Resistor

Abstract

Provided is a resistor having an inorganic material substrate with which deformation can be suppressed in a use temperature range, the resistor being capable of measuring the temperature of a curved surface.　The resistor (1) is provided with: an insulating inorganic material substrate (2) which is flexible, which has a thickness dimension of 1 μm to 100 μm, and deformation of which due to phase transition is suppressed in the use temperature range; a resistance film (4) which is formed on the inorganic material substrate (2); at least a pair of electrode layers (3a, 3b) which are electrically connected to the resistance film (4); and a protective film (5) which covers a region where the resistance film (4) is formed and forms an exposed portion where the electrode layers (3a, 3b) are at least partially exposed.

Description

resistor

[0001] The present invention relates to a resistor that can be made thin.

[0002] Electronic components such as thermal resistance elements are used as resistors in electronic devices such as information and communication devices, including mobile communication terminals and personal computers, as well as wearable devices, medical devices, consumer devices, and automotive electrical equipment. In recent years, there has been a demand for thinner electronic devices, and development is underway to achieve thinner electronic components and suppress their deterioration despite the constraints on the thickness of electronic devices.

[0003] For example, it has been proposed to fabricate resistors using ultrathin substrates with thicknesses of 100 μm or less (see Patent Document 1). However, in addition to reducing the thickness of the substrate, there is a need to improve the flexibility of the substrate and to suppress deterioration of the substrate, specifically, to suppress deformation of the substrate within the operating temperature range. Generally, when manufacturing highly heat-resistant thin-film thermistors using ultrathin inorganic substrates with thicknesses of 100 μm or less, the substrate easily cracks during high-temperature processes, making manufacturing impossible in many cases. As a currently superior technology, a transparent thin-film thermistor using a glass substrate that can withstand temperatures up to 150°C has been disclosed (see Patent Document 2).

[0004] Japanese Patent No. 6225295 JP 2021-131379

[0005] However, for the glass substrate shown in Patent Document 2, no specific thickness dimensions or characteristics of the substrate are disclosed.

[0006] The embodiments of the present invention have been made in consideration of the above-mentioned problems, and have an object to provide a resistor having an inorganic material substrate that can measure the temperature of a curved surface at a heat-resistant temperature of 200°C or higher and that is suppressed from deforming within the operating temperature range.

[0007] A resistor according to an embodiment of the present invention is characterized by comprising: an insulating inorganic material substrate that is flexible and has a thickness of 1 μm to 100 μm, and that is suppressed from deformation due to phase transition within an operating temperature range; a resistive film formed on the inorganic material substrate; at least one pair of electrode layers electrically connected to the resistive film; and a protective film that covers the area where the resistive film is formed and forms exposed portions so that at least a portion of the electrode layer is exposed. The inorganic material substrate can be a glass substrate or a ceramic substrate. According to this invention, for example, an inorganic material substrate that can measure the temperature of a curved surface and is suppressed from deformation within an operating temperature range can be obtained.

[0008] It is possible to provide a thin resistor that includes an inorganic material substrate that is flexible and suppresses deformation within the operating temperature range.

[0009] 1 is a plan view showing a resistor according to an embodiment of the present invention; FIG. 2 is a cross-sectional view showing the resistor; FIG. 3 is a plan view showing a resistor according to another embodiment of the present invention; FIG. 4 is a cross-sectional view showing the resistor; FIG. 5 is a microscope image showing evaluation results of a resistor according to an embodiment of the present invention; FIG. 6 is a microscope image showing the evaluation results; FIG. 7 is a table showing evaluation results of the resistor with a glass substrate and a zirconia substrate; FIG. 8 is a table showing evaluation results of the resistor with and without a protective film; FIG. 9 is a table showing water vapor and oxygen permeability of the glass substrate and a representative resin film of the resistor; FIG. 10 is a table showing the effect of forming a protective film on the glass substrate of the resistor; FIG. 11 is a table showing evaluation results of various forms of forming a protective film on the glass substrate of the resistor; FIG. 12 is a table showing evaluation results for ceramic materials; FIG. 13 is a microscope image showing evaluation results of a resistor with a zirconia substrate; FIG. 14 is a microscope image showing evaluation results of a resistor with a zirconia substrate.

[0010] A resistor according to an embodiment of the present invention will be described with reference to the drawings. First, the prior art (see Patent Document 1) will be described. FIG. 5 of Patent Document 1 (FIG. 12 in the present application) shows the results of an evaluation of whether ceramic materials can be used to fabricate insulating substrates with a thickness of 50 μm. According to these results, Sample No. 5 is made of zirconia, has an average particle size of 0.5 μm after firing, and has a bending strength of 1200 MPa, and is expected to enable the realization of an extremely thin and flexible insulating substrate.

[0011] However, it has been found that resistors with zirconia substrates deform when left in the operating temperature range of the resistor. Figure 13 shows a microscope image of a resistor with a zirconia substrate observed from the side after being left in a temperature environment of 150°C for 1000 hours. Figure 14 shows a microscope image of a resistor with a zirconia substrate observed from the side after being left in a temperature environment of 200°C for 200 hours.

[0012] In Figure 13, it can be seen that the radius of curvature is 15.89 mm, and the deformation amount of the substrate is 0.35 mm, which is a convex arc. In Figure 14, it can be seen that the radius of curvature is 8.47 mm, and the deformation amount of the substrate is 0.62 mm, which is a convex arc. Such deformation makes the substrate brittle and deteriorates, reducing its strength.

[0013] This deformation of the substrate is thought to be due to a phase transition of zirconia. Zirconia is monoclinic at room temperature, but its crystal structure undergoes a phase transition to tetragonal at approximately 1170°C and to cubic at approximately 2200°C. Therefore, zirconia substrates may be damaged in a temperature environment where the temperature rises and falls repeatedly.

[0014] A commonly used zirconia substrate is a partially stabilized zirconia substrate. ２ O ３ However, as mentioned above, a phase transition occurs in a temperature environment of about 200°C, and the phase transition from tetragonal to monoclinic crystals causes deterioration and a decrease in strength.

[0015] However, as a result of various investigations, it was found that cerium oxide (CeO ２ We have found that phase transition can be suppressed by incorporating rare earth oxides such as zirconia into the solid solution. Therefore, we have found that it is possible to realize a substrate that can suppress deterioration due to phase transition, even for zirconia substrates, which are ceramic substrates made of inorganic materials. Furthermore, even in glass substrates, cracks that occur due to volume expansion caused by phase transition in the crystalline layer can progress and lead to sudden breakage.

[0016] The thickness D of the glass plate having high toughness and high flexibility is, for example, 1 μm to 100 μm. The thickness D indicates, for example, an average thickness. Furthermore, in order to obtain a glass tape having sufficiently high toughness and sufficiently high flexibility when producing a glass substrate, the thickness D of the glass tape is preferably 4 μm to 50 μm, and more preferably 10 μm to 30 μm. In light of the above, a resistor according to an embodiment of the present invention will be described with reference to FIGS. 1 to 11.

[0017] 1 to 4 show resistors, and Fig. 5 to Fig. 11 show evaluation results of the resistors. Note that in Fig. 1 to Fig. 4, the scale of each component has been appropriately changed for the purpose of explanation so that each component can be recognized. As shown in Fig. 1 and Fig. 2, the resistor 1 includes an insulating substrate 2, a pair of electrode layers 3a, 3b, a resistive film 4, and a protective film 5.

[0018] In this embodiment, the resistor 1 is a thermal resistance element that functions as a temperature sensor, and is a thin-film thermistor. The resistor may be a resistor having a resistive film regardless of its characteristics, and may be a thermistor simply having electrical resistance, a thermistor having a negative temperature coefficient, or a thermistor having a positive temperature coefficient.

[0019] The resistor 1 is formed in a substantially rectangular parallelepiped shape, with a horizontal dimension of 6.0 mm, a vertical dimension of 2.0 mm, and a total thickness of 60 μm. The shape and dimensions are not particularly limited and can be appropriately selected depending on the application.

[0020] The insulating substrate 2 is a substantially rectangular insulating inorganic material substrate. Specifically, it is a glass substrate made of a glass material, such as silicon dioxide (SiO ２ ) is contained at 40 to 80%.

[0021] Specifically, the glass substrate contains, in mass %, SiO ２ 60-70%, B ２ O ３ 10-20%, Al ２ O ３ 0-10%, CaO0-10%, ZnO0-10%, Sb ２ O ３ The glass substrate contains, in mass %, SiO ２ 55-65%, Al ２ O ３ 13-18%, B ２ O ３ The insulating substrate 2 may contain 8 to 13% of MgO, 10 to 20% of RO (MgO + CaO + SrO + BaO), and 10 to 20% of RO (MgO + CaO + SrO + BaO). The insulating substrate 2 has a thickness of 1 μm to 100 μm, specifically 10 μm to 50 μm, and preferably 30 μm or less.

[0022] Furthermore, insulating substrate 2 is flexible and has a Young's modulus of 250 GPa or less, which makes it possible to measure temperature by fitting resistor 1 along a curved surface, for example. Furthermore, in order to determine the conditions for manufacturing insulating substrate 2 so that the thickness dimension is 50 μm or less, the inventors conducted various investigations and selection processes during the development process, focusing on the Young's modulus of insulating substrate 2, and found that the Young's modulus is a value of 250 GPa or less.

[0023] Furthermore, the linear expansion coefficient of the insulating substrate 2 is 3×10 －６ / ℃ ~18×10 －６ / °C, and preferably 5 x 10 －６ / ℃ ~12 × 10 －６ / °C. By setting the linear expansion coefficient within this range, damage to the resistive film 4 due to dimensional changes caused by temperature changes when forming the resistive film 4 or when the resistor 1 is in use can be suppressed.

[0024] The pair of electrode layers 3a, 3b are formed on the insulating substrate 2 and are electrically connected to the resistive film 4. The pair of electrode layers 3a, 3b are arranged facing each other with a predetermined gap between them. Specifically, the pair of electrode layers 3a, 3b are formed by sputtering a thin metal film. Examples of the metal material include precious metals such as platinum (Pt), gold (Au), silver (Ag), palladium (Pd), and ruthenium (Ru), as well as alloys thereof, such as Ag-Pd alloys. In this embodiment, the electrode layers 3a, 3b are formed below the resistive film 4, but they may also be formed on or within the resistive film 4. Specifically, the electrode layers 3a, 3b are made of platinum, have an oxygen and / or nitrogen content of 0.01% by weight or more and 4.9% by weight or less, and are crystalline.

[0025] The resistive film 4 is a heat-sensitive thin film, which is a thermistor thin film made of an oxide semiconductor having a negative temperature coefficient. The resistive film 4 is formed by sputtering on the insulating substrate 2 and on the electrode layers 3 a and 3 b so as to straddle the electrode layers 3 a and 3 b and is electrically connected to the electrode layers 3 a and 3 b.

[0026] The resistive film 4 is made of a thermistor material containing, as its main component, a composite metal oxide having a spinel structure, composed of two or more elements selected from transition metal elements such as manganese (Mn), nickel (Ni), cobalt (Co), and iron (Fe). Subcomponents may also be included to improve characteristics. The composition and content of the main and subcomponents can be determined appropriately depending on the desired characteristics. In this embodiment, the heat-sensitive thin film of the resistive film 4 is a metal oxide of Mn-Co-Ni.

[0027] The resistive film 4 can also be made of a metal nitride, which can be a nitride expressed by the general formula MxAyNz (where M represents Ta, A represents Al, 0.67≦x≦0.7, 0.01≦y≦0.02, 0.28≦z≦0.32, and x+y+z=1).

[0028] The protective film 5 covers the region where the resistive film 4 is formed, and also covers the electrode layers 3a and 3b by forming exposed portions 31a and 31b so that at least a part of the electrode layers 3a and 3b is exposed. The protective film 5 is made of silicon dioxide (SiO ２ ), silicon nitride (Si ３ N ４ ), etc., can be formed by sputtering, or lead glass, borosilicate glass, lead borosilicate glass, etc., can be formed by printing. The protective film 5 can also have a multi-layer structure by laminating two or more materials selected from the above materials. In other words, a multi-layer structure can be formed by laminating different materials. For example, silicon dioxide (SiO ２ ) and borosilicate glass may be laminated to form a two-layer structure.

[0029] By forming the protective film 5 in a multi-layer structure, the resistive film 4 can be protected, and the fluctuation of the resistance value due to the ambient temperature environment can be reduced, thereby enhancing the effect of suppressing the fluctuation of the characteristics.

[0030] Next, a resistor according to another embodiment will be described with reference to Figures 3 and 4. Note that parts that are the same as or equivalent to those of the resistor shown in Figures 1 and 2 are designated by the same reference numerals, and duplicated explanations will be omitted.

[0031] In this embodiment, a barrier layer 6 is formed on an insulating substrate 2. More specifically, the barrier layer 6 is interposed between the insulating substrate 2 and the electrode layers 3a, 3b and the resistive film 4, to prevent diffusion due to heat between the insulating substrate 2 and the resistive film 4. In this case, the barrier layer 6 is made of silicon dioxide (SiO ２ ), silicon nitride (Si ３ N ４ ) or the like can be formed by sputtering. Next, evaluation results of the resistor according to the above embodiment will be described with reference to FIGS.

[0032] The resistor 1 configured as described above was evaluated when left in the operating temperature range, as described above. Fig. 5 shows a microscope image of the resistor 1 on the glass substrate, observed from the side, after being left in a temperature environment of 150°C for 1000 hours. Fig. 6 shows a microscope image of the resistor 1 on the glass substrate, observed from the side, after being left in a temperature environment of 200°C for 1000 hours.

[0033] As is clear from the figure, the glass substrate of this embodiment is able to suppress deformation due to phase transition and reduce the decrease in strength within the operating temperature range, which is the temperature range in which the resistor 1 is used in various situations, and is assumed to be between -80°C and 300°C.

[0034] 7 is a table showing an evaluation of the glass substrate of this embodiment (sample No. 1) and a commonly used zirconia substrate (sample No. 2). The table shows the appearance, resistance value, and rate of change of the B constant from the initial value after the resistor was left in a temperature environment of 200° C. for 1000 hours. It can be seen that the glass substrate of this embodiment shows no deformation, and the change in resistance value is suppressed to 3.11% even after 1000 hours, and the B constant remains almost unchanged.

[0035] 8 is a table showing the evaluation of the glass substrate of this embodiment when a protective film is formed (sample No. 1) and when a protective film is not formed (sample No. 2). When a protective film is formed, the silicon dioxide (SiO ２ The resistor has a two-layer structure of a protective film and borosilicate glass as the glass. The graph shows the rate of change in resistance and B constant from the initial value after the resistor was left in a 100°C temperature environment for 100 hours. It can be seen that the formation of a protective film can suppress fluctuations in resistance value.

[0036] FIG. 9 is a table showing the water vapor and oxygen permeability of the glass substrate (sample No. 1) of this embodiment and a representative resin film. The table shows the water vapor permeability and oxygen permeability of the resin films polyimide (sample No. 2), polyethylene terephthalate (PET) (sample No. 3), and polyethylene naphthalate (PEN) (sample No. 4). Glass has a significantly lower permeability to both water vapor and oxygen than resin films. Therefore, when a glass substrate is used in a resistor, it can be expected to suppress fluctuations in characteristics and improve reliability.

[0037] 10 is a table showing the effect of forming a protective film on the glass substrate (sample No. 1) of this embodiment. ２ The graph shows the rate of change in the resistance and B constant from the initial value after the resistor was left in an environment of 40°C and 95% RH for 1000 hours. It can be seen that the fluctuations in both the resistance and B constant are very small.

[0038] FIG. 11 shows a glass substrate according to this embodiment in which the protective film is made of silicon dioxide (SiO ２ ) and borosilicate glass (Sample No. 1), silicon dioxide (SiO ２ ) alone (Sample No. 2), silicon nitride (Si ３ N ４ The graph shows the rate of change in the resistance and B constant when only a protective film is formed (Sample No. 3) and when no protective film is formed (Sample No. 4). The rate of change in the resistance and B constant from the initial value after leaving the resistor in a temperature environment of 260°C for 100 hours shows that these fluctuations can be suppressed by forming a protective film. In addition, when the protective film is made of silicon nitride (Si ３ N ４ ) (Sample No. 3), the fluctuations in the rate of change of the resistance value and the B constant can be effectively reduced.

[0039] As described above, according to this embodiment, the insulating substrate 2 can be made thinner, deformation can be suppressed, and fluctuations in characteristics can be suppressed, making it possible to provide a highly accurate resistor 1.

[0040] The present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible within the scope of the invention. Furthermore, the above-described embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0041] 1...Resistor 2...Insulating substrate 3a, 3b...Electrode layer 31a, 31b...Exposed portion 4...Resistive film 5...Protective film 6...Barrier layer

Claims

1. an insulating inorganic material substrate having flexibility and a thickness of 1 μm to 100 μm, made of a ceramic material in which rare earth oxide is solid-solved in zirconia, and in which deformation due to phase transition is suppressed at least in the temperature range of −80° C. to 300° C.; a resistive film formed on the inorganic material substrate; At least one pair of electrode layers electrically connected to the resistive film; a protective film that covers the region where the resistive film is formed and forms an exposed portion so that at least a part of the electrode layer is exposed; A resistor comprising:

2. A resistor as described in claim 1, characterized in that the rare earth oxide of the ceramic material is cerium oxide.

3. An insulating inorganic material substrate having flexibility and a thickness of 1 μm to 100 μm, and made of a glass material that does not undergo a phase transition at least in the temperature range of -80°C to 300°C; a resistive film formed on the inorganic material substrate; At least one pair of electrode layers electrically connected to the resistive film; a protective film that covers the region where the resistive film is formed and forms an exposed portion so that at least a part of the electrode layer is exposed; A resistor comprising:

4. The glass material is A composition of, in mass %, SiO 2 : 60 to 70%, B 2 O 3 : 10 to 20%, Al 2 O 3 : 0 to 10%, CaO: 0 to 10%, ZnO: 0 to 10%, Sb 2 O 3 : 0<1%, or The resistor according to claim 3, characterized in that it has a composition, in mass %, of SiO 2 : 55 to 65%, Al 2 O 3 : 13 to 18%, B 2 O 3 : 8 to 13%, and RO (MgO + CaO + SrO + BaO): 10 to 20%.

5. The inorganic material substrate has a Young's modulus of 250 GPa or less and a linear expansion coefficient of 3×10 －６ / ℃ or more 18 x 10 －６ 5. The resistor according to claim 1, wherein the temperature is 0.15°C or less.

6. 5. The resistor according to claim 1, wherein a barrier layer is formed on the inorganic material substrate.

7. 5. A resistor according to claim 1, wherein the protective film is silicon dioxide or silicon nitride.

8. 5. The resistor according to claim 1, wherein the protective film has a multi-layer structure in which different materials are laminated.

9. 9. The resistor according to claim 8, wherein the protective film has a two-layer structure of silicon dioxide and glass.

10. 5. A resistor according to claim 1, wherein the resistive film is a heat-sensitive thin film.

11. 11. The resistor of claim 10, wherein the heat-sensitive thin film is a metal oxide or a metal nitride.

12. 12. The resistor of claim 11, wherein the metal oxide is a Mn-Co-Ni oxide.

13. 12. The resistor according to claim 11, wherein the metal nitride is a nitride represented by the general formula MxAyNz (wherein M represents Ta, A represents Al, 0.67≦x≦0.7, 0.01≦y≦0.02, 0.28≦z≦0.32, and x+y+z=1).

14. 5. A resistor according to claim 1, wherein the electrode layer is made of platinum, the content of at least one of oxygen and nitrogen is 0.01% by weight or more and 4.9% by weight or less, and the resistor is crystalline.