Resistor and production method

Abstract

This resistor comprises an insulating substrate, a resistance element, and a pair of upper surface electrodes. The resistance element is provided on the insulating substrate. The pair of upper surface electrodes are provided apart from each other on the resistance element. The resistance element includes Cr, Si, N, and O. The atomic percentage of O in the resistance element is greater than 10 atom% and equal to or less than 30 atom% at least in the center of the resistance element in the film thickness direction thereof.

Description

Resistor and manufacturing method

[0001] The present disclosure relates generally to resistors and methods of manufacture, and more particularly to a resistor including an insulating substrate and a resistive element disposed on the insulating substrate, and a method of manufacture of the resistor.

[0002] Patent Document 1 describes a chip resistor including an insulating substrate, a resistor, and a pair of upper electrodes. The resistor is provided on the insulating substrate. The pair of upper electrodes are provided at both longitudinal ends of the resistor so as to cover a portion of the upper surface of the resistor.

[0003] International Publication No. 2022 / 075238

[0004] In a resistor such as the chip resistor described in Patent Document 1, the resistivity of the resistor element changes nonlinearly with temperature.

[0005] A resistor according to one aspect of the present disclosure includes an insulating substrate, a resistive element, and a pair of electrodes. The resistive element is provided on the insulating substrate. The pair of electrodes are provided spaced apart from each other on the resistive element. The resistive element contains Cr, Si, N, and O. The atomic percentage of O in the resistive element is greater than 10 atom % and less than or equal to 30 atom %, at least at the center of the resistive element in the film thickness direction of the resistive element.

[0006] A manufacturing method according to one aspect of the present disclosure is a method for manufacturing a resistor. The manufacturing method includes a substrate preparation step, a resistor formation step, and an electrode formation step. The substrate preparation step includes preparing an insulating substrate. The resistor formation step includes forming a resistor containing Cr, Si, N, and O on the insulating substrate. The electrode formation step includes forming a pair of electrodes on the resistor. The resistor formation step includes a target preparation step and a sputtering step. The target preparation step includes preparing a target containing metal elements that constitute the resistor. The sputtering step includes forming the resistor on the insulating substrate by sputtering using the target. The target contains at least Cr, Si, and O. The sputtering step includes performing reactive sputtering using a reactive gas containing nitrogen.

[0007] According to the present disclosure, there is an advantage that it is possible to make the temperature change of the resistivity of the resistor closer to linear.

[0008] FIG. 1A is a cross-sectional view of a resistor according to an embodiment of the present disclosure. FIG. 1B is a cross-sectional view of another resistor according to an embodiment of the present disclosure. FIG. 2 is a flowchart of a method for manufacturing the resistor shown in FIG. 1A. FIG. 3 is a flowchart of a resistor forming step in the method for manufacturing the resistor according to the same. FIG. 4 is an explanatory diagram showing an example of a sputtering apparatus used in a sputtering step in the resistor forming step in the same. FIG. 5 is an explanatory diagram showing an example of temperature characteristics of the resistor according to the same and a resistor of a comparative example.

[0009] Hereinafter, resistors and methods for manufacturing resistors according to embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the following embodiment is merely one of various embodiments of the present disclosure. The following embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, each diagram described in the following embodiment is a schematic diagram, and the ratios of the sizes and thicknesses of the components in the diagram do not necessarily reflect the actual dimensional ratios.

[0010] (1) Embodiment (1.1) Configuration of Chip Resistor The configuration of a resistor 10 of this embodiment will be described with reference to FIGS. 1A to 5. FIG.

[0011] The resistor 10 of this embodiment is a chip resistor for surface mounting (SMT) that is mounted on the surface (mounting surface) of a printed circuit board using, for example, a surface mounter (chip mounter). The resistor 10 is, for example, a thin-film chip resistor.

[0012] As shown in FIG. 1A , the resistor 10 includes an insulating substrate 1, a resistive element 2, a pair of upper electrodes (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.

[0013] (1.1.1) Insulating Substrate The insulating substrate 1 is, for example, a ceramic substrate. The material of the ceramic substrate is, for example, an alumina sintered body having an alumina content of 96% or more. The insulating substrate 1 is, for example, Al ２ O ３ The alumina substrate contains 96% to 99% of (alumina).

[0014] The insulating substrate 1 has, for example, a rectangular shape in a plan view. As shown in FIG. 1A , the insulating substrate 1 has a first main surface 11, a second main surface 12, and an end surface 13. Each of the first main surface 11 and the second main surface 12 has a rectangular shape in a plan view. The end surface 13 includes four side surfaces connecting the first main surface 11 and the second main surface 12. For ease of explanation, the first main surface 11 and the second main surface 12 are shown in the drawings as the upper surface and the lower surface of the insulating substrate 1, respectively.

[0015] (1.1.2) Resistor The resistor 2 is provided on the insulating substrate 1. The resistor 2 is, for example, a thin film, and is provided on the first main surface 11 of the insulating substrate 1. The film thickness Ft1 of the resistor 2 is not particularly limited, but may be, for example, in the range of 5 nm to 1000 nm.

[0016] The resistor 2 is made of, for example, an alloy containing Cr (chromium), Si (silicon), N (nitrogen), and O (oxygen). That is, the resistor 2 contains Cr, Si, N, and O. The atomic ratio of Si to Cr in the resistor 2 is, for example, 2 / 3 or more and 4 or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. Furthermore, the total atomic amount of N among the total atomic amount of elements constituting the resistor 2 is, for example, 50 atomic % or less. In other words, the atomic percentage of N in the resistor 2 is, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2, 50 atomic % or less. Furthermore, the total atomic amount of O among the total atomic amount of elements constituting the resistor 2 is, for example, greater than 10 atomic % and less than 30 atomic %. In other words, the atomic percentage of O in the resistor 2 is, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2, greater than 10 atomic % and less than 30 atomic %. The atomic percentage of O in the resistor 2 may be greater than 10 atom % and less than or equal to 15 atom %, at least at the center of the resistor 2 in the thickness direction D1 of the resistor 2. In the present disclosure, the "thickness direction D1" refers to the direction along the thickness direction of the insulating substrate 1 in the resistor 2. In the present disclosure, the thickness direction of the insulating substrate 1 is the direction in which the main surfaces 11 and 21 are arranged and is perpendicular to the main surfaces 11 and 21.

[0017] The resistor 2 is formed in a substantially rectangular shape by forming a thin film conductor over the entire first main surface 11 of the insulating substrate 1 by sputtering, and then removing unnecessary portions of the thin film conductor using a photolithography process.

[0018] 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, energy dispersive X-ray spectroscopy (TEM-EDX) or electron energy loss spectroscopy (TEX-EELS) attached to a transmission electron microscope (TEM). Alternatively, the atomic composition ratio of the resistor 2 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).

[0019] In the resistor 10 according to this embodiment, the resistive element 2 includes a crystalline phase and an amorphous phase. The crystalline phase is CrSi ２ or Cr ５ S ｉ３ The amorphous phase is composed of Si ３ N ４ or SiO ２ It is composed of the following:

[0020] The resistivity of the resistor 2 is preferably 1,000 μΩ·cm or more and 100,000 μΩ·cm or less.

[0021] (1.1.3) Top Electrode The pair of top electrodes 3 are provided spaced apart from each other on the top surface 21 of the resistor 2. Each of the pair of top electrodes 3 contains at least one of Cu (copper) and Ag (silver). Each of the pair of top electrodes 3 may contain Cu. Each of the pair of top electrodes 3 may be a CuNi (copper-nickel) alloy.

[0022] The pair of upper electrodes 3 are formed, for example, by forming a metal film on the entire upper surface 21 of the resistor 2 by sputtering, and then removing the central portion of the metal film by wet etching.

[0023] (1.1.4) 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 The first protective film 4 is located on the upper surface 21 of the resistor 2 .

[0024] 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. 1A ). 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 also 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 and the pair of upper electrodes 3 by sputtering, and then removing the portions at both ends by wet etching.

[0025] 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.

[0026] (1.1.5) 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. In this embodiment, the second protective film 5 is provided over the upper surface 41 of the first protective film 4 and the upper surface 31 of the upper electrode 3. That is, when viewed from the 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 also continuously covers the first protective film 4 and at least a portion of the pair of upper electrodes 3. In the resistor 10 of this embodiment, the second protective film 5 covers the resistor 2 via the first protective film 4. That is, the second protective film 5 (protective film) covers at least a portion of the upper surface 21 of the resistor 2 opposite the insulating substrate 1 where the pair of electrodes 3 is not provided.

[0027] 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 top electrodes 3 that are located between both ends (portions covering the pair of top electrodes 3) of the first protective film 4 in the longitudinal direction (the left-right direction in FIG. 1A ) and the plating layer 7 are directly covered with the second protective film 5. By providing the second protective film 5, the resistor 2 can be protected.

[0028] (1.1.6) 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. 1A ). The pair of end electrodes 6 is formed on both longitudinal side surfaces of the insulating substrate 1 by, for example, sputtering. Each of the pair of end electrodes 6 is electrically connected to the corresponding one of the pair of top electrodes 3.

[0029] 1A , 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 electrically 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.

[0030] (1.1.8) 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 of the second main surface 12 of the insulating substrate 1 in the longitudinal direction (left-right direction in FIG. 1A ). The pair of rear surface electrodes 8 is formed, for example, by applying epoxy resin to both ends of the second main surface 12 of the insulating substrate 1 in the longitudinal direction by screen printing, and then irradiating the epoxy resin with ultraviolet light to harden it. The pair of rear surface electrodes 8 corresponds one-to-one to the pair of upper surface electrodes 3. Note that the pair of rear surface electrodes 8 may be omitted.

[0031] (1.1.9) Surface Oxynitride Layer FIG. 1B is a cross-sectional view of another resistor 10A according to an embodiment of the present disclosure. In FIG. 1B, the same components as those in the resistor 10 shown in FIG. 1A are denoted by the same reference numerals. In the resistor 10A shown in FIG. 1B, a surface oxynitride layer 14 is formed between the resistor element 2 and the first protective film 4 in the film thickness direction D1 of the resistor element 2. That is, in the resistor 10A, the surface oxynitride layer 14 is provided on the upper surface 21 of the resistor element 2 opposite the insulating substrate 1. The first protective film 4 is provided on the upper surface 141 of the surface oxynitride layer 14, and similar to the resistor 10 shown in FIG. 1A, the second protective film 5 is provided on the upper surface 41 of the first protective film 4. The surface oxynitride layer 14 may be, for example, an oxynitride film containing at least one of Cr and Al, and Si. In this embodiment, as an example, the surface oxynitride layer 14 may be an oxynitride film containing Cr and Si. More specifically, the surface oxynitride layer 14 may contain Cr oxide and SiON. The surface oxynitride layer 14 may be formed by, for example, performing a heat treatment on the upper surface 21 of the resistor element 2 in a heat treatment step.

[0032] Such a surface oxynitride layer 14 has the advantage that a passivation film is formed by the Cr oxide contained in the surface oxynitride layer 14, thereby improving oxidation resistance. Another advantage of the surface oxynitride layer 14 is that the SiON contained in the surface oxynitride layer 14 improves gas barrier properties. That is, by forming such a surface oxynitride layer 14 on the upper surface 21 of the resistor element 2, the environmental resistance of the resistor element 2 can be improved.

[0033] Furthermore, surface oxynitride layer 14 may be provided on a part of upper surface 21 rather than on the entire upper surface 21 of resistor 2. More specifically, surface oxynitride layer 14 may be provided on upper surface 21 of resistor 2 excluding the portions in contact with the pair of upper electrodes 3. In other words, surface oxynitride layer 14 may be provided on upper surface 21 of resistor 2 opposite insulating substrate 1 excluding the portions where the pair of upper electrodes 3 are formed. In this way, surface oxynitride layer 14 is not provided on the portions in contact between resistor 2 and the pair of upper electrodes 3, thereby making it possible to stabilize the electrical connection between resistor 2 and the pair of upper electrodes 3.

[0034] (1.2) Method for Manufacturing Chip Resistor Next, a method for manufacturing the resistor 10 of this embodiment will be described. As shown in Fig. 2, the method for manufacturing the resistor 10 of this embodiment includes a substrate preparation step ST1, a resistor formation step ST2, an electrode formation step ST3, and a protective film formation step ST4. The method for manufacturing the resistor 10 may further include a surface oxynitride layer formation step.

[0035] (1.2.1) Substrate Preparation Step The substrate preparation step ST1 is a step of preparing the insulating substrate 1. In the substrate preparation step ST1, for example, the insulating substrate 1 is arranged so that the first main surface 11 is on the upper side and the second main surface 12 is on the lower side.

[0036] (1.2.2) Resistor Forming Step The resistor forming step ST2 is a step of forming a resistor 2 containing Cr, Si, N, and O on the insulating substrate 1. In the resistor forming step ST2, the resistor 2 is formed on the first main surface 11 of the insulating substrate 1. As shown in Fig. 3 , the resistor forming step ST2 includes a target preparing step ST21, a sputtering step ST22, and a pattern forming step ST23.

[0037] (1.2.2.1) Target Preparation Step The target preparation step ST21 is a step of preparing a target 90. The target 90 here is a member used as a sputtering target in the sputtering step ST22 (see FIG. 4).

[0038] The target 90 contains a metal element (here, Cr) that constitutes the resistor 2. The target 90 further contains elements (here, Si and O) other than the metal element that constitutes the resistor 2. The target 90 contains at least Cr, Si, and O. Note that the target 90 may further contain unavoidable impurities.

[0039] In one example, in the target preparation step, the target 90 is formed by sintering a mixture of chromium and silicon oxide. In another example, in the target preparation step, the target 90 is formed by sintering a mixture of chromium oxide and silicon oxide. In yet another example, in the target preparation step, the target 90 is formed by sintering a mixture of chromium oxide and silicon oxide. By forming the target 90 by sintering in this manner, it is possible to easily form a target 90 having a desired elemental composition ratio. The elemental composition ratio of the target 90 is reflected in the elemental composition ratio of the resistor 2 formed by sputtering using this target 90. The elemental composition ratio of the target 90 is set, for example, so that the atomic ratio of Si to Cr is 2 / 3 or more and 4 or less.

[0040] (1.2.2.2) Sputtering Step The sputtering step ST22 is a step of forming the resistor 2 on the insulating substrate 1 by sputtering using a target 90. In the sputtering step ST22, reactive sputtering is performed using a reactive gas. The reactive gas contains at least nitrogen (N ２ ), optionally containing oxygen (O ２ ) further included.

[0041] That is, in the sputtering step ST22, the resistor 2 is formed on the first main surface 11 of the insulating substrate 1 by, for example, reactive sputtering with nitrogen or reactive sputtering with nitrogen and oxygen. As described above, the target 90 for reactive sputtering (sputtering target) contains Cr, Si, and O. The atomic ratio of Cr to Si in the target 90 is, for example, in the range of 40:60 to 20:80, and in one specific example, may be 30:70. The atomic percentage of O in the target 90 may be 50 atom %. That is, the sputtering target for reactive sputtering contains 50 atom % or less of oxygen (O).

[0042] In the sputtering step ST22, for example, the resistor 2 (more specifically, a thin film that will become the resistor 2 by patterning) is formed over the entire first main surface 11 of the insulating substrate 1.

[0043] 4 shows an example of a sputtering apparatus 9 for performing the sputtering step ST22. The sputtering apparatus 9 includes a vacuum chamber 91, a vacuum pump 92, a valve 93, a gas supply source 94, a substrate holder 95, a backing plate 96, and a power supply 97.

[0044] The vacuum chamber 91 can be evacuated to a vacuum state by evacuating it with a vacuum pump 92 connected via a valve 93. A gas supply source 94 can supply a reactive gas required for sputtering to the vacuum chamber 91 at a constant rate. The valve 93 can control the degree of vacuum in the vacuum chamber 91 to a desired gas pressure by changing its opening / closing ratio. A substrate holder 95 supports an insulating substrate 1 in the vacuum chamber 91 so as to face the target 90. A backing plate 96 supports the target 90 in the vacuum chamber 91. A power supply 97 is electrically connected to the backing plate 96, and by applying a voltage to the target 90 via the backing plate 96, a portion of the gas in the vacuum chamber 91 can be dissociated, generating plasma.

[0045] When the voltage application is on, the target 90 is sputtered by the pulsed plasma generated in the vacuum chamber 91 and ejected, reaching the insulating substrate 1 where a thin film is deposited on the target 90. At the same time, the gas and plasma in the vacuum chamber 91 react with the target 90 being deposited on the insulating substrate 1. Also, when the voltage application is off, the gas and plasma in the vacuum chamber 91 react with the target 90 deposited on the insulating substrate 1, forming a dense compound resulting from the reaction between the target 90 and the gas. In the sputtering device 9, a series of these pulse film formation processes is repeated a predetermined number of times to obtain a high-density compound thin film.

[0046] In the sputtering step ST22, the resistor 2 is formed by reactive sputtering, so the ratio of elements contained in the target 90 of the resistor 2 (atomic ratio of Cr to Si) is substantially the same as the target composition (atomic ratio of Cr to Si). This makes it possible to control the chemical composition of the resistor 2.

[0047] In addition, oxygen (O ２ By adjusting the amount (including zero) of O, the atomic percentage of O in the resistor 2 can be easily controlled.

[0048] (1.2.2.3) Pattern Forming Step The pattern forming step ST23 is a step of forming a pattern of the resistor 2. In the pattern forming step ST23, the resistor 2 is etched by, for example, photolithography to form a pattern of the resistor 2. In the pattern forming step, an etching solution containing, for example, hydrofluoric acid is used. Note that the resistor forming step ST2 does not necessarily have to include the pattern forming step ST23.

[0049] (1.2.3) Electrode Forming Step The electrode forming step ST3 is a step of forming a pair of upper surface electrodes 3 on the resistor 2. In the electrode forming step ST3, a metal film is formed on the entire upper surface 21 of the resistor 2 by, for example, sputtering.

[0050] In the electrode formation process ST3, for example, wet etching is used to remove central portions of the metal film to form a pattern of a pair of upper electrodes 3. In the electrode formation process ST3, for example, an etching solution containing hydrofluoric acid, sulfuric acid, nitric acid, or hydrochloric acid is used.

[0051] (1.2.4) Surface Oxynitride Layer Formation Step The surface oxynitride layer formation step is a step of forming a surface oxynitride layer 14 on the upper surface 21 of the resistor 2 by performing a heat treatment on the resistor 2 to obtain the resistor 10A shown in FIG. 1B.

[0052] In one example, the surface oxynitride layer forming step is performed after the electrode forming step ST3. In this case, the surface oxynitride layer forming step includes a heat treatment step. In the heat treatment step, the resistor 2 is heat-treated after the pair of upper electrodes 3 pattern is formed on the resistor 2 in the electrode forming step ST3. As a result, a surface oxynitride layer 14, which is a surface oxynitride film, is formed on the upper surface 21 of the resistor 2 shown in FIG. 1B. In the heat treatment step, the heat treatment temperature is 500°C or higher and 800°C or lower. In this embodiment, the "heat treatment temperature" refers to the actual temperature of the resistor 2, but may also refer to the ambient temperature. Furthermore, in the heat treatment step, the oxygen concentration is 1000 ppm or lower. When the surface oxynitride layer forming step (heat treatment step) is performed after the electrode forming step ST3, each of the pair of upper electrodes 3 preferably contains a high-melting-point metal. Here, the "high-melting-point metal" refers to a metal whose melting point is equal to or higher than the heat treatment temperature (e.g., 800°C or higher). Examples of high-melting-point metals include W (tungsten), Re (rhenium), Os (osmium), Ta (tantalum), Mo (molybdenum), Ir (iridium), Ru (ruthenium), B (boron), Rh (rhodium), V (vanadium), Cr (chromium), Zr (zirconium), Pt (platinum), Ti (titanium), Pd (palladium), Fe (iron), Y (yttrium), Co (cobalt), Ni (nickel), Si (silicon), Gd (gadolinium), Be (beryllium), Mn (manganese), Cu (copper), Sm (samarium), Au (gold), Ag (silver), Ge (germanium), and Ca (calcium). In this case, after the surface oxynitride layer formation step, a first protective film formation step is performed to form the first protective film 4.

[0053] In another example, the surface oxynitride layer forming step is performed before the electrode forming step ST3. In this case, the surface oxynitride layer forming step includes, for example, a heat treatment step, a first protective film forming step, and an etching step. In the heat treatment step, a heat treatment is performed on the resistor 2 before the upper electrode 3 (metal film) is formed, thereby forming a surface oxynitride film on the entire upper surface 21 of the resistor 2. For example, in the heat treatment step, the insulating substrate 1 on which the resistor 2 is formed is placed in a heat treatment furnace, and heat treatment is performed. As a result, a surface oxynitride film is formed on the upper surface 21 of the resistor 2. The heat treatment temperature is, for example, 400°C or higher and 800°C or lower. In the first protective film forming step, a first protective film 4 is formed on a portion of the surface oxynitride film. In the first protective film forming step, for example, alumina paste is applied to form the first protective film 4 on a portion (central portion) of the surface oxynitride film. In the etching step, the surface oxynitride film provided on the upper surface 21 of the resistor 2 other than the portion on which the first protective film 4 is formed is removed by etching. In the etching step, for example, portions of the surface oxynitride film formed on the upper surface 21 of the resistor 2 that cover regions where the pair of upper electrodes 3 are to be formed are removed. As a result, a surface oxynitride layer 14 is formed on the upper surface 21 of the resistor 2 as shown in FIG. 1B . The etching step may be dry etching or wet etching. In this case, in the electrode formation step ST3, the pair of upper electrodes 3 are formed on the portions of the upper surface 21 of the resistor 2 from which the surface oxynitride film was removed in the etching step.

[0054] (1.2.5) Protective Film Forming Step The protective film forming step (second protective film forming step) ST4 is a step of forming a second protective film 5 (protective film) on the resistor element 2. In the protective film forming step ST4, for example, an epoxy resin is applied by screen printing, and then the epoxy resin is cured by irradiating it with ultraviolet light, thereby forming the second protective film 5.

[0055] (1.2.6) Summary of Manufacturing Method As described above, in the manufacturing method of the resistor 10 of this embodiment, the target 90 used in the sputtering step ST32 contains at least Cr, Si, and O. Then, in the sputtering step ST32, reactive sputtering is performed using a reactive gas that contains nitrogen and optionally contains oxygen. That is, in the manufacturing method of the resistor 10 of this embodiment, the oxygen concentration (atomic percentage of oxygen) of the resistor 2 can be adjusted in both the target preparation step ST31 and the sputtering step ST32. This makes it possible to control the atomic percentage of oxygen in the resistor 2 with high precision, even at a high atomic percentage exceeding 10 atom %.

[0056] Furthermore, in the target preparation step ST31, the target 90 is formed by sintering a mixture of chromium and silicon oxide, or a mixture of chromium oxide and silicon, thereby making it possible to control the composition (Cr:Si:O ratio) of the target 90 with high precision.

[0057] 2 and 3, the manufacturing method of the resistor 10 according to the present embodiment may be modified in order to add or remove processes as appropriate. For example, the target preparation step ST21 may be performed before the substrate preparation step ST1.

[0058] (1.3) Characteristics of Resistor The characteristics of the resistor 2 included in the resistor 10 of this embodiment will be described.

[0059] As described above, in the resistor 10 of this embodiment, the atomic percentage of O in the resistor 2 is greater than 10 atomic % and less than or equal to 30 atomic %, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. As a result of extensive research, the inventors of the present application have found that, when the atomic percentage of O is in the above range, it is possible to realize a resistor 2 having a resistivity in the range of 1000 μΩ cm or more and 50000 μΩ cm or less, a small temperature coefficient of resistance (TCR) of the resistor 10 (for example, −100 to +100), and a sufficiently small difference between hot and cold TCRs (preferably 0).

[0060] Here, TCR is an index (unit: ppm / °C) that indicates how much the resistance value of the resistor 10 changes with temperature change, and is expressed by the following formula (1): ｒ is the reference temperature [°C], and R ｒ is the resistance value [Ω] of the resistor 10 at the reference temperature, T is the test temperature [°C], and R is the resistance value [Ω] of the resistor 10 at the test temperature. ｒ is, for example, 25°C.

[0061]

[0062] The "difference between hot and cold TCR" here refers to the reference temperature T ｒ TCR at a test temperature (hereinafter also referred to as "first temperature T1") higher than Ｈｏｔ ") and the reference temperature T ｒ TCR at a test temperature (hereinafter also referred to as "second temperature T2") lower than Ｃｏｌｄ ") and the difference (TCR Ｈｏｔ -TCR Ｃｏｌｄ ) High temperature side TCR (TCR Ｈｏｔ ) can be calculated by substituting the resistance value R1 measured at a first temperature T1 (for example, 125° C.) as the test temperature and the first temperature T1 into equation (1). Ｃｏｌｄ ) can be obtained by substituting the resistance value R2 measured at the second temperature T2 (for example, -55°C) as the test temperature and the second temperature T2 into equation (1). The fact that the difference between the hot and cold TCRs is sufficiently small (close to 0) means that the high temperature TCR (TCR at the first temperature T1) Ｈｏｔ ) and the low-temperature TCR (TCR at the second temperature T2 Ｃｏｌｄ That is, when the difference between the hot and cold TCRs is sufficiently small, the amount of change in resistivity per unit amount of temperature change (the slope of a graph plotted with the horizontal axis representing temperature and the vertical axis representing the resistivity of resistor 2) is approximately the same at both the first temperature T1 and the second temperature T2.

[0063] 5 shows an example of measurement results of resistance values ​​with respect to temperature changes for a resistor 10 (with O addition) according to an example of this embodiment and a resistor (without O addition) according to a comparative example. Graph G1 is a line connecting the measurement results for the resistor 10 according to the example. Graph G2 is a line connecting the measurement results for the resistor according to the comparative example.

[0064] The resistor 10 of one example is a resistor including a resistor 2 in which the atomic percentage of O at the center of the resistor 2 in the film thickness direction D1 of the resistor 2 is 10.9 atom %. That is, in the resistor 10 of one example, the atomic percentage of O in the resistor 2 is greater than 10 atom % and not more than 30 atom % at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2. On the other hand, the resistor of the comparative example is a resistor formed by reactive sputtering using a target to which oxygen (O) is not added and a reactive gas that does not contain oxygen. That is, the resistor of the comparative example does not contain oxygen other than unintended impurities.

[0065] As shown in graph G2 of Fig. 5, the resistor of the comparative example has different low-temperature side TCR and high-temperature side TCR, and the resistance value changes nonlinearly with temperature. On the other hand, as shown in graph G1 of Fig. 5, the resistor 10 of one example of this embodiment has a sufficiently small difference between the hot and cold TCRs, and the resistance value of the resistor 10 changes approximately linearly with temperature.

[0066] As described above, in the resistor 10 of this embodiment, the resistivity of the resistive element 2 changes linearly with temperature, and the resistance value of the resistor 10 changes linearly with temperature. As a result, it is possible to easily perform temperature compensation for the resistance value of the resistor 10.

[0067] From the viewpoint of reducing the difference between hot and cold TCR and making the temperature change of the resistance value of the resistor 10 closer to linearity, it is desirable that the atomic percentage of O in the resistor 2 is greater than 10 atomic % at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0068] On the other hand, if the atomic percentage of O in the resistor 2 is greater than 30 atomic %, the resistivity increases and the resistor becomes closer to an insulator, making it difficult to function as the resistor 10. Therefore, it is desirable that the atomic percentage of O in the resistor 2 be 30 atomic % or less, at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0069] (2) Modifications The above embodiment is merely one of various embodiments of the present disclosure. Modifications of the embodiment are listed below. The above embodiment and the modifications described below can be applied in appropriate combinations.

[0070] In one modification, the resistor 2 may contain Al (aluminum) in addition to Cr, Si, N, and O. The atomic percentage of Al in the resistor 2 is preferably 30 atomic % or less at least at the center of the resistor 2 in the film thickness direction D1 of the resistor 2.

[0071] In one modified example, each of the pair of upper electrodes 3 may contain two or more high-melting-point metals. In this case, each of the pair of upper electrodes 3 may have a single-layer structure of an alloy made of two or more high-melting-point metals, or may have a multilayer structure in which two or more high-melting-point metals are stacked.

[0072] In one variant, the pair of top electrodes 3 may be patterned by dry etching.

[0073] In one modified example, the pair of upper electrodes 3 may be formed by screen printing using a paste material.

[0074] In the embodiments, terms indicating directions such as "top surface" indicate relative directions determined only by the relative positional relationship of the constituent components of the resistor, such as the insulating substrate and the resistive element, and do not indicate absolute directions such as the vertical direction.

[0075] (3) Aspects As is clear from the above-described embodiments and modifications, the present specification discloses the following aspects.

[0076] The resistor (10) of the first aspect comprises an insulating substrate (1), a resistive element (2), and a pair of electrodes (upper surface electrodes 3). The resistive element (2) is provided on the insulating substrate (1). The pair of electrodes are provided spaced apart from each other on the resistive element (2). The resistive element (2) contains Cr, Si, N, and O. The atomic percentage of O in the resistive element (2) is greater than 10 atom % and less than or equal to 30 atom %, at least at the center of the resistive element (2) in the film thickness direction (D1) of the resistive element (2).

[0077] According to this embodiment, it is possible to make the temperature change of the resistivity of the resistor 2 closer to linear, and it is also possible to make the temperature change of the resistance value of the resistor 10 closer to linear, so that when the resistance value of the resistor 10 changes due to a change in temperature, it is possible to easily perform temperature compensation.

[0078] The resistor (10) of the second aspect is the same as the resistor (10) of the first aspect, but further includes a protective film (second protective film 5). The protective film covers at least a portion of the upper surface (21) of the resistor (2) opposite the insulating substrate (1) where the pair of electrodes (upper surface electrodes 3) are not provided.

[0079] According to this embodiment, the resistor (2) can be protected by providing the protective film (second protective film 5).

[0080] The manufacturing method of the third aspect is a method for manufacturing a resistor (10) and includes a substrate preparation step (ST1), a resistor formation step (ST2), and an electrode formation step (ST3). The substrate preparation step (ST1) includes preparing an insulating substrate (1). The resistor formation step (ST2) includes forming a resistor (2) containing Cr, Si, N, and O on the insulating substrate (1). The electrode formation step (ST3) includes forming a pair of electrodes (upper electrodes 3) on the resistor (2). The resistor formation step (ST2) includes a target preparation step (ST21) and a sputtering step (ST22). The target preparation step (ST21) includes preparing a target (90) containing metal elements that constitute the resistor (2). The sputtering step (ST22) includes forming the resistor (2) on the insulating substrate (1) by sputtering using the target (90). The target (90) contains at least Cr, Si, and O. The sputtering step (ST22) includes performing reactive sputtering using a reactive gas containing nitrogen.

[0081] According to this embodiment, it is possible to control the atomic percentage of oxygen in the resistor (2) with high precision even if it is a high atomic percentage exceeding 10 atom %.

[0082] In the method for manufacturing the resistor (10) of the fourth aspect, the target preparation step (ST21) in the third aspect includes sintering a mixture of chromium and silicon oxide.

[0083] According to this embodiment, it becomes possible to control the composition (Cr:Si:O ratio) of the target (90) with high precision.

[0084] In the method for manufacturing a resistor (10) of the fifth aspect, in the third aspect, the target preparation step (ST21) includes sintering a mixture of chromium oxide and silicon.

[0085] In the method for manufacturing a resistor (10) of the sixth aspect, in the third aspect, the target preparation step (ST21) includes sintering a mixture of chromium oxide and silicon oxide.

[0086] According to this embodiment, it becomes possible to control the composition (Cr:Si:O ratio) of the target (90) with high precision.

[0087] The method for manufacturing the resistor (10) of the seventh aspect, in any one of the third to sixth aspects, further includes a protective film forming step (ST4) of forming a protective film (second protective film 5) on the resistor (2).

[0088] According to this embodiment, the resistor (2) can be protected by providing the protective film (second protective film 5).

[0089] In the method for manufacturing a resistor (10) of the eighth aspect, in any one of the third to seventh aspects, the reactive gas further contains oxygen.

[0090] According to this embodiment, it is possible to control the atomic percentage of oxygen in the resistor (2) with high precision even if it is a high atomic percentage exceeding 10 atom %.

[0091] REFERENCE SIGNS LIST 10 resistor 1 insulating substrate 2 resistor 21 upper surface 3 upper surface electrode (electrode) 5 second protective film (protective film) 90 target D1 film thickness direction ST1 substrate preparation step ST2 resistor formation step ST21 target preparation step ST22 sputtering step ST3 electrode formation step ST4 protective film formation step

Claims

1. A resistor comprising: an insulating substrate; a resistor provided on an upper surface of the insulating substrate; and a pair of electrodes provided spaced apart on the resistor, wherein the resistor contains Cr, Si, N, and O, and the atomic percentage of O in the resistor is greater than 10 atom % and less than or equal to 30 atom %, at least at the center of the resistor in the film thickness direction of the resistor.

2. The resistor according to claim 1, further comprising a protective film that covers at least a portion of the upper surface of the resistor element where the pair of electrodes is not provided.

3. A method for manufacturing a resistor, comprising the steps of: preparing an insulating substrate; forming a resistor containing Cr, Si, N, and O on the insulating substrate; and forming a pair of electrodes on the resistor, wherein the step of forming the resistor comprises the steps of: preparing a target containing Cr, Si, and O, the metal elements that constitute the resistor; and forming the resistor on the insulating substrate by reactive sputtering using a reactive gas containing nitrogen, using the target.

4. The manufacturing method according to claim 3, wherein the step of preparing the target includes a step of sintering a mixture of chromium and silicon oxide.

5. The manufacturing method according to claim 3, wherein the step of preparing the target includes a step of sintering a mixture of chromium oxide and silicon.

6. The manufacturing method according to claim 3, wherein the step of preparing the target includes a step of sintering a mixture of chromium oxide and silicon oxide.

7. The manufacturing method according to any one of claims 3 to 6, further comprising the step of forming a protective film on the resistor.

8. The manufacturing method according to any one of claims 3 to 6, wherein the reactive gas further contains oxygen.

Images