WO2023140054A1 - Thermistor element and method for manufacturing same - Google Patents
Thermistor element and method for manufacturing same Download PDFInfo
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- WO2023140054A1 WO2023140054A1 PCT/JP2022/047772 JP2022047772W WO2023140054A1 WO 2023140054 A1 WO2023140054 A1 WO 2023140054A1 JP 2022047772 W JP2022047772 W JP 2022047772W WO 2023140054 A1 WO2023140054 A1 WO 2023140054A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
- H01C17/02—Apparatus or processes specially adapted for manufacturing resistors adapted for manufacturing resistors with envelope or housing
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient
Definitions
- the present invention relates to a thermistor element suitable for temperature sensors, protection circuits of electronic devices, and the like, and a method for manufacturing the same.
- Thermistors are widely used in temperature sensors, protection circuits of electronic devices, etc., because their resistance values change with temperature and the changes are very sensitive to temperature. Transition metals constituting such thermistors, for example, NTC thermistors, can take a wide variety of valence states, and thermistor materials are easily affected by the outside air. In particular, in a glass diode-type thermistor element enclosed in a glass tube, oxygen defects occur in the thermistor material in an inert atmosphere during encapsulation, and in a reducing atmosphere when solder reflow is performed for flake-type thermistors, resulting in changes in their characteristics.
- Patent Document 1 describes a method of forming a glass layer by applying and baking a glass paste from the electrode surface and exposing a region on the ridge of the thermistor body to make contact with the electrode film.
- the glass layer formed on the thermistor element is thick, and the melted and solidified glass adheres firmly to the surface of the electrode, making it difficult to peel off in some cases.
- the present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a thermistor element that has good electrical connection and high mountability and suppresses the formation of oxygen defects, and a method for manufacturing the same.
- the thermistor element of the first invention is characterized by comprising a chip-shaped or plate-shaped thermistor body, a pair of electrode films formed on the upper and lower surfaces of the thermistor body, and an insulating protective film formed on the outer peripheral surface of the thermistor body and the pair of electrode films, wherein the protective film is removed and an electrode film exposed portion is provided at least in the central portion of the surface of the electrode film.
- the protective film since the protective film is removed and the electrode film exposed portion is provided at least in the central portion of the surface of the electrode film, the protective film covering the outer peripheral surface can ensure reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability. It should be noted that it is not necessary to provide the electrode film exposed portion on the entire central portion, and it is sufficient that the electrode film exposed portion is provided on at least a part of the central portion.
- a thermistor element according to a second aspect of the invention is characterized in that, in the first aspect, the protective film is made of a material having a weaker adhesion strength to the electrode film than to the thermistor body. That is, in this thermistor element, since the protective film is made of a material having a weaker adhesion strength to the electrode film than to the thermistor element body, the protective film is firmly adhered to the outer peripheral surface of the thermistor element body, and the protective film on the electrode film is easily peeled off, so that the electrode film exposed portion can be easily formed partially.
- a thermistor element of a third invention is characterized in that, in the first or second invention, the electrode film is made of a noble metal, and the protective film is an oxide film or a nitride film. That is, in this thermistor element, the electrode film is formed of a noble metal, and the protective film is an oxide film or a nitride film. Therefore, an oxide film or a nitride film having strong adhesion to the oxide material (for example, perovskite-based material or spinel-based material) constituting the thermistor of the thermistor element and weak adhesion to the noble metal can be easily formed by a vapor phase method such as sputtering or CVD or a liquid phase deposition method.
- a vapor phase method such as sputtering or CVD or a liquid phase deposition method.
- a thermistor element of a fourth invention is characterized in that, in any one of the first to third inventions, the protective film has a thickness of 10 nm or more and 1000 nm or less. That is, in this thermistor element, the reason why the thickness of the protective film is set to 10 nm or more and 1000 nm or less is that if the thickness is less than 10 nm, the reduction resistance is not sufficient and the effect of suppressing oxygen defects is reduced, and if it exceeds 1000 nm, the protective film is too thick to be easily peeled off and the step with the exposed portion of the electrode film becomes large, resulting in insufficient electrical conduction.
- a thermistor element of a fifth invention is the thermistor element according to any one of the first to fourth inventions, characterized in that the coverage of the protective film on the outer peripheral surface of the thermistor body is larger than the coverage of the protective film on the surface of the electrode film.
- a thermistor element of a sixth aspect of the invention is characterized in that, in any one of the first to fifth aspects of the invention, a coverage ratio of the protective film in the surface of the electrode film is 90% or less. That is, in this thermistor element, the reason why the coverage of the protective film in the plane of the electrode film is set to 90% or less is that if the coverage exceeds 90%, the area of the exposed portion of the electrode film becomes too small and sufficient mounting strength may not be obtained.
- a method for manufacturing a thermistor element according to a seventh invention is a method for manufacturing the thermistor element according to any one of the first to sixth inventions, comprising: an electrode film forming step of forming a pair of electrode films on the upper and lower surfaces of a chip-shaped or plate-shaped thermistor element; a protective film forming step of forming an insulating protective film on the outer peripheral surface of the thermistor element and the pair of electrode films to produce a protective film-formed chip; and a protective film peeling step of forming an electrode film exposed portion where the electrode film is exposed by peeling.
- this method for manufacturing the thermistor element includes a protective film peeling step of peeling off the protective film at least in the central portion of the electrode film to form an electrode film exposed portion where the electrode film is exposed, the electrode film exposed portion can be formed in the central portion of the electrode film while leaving the protective film on the outer peripheral surface.
- a protective film is once formed on the outer peripheral surface of the thermistor element and the pair of electrode films, i.e., the entire surface, and then the protective film is peeled off at the central portion within the surface of the electrode film.
- a method for manufacturing a thermistor element according to an eighth invention is characterized in that, in the seventh invention, in the protective film forming step, the protective film is formed of a material having a weaker adhesion strength to the electrode film than to the thermistor body.
- a method for manufacturing a thermistor element according to the seventh or eighth aspect wherein in the protective film stripping step, the protective film-forming chip is barrel-polished to strip the protective film at least at the central portion within the plane of the electrode film. That is, in this method for manufacturing a thermistor element, in the protective film peeling step, the protective film-formed chip is barrel-polished to peel off at least the protective film in the center of the surface of the electrode film.
- the protective film on the electrode film can be peeled off by barrel polishing while leaving the protective film on the outer peripheral surface of the thermistor element body.
- the protective film is removed and the electrode film exposed portion is provided at least in the central portion in the plane of the electrode film, the protective film covering the outer peripheral surface can ensure the reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability. Therefore, according to the thermistor element and the manufacturing method thereof of the present invention, it is possible to obtain a chip-shaped thermistor element that has stable characteristics with a small change in resistance value after heat treatment, etc., and high mountability.
- FIG. 1 is a cross-sectional view showing a thermistor element in an embodiment of the thermistor element and method for manufacturing the same according to the present invention
- FIG. FIG. 2 is a cross-sectional view showing a protective film forming chip in this embodiment.
- 1 is an electron microscope image of a top surface of a thermistor element in Example 1 of the thermistor element and the manufacturing method thereof according to the present invention.
- 1 is an electron microscope image of a top surface of a thermistor element in Comparative Example 1 of the thermistor element and the method of manufacturing the same according to the present invention.
- FIG. 10 is an electron microscopic image of the top surface of the thermistor element in Comparative Example 2 of the thermistor element and the manufacturing method thereof according to the present invention.
- FIG. FIG. 10 is an electron microscope image of the top surface of the thermistor element in Example 6 of the thermistor element and the method of manufacturing the same according to the present invention.
- FIG. FIG. 10 is an electron microscopic image of a side view of a thermistor element in Example 6 of the thermistor element and the manufacturing method thereof according to the present invention.
- FIG. 1 An embodiment of a thermistor element and a method for manufacturing the same according to the present invention will be described below with reference to FIGS. 1 and 2.
- FIG. 1 the reduced scale is appropriately changed in order to make each member recognizable or easily recognizable.
- the thermistor element 1 of the present embodiment includes a chip-shaped or plate-shaped (flake-shaped) thermistor body 2a, a pair of electrode films 2b formed on the upper and lower surfaces of the thermistor body 2a, and an insulating protective film 2c formed on the outer peripheral surface of the thermistor body 2a and the pair of electrode films 2b.
- An electrode film exposed portion 2d is provided by removing the protective film 2c at least in the central portion of the surface of the electrode film 2b.
- the chip-shaped thermistor element is an element made of a thermistor material having a shape such as a cube, which is thicker than a plate-like shape. In other words, the chip-shaped thermistor element does not mean a so-called chip thermistor that is generally used for surface mounting.
- electrode film exposed portion 2d there is a portion (electrode film exposed portion 2d) where the protective film 2c is peeled off inside the ridge line of the thermistor body 2a in the plane of the electrode film 2b.
- the protective film 2c is peeled off and the electrode film exposed portion 2d exists at least in the central portion of the surface of the electrode film 2b.
- the central portion indicates a range in which the shape is similar to that of the electrode film 2b and the area is 1/4 at the center of the electrode film 2b.
- the electrode film 2b has a square shape, it is a region inside from the outer peripheral edge to 1/4 of the length of one side of the electrode film 2b.
- barrel polishing which will be described later, to form an electrode film exposed portion 2d.
- the protective film 2c is made of a material having a weaker adhesion strength with the electrode film 2b than with the thermistor body 2a. That is, the electrode film 2b is made of a noble metal, and the protective film 2c is an oxide film or a nitride film.
- the electrode film 2b is a metal film containing at least one of Pt, Au and Ag
- the protective film 2c is an oxide film such as SiO 2 , Al 2 O 3 , ZrO 2 and HfO 2 or a nitride film such as AlN and Si 3 N 4 .
- the protective film 2c is a thin film having a thickness of 10 nm or more and 1000 nm or less.
- the thickness of the protective film 2c may be 100 nm or more and 800 nm or less.
- the coverage ratio of the protective film 2c in the surface of the electrode film 2b is preferably more than 0% and 90% or less, and may be 10% or more or 50% or less. That is, it is preferable that the electrode film exposed portion 2d occupy 10% or more of the surface of the electrode film 2b.
- the thermistor body 2a is an NTC thermistor containing a transition metal, and a perovskite-based material or a spinel-based material is employed.
- the thermistor body 2a is a metal oxide sintered body containing a perovskite-type oxide, such as a sintered body containing a composite oxide represented by the general formula: La 1-y Ca y (Cr 1-x Mn x )O 3 (0.0 ⁇ x ⁇ 1.0, 0.0 ⁇ y ⁇ 0.7).
- Y 2 O 3 , ZrO 2 , MgO, Al 2 O 3 and CeO 2 may be further added to this sintered body as insulator materials.
- the method of manufacturing the thermistor element of the present embodiment comprises: an electrode film forming step of forming a pair of electrode films 2b on the upper and lower surfaces of a chip-shaped or plate-shaped thermistor element 2a; a protective film forming step of forming an insulating protective film 2c on the outer peripheral surface of the thermistor element 2a and the pair of electrode films 2b to fabricate a protective film-forming chip 1a; and a protective film peeling step for forming the exposed portion 2d.
- the protective film 2c is formed of the above-described material whose adhesive strength with the electrode film 2b is smaller than the adhesive strength with the thermistor element body 2a.
- the strength of adhesion can be determined by, for example, performing an indentation test by a linear load process in the load-unload test mode using an ultra-micro indentation hardness tester, and judging the presence or absence of peeling of the protective film at the indenter indentation part and the size of the peeling area. In this test, the adhesion is highest when there is no peeling, and the smaller the peeling area is, the higher the adhesion is.
- a gas phase method such as sputtering or CVD can be used as a film forming method (coating method) of the protective film 2c, and a liquid phase deposition method can be used in a wet process.
- a gas phase method since the film is formed in a vacuum, oxygen defects may be formed in the thermistor material depending on the conditions. Therefore, a liquid phase deposition method using an alkoxide is preferable.
- the protective film 2c is removed and the electrode film exposed portion 2d is provided at least in the central portion of the surface of the electrode film 2b. Therefore, the protective film 2c covering the outer peripheral surface can ensure reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability.
- the protective film 2c is made of a material having a weaker adhesion strength with the electrode film 2b than with the thermistor element body 2a, the protective film 2c is firmly adhered to the outer peripheral surface of the thermistor element body 2a, and the protective film 2c on the electrode film 2b is easily peeled off.
- the electrode film 2b is made of a noble metal and the protective film 2c is an oxide film or a nitride film
- an oxide film or a nitride film having strong adhesion to the thermistor material (for example, perovskite-based material or spinel-based material) of the thermistor element body 2a and weak adhesion to the noble metal can be easily obtained by a vapor phase method such as sputtering or CVD or a liquid phase deposition method.
- the thermistor element body 2a exposed by the holes in the electrode film 2b is coated with the protective film 2c that has high adhesion to the thermistor material, and only the protective film 2c on the noble metal electrode film 2b that has weak adhesion is peeled off. The effect of suppressing the formation of oxygen defects is greater than in the case of coating with
- the manufacturing method of the thermistor element 1 of the present embodiment includes a protective film peeling step of peeling off at least the protective film 2c in the central portion of the electrode film 2b to form the electrode film exposed portion 2d in which the electrode film 2b is exposed. Therefore, the electrode film exposed portion 2d can be formed in the central portion of the electrode film 2b while leaving the protective film 2c on the outer peripheral surface.
- the protective film 2c is once formed on the outer peripheral surface of the thermistor body 2a and the pair of electrode films 2b, i.e., the entire surface.
- the protective film forming chip 1a is subjected to barrel polishing or the like to peel off the protective film 2c at least in the central portion within the surface of the electrode film 2b. Since the protective film 2c has strong adhesion to the thermistor element body 2a, the electrode film 2b can be exposed by mechanically peeling off the protective film 2c having weak adhesion to the electrode film 2b by barrel polishing or the like while leaving the protective film 2c on the outer peripheral surface of the thermistor element body 2a.
- the protective film peeling process does not necessarily have to be a single process, and the protective film may be peeled off by bringing it into strong contact with other elements or devices in the cleaning process or transfer process.
- Example 1 in which the thermistor element of the above-described embodiment was actually manufactured by the above-described manufacturing method, the rate of change in resistance value was measured in a heat treatment test in order to verify the effect of suppressing the formation of oxygen defects.
- the specific manufacturing method of Example 1 of the present invention first, an Au paste was printed and baked on a thermistor wafer with a thickness of 0.2 mm to form an Au electrode film, and then cut into 0.5 mm squares to produce flake-shaped chips.
- a protective film forming step 100 g of a water-ethanol mixed solvent and the flaky chips were placed in a beaker, and 5.2 g of normal ethyl silicate and 16.6 g of an aqueous NaOH solution (0.2 mol/L) were added while stirring so that the flaky chips would float in the liquid, to form a protective film made of silicon oxide as a protective coating film on the entire surface of the flaky chips. Furthermore, in order to improve the strength of the protective film, the film was baked at 700° C. after the film formation, and the film formation and baking were repeatedly performed to fabricate a chip with a protective film having a film thickness of 100 nm. Next, the thermistor element of this example was manufactured by partially exfoliating the protective film on the electrode film of the manufactured protective film formed chip by rotary barrel polishing.
- Example 6 a protective film-formed chip formed by forming a SiO 2 film as a protective film by a liquid phase deposition method on a flake-shaped chip on which a Pt electrode film was formed by printing and baking a Pt paste was barrel-polished.
- the rate of change in resistance value was measured before and after a heat treatment test at 700° C. in an Ar atmosphere with an oxygen concentration of 100 ppm or less.
- Comparative Example 1 of the present invention a thermistor element in which an electrode film was formed by applying Au paste to the upper and lower surfaces of the thermistor element body without forming the protective film and baking the thermistor element, and as Comparative Example 2, a thermistor element in which SiO 2 protective films were formed on the upper and lower surfaces of Comparative Example 1 by a liquid phase deposition method, and the protective film was not peeled off, were produced and subjected to the same measurement.
- Table 1 shows the electrode film, the method of forming the protective film, the material of the protective film, and the presence or absence of the protective film peeling process for each of the examples and comparative examples of the present invention.
- Comparative Example 1 which is not coated with a protective film, has a high resistance value change rate of 29% in the heat treatment test, whereas each example of the present invention, which is coated with a protective film, has a small resistance value change rate of 5% or less in the heat treatment test.
- Comparative Example 2 in which the protective film was not peeled off, the chip side surface coverage was 100% and the electrode surface coverage was 99%.
- 3, 4, 5 and 6 show electron microscope images of the electrode surfaces of Example 1, Comparative Example 1, Comparative Example 2 and Example 6 of the present invention.
- the white portions are the electrode film exposed portions due to the protective film peeling process.
- FIG. 7 also shows an electron microscope image of a side surface of Example 6 of the present invention.
- the upper and lower white portions in FIG. 7 are the Pt electrodes, and the stripped portions are light gray portions on the left and right sides of the device.
- the mountability was evaluated for each of the examples of the present invention and each of the comparative examples.
- the results are also shown in Table 2.
- the thermistor elements of each of the prepared examples and comparative examples were mounted on a metallized substrate with AuSn solder, and the shear strength was measured at a scanning speed of 5 mm/min with the clearance between the substrate and jig being 1/4 or less of the element thickness.
- good mountability is indicated by " ⁇ ”
- mountability poor is indicated by "x”.
- the protective film on the electrode film is peeled off by barrel polishing, but the protective film on the electrode film may be peeled off by ultrasonic cleaning or the like.
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Abstract
Provided are a thermistor element and a method for manufacturing the same, the thermistor element having good electrical connection and high mountability, and in which formation of oxygen deficiency is suppressed. A thermistor element according to the present invention comprises: a chip-shaped or plate-shaped thermistor element body 2a; a pair of electrode films 2b formed on upper and lower surfaces of the thermistor element body; and an insulating protection film 2c formed on an outer peripheral surface of the thermistor element body and on the pair of electrode films. An electrode-film-exposed portion 2d is provided in at least the center in the plane of the electrode film from which the protection film is removed. Further, the protection film is formed of a material of which the adhesive strength with the electrode film is smaller than with the thermistor element body.
Description
本発明は、温度センサや電子機器の保護回路などに好適なサーミスタ素子及びその製造方法に関する。
The present invention relates to a thermistor element suitable for temperature sensors, protection circuits of electronic devices, and the like, and a method for manufacturing the same.
サーミスタは、温度によって抵抗値が変化し、その変化が温度に対して非常に敏感なことから、温度センサや電子機器の保護回路など、幅広く使用されている。
このようなサーミスタとして、例えばＮＴＣサーミスタを構成する遷移金属は実に多様な価数状態をとることができ、この影響でサーミスタ材料は外気の影響を受け易い。特に、ガラス管へ封入するガラスダイオード型のサーミスタ素子では封入時の不活性雰囲気下において、また、フレークタイプのサーミスタなどのはんだリフローを行う場合は還元雰囲気下において、サーミスタ材料の酸素欠陥が生じ、その特性が変化してしまう問題がある。 Thermistors are widely used in temperature sensors, protection circuits of electronic devices, etc., because their resistance values change with temperature and the changes are very sensitive to temperature.
Transition metals constituting such thermistors, for example, NTC thermistors, can take a wide variety of valence states, and thermistor materials are easily affected by the outside air. In particular, in a glass diode-type thermistor element enclosed in a glass tube, oxygen defects occur in the thermistor material in an inert atmosphere during encapsulation, and in a reducing atmosphere when solder reflow is performed for flake-type thermistors, resulting in changes in their characteristics.
このようなサーミスタとして、例えばＮＴＣサーミスタを構成する遷移金属は実に多様な価数状態をとることができ、この影響でサーミスタ材料は外気の影響を受け易い。特に、ガラス管へ封入するガラスダイオード型のサーミスタ素子では封入時の不活性雰囲気下において、また、フレークタイプのサーミスタなどのはんだリフローを行う場合は還元雰囲気下において、サーミスタ材料の酸素欠陥が生じ、その特性が変化してしまう問題がある。 Thermistors are widely used in temperature sensors, protection circuits of electronic devices, etc., because their resistance values change with temperature and the changes are very sensitive to temperature.
Transition metals constituting such thermistors, for example, NTC thermistors, can take a wide variety of valence states, and thermistor materials are easily affected by the outside air. In particular, in a glass diode-type thermistor element enclosed in a glass tube, oxygen defects occur in the thermistor material in an inert atmosphere during encapsulation, and in a reducing atmosphere when solder reflow is performed for flake-type thermistors, resulting in changes in their characteristics.
その対策として、表面実装タイプのサーミスタ、いわゆるチップサーミスタでは、側面（外周面）をガラスでコーティングするなど酸素欠陥形成への対策が取られているが、フレークタイプのサーミスタでは側面のみに保護コーティングを施すことが困難であった。
なお、特許文献１では、電極面からガラスペーストを塗布、焼き付けてガラス層を形成すると共にサーミスタ素体の稜線部上の領域を露出させて電極膜との接触を図る方法が記載されている。 As a countermeasure, surface-mount type thermistors, so-called chip thermistors, are protected against the formation of oxygen defects by coating the side surfaces (peripheral surfaces) with glass.
Patent Document 1 describes a method of forming a glass layer by applying and baking a glass paste from the electrode surface and exposing a region on the ridge of the thermistor body to make contact with the electrode film.
なお、特許文献１では、電極面からガラスペーストを塗布、焼き付けてガラス層を形成すると共にサーミスタ素体の稜線部上の領域を露出させて電極膜との接触を図る方法が記載されている。 As a countermeasure, surface-mount type thermistors, so-called chip thermistors, are protected against the formation of oxygen defects by coating the side surfaces (peripheral surfaces) with glass.
上記従来の技術には、以下の課題が残されている。
従来のサーミスタ素子では、サーミスタ素体に形成したガラス層が厚く、電極表面で溶融・固化したガラスが強固に密着しているため剥離が困難な場合があり、電極の露出部分がサーミスタ素体の稜線部のみの場合に対して、更なる実装性の向上が求められていた。 The following problems remain in the above conventional technique.
In conventional thermistor elements, the glass layer formed on the thermistor element is thick, and the melted and solidified glass adheres firmly to the surface of the electrode, making it difficult to peel off in some cases.
従来のサーミスタ素子では、サーミスタ素体に形成したガラス層が厚く、電極表面で溶融・固化したガラスが強固に密着しているため剥離が困難な場合があり、電極の露出部分がサーミスタ素体の稜線部のみの場合に対して、更なる実装性の向上が求められていた。 The following problems remain in the above conventional technique.
In conventional thermistor elements, the glass layer formed on the thermistor element is thick, and the melted and solidified glass adheres firmly to the surface of the electrode, making it difficult to peel off in some cases.
本発明は、前述の課題に鑑みてなされたもので、良好な電気的接続と高い実装性とを有すると共に酸素欠陥形成を抑制したサーミスタ素子及びその製造方法を提供することを目的とする。
The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a thermistor element that has good electrical connection and high mountability and suppresses the formation of oxygen defects, and a method for manufacturing the same.
本発明は、前記課題を解決するために以下の構成を採用した。すなわち、第１の発明のサーミスタ素子は、チップ状又は板状のサーミスタ素体と、前記サーミスタ素体の上下面に形成された一対の電極膜と、前記サーミスタ素体の外周面及び前記一対の電極膜上に形成された絶縁性の保護膜とを備え、前記電極膜の面内の少なくとも中央部に、前記保護膜が除かれて電極膜露出部が設けられていることを特徴とする。
The present invention adopts the following configuration in order to solve the above problems. That is, the thermistor element of the first invention is characterized by comprising a chip-shaped or plate-shaped thermistor body, a pair of electrode films formed on the upper and lower surfaces of the thermistor body, and an insulating protective film formed on the outer peripheral surface of the thermistor body and the pair of electrode films, wherein the protective film is removed and an electrode film exposed portion is provided at least in the central portion of the surface of the electrode film.
このサーミスタ素子では、電極膜の面内の少なくとも中央部に、保護膜が除かれて電極膜露出部が設けられているので、電気的な導通及び実装性を阻害することなく、外周面を覆った保護膜により耐還元性を担保し酸素欠陥形成を抑制することができる。なお、中央部の全面に電極膜露出部が設けられている必要はなく、少なくとも中央部の一部に電極膜露出部が設けられていればよい。
In this thermistor element, since the protective film is removed and the electrode film exposed portion is provided at least in the central portion of the surface of the electrode film, the protective film covering the outer peripheral surface can ensure reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability. It should be noted that it is not necessary to provide the electrode film exposed portion on the entire central portion, and it is sufficient that the electrode film exposed portion is provided on at least a part of the central portion.
第２の発明のサーミスタ素子は、第１の発明において、前記保護膜が、前記サーミスタ素体との密着強度よりも前記電極膜との密着強度が小さい材料で形成されていることを特徴とする。
すなわち、このサーミスタ素子では、保護膜が、サーミスタ素体との密着強度よりも電極膜との密着強度が小さい材料で形成されているので、サーミスタ素体の外周面では保護膜が強固に密着すると共に、電極膜上の保護膜が容易に剥がれ易く、部分的に電極膜露出部を容易に形成することができる。 A thermistor element according to a second aspect of the invention is characterized in that, in the first aspect, the protective film is made of a material having a weaker adhesion strength to the electrode film than to the thermistor body.
That is, in this thermistor element, since the protective film is made of a material having a weaker adhesion strength to the electrode film than to the thermistor element body, the protective film is firmly adhered to the outer peripheral surface of the thermistor element body, and the protective film on the electrode film is easily peeled off, so that the electrode film exposed portion can be easily formed partially.
すなわち、このサーミスタ素子では、保護膜が、サーミスタ素体との密着強度よりも電極膜との密着強度が小さい材料で形成されているので、サーミスタ素体の外周面では保護膜が強固に密着すると共に、電極膜上の保護膜が容易に剥がれ易く、部分的に電極膜露出部を容易に形成することができる。 A thermistor element according to a second aspect of the invention is characterized in that, in the first aspect, the protective film is made of a material having a weaker adhesion strength to the electrode film than to the thermistor body.
That is, in this thermistor element, since the protective film is made of a material having a weaker adhesion strength to the electrode film than to the thermistor element body, the protective film is firmly adhered to the outer peripheral surface of the thermistor element body, and the protective film on the electrode film is easily peeled off, so that the electrode film exposed portion can be easily formed partially.
第３の発明のサーミスタ素子は、第１又は第２の発明において、前記電極膜が、貴金属で形成され、前記保護膜が、酸化膜又は窒化膜であることを特徴とする。
すなわち、このサーミスタ素子では、電極膜が貴金属で形成され、保護膜が酸化膜又は窒化膜であるので、サーミスタ素体のサーミスタを構成する酸化物材料（例えば、ペロブスカイト系材料やスピネル系材料）との密着性が強いと共に貴金属との密着性が弱い酸化膜又は窒化膜を、スパッタリングやＣＶＤ等の気相法又は液相析出法等により容易に成膜することができる。 A thermistor element of a third invention is characterized in that, in the first or second invention, the electrode film is made of a noble metal, and the protective film is an oxide film or a nitride film.
That is, in this thermistor element, the electrode film is formed of a noble metal, and the protective film is an oxide film or a nitride film. Therefore, an oxide film or a nitride film having strong adhesion to the oxide material (for example, perovskite-based material or spinel-based material) constituting the thermistor of the thermistor element and weak adhesion to the noble metal can be easily formed by a vapor phase method such as sputtering or CVD or a liquid phase deposition method.
すなわち、このサーミスタ素子では、電極膜が貴金属で形成され、保護膜が酸化膜又は窒化膜であるので、サーミスタ素体のサーミスタを構成する酸化物材料（例えば、ペロブスカイト系材料やスピネル系材料）との密着性が強いと共に貴金属との密着性が弱い酸化膜又は窒化膜を、スパッタリングやＣＶＤ等の気相法又は液相析出法等により容易に成膜することができる。 A thermistor element of a third invention is characterized in that, in the first or second invention, the electrode film is made of a noble metal, and the protective film is an oxide film or a nitride film.
That is, in this thermistor element, the electrode film is formed of a noble metal, and the protective film is an oxide film or a nitride film. Therefore, an oxide film or a nitride film having strong adhesion to the oxide material (for example, perovskite-based material or spinel-based material) constituting the thermistor of the thermistor element and weak adhesion to the noble metal can be easily formed by a vapor phase method such as sputtering or CVD or a liquid phase deposition method.
第４の発明のサーミスタ素子は、第１から第３の発明のいずれかにおいて、前記保護膜の厚さが、１０ｎｍ以上１０００ｎｍ以下であることを特徴とする。
すなわち、このサーミスタ素子では、保護膜の厚さを１０ｎｍ以上１０００ｎｍ以下とした理由は、１０ｎｍ未満であると耐還元性が十分でなく酸素欠陥を抑制する効果が低くなり、また１０００ｎｍを越えると厚くなり過ぎて剥離し難いと共に電極膜露出部との段差が大きくなり、電気的な導通が不十分になる場合があるためである。 A thermistor element of a fourth invention is characterized in that, in any one of the first to third inventions, the protective film has a thickness of 10 nm or more and 1000 nm or less.
That is, in this thermistor element, the reason why the thickness of the protective film is set to 10 nm or more and 1000 nm or less is that if the thickness is less than 10 nm, the reduction resistance is not sufficient and the effect of suppressing oxygen defects is reduced, and if it exceeds 1000 nm, the protective film is too thick to be easily peeled off and the step with the exposed portion of the electrode film becomes large, resulting in insufficient electrical conduction.
すなわち、このサーミスタ素子では、保護膜の厚さを１０ｎｍ以上１０００ｎｍ以下とした理由は、１０ｎｍ未満であると耐還元性が十分でなく酸素欠陥を抑制する効果が低くなり、また１０００ｎｍを越えると厚くなり過ぎて剥離し難いと共に電極膜露出部との段差が大きくなり、電気的な導通が不十分になる場合があるためである。 A thermistor element of a fourth invention is characterized in that, in any one of the first to third inventions, the protective film has a thickness of 10 nm or more and 1000 nm or less.
That is, in this thermistor element, the reason why the thickness of the protective film is set to 10 nm or more and 1000 nm or less is that if the thickness is less than 10 nm, the reduction resistance is not sufficient and the effect of suppressing oxygen defects is reduced, and if it exceeds 1000 nm, the protective film is too thick to be easily peeled off and the step with the exposed portion of the electrode film becomes large, resulting in insufficient electrical conduction.
第５の発明のサーミスタ素子は、第１から第４の発明のいずれかにおいて、前記サーミスタ素体の外周面において前記保護膜の占める被覆率が、前記電極膜の面内において前記保護膜の占める被覆率より大きいことを特徴とする。
A thermistor element of a fifth invention is the thermistor element according to any one of the first to fourth inventions, characterized in that the coverage of the protective film on the outer peripheral surface of the thermistor body is larger than the coverage of the protective film on the surface of the electrode film.
第６の発明のサーミスタ素子は、第１から第５の発明のいずれかにおいて、前記電極膜の面内において前記保護膜の占める被覆率が、９０％以下であることを特徴とする。
すなわち、このサーミスタ素子では、電極膜の面内において保護膜の占める被覆率が９０％以下とした理由は、９０％を越えると電極膜露出部の面積が少なくなり過ぎて十分な実装強度が得られない場合があるためである。 A thermistor element of a sixth aspect of the invention is characterized in that, in any one of the first to fifth aspects of the invention, a coverage ratio of the protective film in the surface of the electrode film is 90% or less.
That is, in this thermistor element, the reason why the coverage of the protective film in the plane of the electrode film is set to 90% or less is that if the coverage exceeds 90%, the area of the exposed portion of the electrode film becomes too small and sufficient mounting strength may not be obtained.
すなわち、このサーミスタ素子では、電極膜の面内において保護膜の占める被覆率が９０％以下とした理由は、９０％を越えると電極膜露出部の面積が少なくなり過ぎて十分な実装強度が得られない場合があるためである。 A thermistor element of a sixth aspect of the invention is characterized in that, in any one of the first to fifth aspects of the invention, a coverage ratio of the protective film in the surface of the electrode film is 90% or less.
That is, in this thermistor element, the reason why the coverage of the protective film in the plane of the electrode film is set to 90% or less is that if the coverage exceeds 90%, the area of the exposed portion of the electrode film becomes too small and sufficient mounting strength may not be obtained.
第７の発明のサーミスタ素子の製造方法は、第１から第６の発明のいずれかのサーミスタ素子を製造する方法であって、チップ状又は板状のサーミスタ素体の上下面に一対の電極膜を形成する電極膜形成工程と、前記サーミスタ素体の外周面及び前記一対の電極膜上に絶縁性の保護膜を形成し保護膜形成チップを作製する保護膜形成工程と、前記保護膜形成チップにおける前記電極膜の面内の少なくとも中央部の前記保護膜を剥離して前記電極膜が露出した電極膜露出部を形成する保護膜剥離工程とを有していることを特徴とする。
A method for manufacturing a thermistor element according to a seventh invention is a method for manufacturing the thermistor element according to any one of the first to sixth inventions, comprising: an electrode film forming step of forming a pair of electrode films on the upper and lower surfaces of a chip-shaped or plate-shaped thermistor element; a protective film forming step of forming an insulating protective film on the outer peripheral surface of the thermistor element and the pair of electrode films to produce a protective film-formed chip; and a protective film peeling step of forming an electrode film exposed portion where the electrode film is exposed by peeling.
すなわち、このサーミスタ素子の製造方法では、電極膜の面内の少なくとも中央部の保護膜を剥離して電極膜が露出した電極膜露出部を形成する保護膜剥離工程を有するので、外周面に保護膜を残したまま電極膜の中央部に電極膜露出部を形成することができる。特に、薄い板状（フレーク状）のサーミスタ素体であっても、サーミスタ素体の外周面及び一対の電極膜上、すなわち全面に一旦、保護膜を形成し、その後、電極膜の面内の中央部において保護膜を剥離させるので、外周面（側面）に保護膜を形成すると共に電極膜を露出させることができる。
That is, since this method for manufacturing the thermistor element includes a protective film peeling step of peeling off the protective film at least in the central portion of the electrode film to form an electrode film exposed portion where the electrode film is exposed, the electrode film exposed portion can be formed in the central portion of the electrode film while leaving the protective film on the outer peripheral surface. In particular, even in the case of a thin plate-like (flake-like) thermistor element, a protective film is once formed on the outer peripheral surface of the thermistor element and the pair of electrode films, i.e., the entire surface, and then the protective film is peeled off at the central portion within the surface of the electrode film.
第８の発明のサーミスタ素子の製造方法は、第７の発明において、前記保護膜形成工程で、前記保護膜を前記サーミスタ素体との密着強度よりも前記電極膜との密着強度が小さい材料で形成することを特徴とする。
A method for manufacturing a thermistor element according to an eighth invention is characterized in that, in the seventh invention, in the protective film forming step, the protective film is formed of a material having a weaker adhesion strength to the electrode film than to the thermistor body.
第９の発明のサーミスタ素子の製造方法は、第７又は第８の発明において、前記保護膜剥離工程で、前記保護膜形成チップをバレル研磨することで、前記電極膜の面内の少なくとも中央部の前記保護膜を剥離することを特徴とする。
すなわち、このサーミスタ素子の製造方法では、保護膜剥離工程で、保護膜形成チップをバレル研磨することで、電極膜の面内の少なくとも中央部の保護膜を剥離するので、電極膜上の保護膜をバレル研磨により機械的に剥離して電極膜を露出させることができる。
特に、保護膜をサーミスタ素体との密着強度よりも電極膜との密着強度が小さい材料で形成することで、サーミスタ素体外周面の保護膜を残しつつ、電極膜上の保護膜をバレル研磨により剥離させることができる。 According to a ninth aspect of the present invention, there is provided a method for manufacturing a thermistor element according to the seventh or eighth aspect, wherein in the protective film stripping step, the protective film-forming chip is barrel-polished to strip the protective film at least at the central portion within the plane of the electrode film.
That is, in this method for manufacturing a thermistor element, in the protective film peeling step, the protective film-formed chip is barrel-polished to peel off at least the protective film in the center of the surface of the electrode film.
In particular, by forming the protective film from a material whose adhesive strength with the electrode film is lower than that with the thermistor element body, the protective film on the electrode film can be peeled off by barrel polishing while leaving the protective film on the outer peripheral surface of the thermistor element body.
すなわち、このサーミスタ素子の製造方法では、保護膜剥離工程で、保護膜形成チップをバレル研磨することで、電極膜の面内の少なくとも中央部の保護膜を剥離するので、電極膜上の保護膜をバレル研磨により機械的に剥離して電極膜を露出させることができる。
特に、保護膜をサーミスタ素体との密着強度よりも電極膜との密着強度が小さい材料で形成することで、サーミスタ素体外周面の保護膜を残しつつ、電極膜上の保護膜をバレル研磨により剥離させることができる。 According to a ninth aspect of the present invention, there is provided a method for manufacturing a thermistor element according to the seventh or eighth aspect, wherein in the protective film stripping step, the protective film-forming chip is barrel-polished to strip the protective film at least at the central portion within the plane of the electrode film.
That is, in this method for manufacturing a thermistor element, in the protective film peeling step, the protective film-formed chip is barrel-polished to peel off at least the protective film in the center of the surface of the electrode film.
In particular, by forming the protective film from a material whose adhesive strength with the electrode film is lower than that with the thermistor element body, the protective film on the electrode film can be peeled off by barrel polishing while leaving the protective film on the outer peripheral surface of the thermistor element body.
本発明によれば、以下の効果を奏する。
すなわち、本発明に係るサーミスタ素子及びその製造方法によれば、電極膜の面内の少なくとも中央部に、保護膜が除かれて電極膜露出部が設けられているので、電気的な導通及び実装性を阻害することなく、外周面を覆った保護膜により耐還元性を担保し酸素欠陥形成を抑制することができる。
したがって、本発明のサーミスタ素子及びその製造方法では、熱処理後等での抵抗値変化が小さく安定した特性を有すると共に高い実装性をチップ状のサーミスタ素子を得ることができる。 ADVANTAGE OF THE INVENTION According to this invention, there exist the following effects.
That is, according to the thermistor element and the manufacturing method thereof according to the present invention, since the protective film is removed and the electrode film exposed portion is provided at least in the central portion in the plane of the electrode film, the protective film covering the outer peripheral surface can ensure the reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability.
Therefore, according to the thermistor element and the manufacturing method thereof of the present invention, it is possible to obtain a chip-shaped thermistor element that has stable characteristics with a small change in resistance value after heat treatment, etc., and high mountability.
すなわち、本発明に係るサーミスタ素子及びその製造方法によれば、電極膜の面内の少なくとも中央部に、保護膜が除かれて電極膜露出部が設けられているので、電気的な導通及び実装性を阻害することなく、外周面を覆った保護膜により耐還元性を担保し酸素欠陥形成を抑制することができる。
したがって、本発明のサーミスタ素子及びその製造方法では、熱処理後等での抵抗値変化が小さく安定した特性を有すると共に高い実装性をチップ状のサーミスタ素子を得ることができる。 ADVANTAGE OF THE INVENTION According to this invention, there exist the following effects.
That is, according to the thermistor element and the manufacturing method thereof according to the present invention, since the protective film is removed and the electrode film exposed portion is provided at least in the central portion in the plane of the electrode film, the protective film covering the outer peripheral surface can ensure the reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability.
Therefore, according to the thermistor element and the manufacturing method thereof of the present invention, it is possible to obtain a chip-shaped thermistor element that has stable characteristics with a small change in resistance value after heat treatment, etc., and high mountability.
以下、本発明に係るサーミスタ素子及びその製造方法の一実施形態を、図１及び図２を参照しながら説明する。なお、以下の説明に用いる各図面では、各部材を認識可能又は認識容易な大きさとするために縮尺を適宜変更している。
An embodiment of a thermistor element and a method for manufacturing the same according to the present invention will be described below with reference to FIGS. 1 and 2. FIG. In addition, in each drawing used for the following explanation, the reduced scale is appropriately changed in order to make each member recognizable or easily recognizable.
本実施形態のサーミスタ素子１は、図１及び図２に示すように、チップ状又は板状（フレーク状）のサーミスタ素体２ａ、サーミスタ素体２ａの上下面に形成された一対の電極膜２ｂと、サーミスタ素体２ａの外周面及び一対の電極膜２ｂ上に形成された絶縁性の保護膜２ｃとを備えている。
上記電極膜２ｂの面内の少なくとも中央部には、保護膜２ｃが除かれて電極膜露出部２ｄが設けられている。
なお、上記チップ状のサーミスタ素体とは、立方体形状のような板状よりも厚みのある形状のサーミスタ材料で構成された素体である。つまり、上記チップ状のサーミスタ素体とは、一般的に表面実装用として用いられる、いわゆるチップサーミスタを示しているものではない。 As shown in FIGS. 1 and 2, thethermistor element 1 of the present embodiment includes a chip-shaped or plate-shaped (flake-shaped) thermistor body 2a, a pair of electrode films 2b formed on the upper and lower surfaces of the thermistor body 2a, and an insulating protective film 2c formed on the outer peripheral surface of the thermistor body 2a and the pair of electrode films 2b.
An electrode film exposedportion 2d is provided by removing the protective film 2c at least in the central portion of the surface of the electrode film 2b.
The chip-shaped thermistor element is an element made of a thermistor material having a shape such as a cube, which is thicker than a plate-like shape. In other words, the chip-shaped thermistor element does not mean a so-called chip thermistor that is generally used for surface mounting.
上記電極膜２ｂの面内の少なくとも中央部には、保護膜２ｃが除かれて電極膜露出部２ｄが設けられている。
なお、上記チップ状のサーミスタ素体とは、立方体形状のような板状よりも厚みのある形状のサーミスタ材料で構成された素体である。つまり、上記チップ状のサーミスタ素体とは、一般的に表面実装用として用いられる、いわゆるチップサーミスタを示しているものではない。 As shown in FIGS. 1 and 2, the
An electrode film exposed
The chip-shaped thermistor element is an element made of a thermistor material having a shape such as a cube, which is thicker than a plate-like shape. In other words, the chip-shaped thermistor element does not mean a so-called chip thermistor that is generally used for surface mounting.
本実施形態では、電極膜２ｂの面内のうちサーミスタ素体２ａの稜線よりも内側で保護膜２ｃが剥離した部分（電極膜露出部２ｄ）が存在している。特に、電極膜２ｂの面内の少なくとも中央部に、保護膜２ｃが剥離し電極膜露出部２ｄが存在している。
なお、上記中央部は、電極膜２ｂの中央において、電極膜２ｂと相似形状で面積が１／４となる範囲を示す。例えば、電極膜２ｂが四角形状であれば、外周縁から電極膜２ｂの一辺の長さの１／４より内側の領域である。
また、サーミスタ素体２ａの稜線部上は、後述するバレル研磨により、保護膜２ｃの多くが剥離されて電極膜露出部２ｄとなっている。 In this embodiment, there is a portion (electrode film exposedportion 2d) where the protective film 2c is peeled off inside the ridge line of the thermistor body 2a in the plane of the electrode film 2b. In particular, the protective film 2c is peeled off and the electrode film exposed portion 2d exists at least in the central portion of the surface of the electrode film 2b.
Note that the central portion indicates a range in which the shape is similar to that of theelectrode film 2b and the area is 1/4 at the center of the electrode film 2b. For example, if the electrode film 2b has a square shape, it is a region inside from the outer peripheral edge to 1/4 of the length of one side of the electrode film 2b.
On the ridge of thethermistor body 2a, much of the protective film 2c is peeled off by barrel polishing, which will be described later, to form an electrode film exposed portion 2d.
なお、上記中央部は、電極膜２ｂの中央において、電極膜２ｂと相似形状で面積が１／４となる範囲を示す。例えば、電極膜２ｂが四角形状であれば、外周縁から電極膜２ｂの一辺の長さの１／４より内側の領域である。
また、サーミスタ素体２ａの稜線部上は、後述するバレル研磨により、保護膜２ｃの多くが剥離されて電極膜露出部２ｄとなっている。 In this embodiment, there is a portion (electrode film exposed
Note that the central portion indicates a range in which the shape is similar to that of the
On the ridge of the
また、上記保護膜２ｃは、サーミスタ素体２ａとの密着強度よりも電極膜２ｂとの密着強度が小さい材料で形成されている。
すなわち、電極膜２ｂが貴金属で形成され、保護膜２ｃが酸化膜又は窒化膜である。
例えば、電極膜２ｂが、例えばＰｔ，Ａｕ，Ａｇの少なくとも一種を含んだ金属膜であり、保護膜２ｃがＳｉＯ２，Ａｌ２Ｏ３，ＺｒＯ２，ＨｆＯ２等の酸化膜、又はＡｌＮ，Ｓｉ３Ｎ４等の窒化膜である。 Moreover, theprotective film 2c is made of a material having a weaker adhesion strength with the electrode film 2b than with the thermistor body 2a.
That is, theelectrode film 2b is made of a noble metal, and the protective film 2c is an oxide film or a nitride film.
For example, theelectrode film 2b is a metal film containing at least one of Pt, Au and Ag, and the protective film 2c is an oxide film such as SiO 2 , Al 2 O 3 , ZrO 2 and HfO 2 or a nitride film such as AlN and Si 3 N 4 .
すなわち、電極膜２ｂが貴金属で形成され、保護膜２ｃが酸化膜又は窒化膜である。
例えば、電極膜２ｂが、例えばＰｔ，Ａｕ，Ａｇの少なくとも一種を含んだ金属膜であり、保護膜２ｃがＳｉＯ２，Ａｌ２Ｏ３，ＺｒＯ２，ＨｆＯ２等の酸化膜、又はＡｌＮ，Ｓｉ３Ｎ４等の窒化膜である。 Moreover, the
That is, the
For example, the
さらに、保護膜２ｃは、１０ｎｍ以上１０００ｎｍ以下の厚さに設定された薄膜である。保護膜２ｃの厚みは、１００ｎｍ以上８００ｎｍ以下であってもよい。
また、電極膜２ｂの面内において保護膜２ｃの占める被覆率は、０％を超え、かつ９０％以下が好ましく、１０％以上や５０％以下であってもよい。すなわち、電極膜２ｂの面内で電極膜露出部２ｄが占める率は、１０％以上であることが良い。 Furthermore, theprotective film 2c is a thin film having a thickness of 10 nm or more and 1000 nm or less. The thickness of the protective film 2c may be 100 nm or more and 800 nm or less.
Moreover, the coverage ratio of theprotective film 2c in the surface of the electrode film 2b is preferably more than 0% and 90% or less, and may be 10% or more or 50% or less. That is, it is preferable that the electrode film exposed portion 2d occupy 10% or more of the surface of the electrode film 2b.
また、電極膜２ｂの面内において保護膜２ｃの占める被覆率は、０％を超え、かつ９０％以下が好ましく、１０％以上や５０％以下であってもよい。すなわち、電極膜２ｂの面内で電極膜露出部２ｄが占める率は、１０％以上であることが良い。 Furthermore, the
Moreover, the coverage ratio of the
上記サーミスタ素体２ａは、遷移金属を含むＮＴＣサーミスタであって、ペロブスカイト系材料やスピネル系材料が採用される。
例えばサーミスタ素体２ａは、ペロブスカイト型酸化物を含有する金属酸化物焼結体であって、例えば一般式：Ｌａ１－ｙＣａｙ（Ｃｒ１－ｘＭｎｘ）Ｏ３（０．０≦ｘ≦１．０、０．０＜ｙ≦０．７）で示される複合酸化物を含む焼結体で構成されている。なお、この焼結体に、さらに絶縁体材料として、例えばＹ２Ｏ３，ＺｒＯ２，ＭｇＯ，Ａｌ２Ｏ３，ＣｅＯ２を添加しても構わない。 Thethermistor body 2a is an NTC thermistor containing a transition metal, and a perovskite-based material or a spinel-based material is employed.
For example, thethermistor body 2a is a metal oxide sintered body containing a perovskite-type oxide, such as a sintered body containing a composite oxide represented by the general formula: La 1-y Ca y (Cr 1-x Mn x )O 3 (0.0≦x≦1.0, 0.0<y≦0.7). It should be noted that Y 2 O 3 , ZrO 2 , MgO, Al 2 O 3 and CeO 2 may be further added to this sintered body as insulator materials.
例えばサーミスタ素体２ａは、ペロブスカイト型酸化物を含有する金属酸化物焼結体であって、例えば一般式：Ｌａ１－ｙＣａｙ（Ｃｒ１－ｘＭｎｘ）Ｏ３（０．０≦ｘ≦１．０、０．０＜ｙ≦０．７）で示される複合酸化物を含む焼結体で構成されている。なお、この焼結体に、さらに絶縁体材料として、例えばＹ２Ｏ３，ＺｒＯ２，ＭｇＯ，Ａｌ２Ｏ３，ＣｅＯ２を添加しても構わない。 The
For example, the
次に、本実施形態のサーミスタ素子を製造する方法について説明する。
本実施形態のサーミスタ素子の製造方法は、チップ状又は板状のサーミスタ素体２ａの上下面に一対の電極膜２ｂを形成する電極膜形成工程と、サーミスタ素体２ａの外周面及び一対の電極膜２ｂ上に絶縁性の保護膜２ｃを形成し保護膜形成チップ１ａを作製する保護膜形成工程と、保護膜形成チップ１ａにおける電極膜２ｂの面内の少なくとも中央部の保護膜２ｃを剥離して電極膜２ｂが露出した電極膜露出部２ｄを形成する保護膜剥離工程とを有している。 Next, a method for manufacturing the thermistor element of this embodiment will be described.
The method of manufacturing the thermistor element of the present embodiment comprises: an electrode film forming step of forming a pair ofelectrode films 2b on the upper and lower surfaces of a chip-shaped or plate-shaped thermistor element 2a; a protective film forming step of forming an insulating protective film 2c on the outer peripheral surface of the thermistor element 2a and the pair of electrode films 2b to fabricate a protective film-forming chip 1a; and a protective film peeling step for forming the exposed portion 2d.
本実施形態のサーミスタ素子の製造方法は、チップ状又は板状のサーミスタ素体２ａの上下面に一対の電極膜２ｂを形成する電極膜形成工程と、サーミスタ素体２ａの外周面及び一対の電極膜２ｂ上に絶縁性の保護膜２ｃを形成し保護膜形成チップ１ａを作製する保護膜形成工程と、保護膜形成チップ１ａにおける電極膜２ｂの面内の少なくとも中央部の保護膜２ｃを剥離して電極膜２ｂが露出した電極膜露出部２ｄを形成する保護膜剥離工程とを有している。 Next, a method for manufacturing the thermistor element of this embodiment will be described.
The method of manufacturing the thermistor element of the present embodiment comprises: an electrode film forming step of forming a pair of
特に、保護膜形成工程では、保護膜２ｃをサーミスタ素体２ａとの密着強度よりも電極膜２ｂとの密着強度が小さい上述した材料で形成し、保護膜剥離工程では、保護膜形成チップをバレル研磨や、超音波を用いた洗浄などで、電極膜２ｂの面内の少なくとも中央部の保護膜２ｃを剥離する。密着力の強さは、例えば、超微小押込み硬さ試験機を用いた、負荷－除荷試験モードの直線負荷プロセスによって押込試験を行い、圧子押し込み部の保護膜の剥離有無や剥離面積の大小によって判断できる。なお、この試験では、剥離がない場合の密着力が最も高く、剥離面積が小さいほど密着力は高いことを示している。
In particular, in the protective film forming step, the protective film 2c is formed of the above-described material whose adhesive strength with the electrode film 2b is smaller than the adhesive strength with the thermistor element body 2a. The strength of adhesion can be determined by, for example, performing an indentation test by a linear load process in the load-unload test mode using an ultra-micro indentation hardness tester, and judging the presence or absence of peeling of the protective film at the indenter indentation part and the size of the peeling area. In this test, the adhesion is highest when there is no peeling, and the smaller the peeling area is, the higher the adhesion is.
上記保護膜形成工程では、保護膜２ｃの成膜方法（コーティング方法）としてスパッタリングやＣＶＤなどの気相法を用いることができ、湿式では液相析出法を用いることができる。
なお、気相法では真空中での成膜となるため、条件によってサーミスタ材料に酸素欠陥が形成されてしまうことから、アルコキシドを用いた液相析出法が好ましい。 In the protective film forming step, a gas phase method such as sputtering or CVD can be used as a film forming method (coating method) of theprotective film 2c, and a liquid phase deposition method can be used in a wet process.
In the gas phase method, since the film is formed in a vacuum, oxygen defects may be formed in the thermistor material depending on the conditions. Therefore, a liquid phase deposition method using an alkoxide is preferable.
なお、気相法では真空中での成膜となるため、条件によってサーミスタ材料に酸素欠陥が形成されてしまうことから、アルコキシドを用いた液相析出法が好ましい。 In the protective film forming step, a gas phase method such as sputtering or CVD can be used as a film forming method (coating method) of the
In the gas phase method, since the film is formed in a vacuum, oxygen defects may be formed in the thermistor material depending on the conditions. Therefore, a liquid phase deposition method using an alkoxide is preferable.
このように本実施形態のサーミスタ素子１では、電極膜２ｂの面内の少なくとも中央部に、保護膜２ｃが除かれて電極膜露出部２ｄが設けられているので、電気的な導通及び実装性を阻害することなく、外周面を覆った保護膜２ｃにより耐還元性を担保し酸素欠陥形成を抑制することができる。
また、保護膜２ｃが、サーミスタ素体２ａとの密着強度よりも電極膜２ｂとの密着強度が小さい材料で形成されているので、サーミスタ素体２ａの外周面では保護膜２ｃが強固に密着すると共に、電極膜２ｂ上の保護膜２ｃが容易に剥がれ易く、部分的に電極膜露出部２ｄを容易に形成することができる。 As described above, in thethermistor element 1 of the present embodiment, the protective film 2c is removed and the electrode film exposed portion 2d is provided at least in the central portion of the surface of the electrode film 2b. Therefore, the protective film 2c covering the outer peripheral surface can ensure reduction resistance and suppress the formation of oxygen defects without hindering electrical continuity and mountability.
In addition, since theprotective film 2c is made of a material having a weaker adhesion strength with the electrode film 2b than with the thermistor element body 2a, the protective film 2c is firmly adhered to the outer peripheral surface of the thermistor element body 2a, and the protective film 2c on the electrode film 2b is easily peeled off.
また、保護膜２ｃが、サーミスタ素体２ａとの密着強度よりも電極膜２ｂとの密着強度が小さい材料で形成されているので、サーミスタ素体２ａの外周面では保護膜２ｃが強固に密着すると共に、電極膜２ｂ上の保護膜２ｃが容易に剥がれ易く、部分的に電極膜露出部２ｄを容易に形成することができる。 As described above, in the
In addition, since the
特に、電極膜２ｂが貴金属で形成され、保護膜２ｃが酸化膜又は窒化膜であるので、サーミスタ素体２ａのサーミスタ材料（例えば、ペロブスカイト系材料やスピネル系材料）との密着性が強いと共に貴金属との密着性が弱い酸化膜又は窒化膜をスパッタリングやＣＶＤ等の気相法又は液相析出法等により容易に得ることができる。
In particular, since the electrode film 2b is made of a noble metal and the protective film 2c is an oxide film or a nitride film, an oxide film or a nitride film having strong adhesion to the thermistor material (for example, perovskite-based material or spinel-based material) of the thermistor element body 2a and weak adhesion to the noble metal can be easily obtained by a vapor phase method such as sputtering or CVD or a liquid phase deposition method.
また、貴金属ペーストを焼き付けて形成した電極膜２ｂでは、電極膜２ｂの一部に空孔ができ、サーミスタ素体２ａが露出することが多いが、本実施形態のサーミスタ素子１では、電極膜２ｂの空孔により露出したサーミスタ素体２ａを、サーミスタ材料との密着性の高い保護膜２ｃでコーティングし、密着性の弱い貴金属の電極膜２ｂ上の保護膜２ｃのみを剥離するので、外周面（側面）のみを保護膜でコーティングする場合よりも酸素欠陥形成を抑制する効果が大きい。
In addition, in the electrode film 2b formed by baking noble metal paste, holes are formed in part of the electrode film 2b, and the thermistor element body 2a is often exposed. However, in the thermistor element 1 of the present embodiment, the thermistor element body 2a exposed by the holes in the electrode film 2b is coated with the protective film 2c that has high adhesion to the thermistor material, and only the protective film 2c on the noble metal electrode film 2b that has weak adhesion is peeled off. The effect of suppressing the formation of oxygen defects is greater than in the case of coating with
本実施形態のサーミスタ素子１の製造方法では、電極膜２ｂの面内の少なくとも中央部の保護膜２ｃを剥離して電極膜２ｂが露出した電極膜露出部２ｄを形成する保護膜剥離工程を有するので、外周面に保護膜２ｃを残したまま電極膜２ｂの中央部に電極膜露出部２ｄを形成することができる。特に、薄い板状（フレーク状）のサーミスタ素体２ａであっても、サーミスタ素体２ａの外周面及び一対の電極膜２ｂ上、すなわち全面に一旦、保護膜２ｃを形成し、その後、電極膜２ｂの面内の中央部において保護膜２ｃを剥離させるので、外周面（側面）に保護膜２ｃを形成すると共に電極膜２ｂを露出させることができる。
The manufacturing method of the thermistor element 1 of the present embodiment includes a protective film peeling step of peeling off at least the protective film 2c in the central portion of the electrode film 2b to form the electrode film exposed portion 2d in which the electrode film 2b is exposed. Therefore, the electrode film exposed portion 2d can be formed in the central portion of the electrode film 2b while leaving the protective film 2c on the outer peripheral surface. In particular, even when the thermistor body 2a is thin plate-like (flake-shaped), the protective film 2c is once formed on the outer peripheral surface of the thermistor body 2a and the pair of electrode films 2b, i.e., the entire surface.
また、保護膜剥離工程では、保護膜形成チップ１ａをバレル研磨等で、電極膜２ｂの面内の少なくとも中央部の保護膜２ｃを剥離する。保護膜２ｃはサーミスタ素体２ａとの密着性が強いので、サーミスタ素体２ａ外周面の保護膜２ｃを残しつつ、電極膜２ｂとの密着性が弱い保護膜２ｃをバレル研磨等により機械的に剥離して電極膜２ｂを露出させることができる。
なお、保護膜剥離工程は、必ずしも単独の工程とする必要はなく、洗浄工程や移送工程で他の素子や機器と強く接触させることで剥離させてもよい。 In the protective film peeling process, the protectivefilm forming chip 1a is subjected to barrel polishing or the like to peel off the protective film 2c at least in the central portion within the surface of the electrode film 2b. Since the protective film 2c has strong adhesion to the thermistor element body 2a, the electrode film 2b can be exposed by mechanically peeling off the protective film 2c having weak adhesion to the electrode film 2b by barrel polishing or the like while leaving the protective film 2c on the outer peripheral surface of the thermistor element body 2a.
The protective film peeling process does not necessarily have to be a single process, and the protective film may be peeled off by bringing it into strong contact with other elements or devices in the cleaning process or transfer process.
なお、保護膜剥離工程は、必ずしも単独の工程とする必要はなく、洗浄工程や移送工程で他の素子や機器と強く接触させることで剥離させてもよい。 In the protective film peeling process, the protective
The protective film peeling process does not necessarily have to be a single process, and the protective film may be peeled off by bringing it into strong contact with other elements or devices in the cleaning process or transfer process.
次に、上記実施形態のサーミスタ素子を上記製造方法で実際に作製した実施例１について、酸素欠陥形成の抑制効果を検証するため、熱処理試験での抵抗値の変化率を測定した。
本発明の実施例１の具体的な製造方法は、まず厚さ０．２ｍｍのサーミスタウェハにＡｕペーストを印刷、焼き付けることでＡｕの電極膜を形成した後、０．５ｍｍ角に切断することで、フレーク状チップを作製した。 Next, for Example 1, in which the thermistor element of the above-described embodiment was actually manufactured by the above-described manufacturing method, the rate of change in resistance value was measured in a heat treatment test in order to verify the effect of suppressing the formation of oxygen defects.
In the specific manufacturing method of Example 1 of the present invention, first, an Au paste was printed and baked on a thermistor wafer with a thickness of 0.2 mm to form an Au electrode film, and then cut into 0.5 mm squares to produce flake-shaped chips.
本発明の実施例１の具体的な製造方法は、まず厚さ０．２ｍｍのサーミスタウェハにＡｕペーストを印刷、焼き付けることでＡｕの電極膜を形成した後、０．５ｍｍ角に切断することで、フレーク状チップを作製した。 Next, for Example 1, in which the thermistor element of the above-described embodiment was actually manufactured by the above-described manufacturing method, the rate of change in resistance value was measured in a heat treatment test in order to verify the effect of suppressing the formation of oxygen defects.
In the specific manufacturing method of Example 1 of the present invention, first, an Au paste was printed and baked on a thermistor wafer with a thickness of 0.2 mm to form an Au electrode film, and then cut into 0.5 mm squares to produce flake-shaped chips.
次に、保護膜形成工程として、ビーカーに水―エタノール混合溶媒１００ｇ、上記フレーク状チップを入れ、フレーク状チップが液中に舞うように攪拌しながら正珪酸エチル５．２ｇとＮａＯＨ水溶液（０．２ｍｏｌ／Ｌ）１６．６ｇとを加えて、フレーク状チップの全面に保護コーティング膜としてシリコン酸化物からなる保護膜を形成した。
さらに、保護膜の強度を向上させるために、成膜後に７００℃で焼き付けを行い、成膜と焼き付けとを繰り返し実施し、保護膜の膜厚を１００ｎｍとした保護膜形成チップを作製した。
次に、作製した保護膜形成チップを、回転式のバレル研磨によって電極膜上の保護膜を部分的に剥離させることで、本実施例のサーミスタ素子を作製した。 Next, as a protective film forming step, 100 g of a water-ethanol mixed solvent and the flaky chips were placed in a beaker, and 5.2 g of normal ethyl silicate and 16.6 g of an aqueous NaOH solution (0.2 mol/L) were added while stirring so that the flaky chips would float in the liquid, to form a protective film made of silicon oxide as a protective coating film on the entire surface of the flaky chips.
Furthermore, in order to improve the strength of the protective film, the film was baked at 700° C. after the film formation, and the film formation and baking were repeatedly performed to fabricate a chip with a protective film having a film thickness of 100 nm.
Next, the thermistor element of this example was manufactured by partially exfoliating the protective film on the electrode film of the manufactured protective film formed chip by rotary barrel polishing.
さらに、保護膜の強度を向上させるために、成膜後に７００℃で焼き付けを行い、成膜と焼き付けとを繰り返し実施し、保護膜の膜厚を１００ｎｍとした保護膜形成チップを作製した。
次に、作製した保護膜形成チップを、回転式のバレル研磨によって電極膜上の保護膜を部分的に剥離させることで、本実施例のサーミスタ素子を作製した。 Next, as a protective film forming step, 100 g of a water-ethanol mixed solvent and the flaky chips were placed in a beaker, and 5.2 g of normal ethyl silicate and 16.6 g of an aqueous NaOH solution (0.2 mol/L) were added while stirring so that the flaky chips would float in the liquid, to form a protective film made of silicon oxide as a protective coating film on the entire surface of the flaky chips.
Furthermore, in order to improve the strength of the protective film, the film was baked at 700° C. after the film formation, and the film formation and baking were repeatedly performed to fabricate a chip with a protective film having a film thickness of 100 nm.
Next, the thermistor element of this example was manufactured by partially exfoliating the protective film on the electrode film of the manufactured protective film formed chip by rotary barrel polishing.
上記実施例１の他に、表１に示すように、保護膜としてバレルスパッタリングによりＳｉ３Ｎ４を成膜した保護膜形成チップを上記バレル研磨した実施例２と、保護膜としてバレルスパッタリングによりＳｉＯ２を成膜した保護膜形成チップを上記バレル研磨した実施例３と、保護膜としてバレルプラズマＣＶＤによりＡｌ２Ｏ３を成膜した保護膜形成チップを上記バレル研磨した実施例４と、電極膜としてスパッタリングによりＰｔを形成したフレーク状チップに保護膜として液相析出法によりＳｉＯ２を成膜した保護膜形成チップを上記バレル研磨した実施例５とを作製した。
さらに、実施例６として、Ｐｔペーストを印刷、焼き付けることでＰｔの電極膜を形成したフレーク状チップに保護膜として液相析出法によりＳｉＯ２を成膜した保護膜形成チップを上記バレル研磨したもの作製した。 上記実施例１の他に、表１に示すように、保護膜としてバレルスパッタリングによりＳｉ ３ Ｎ ４を成膜した保護膜形成チップを上記バレル研磨した実施例２と、保護膜としてバレルスパッタリングによりＳｉＯ ２を成膜した保護膜形成チップを上記バレル研磨した実施例３と、保護膜としてバレルプラズマＣＶＤによりＡｌ ２ Ｏ ３を成膜した保護膜形成チップを上記バレル研磨した実施例４と、電極膜としてスパッタリングによりＰｔを形成したフレーク状チップに保護膜として液相析出法によりＳｉＯ ２を成膜した保護膜形成チップを上記バレル研磨した実施例５とを作製した。
Furthermore, as Example 6, a protective film-formed chip formed by forming a SiO 2 film as a protective film by a liquid phase deposition method on a flake-shaped chip on which a Pt electrode film was formed by printing and baking a Pt paste was barrel-polished.
さらに、実施例６として、Ｐｔペーストを印刷、焼き付けることでＰｔの電極膜を形成したフレーク状チップに保護膜として液相析出法によりＳｉＯ２を成膜した保護膜形成チップを上記バレル研磨したもの作製した。 上記実施例１の他に、表１に示すように、保護膜としてバレルスパッタリングによりＳｉ ３ Ｎ ４を成膜した保護膜形成チップを上記バレル研磨した実施例２と、保護膜としてバレルスパッタリングによりＳｉＯ ２を成膜した保護膜形成チップを上記バレル研磨した実施例３と、保護膜としてバレルプラズマＣＶＤによりＡｌ ２ Ｏ ３を成膜した保護膜形成チップを上記バレル研磨した実施例４と、電極膜としてスパッタリングによりＰｔを形成したフレーク状チップに保護膜として液相析出法によりＳｉＯ ２を成膜した保護膜形成チップを上記バレル研磨した実施例５とを作製した。
Furthermore, as Example 6, a protective film-formed chip formed by forming a SiO 2 film as a protective film by a liquid phase deposition method on a flake-shaped chip on which a Pt electrode film was formed by printing and baking a Pt paste was barrel-polished.
このように作製した本発明の各実施例について、酸素濃度１００ｐｐｍ以下のＡｒ雰囲気下、７００℃の熱処理試験を実施した前後での抵抗値の変化率を測定した。
なお、本発明の比較例１として、上記保護膜を形成せずに、サーミスタ素体の上下面にＡｕペーストを塗布して焼き付けして電極膜を形成したサーミスタ素子と、比較例２として、比較例１の上下面に液相析出法によりＳｉＯ２の保護膜を形成したもので、保護膜を剥離しないサーミスタ素子とを作製し、同様の測定を行った。
これら本発明の各実施例及び各比較例について、電極膜，保護膜形成方法，保護膜材料及び保護膜剥離工程の有無を表１に示すと共に、熱処理試験での抵抗値の変化率を測定した結果を表２に示す。 For each example of the present invention thus produced, the rate of change in resistance value was measured before and after a heat treatment test at 700° C. in an Ar atmosphere with an oxygen concentration of 100 ppm or less.
As Comparative Example 1 of the present invention, a thermistor element in which an electrode film was formed by applying Au paste to the upper and lower surfaces of the thermistor element body without forming the protective film and baking the thermistor element, and as Comparative Example 2, a thermistor element in which SiO 2 protective films were formed on the upper and lower surfaces of Comparative Example 1 by a liquid phase deposition method, and the protective film was not peeled off, were produced and subjected to the same measurement.
Table 1 shows the electrode film, the method of forming the protective film, the material of the protective film, and the presence or absence of the protective film peeling process for each of the examples and comparative examples of the present invention.
なお、本発明の比較例１として、上記保護膜を形成せずに、サーミスタ素体の上下面にＡｕペーストを塗布して焼き付けして電極膜を形成したサーミスタ素子と、比較例２として、比較例１の上下面に液相析出法によりＳｉＯ２の保護膜を形成したもので、保護膜を剥離しないサーミスタ素子とを作製し、同様の測定を行った。
これら本発明の各実施例及び各比較例について、電極膜，保護膜形成方法，保護膜材料及び保護膜剥離工程の有無を表１に示すと共に、熱処理試験での抵抗値の変化率を測定した結果を表２に示す。 For each example of the present invention thus produced, the rate of change in resistance value was measured before and after a heat treatment test at 700° C. in an Ar atmosphere with an oxygen concentration of 100 ppm or less.
As Comparative Example 1 of the present invention, a thermistor element in which an electrode film was formed by applying Au paste to the upper and lower surfaces of the thermistor element body without forming the protective film and baking the thermistor element, and as Comparative Example 2, a thermistor element in which SiO 2 protective films were formed on the upper and lower surfaces of Comparative Example 1 by a liquid phase deposition method, and the protective film was not peeled off, were produced and subjected to the same measurement.
Table 1 shows the electrode film, the method of forming the protective film, the material of the protective film, and the presence or absence of the protective film peeling process for each of the examples and comparative examples of the present invention.
これらの結果からわかるように、保護膜がコーティングされていない比較例１では熱処理試験での抵抗値変化率が２９％と大きいのに対し、保護膜がコーティングされている本発明の各実施例では、いずれも熱処理試験での抵抗値変化率が５％以下と小さくなっている。
As can be seen from these results, Comparative Example 1, which is not coated with a protective film, has a high resistance value change rate of 29% in the heat treatment test, whereas each example of the present invention, which is coated with a protective film, has a small resistance value change rate of 5% or less in the heat treatment test.
次に、上記本発明の各実施例及び各比較例について、ＳＥＭ―ＥＤＳによって電極表面とチップ側面との元素マッピングを行い、保護膜の被覆率を求めた。その結果を、表２に示す。
これらの結果からわかるように、本発明の各実施例ではチップ側面の被覆率が９０％以上であるのに対し、電極表面の被覆率が８６％以下と低く、電極膜上で保護膜が部分的に剥離されて電極膜露出部が形成されている。
特に、本発明の実施例６では、電極表面の被覆率が０．８％とかなり低く、電極膜上で保護膜の多くが剥離されて電極膜露出部が形成されている。
このように本発明の実施例では、コーティング材料の種類やコーティング形成方法，及び電極の材料や形成方法が異なっていても、チップ側面の被覆率が高く維持されていると共に電極表面に電極膜露出部が形成されている。 Next, for each of the examples of the present invention and each of the comparative examples, elemental mapping was performed on the electrode surface and the chip side surface by SEM-EDS to determine the coverage of the protective film. The results are shown in Table 2.
As can be seen from these results, in each example of the present invention, the coverage of the chip side surface was 90% or more, whereas the coverage of the electrode surface was as low as 86% or less.
In particular, in Example 6 of the present invention, the coverage of the electrode surface was as low as 0.8%, and most of the protective film on the electrode film was peeled off to form an electrode film exposed portion.
As described above, in the embodiment of the present invention, even if the type of coating material, the coating forming method, and the electrode material and forming method are different, the chip side surface coverage is maintained high and the electrode film exposed portion is formed on the electrode surface.
これらの結果からわかるように、本発明の各実施例ではチップ側面の被覆率が９０％以上であるのに対し、電極表面の被覆率が８６％以下と低く、電極膜上で保護膜が部分的に剥離されて電極膜露出部が形成されている。
特に、本発明の実施例６では、電極表面の被覆率が０．８％とかなり低く、電極膜上で保護膜の多くが剥離されて電極膜露出部が形成されている。
このように本発明の実施例では、コーティング材料の種類やコーティング形成方法，及び電極の材料や形成方法が異なっていても、チップ側面の被覆率が高く維持されていると共に電極表面に電極膜露出部が形成されている。 Next, for each of the examples of the present invention and each of the comparative examples, elemental mapping was performed on the electrode surface and the chip side surface by SEM-EDS to determine the coverage of the protective film. The results are shown in Table 2.
As can be seen from these results, in each example of the present invention, the coverage of the chip side surface was 90% or more, whereas the coverage of the electrode surface was as low as 86% or less.
In particular, in Example 6 of the present invention, the coverage of the electrode surface was as low as 0.8%, and most of the protective film on the electrode film was peeled off to form an electrode film exposed portion.
As described above, in the embodiment of the present invention, even if the type of coating material, the coating forming method, and the electrode material and forming method are different, the chip side surface coverage is maintained high and the electrode film exposed portion is formed on the electrode surface.
なお、保護膜の剥離工程を施していない比較例２では、チップ側面の被覆率が１００％であると共に電極表面の被覆率が９９％であり、当然にほとんど保護膜が剥離されていない。
また、本発明の実施例１，比較例１，比較例２及び実施例６について電極表面の電子顕微鏡画像を、図３，図４，図５及び図６に示す。なお、本発明の実施例１及び実施例６の電極表面を示す図３及び図６では、白い部分が保護膜剥離工程によって電極膜露出部である。
さらに、本発明の実施例６については、側面の電子顕微鏡画像も図７に示す。なお、図７の上下の白い部分は、Ｐｔ電極であって、剥離部は素子の左右辺部分の薄いグレーの部分である。 In Comparative Example 2, in which the protective film was not peeled off, the chip side surface coverage was 100% and the electrode surface coverage was 99%.
3, 4, 5 and 6 show electron microscope images of the electrode surfaces of Example 1, Comparative Example 1, Comparative Example 2 and Example 6 of the present invention. In addition, in FIGS. 3 and 6 showing the electrode surfaces of Examples 1 and 6 of the present invention, the white portions are the electrode film exposed portions due to the protective film peeling process.
Furthermore, FIG. 7 also shows an electron microscope image of a side surface of Example 6 of the present invention. The upper and lower white portions in FIG. 7 are the Pt electrodes, and the stripped portions are light gray portions on the left and right sides of the device.
また、本発明の実施例１，比較例１，比較例２及び実施例６について電極表面の電子顕微鏡画像を、図３，図４，図５及び図６に示す。なお、本発明の実施例１及び実施例６の電極表面を示す図３及び図６では、白い部分が保護膜剥離工程によって電極膜露出部である。
さらに、本発明の実施例６については、側面の電子顕微鏡画像も図７に示す。なお、図７の上下の白い部分は、Ｐｔ電極であって、剥離部は素子の左右辺部分の薄いグレーの部分である。 In Comparative Example 2, in which the protective film was not peeled off, the chip side surface coverage was 100% and the electrode surface coverage was 99%.
3, 4, 5 and 6 show electron microscope images of the electrode surfaces of Example 1, Comparative Example 1, Comparative Example 2 and Example 6 of the present invention. In addition, in FIGS. 3 and 6 showing the electrode surfaces of Examples 1 and 6 of the present invention, the white portions are the electrode film exposed portions due to the protective film peeling process.
Furthermore, FIG. 7 also shows an electron microscope image of a side surface of Example 6 of the present invention. The upper and lower white portions in FIG. 7 are the Pt electrodes, and the stripped portions are light gray portions on the left and right sides of the device.
次に、上記本発明の各実施例及び各比較例について、実装性について評価した。その結果も、表２に示す。
実装性の評価方法としては、作製した各実施例及び各比較例のサーミスタ素子をＡｕＳｎはんだによってメタライズ基板に実装すると共に、基板と治具とのクリアランスを素子厚みの１/４以下として、５ｍｍ／ｍｉｎの走査速度でシェア強度を測定し、１Ｎ以上のものを実装性良好とし、１Ｎ未満のものを実装性不良とした。
なお、表２では実装性良好を「○」と表示し、実装性不良を「×」と表示している。 Next, the mountability was evaluated for each of the examples of the present invention and each of the comparative examples. The results are also shown in Table 2.
As a method for evaluating mountability, the thermistor elements of each of the prepared examples and comparative examples were mounted on a metallized substrate with AuSn solder, and the shear strength was measured at a scanning speed of 5 mm/min with the clearance between the substrate and jig being 1/4 or less of the element thickness.
In Table 2, good mountability is indicated by "◯", and mountability poor is indicated by "x".
実装性の評価方法としては、作製した各実施例及び各比較例のサーミスタ素子をＡｕＳｎはんだによってメタライズ基板に実装すると共に、基板と治具とのクリアランスを素子厚みの１/４以下として、５ｍｍ／ｍｉｎの走査速度でシェア強度を測定し、１Ｎ以上のものを実装性良好とし、１Ｎ未満のものを実装性不良とした。
なお、表２では実装性良好を「○」と表示し、実装性不良を「×」と表示している。 Next, the mountability was evaluated for each of the examples of the present invention and each of the comparative examples. The results are also shown in Table 2.
As a method for evaluating mountability, the thermistor elements of each of the prepared examples and comparative examples were mounted on a metallized substrate with AuSn solder, and the shear strength was measured at a scanning speed of 5 mm/min with the clearance between the substrate and jig being 1/4 or less of the element thickness.
In Table 2, good mountability is indicated by "◯", and mountability poor is indicated by "x".
これらの結果からわかるように、電極膜が露出している本発明の各実施例及び比較例１では、いずれもシェア強度が１Ｎ以上と十分な実装性が得られている。
なお、保護膜が電極膜上全体にコーティングされている比較例２では、熱処理試験での抵抗値変化率が２．５％と小さいが、保護膜の剥離工程が施されていないために、電極膜が露出しておらず、実装性不良となっている。 As can be seen from these results, in each of the examples of the present invention and the comparative example 1 in which the electrode film is exposed, the shear strength is 1 N or more, and sufficient mountability is obtained.
In Comparative Example 2 in which the protective film is coated on the entire electrode film, the resistance value change rate in the heat treatment test is as small as 2.5%, but since the protective film is not removed, the electrode film is not exposed, resulting in poor mountability.
なお、保護膜が電極膜上全体にコーティングされている比較例２では、熱処理試験での抵抗値変化率が２．５％と小さいが、保護膜の剥離工程が施されていないために、電極膜が露出しておらず、実装性不良となっている。 As can be seen from these results, in each of the examples of the present invention and the comparative example 1 in which the electrode film is exposed, the shear strength is 1 N or more, and sufficient mountability is obtained.
In Comparative Example 2 in which the protective film is coated on the entire electrode film, the resistance value change rate in the heat treatment test is as small as 2.5%, but since the protective film is not removed, the electrode film is not exposed, resulting in poor mountability.
なお、本発明の技術範囲は上記実施形態及び実施例に限定されるものではなく、本発明の趣旨を逸脱しない範囲において種々の変更を加えることが可能である。
例えば、上記実施形態及び実施例では、バレル研磨により電極膜上の保護膜を剥離しているが、超音波洗浄等によって電極膜上の保護膜を剥離してもよい。 The technical scope of the present invention is not limited to the above embodiments and examples, and various modifications can be made without departing from the scope of the present invention.
For example, in the above embodiments and examples, the protective film on the electrode film is peeled off by barrel polishing, but the protective film on the electrode film may be peeled off by ultrasonic cleaning or the like.
例えば、上記実施形態及び実施例では、バレル研磨により電極膜上の保護膜を剥離しているが、超音波洗浄等によって電極膜上の保護膜を剥離してもよい。 The technical scope of the present invention is not limited to the above embodiments and examples, and various modifications can be made without departing from the scope of the present invention.
For example, in the above embodiments and examples, the protective film on the electrode film is peeled off by barrel polishing, but the protective film on the electrode film may be peeled off by ultrasonic cleaning or the like.
１…サーミスタ素子、１ａ…保護膜形成チップ、２ａ…サーミスタ素体、２ｂ…電極膜、２ｃ…保護膜、２ｄ…電極膜露出部
DESCRIPTION OFSYMBOLS 1... Thermistor element 1a... Protective film formation chip 2a... Thermistor element body 2b... Electrode film 2c... Protective film 2d... Electrode film exposed part
DESCRIPTION OF
Claims (9)
- チップ状又は板状のサーミスタ素体と、
前記サーミスタ素体の上下面に形成された一対の電極膜と、
前記サーミスタ素体の外周面及び前記一対の電極膜上に形成された絶縁性の保護膜とを備え、
前記電極膜の面内の少なくとも中央部に、前記保護膜が除かれて前記電極膜が露出した電極膜露出部が設けられていることを特徴とするサーミスタ素子。 a chip-shaped or plate-shaped thermistor element;
a pair of electrode films formed on the upper and lower surfaces of the thermistor body;
An insulating protective film formed on the outer peripheral surface of the thermistor element and the pair of electrode films,
A thermistor element, wherein an electrode film exposed portion in which the electrode film is exposed by removing the protective film is provided at least in a central portion of the surface of the electrode film. - 請求項１に記載のサーミスタ素子において、
前記保護膜が、前記サーミスタ素体との密着強度よりも前記電極膜との密着強度が小さい材料で形成されていることを特徴とするサーミスタ素子。 The thermistor element according to claim 1,
1. A thermistor element according to claim 1, wherein said protective film is made of a material having a weaker adhesion strength with said electrode film than with said thermistor body. - 請求項１に記載のサーミスタ素子において、
前記電極膜が、貴金属で形成され、
前記保護膜が、酸化膜又は窒化膜であることを特徴とするサーミスタ素子。 The thermistor element according to claim 1,
the electrode film is formed of a noble metal,
A thermistor element, wherein the protective film is an oxide film or a nitride film. - 請求項１に記載のサーミスタ素子において、
前記保護膜の厚さが、１０ｎｍ以上１０００ｎｍ以下であることを特徴とするサーミスタ素子。 The thermistor element according to claim 1,
A thermistor element, wherein the protective film has a thickness of 10 nm or more and 1000 nm or less. - 請求項１に記載のサーミスタ素子において、
前記サーミスタ素体の外周面において前記保護膜の占める被覆率が、前記電極膜の面内において前記保護膜の占める被覆率より大きいことを特徴とするサーミスタ素子。 The thermistor element according to claim 1,
A thermistor element, wherein a coverage of the protective film on the outer peripheral surface of the thermistor body is larger than a coverage of the protective film on the surface of the electrode film. - 請求項１に記載のサーミスタ素子において、
前記電極膜の面内において前記保護膜の占める被覆率が、９０％以下であることを特徴とするサーミスタ素子。 The thermistor element according to claim 1,
A thermistor element, wherein a coverage ratio of the protective film in the plane of the electrode film is 90% or less. - 請求項１に記載のサーミスタ素子を製造する方法であって、
チップ状又は板状のサーミスタ素体の上下面に一対の電極膜を形成する電極膜形成工程と、
前記サーミスタ素体の外周面及び前記一対の電極膜上に絶縁性の保護膜を形成し保護膜形成チップを作製する保護膜形成工程と、
前記保護膜形成チップにおける前記電極膜の面内の少なくとも中央部の前記保護膜を剥離して前記電極膜が露出した電極膜露出部を形成する保護膜剥離工程とを有していることを特徴とするサーミスタ素子の製造方法。 A method for manufacturing the thermistor element according to claim 1, comprising:
an electrode film forming step of forming a pair of electrode films on the upper and lower surfaces of a chip-shaped or plate-shaped thermistor body;
a protective film forming step of forming an insulating protective film on the outer peripheral surface of the thermistor element and the pair of electrode films to fabricate a protective film formed chip;
and a protective film stripping step of stripping the protective film from at least a central portion in the plane of the electrode film in the protective film-formed chip to form an electrode film exposed portion in which the electrode film is exposed. - 請求項７に記載のサーミスタ素子の製造方法において、
前記保護膜形成工程で、前記保護膜を前記サーミスタ素体との密着強度よりも前記電極膜との密着強度が小さい材料で形成することを特徴とするサーミスタ素子の製造方法。 In the method for manufacturing a thermistor element according to claim 7,
A method of manufacturing a thermistor element, wherein in the protective film forming step, the protective film is formed of a material having a smaller adhesion strength to the electrode film than to the thermistor body. - 請求項７に記載のサーミスタ素子の製造方法において、
前記保護膜剥離工程で、前記保護膜形成チップをバレル研磨することで、前記電極膜の面内の少なくとも中央部の前記保護膜を剥離することを特徴とするサーミスタ素子の製造方法。
In the method for manufacturing a thermistor element according to claim 7,
A method of manufacturing a thermistor element, wherein in the protective film peeling step, the protective film formed on the chip is barrel-polished to peel off the protective film at least at the central portion within the surface of the electrode film.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2022-006528 | 2022-01-19 | ||
| JP2022006528 | 2022-01-19 | ||
| JP2022134194A JP2023105779A (en) | 2022-01-19 | 2022-08-25 | Thermistor element and manufacturing method for the same |
| JP2022-134194 | 2022-08-25 |
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| Publication Number | Publication Date |
|---|---|
| WO2023140054A1 true WO2023140054A1 (en) | 2023-07-27 |
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| Application Number | Title | Priority Date | Filing Date |
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| PCT/JP2022/047772 WO2023140054A1 (en) | 2022-01-19 | 2022-12-23 | Thermistor element and method for manufacturing same |
Country Status (2)
| Country | Link |
|---|---|
| TW (1) | TW202345176A (en) |
| WO (1) | WO2023140054A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6480002A (en) * | 1987-09-21 | 1989-03-24 | Chichibu Cement Kk | Nonlinear resistor |
| JPH1022104A (en) * | 1996-07-04 | 1998-01-23 | Murata Mfg Co Ltd | Positive temperature coefficient thermistor |
| JP2014154830A (en) * | 2013-02-13 | 2014-08-25 | Mitsubishi Materials Corp | Thermistor element and manufacturing method thereof |
-
2022
- 2022-12-23 WO PCT/JP2022/047772 patent/WO2023140054A1/en unknown
-
2023
- 2023-01-05 TW TW112100336A patent/TW202345176A/en unknown
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6480002A (en) * | 1987-09-21 | 1989-03-24 | Chichibu Cement Kk | Nonlinear resistor |
| JPH1022104A (en) * | 1996-07-04 | 1998-01-23 | Murata Mfg Co Ltd | Positive temperature coefficient thermistor |
| JP2014154830A (en) * | 2013-02-13 | 2014-08-25 | Mitsubishi Materials Corp | Thermistor element and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| TW202345176A (en) | 2023-11-16 |
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