.5) Summary of the Second Embodiment The atomic ratio of Si to Cr in the resistor 2 is 7.15 / 2.85 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2, thereby achieving a high resistance ratio and suppressing temperature dependency (improving linearity). Note that the atomic ratio of Si to Cr in the resistor 2 may be 7.1 / 2.9 or more and 7.2 / 2.8 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0082] Furthermore, the TCR difference is −10 ppm / K when the resistivity is 1500 μΩ·cm and the atomic percentage of N in resistor 2 is 26 atom %. Furthermore, the TCR difference is 10 ppm / K when the resistivity is 15000 μΩ·cm and the atomic percentage of N in resistor 2 is 36 atom %. As a result, the TCR difference (ppm / K) is −10 ppm or more and 10 ppm or less, achieving a low TCR difference.

[0083] (3) Third Embodiment The outline of the chip resistor 10 according to the third embodiment will be described. The chip resistor 10 according to the third embodiment is mostly the same as the chip resistor 10 according to the first embodiment, and is different from the chip resistor 10 according to the first embodiment only in the composition of the resistor 2.

[0084] (3.1) Outline of Chip Resistor As shown in FIG. 1, the chip resistor 10 according to the third embodiment includes an insulating substrate 1 and a resistor 2. In the third embodiment, the resistor 2 contains Cr (chromium), Si (silicon), N (nitrogen), and O (oxygen). The resistor 2 is provided on the insulating substrate 1. The atomic ratio of Si to Cr in the resistor 2 is at least 7.2 / 2.8 or more and 7.4 / 2.6 or less at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic percentage of N in the resistor 2 is at least 26 atom% or more and 37 atom% or less at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0085] The atomic percentage of O in the resistor 2 is at least 10 atom% or less at the center of the resistor 2 in the film thickness direction D1.

[0086] The specific resistance of the resistor 2 is 10000 μΩ·cm or more and 40,000 μΩ·cm or less.

[0087] In the chip resistor 10 according to the third embodiment, the atomic ratio of Si to Cr in the resistor 2 is at least 7.2 / 2.8 or more and 7.4 / 2.6 or less at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. Thereby, it becomes possible to lower the TCR of the resistor 2.

[0088] Furthermore, in the chip resistor 10 according to the third embodiment, the atomic percentage of N in the resistor 2 is 26 atom % or more and 37 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. Furthermore, in the chip resistor 10 according to the third embodiment, the atomic percentage of O in the resistor 2 is 10 atom % or less, at least at the center of the resistor 2 in the film thickness direction D1. Furthermore, in the chip resistor 10 according to the third embodiment, the resistivity of the resistor 2 is 10,000 μΩ cm or more and 40,000 μΩ cm or less.

[0089] This makes it possible to increase the resistivity of the resistor 2. That is, the chip resistor 10 according to the third embodiment makes it possible to achieve both high resistivity and low TCR difference.

[0090] (3.2) Configuration of Chip Resistor Since the chip resistor 10 according to the third embodiment is largely the same as the chip resistor 10 according to the first embodiment, explanations that overlap with the first embodiment will be omitted and the differences in configuration will be mainly described.

[0091] 1, the chip resistor 10 according to the third embodiment includes an insulating substrate 1 and a resistor 2. The chip resistor 10 also includes a pair of upper electrodes 3, a first protective film 4, a second protective film 5, a pair of end electrodes 6, a pair of plating layers 7, and a pair of back electrodes 8. The descriptions of the insulating substrate 1, resistor 2, pair of upper electrodes 3, first protective film 4, second protective film 5, pair of end electrodes 6, pair of plating layers 7, and pair of back electrodes 8 according to the third embodiment are the same as those in (1.2.1) to (1.2.8) of the first embodiment, and therefore will not be repeated. However, the third embodiment differs from the first embodiment in the following respects.

[0092] That is, the atomic ratio of Si to Cr in the resistor 2 is 7.2 / 2.8 or more and 7.4 / 2.6 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic percentage of N in the resistor 2 is 26 atom % or more and 37 atom % or less at least at the center of the resistor 2 in the film thickness direction D1.

[0093] (3.3) Method for Manufacturing Chip Resistor The method for manufacturing the chip resistor 10 according to the third embodiment is similar to that described in (1.3) of the first embodiment (except for the composition of the resistor 2), and therefore will not be described here.

[0094] (3.4) Characteristics of Chip Resistor Next, the characteristics of the chip resistor 10 according to the third embodiment will be described.

[0095] The resistivity is the same as that explained in (1.4.1) of the first embodiment, and therefore will not be explained again.

[0096] (3.4.1) TCR In a resistor 2 containing Cr, Si, and N, the TCR increases as the atomic ratio of Cr to Si increases. The reason for this is as explained in (1.4.2) of the first embodiment, and it is preferable that the atomic ratio of Cr to Si is 3 / 7 or less.

[0097] Furthermore, the larger the atomic ratio of Si to Cr in the resistor 2, the more the linearity of the resistance value of the resistor 2 as a function of temperature is impaired. Therefore, in the third embodiment, the atomic ratio of Si to Cr in the resistor 2 is set to 7.3 / 2.7 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. The atomic ratio of Si to Cr in the resistor 2 may be 7.2 / 2.8 or 7.4 / 2.6 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. That is, as described above, the atomic ratio of Si to Cr in the resistor 2 may be 7.2 / 2.8 or more and 7.4 / 2.6 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0098] (3.4.2) TCR Difference Next, the TCR difference in the chip resistor 10 according to the third embodiment will be described with reference to Fig. 4. The horizontal axis of Fig. 4 is resistivity (μΩ cm), and the vertical axis of Fig. 4 is TCR difference (ppm / K), and a resistivity-TCR difference relationship curve is plotted using the atomic percentage (atom %) of N in the resistor 2 as a parameter.

[0099] In the resistivity-TCR difference relationship curve, as the resistivity increases, the TCR difference also increases. Also, as the atomic ratio of N in the resistor 2 increases, the resistivity (and TCR difference) increases.

[0100] When the resistivity is 10,000 μΩ·cm and the atomic percentage of N in resistor 2 is 26 atom %, the TCR difference is −10 ppm / K. Furthermore, when the resistivity is 40,000 μΩ·cm and the atomic percentage of N in resistor 2 is 37 atom %, the TCR difference is −1 ppm / K. That is, as described above, the atomic percentage of N in resistor 2 is 26 atom % or more and 37 atom % or less at least at the center of resistor 2 in the film thickness direction D1. Furthermore, the resistivity of resistor 2 is 10,000 μΩ·cm or more and 40,000 μΩ·cm or less. As a result, the TCR difference (ppm / K) is −10 ppm or more and −1 ppm or less, which is a preferable value.

[0101] The effects of oxygen on resistivity and the surface oxynitride layer 9 are similar to those described in (1.4.4) and (1.4.5) of the first embodiment, and therefore will not be described again.

[0102] (3.5) Summary of the Third Embodiment The atomic ratio of Si to Cr in the resistor 2 is 7.3 / 2.7 at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2, thereby achieving a high resistance ratio and suppressing temperature dependency (improving linearity). Note that the atomic ratio of Si to Cr in the resistor 2 may be 7.2 / 2.8 or more and 7.4 / 2.6 or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0103] Furthermore, the TCR difference is −10 ppm / K when the resistivity is 10,000 μΩ·cm and the atomic percentage of N in resistor 2 is 26 atom %. Furthermore, the TCR difference is −1 ppm / K when the resistivity is 40,000 μΩ·cm and the atomic percentage of N in resistor 2 is 37 atom %. As a result, the TCR difference (ppm / K) is −10 ppm or more and −1 ppm or less, achieving a low TCR difference.

[0104] (4) Modifications The above-described embodiment is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the above-described embodiment are listed below. The modifications described below can be applied in appropriate combinations.

[0105] (4.1) Modification 1 In the above-described embodiment, the resistor 2 contains Cr, Si, N, and O. However, the resistor 2 may contain Al (aluminum) in addition to Cr, Si, N, and O. In other words, in the chip resistor 10 according to Modification 1, the resistor 2 contains Cr, Si, N, and Al. As described above, the atomic percentage of Al in the resistor 2 is preferably 30 atom % or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0106] In the chip resistor 10 according to the first modification, the resistor 2 contains Al in addition to Cr, Si, N, and O. This allows the resistivity of the resistor 2 to be higher than when the resistor 2 does not contain Al.

[0107] (4.2) Other Modifications In the above-described embodiment, in the manufacturing method of the chip resistor 10, a heat treatment process is performed after the pattern formation process, but for example, a heat treatment process may be performed between the resistor formation process and the pattern formation process.

[0108] Moreover, a trimming groove (not shown) for adjusting the resistance value may be provided in the resistor 2, and the resistor 2 may have a serpentine shape.

[0109] (Summary) As described above, the chip resistor (10) according to the first aspect includes an insulating substrate (1) and a resistor (2). The resistor (2) contains Cr, Si, N, and O. The resistor (2) is disposed on the insulating substrate (1). The atomic ratio of Si to Cr in the resistor (2) is 7.0 / 3.0 or more and 7.1 / 2.9 or less, at least at the center of the resistor (2) in the film thickness direction (D1) of the resistor (2). The atomic percentage of N in the resistor (2) is 25 atom% or more and 33 atom% or less, at least at the center of the resistor (2) in the film thickness direction (D1). The atomic percentage of O in the resistor (2) is 10 atom% or less, at least at the center of the resistor (2) in the film thickness direction (D1). The resistivity of the resistor (2) is 1200 μΩ·cm or more and 5000 μΩ·cm or less.

[0110] According to this embodiment, it is possible to achieve both high resistivity and low TCR difference.

[0111] A chip resistor (10) according to a second aspect includes an insulating substrate (1) and a resistor (2). The resistor (2) contains Cr, Si, N, and O. The resistor (2) is disposed on the insulating substrate (1). The atomic ratio of Si to Cr in the resistor (2) is 7.1 / 2.9 or more and 7.2 / 2.8 or less, at least at the center of the resistor (2) in the film thickness direction (D1) of the resistor (2). The atomic percentage of N in the resistor (2) is 26 atom% or more and 36 atom% or less, at least at the center of the resistor (2) in the film thickness direction (D1). The atomic percentage of O in the resistor (2) is 10 atom% or less, at least at the center of the resistor (2) in the film thickness direction (D1). The resistivity of the resistor (2) is 1500 μΩ·cm or more and 15000 μΩ·cm or less.

[0112] According to this embodiment, it is possible to achieve both high resistivity and low TCR difference.

[0113] A chip resistor (10) according to a third aspect includes an insulating substrate (1) and a resistor (2). The resistor (2) contains Cr, Si, N, and O. The resistor (2) is disposed on the insulating substrate (1). The atomic ratio of Si to Cr in the resistor (2) is 7.2 / 2.8 or more and 7.4 / 2.6 or less, at least at the center of the resistor (2) in the film thickness direction (D1) of the resistor (2). The atomic percentage of N in the resistor (2) is 26 atom% or more and 37 atom% or less, at least at the center of the resistor (2) in the film thickness direction (D1). The atomic percentage of O in the resistor (2) is 10 atom% or less, at least at the center of the resistor (2) in the film thickness direction (D1). The resistivity of the resistor (2) is 10,000 μΩ·cm or more and 40,000 μΩ·cm or less.

[0114] According to this embodiment, it is possible to achieve both high resistivity and low TCR difference.

[0115] A chip resistor (10) according to a fourth aspect is any one of the first to third aspects, further comprising a surface oxynitride layer (9). The surface oxynitride layer (9) is made of an oxynitride film containing at least one of Cr and Al, and Si. The surface oxynitride layer (9) is provided on a surface (2A) of the resistor (2) opposite to the insulating substrate (1).

[0116] According to this aspect, it is possible to improve environmental resistance.

[0117] In the chip resistor (10) according to the fifth aspect, in the fourth aspect, the surface oxynitride layer (9) is provided on a part of the surface (2A) of the resistor (2).

[0118] According to this embodiment, it is possible to electrically connect the resistor (2) and the electrode (upper electrode 3).

[0119] In the chip resistor (10) according to the sixth aspect, in the fourth or fifth aspect, the surface oxynitride layer (9) has a composition gradient in the film thickness direction (D1) from the surface of the surface oxynitride layer (9) opposite the resistor (2) to the interior of the surface oxynitride layer (9).

[0120] This embodiment has the advantage that it is difficult to peel off from the resistor (2).

[0121] In the chip resistor (10) according to the seventh aspect, in the sixth aspect, the surface oxynitride layer (9) has a higher atomic ratio of Cr to Si at the outermost surface in the film thickness direction (D1) than at the center of the resistor (2) in the film thickness direction (D1).

[0122] This embodiment has the advantage of improving the protection performance of the resistor (2).

[0123] The configurations according to the fourth to seventh aspects are not essential for the chip resistor (10) and can be omitted as appropriate.

[0124] REFERENCE SIGNS LIST 1 insulating substrate 2 resistor 9 surface oxynitride layer 10 chip resistor D1 film thickness direction

Claims

1. A chip resistor comprising: an insulating substrate; and a resistor comprising Cr, Si, N, and O and disposed on the insulating substrate, wherein the atomic ratio of Si to Cr in the resistor is 7.0 / 3.0 or more and 7.1 / 2.9 or less at least at the center of the resistor in the film thickness direction of the resistor; the atomic percentage of N in the resistor is 25 atom % or more and 33 atom % or less at least at the center of the resistor in the film thickness direction; the atomic percentage of O in the resistor is 10 atom % or less at least at the center of the resistor in the film thickness direction; and the resistivity of the resistor is 1200 μΩ·cm or more and 5000 μΩ·cm or less.

2. A chip resistor comprising: an insulating substrate; and a resistor comprising Cr, Si, N, and O and disposed on the insulating substrate, wherein the atomic ratio of Si to Cr in the resistor is 7.1 / 2.9 or more and 7.2 / 2.8 or less at least at the center of the resistor in the film thickness direction of the resistor; the atomic percentage of N in the resistor is 26 atom % or more and 36 atom % or less at least at the center of the resistor in the film thickness direction; the atomic percentage of O in the resistor is 10 atom % or less at least at the center of the resistor in the film thickness direction; and the resistivity of the resistor is 1500 μΩ cm or more and 15000 μΩ cm or less.

3. A chip resistor comprising: an insulating substrate; and a resistor comprising Cr, Si, N, and O and disposed on the insulating substrate, wherein the atomic ratio of Si to Cr in the resistor is 7.2 / 2.8 or more and 7.4 / 2.6 or less at least at the center of the resistor in the film thickness direction of the resistor; the atomic percentage of N in the resistor is 26 atom % or more and 37 atom % or less at least at the center of the resistor in the film thickness direction; the atomic percentage of O in the resistor is 10 atom % or less at least at the center of the resistor in the film thickness direction; and the resistivity of the resistor is 10,000 μΩ·cm or more and 40,000 μΩ·cm or less.

4. A chip resistor according to any one of claims 1 to 3, further comprising a surface oxynitride layer made of an oxynitride film containing at least one of Cr and Al, and Si, said surface oxynitride layer being provided on the surface of said resistor element opposite to said insulating substrate.

5. The chip resistor according to claim 4, wherein the surface oxynitride layer is provided on a portion of the surface of the resistor.

6. The chip resistor according to claim 4, wherein the surface oxynitride layer has a composition gradient in the film thickness direction from the surface of the surface oxynitride layer opposite the resistor element to the interior of the surface oxynitride layer.

7. The chip resistor according to claim 6, wherein the surface oxynitride layer has a higher atomic ratio of Cr to Si at the outermost surface in the film thickness direction than at the center of the resistor in the film thickness direction.

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