JP2016136609A - Metal nitride material for thermistor, manufacturing method for the same and film type thermistor sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal nitride material for a thermistor that can be directly formed on a film or the like with non-burning and has high heat resistance and high reliability, a manufacturing method for the same and a film type thermistor sensor.SOLUTION: A metal nitride material used for a thermistor is represented by a general formula: MAlN(here, M represents at least one element selected from the group consisting of Zr, Nb, Mo, Hf, Ta and W, and 0.65≤y/(x+y)≤0.98, 0.35≤z≤0.5, x+y+z=1). The crystal structure is a wurtzite type single phase of hexagonal system. A method of manufacturing the metal nitride material for the thermistor has a film forming step of forming a film by performing reactive spattering in a nitrogen-contained atmosphere by using an M-Al alloy spattering target (here, M represents at least one element selected from the group consisting of Zr, Nb, Mo, Hf, Ta and W).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal nitride material for a thermistor that can be directly formed on a film or the like without firing, a method for manufacturing the material, and a film type thermistor sensor.

  A thermistor material used for a temperature sensor or the like is required to have a high B constant for high accuracy and high sensitivity. Conventionally, transition metal oxides such as Mn, Co, and Fe are generally used for such thermistor materials (see Patent Documents 1 to 3). In addition, these thermistor materials require heat treatment such as firing at 550 ° C. or higher in order to obtain stable thermistor characteristics.

In addition to the thermistor material composed of the metal oxide as described above, for example, in Patent Document 4, the general formula: M _x A _y N _z (where M is at least one of Ta, Nb, Cr, Ti, and Zr) , A represents at least one of Al, Si, and B. 0.1 ≦ x ≦ 0.8, 0 <y ≦ 0.6, 0.1 ≦ z ≦ 0.8, x + y + z = 1) A thermistor material made of nitride has been proposed. Moreover, in this patent document 4, it is Ta-Al-N type material, 0.5 <= x <= 0.8, 0.1 <= y <= 0.5, 0.2 <= z <= 0.7, x + y + z = 1. Only those described above are described as examples. This Ta—Al—N-based material is produced by performing sputtering in a nitrogen gas-containing atmosphere using a material containing the above elements as a target. Moreover, the obtained thin film is heat-processed at 350-600 degreeC as needed.

As examples different from the thermistor material, for example, Patent Document 5, the general _{formula: Cr 100-x-y N} x M y ( where, M is Ti, V, Nb, Ta, Ni, Zr, Hf, Si, Ge, C, O, P, Se, Te, Zn, Cu, Bi, Fe, Mo, W, As, Sn, Sb, Pb, B, Ga, In, Tl, Ru, Rh, Re, Os, Ir, It is one or more elements selected from Pt, Pd, Ag, Au, Co, Be, Mg, Ca, Sr, Ba, Mn, Al and rare earth elements, and the crystal structure is mainly bcc structure or mainly bcc A strain film resistance film material made of a nitride represented by 0.0001 ≦ x ≦ 30, 0 ≦ y ≦ 30, 0.0001 ≦ x + y ≦ 50) is proposed. ing. This resistance film material for strain sensors measures and converts strains and stresses from changes in the resistance of the Cr-N-based strain resistance film sensor in a composition where both the nitrogen content x and the subcomponent element M content y are 30 atomic% or less. Used for. In addition, this Cr—N—M-based material is produced by performing reactive sputtering in a film-forming atmosphere containing the subcomponent gas, using it as a target such as a material containing the element. Moreover, the obtained thin film is heat-processed at 200-1000 degreeC as needed.

  In recent years, development of a film type thermistor sensor in which a thermistor material is formed on a resin film has been studied, and development of a thermistor material that can be directly formed on a film is desired. That is, it is expected that a flexible thermistor sensor can be obtained by using a film. Furthermore, although development of a very thin thermistor sensor having a thickness of about 0.1 mm is desired, conventionally, a substrate material using ceramics such as alumina is often used. When thinned, there were problems such as being very brittle and fragile, but it is expected that a very thin thermistor sensor can be obtained by using a film.

However, since a film made of a resin material generally has a heat resistant temperature as low as 150 ° C. or less, and polyimide known as a material having a relatively high heat resistant temperature has only a heat resistance of about 200 ° C., a thermistor material forming process In the case where heat treatment is applied, application is difficult. The conventional oxide thermistor material requires firing at 550 ° C. or higher in order to realize desired thermistor characteristics, and there is a problem that a film type thermistor sensor directly formed on a film cannot be realized. Therefore, it is desired to develop a thermistor material that can be directly film-formed without firing, but even with the thermistor material described in Patent Document 4, the obtained thin film can be obtained as necessary in order to obtain desired thermistor characteristics. It was necessary to perform heat treatment at 350 to 600 ° C. Further, in this example of the thermistor material, a material having a B constant of about 500 to 3000 K is obtained in the example of the Ta-Al-N material, but there is no description regarding heat resistance, and the thermal reliability of the nitride material. Sex was unknown.
Further, the Cr—N—M material of Patent Document 5 is a material having a B constant as small as 500 or less, and heat resistance within 200 ° C. cannot be ensured unless heat treatment at 200 ° C. or more and 1000 ° C. or less is performed. Therefore, there has been a problem that a film type thermistor sensor formed directly on a film cannot be realized. Therefore, it has been desired to develop a thermistor material that can be directly formed without firing.

Therefore, the inventors of the present application are metal nitride materials used for the thermistor described in Patent Document 6 as a thermistor material that can be directly formed on a film without firing, and have the general formula: Ti _x Al _y N _z ( 0.70 ≦ y / (x + y) ≦ 0.95, 0.4 ≦ z ≦ 0.5, x + y + z = 1), the crystal structure of which is a hexagonal wurtzite type A single phase metal nitride material for thermistors has been developed.
Further, as described in Patent Document 7, it is formed of a nitride composed of Hf, Al, and N, has a resistivity of 1 to 10000 Ωcm, a B constant of 2000 K or more, and is a three component of Hf—Al—N. In the system phase diagram, the composition ratio of Hf: Al: N is atomic%, 13.1: 21.9: 65.0 (point A), 20.6: 19.9: 59.5 (point B), 28.6: 12.4: 58.9 (point C), 43.4: 0.1: 56.4 (point D), 37.1: 0.5: 62.4 (point E), 23. 6: 11.9: 64.5 (point F) A thermistor material in a range surrounded by points A to F has been developed.

JP 2000-068110 A JP 2000-348903 A JP 2006-324520 A JP 2004-319737 A Japanese Patent Laid-Open No. 10-270201 JP 2013-179161 A JP 2013-4640 A

  In addition to the metal nitride materials for thermistors described in Patent Documents 6 and 7, it is desired to develop other thermistor materials that have the same characteristics as this material and can be directly formed on a film without firing.

  The present invention has been made in view of the above-described problems. The metal nitride material for a thermistor, which can be directly formed on a film or the like without being baked, has high heat resistance, and has high reliability, and a method for manufacturing the same. It is another object of the present invention to provide a film type thermistor sensor.

The inventors of the present invention focused on the AlN system among the nitride materials and made extensive research. As a result, it is difficult for AlN as an insulator to obtain optimum thermistor characteristics (B constant: about 1000 to 6000 K). However, it has been found that by replacing the Al site with a specific metal element that improves electrical conduction and having a specific crystal structure, a good B constant and heat resistance can be obtained without firing.
Therefore, the present invention has been obtained from the above findings, and the following configuration has been adopted in order to solve the above problems.

That is, the metal nitride material for a thermistor according to the first invention is a metal nitride material used in a thermistor, the general _formula: M x _Al y _{N z} (where, M is Zr, Nb, Mo, Hf, It represents at least one of Ta and W. It consists of a metal nitride represented by 0.65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = 1), and its crystal structure Is a single phase of a hexagonal wurtzite type.
This metal thermistor nitride material, a metal nitride material used in a thermistor, the general _formula: M x _Al y _{N z} (where, M is Zr, Nb, Mo, Hf, at least one of Ta and W 0.65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = 1), the crystal structure of which is a hexagonal wurtzite Since it is an ore-type single phase, a good B constant can be obtained without firing, and it has high heat resistance.

When the above “y / (x + y)” (ie, Al / (M + Al)) is less than 0.65, a wurtzite type single phase cannot be obtained, and in some M elements, a NaCl type phase is obtained. Coexisting phase or a crystal phase of only NaCl type, and a sufficiently high resistance and a high B constant cannot be obtained.
Further, if the above “y / (x + y)” (that is, Al / (M + Al)) exceeds 0.98, the resistivity is very high and the insulating property is extremely high, so that it cannot be applied as a thermistor material.
Further, when the “z” (that is, N / (M + Al + N)) is less than 0.35, since the amount of metal nitriding is small, a wurtzite type single phase cannot be obtained, and sufficient high resistance and high B A constant cannot be obtained.
Further, if the “z” (that is, N / (M + Al + N)) exceeds 0.5, a wurtzite single phase cannot be obtained. This is due to the fact that in the wurtzite type single phase, the stoichiometric ratio in the absence of defects at the nitrogen site is 0.5 (that is, N / (M + Al + N) = 0.5).

The metal nitride material for a thermistor according to the second invention is a columnar crystal formed in a film shape and extending in a direction perpendicular to the surface of the film in the first invention. .
That is, the metal nitride material for thermistor is a columnar crystal extending in a direction perpendicular to the surface of the film, so that the film has high crystallinity and high heat resistance.

A film-type thermistor sensor according to a third aspect of the invention includes an insulating film, a thin film thermistor portion formed on the insulating film with the metal nitride material for the thermistor of the first or second aspect, and at least the thin film thermistor. And a pair of pattern electrodes formed above or below the portion.
That is, in this film type thermistor sensor, since the thin film thermistor portion is formed of the metal nitride material for thermistor of the first or second invention on the insulating film, it is formed by non-firing and has a high B constant and heat resistance. A thin and thin thermistor sensor having good thermistor characteristics can be obtained while an insulating film having a low heat resistance such as a resin film can be used by the thin film thermistor portion having a high thickness.
Conventionally, substrate materials using ceramics such as alumina are often used. For example, when the thickness is reduced to 0.1 mm, the substrate material is very brittle and easily broken. Therefore, for example, a very thin film type thermistor sensor having a thickness of 0.1 mm can be obtained.

A method for producing a metal nitride material for a thermistor according to a fourth invention is a method for producing the metal nitride material for a thermistor according to the first or second invention, wherein the M-Al alloy sputtering target (where M is And at least one of Zr, Nb, Mo, Hf, Ta, and W.) is used to perform film formation by performing reactive sputtering in a nitrogen-containing atmosphere.
That is, in this method for producing a metal nitride material for a thermistor, a nitrogen-containing atmosphere using an M-Al alloy sputtering target (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W). Since the film is formed by sputtering (reactive sputtering), the metal nitride material for the thermistor of the present invention made of M _x Al _y N _z can be formed without firing.

The present invention has the following effects.
That is, according to the metal nitride material for a thermistor according to the present invention, the general _formula: M x _Al y _{N z} (where, M represents Zr, Nb, Mo, Hf, at least one of Ta and W .0. 65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = 1), the crystal structure of which is a hexagonal wurtzite single phase Therefore, a good B constant can be obtained by non-firing and has high heat resistance. Moreover, according to the manufacturing method of the metal nitride material for thermistors according to the present invention, the M-Al alloy sputtering target (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W). Since the film is formed by performing reactive sputtering in a nitrogen-containing atmosphere, the metal nitride material for thermistor of the present invention made of M _x Al _y N _z can be formed without firing. Furthermore, according to the film type thermistor sensor according to the present invention, since the thin film thermistor portion is formed of the metal nitride material for thermistor of the present invention on the insulating film, the insulating film having low heat resistance such as a resin film. Can be used to obtain a thin and flexible thermistor sensor having good thermistor characteristics. Furthermore, since the substrate material is not a ceramic that is very brittle and fragile when thin, but a resin film, a very thin film type thermistor sensor having a thickness of 0.1 mm can be obtained.

1 is a Zr—Al—N-based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a thermistor metal nitride material, a manufacturing method thereof, and a film type thermistor sensor according to the present invention. 1 is an Nb—Al—N-based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a metal thermistor material for thermistor, a manufacturing method thereof, and a film type thermistor sensor according to the present invention. 1 is a Mo—Al—N-based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a thermistor metal nitride material, a manufacturing method thereof, and a film type thermistor sensor according to the present invention. 1 is an Hf—Al—N-based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a thermistor metal nitride material, a method for producing the same, and a film type thermistor sensor according to the present invention. 1 is a Ta—Al—N-based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a thermistor metal nitride material, a method for producing the same, and a film type thermistor sensor according to the present invention. 1 is a W—Al—N-based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a thermistor metal nitride material, a manufacturing method thereof, and a film type thermistor sensor according to the present invention. In this embodiment, it is a perspective view which shows a film type thermistor sensor. In this embodiment, it is a perspective view which shows the manufacturing method of a film type thermistor sensor in order of a process. In the Example of the metal nitride material for thermistors which concerns on this invention, its manufacturing method, and a film type thermistor sensor, it is the front view and top view which show the element | device for film | membrane evaluation of the metal nitride material for thermistors. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between 25 degreeC resistivity and B constant about the case where M = Zr. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between a 25 degreeC resistivity and a B constant about the case where M = Nb. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between 25 degreeC resistivity and B constant about the case where M = Mo. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between 25 degreeC resistivity and B constant about the case where M = Hf. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between 25 degreeC resistivity and B constant about the case where M = Ta. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between 25 degreeC resistivity and B constant about the case where M = W. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Al / (Zr + Al) ratio and B constant. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Al / (Nb + Al) ratio and B constant. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Al / (Mo + Al) ratio and B constant. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Al / (Hf + Al) ratio and B constant. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Al / (Ta + Al) ratio and B constant. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Al / (W + Al) ratio and B constant. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD) in case c / axis orientation with Al / (Zr + Al) = 0.84 is strong. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD) in case c / axis orientation with Al / (Nb + Al) = 0.92 is strong. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD) in case c / axis orientation with strong Al / (Mo + Al) = 0.92. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD) in case c / axis orientation with Al / (Hf + Al) = 0.74 is strong. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD) in case c / axis orientation with Al / (Ta + Al) = 0.83 is strong. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD) in case c / axis orientation with Al / (W + Al) = 0.91 is strong. In the Example which concerns on this invention, it is a cross-sectional SEM photograph in the case of M = Zr. In the Example which concerns on this invention, it is a cross-sectional SEM photograph in the case of M = Nb. In the Example which concerns on this invention, it is a cross-sectional SEM photograph in the case of M = Mo. In the Example which concerns on this invention, it is a cross-sectional SEM photograph in the case of M = Hf. In the Example which concerns on this invention, it is a cross-sectional SEM photograph in the case of M = Ta. In the Example which concerns on this invention, it is a cross-sectional SEM photograph in the case of M = W.

  Hereinafter, an embodiment of a metal nitride material for a thermistor, a manufacturing method thereof, and a film type thermistor sensor according to the present invention will be described with reference to FIGS. In the drawings used for the following description, the scale is appropriately changed as necessary to make each part recognizable or easily recognizable.

The metal nitride material for a thermistor of this embodiment is a metal nitride material used for the thermistor, and has a general formula: M _x Al _y N _z (where M is Zr, Nb, Mo, Hf, Ta and W). At least one kind, which is made of a metal nitride represented by 0.65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = 1), and has a crystal structure of hexagonal crystal This is a single phase of the system wurtzite type (space group P6 ₃ mc (No. 186)).

That is, when M = Zr, the metal nitride material for the thermistor is in a region surrounded by points A, B, C, D in the Zr—Al—N ternary phase diagram as shown in FIG. It is a metal nitride having a composition and a crystalline phase of wurtzite type.
When M = Nb, the metal nitride material for the thermistor is formed in a region surrounded by points A, B, C, and D in the Nb—Al—N ternary phase diagram as shown in FIG. It is a metal nitride having a composition and a crystalline phase of wurtzite type.
Further, when M = Mo, the metal nitride material for the thermistor is formed in a region surrounded by points A, B, C, and D in the Mo—Al—N ternary phase diagram as shown in FIG. It is a metal nitride having a composition and a crystalline phase of wurtzite type.
Further, when M = Hf, the metal nitride material for the thermistor is formed in a region surrounded by points A, B, C, D in the Hf—Al—N ternary phase diagram as shown in FIG. It is a metal nitride having a composition and a crystalline phase of wurtzite type.
When M = Ta, the metal nitride material for the thermistor is formed in a region surrounded by points A, B, C, and D in the Ta—Al—N ternary phase diagram as shown in FIG. It is a metal nitride having a composition and a crystalline phase of wurtzite type.
Further, when M = W, the metal nitride material for the thermistor is formed in a region surrounded by points A, B, C, and D in the W—Al—N ternary phase diagram as shown in FIG. It is a metal nitride having a composition and a crystalline phase of wurtzite type.

  The composition ratios (x, y, z) (atm%) of the points A, B, C, and D are A (17.50, 32.50, 50.00), B (1.00, 49). .0.00, 50.00), C (1.30, 63.70, 35.00), D (22.75, 42.25, 35.00).

The metal nitride material for the thermistor is a columnar crystal formed in a film shape and extending in a direction perpendicular to the surface of the film.
Whether the a-axis orientation (100) is strong or the c-axis orientation (002) is strong in the direction perpendicular to the film surface (film thickness direction) is determined using X-ray diffraction (XRD). The orientation was investigated, and the peak intensity ratio of (100) (hkl index indicating a-axis orientation) and (002) (hkl index indicating c-axis orientation) was calculated as “(100) peak intensity” / “(002) When the “peak intensity of” is less than 1, the c-axis orientation is strong.

  Next, a film type thermistor sensor using the metal nitride material for the thermistor of this embodiment will be described. As shown in FIG. 7, the film type thermistor sensor 1 includes an insulating film 2, a thin film thermistor section 3 formed on the insulating film 2 with the metal nitride material for the thermistor, and at least the thin film thermistor section 3. And a pair of pattern electrodes 4 formed thereon.

The insulating film 2 is formed in a band shape with, for example, a polyimide resin sheet. In addition, as the insulating film 2, PET: polyethylene terephthalate, PEN: polyethylene naphthalate, or the like may be used.
The pair of pattern electrodes 4 is formed by patterning a laminated metal film of, for example, a Cr film and an Au film, and a pair of comb-shaped electrode portions 4a having a comb-shaped pattern arranged on the thin film thermistor portion 3 so as to face each other, and these comb-shaped electrodes A tip end portion is connected to the portion 4a, and a base end portion is disposed at an end portion of the insulating film 2 and has a pair of linear extending portions 4b extending.

  On the base end portion of the pair of linearly extending portions 4b, a plating portion 4c such as Au plating is formed as a lead wire lead-out portion. One end of a lead wire is joined to the plating portion 4c with a solder material or the like. Further, the polyimide coverlay film 5 is pressure-bonded on the insulating film 2 except for the end of the insulating film 2 including the plated portion 4c. In place of the polyimide coverlay film 5, a polyimide or epoxy resin material layer may be formed on the insulating film 2 by printing.

  A manufacturing method of the metal nitride material for the thermistor and a manufacturing method of the film type thermistor sensor 1 using the same will be described below with reference to FIG.

First, the manufacturing method of the metal nitride material for thermistors of this embodiment uses an M-Al alloy sputtering target (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W). It has a film forming step of forming a film by reactive sputtering in a nitrogen-containing atmosphere.
For example, when M = Zr, a Zr-Al alloy sputtering target is used. When M = Nb, a Nb-Al alloy sputtering target is used. When M = Mo, a Mo-Al alloy sputtering target is used. When M = Hf, an Hf—Al alloy sputtering target is used. When M = Ta, a Ta—Al alloy sputtering target is used. When M = W, a W—Al alloy sputtering target is used.
Further, the sputtering gas pressure in the reactive sputtering is set to less than 1.5 Pa.
Furthermore, it is preferable to irradiate the formed film with nitrogen plasma after the film formation step.

More specifically, for example, the present embodiment is formed on the insulating film 2 of a polyimide film having a thickness of 50 μm shown in FIG. 8A by reactive sputtering as shown in FIG. 8B. A thin film thermistor portion 3 made of the metal nitride material for thermistor is formed to a thickness of 200 nm.
When M = Zr, sputtering conditions at that time are, for example, ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.4 Pa, target input power (output): 500 W, and mixing Ar gas + nitrogen gas The partial pressure of nitrogen gas is 30% in a gas atmosphere.
When M = Nb, sputtering conditions at that time are, for example, ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.4 Pa, target input power (output): 300 W, Ar gas + nitrogen gas mixture Nitrogen gas partial pressure is 40% in a gas atmosphere.
When M = Mo, sputtering conditions at that time are, for example, ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.67 Pa, target input power (output): 300 W, and Ar gas + nitrogen gas mixture The partial pressure of nitrogen gas is 30% in a gas atmosphere.
When M = Hf, sputtering conditions at that time are, for example, ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.27 Pa, target input power (output): 300 W, and mixing Ar gas + nitrogen gas The nitrogen gas partial pressure is 25% in a gas atmosphere.
When M = Ta, sputtering conditions at that time are, for example, ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.4 Pa, target input power (output): 300 W, and Ar gas + nitrogen gas mixture The partial pressure of nitrogen gas is 30% in a gas atmosphere.
When M = W, sputtering conditions at that time are, for example, ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.4 Pa, target input power (output): 300 W, and Ar gas + nitrogen gas mixture The partial pressure of nitrogen gas is 30% in a gas atmosphere.

The thin film thermistor portion 3 is formed by forming a metal nitride material for the thermistor into a desired size using a metal mask. Note that it is desirable to irradiate the formed thin film thermistor portion 3 with nitrogen plasma. For example, the thin film thermistor section 3 is irradiated with nitrogen plasma under a vacuum degree: 6.7 Pa, an output: 200 W, and an N ₂ gas atmosphere.

  Next, by sputtering, for example, a Cr film is formed to 20 nm, and an Au film is further formed to 200 nm. Further, after applying a resist solution thereon with a bar coater, prebaking is performed at 110 ° C. for 1 minute 30 seconds, and after exposure with an exposure apparatus, unnecessary portions are removed with a developer, and post baking is performed at 150 ° C. for 5 minutes. Patterning is performed at. Thereafter, unnecessary electrode portions are wet-etched with a commercially available Au etchant and Cr etchant, and as shown in FIG. 8C, a patterned electrode 4 having a desired comb-shaped electrode portion 4a is formed by resist stripping. . Alternatively, the pattern electrode 4 may be formed on the insulating film 2 first, and the thin film thermistor portion 3 may be formed on the comb electrode portion 4a. In this case, the comb electrode portion 4 a of the pattern electrode 4 is formed under the thin film thermistor portion 3.

  Next, as shown in FIG. 8 (d), for example, a polyimide coverlay film 5 with an adhesive having a thickness of 50 μm is placed on the insulating film 2, and pressed by a press at 150 ° C. and 2 MPa for 10 minutes. Adhere. Further, as shown in FIG. 8E, an end portion of the linearly extending portion 4b is formed with a 2 μm Au thin film by using, for example, an Au plating solution to form a plated portion 4c.

When a plurality of film type thermistor sensors 1 are manufactured simultaneously, after forming the plurality of thin film thermistor portions 3 and the pattern electrodes 4 on the large sheet of the insulating film 2 as described above, each film type thermistor sensor is formed from the large sheet. Cut to 1.
In this way, for example, a thin film thermistor sensor 1 having a size of 25 × 3.6 mm and a thickness of 0.1 mm is obtained.

Thus a metal nitride material thermistor of this embodiment, the general _formula: M x _Al y _{N z} (where, M represents Zr, Nb, Mo, Hf, at least one of Ta and W .0.65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = 1), the crystal structure of which is a hexagonal wurtzite type (space group P6 ₃ mc (No. 186)), a good B constant is obtained without firing and high heat resistance.
In addition, since the metal nitride material for the thermistor is a columnar crystal extending in a direction perpendicular to the surface of the film, the film has high crystallinity and high heat resistance.

In the manufacturing method of the metal nitride material for thermistors of this embodiment, nitrogen is contained using an M-Al alloy sputtering target (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W). Since the film is formed by reactive sputtering in the atmosphere, the metal nitride material for thermistor made of M _x Al _y N _z can be formed without firing.
In addition, since the formed film is irradiated with nitrogen plasma after the film forming process, the number of nitrogen defects in the film is reduced and the heat resistance is further improved.

Therefore, in the film thermistor sensor 1 using the thermistor metal nitride material of the present embodiment, the thin film thermistor portion 3 is formed on the insulating film 2 from the thermistor metal nitride material. The formed thin film thermistor portion 3 having a high B constant and high heat resistance allows the use of an insulating film 2 having low heat resistance such as a resin film, and a thin and flexible thermistor sensor having good thermistor characteristics. It is done.
Conventionally, substrate materials using ceramics such as alumina are often used. For example, when the thickness is reduced to 0.1 mm, there is a problem that the substrate material is very brittle and easily broken. In this embodiment, a film is used. Therefore, for example, a very thin film type thermistor sensor having a thickness of 0.1 mm can be obtained.

  Next, with respect to the metal nitride material for thermistor according to the present invention, the manufacturing method thereof, and the film type thermistor sensor, the results of evaluation based on the example manufactured based on the above embodiment will be described in detail with reference to FIGS. I will explain it.

<Production of film evaluation element>
As an example of the present invention and a comparative example, a film evaluation element 121 shown in FIG. 9 was produced as follows.
First, Zr-Al alloy target, Nb-Al alloy target, Mo-Al alloy target, Hf-Al alloy target, Ta-Al alloy target, W-Al alloy target with various composition ratios are prepared by reactive sputtering. The thin film thermistor portion 3 of the metal nitride material for thermistor formed with various composition ratios shown in Tables 1 to 6 having a thickness of 500 nm was formed on the Si wafer with the thermal oxide film to be the Si substrate S. . The sputtering conditions at that time were: ultimate vacuum: 5 × 10 ⁻⁶ Pa, sputtering gas pressure: 0.1-1.5 Pa, target input power (output): 100-500 W, Ar gas + nitrogen gas mixed gas atmosphere Below, it produced by changing nitrogen gas partial pressure with 10 to 100%.

Next, a 20 nm Cr film was formed on the thin film thermistor portion 3 by sputtering, and a 200 nm Au film was further formed. Further, after applying a resist solution thereon with a spin coater, pre-baking is performed at 110 ° C. for 1 minute 30 seconds. After exposure with an exposure apparatus, unnecessary portions are removed with a developing solution, and post-baking is performed at 150 ° C. for 5 minutes. Then, patterning was performed. Thereafter, unnecessary electrode portions were wet-etched with a commercially available Au etchant and Cr etchant, and a patterned electrode 124 having a desired comb-shaped electrode portion 124a was formed by resist stripping. Then, this was diced into chips to obtain a film evaluation element 121 for B constant evaluation and heat resistance test.
Incidentally, _M x _Al y _{N z} (where, M is Zr, Nb, Mo, Hf, . Indicating at least one of Ta and W) crystal system composition ratio be outside the scope of the present invention is different as compared A comparative example was similarly prepared and evaluated.

<Evaluation of membrane>
(1) Composition analysis About the thin film thermistor part 3 obtained by the reactive sputtering method, the elemental analysis was conducted by X-ray photoelectron spectroscopy (XPS). In this XPS, quantitative analysis was performed on the sputtered surface having a depth of 20 nm from the outermost surface by Ar sputtering. The results are shown in Tables 1 to 6. In addition, the composition ratio in the following table | surface is shown by "atomic%". Quantitative analysis was performed on a sputter surface having a depth of 100 nm from the outermost surface of some samples, and it was confirmed that the composition was the same as that of the sputter surface having a depth of 20 nm within the range of quantitative accuracy.

  In the X-ray photoelectron spectroscopy (XPS), the X-ray source is AlKα (350 W), the path energy is 46.95 eV, the measurement interval is 0.1 eV, the photoelectron extraction angle with respect to the sample surface is 45 deg, and the analysis area is about Quantitative analysis was performed under the condition of 800 μmφ. As for the quantitative accuracy, the quantitative accuracy of N / (M + Al + N) is ± 2%, and the quantitative accuracy of Al / (M + Al) is ± 1% (provided that M is Zr, Nb, Mo, Hf, Ta and W). At least one is shown).

(2) Specific resistance measurement About the thin film thermistor part 3 obtained by the reactive sputtering method, the specific resistance in 25 degreeC was measured by the 4 terminal method (van der pauw method). The results are shown in Tables 1 to 6.
(3) B constant measurement The resistance value of 25 degreeC and 50 degreeC of the element 121 for film | membrane evaluation was measured within the thermostat, and B constant was computed from the resistance value of 25 degreeC and 50 degreeC. The results are shown in Tables 1 to 6. Further, it has been confirmed that the thermistor has a negative temperature characteristic from resistance values of 25 ° C. and 50 ° C.

In addition, the B constant calculation method in this invention is calculated | required by the following formula | equation from each resistance value of 25 degreeC and 50 degreeC as mentioned above.
B constant (K) = ln (R25 / R50) / (1 / T25-1 / T50)
R25 (Ω): resistance value at 25 ° C. R50 (Ω): resistance value at 50 ° C. T25 (K): 298.15K 25 ° C. is displayed as an absolute temperature T50 (K): 323.15K 50 ° C. is displayed as an absolute temperature

As can be seen from these _results, M x _Al y _{N z} (where, M is Zr, Nb, Mo, Hf, exhibits at least one of Ta and W.) The composition ratio of shown in FIGS. 1 to 6 3 In the triangular diagram of the original system, within the region surrounded by points A, B, C, and D, that is, “0.65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = Thermistor characteristics of resistivity: 10 Ωcm or more and B constant: 1200 K or more are achieved in all the examples in the region “1”.

  Graphs showing the relationship between the resistivity at 25 ° C. and the B constant based on the above results are shown in FIGS. FIG. 16 is a graph showing the relationship between the Al / (Zr + Al) ratio and the B constant. A graph showing the relationship between the Al / (Nb + Al) ratio and the B constant is shown in FIG. A graph showing the relationship between the Al / (Mo + Al) ratio and the B constant is shown in FIG. A graph showing the relationship between the Al / (Hf + Al) ratio and the B constant is shown in FIG. A graph showing the relationship between the Al / (Ta + Al) ratio and the B constant is shown in FIG. A graph showing the relationship between the Al / (W + Al) ratio and the B constant is shown in FIG.

From these graphs, in the region of Al / (M + Al) = 0.65 to 0.98 and N / (M + Al + N) = 0.35 to 0.5, the wurtzite single crystal system is hexagonal. As a phase, a high resistance and high B constant region having a specific resistance value at 25 ° C. of 10 Ωcm or more and a B constant of 1200 K or more can be realized.
In the data of FIGS. 16 to 21, the same Al / (Zr + Al) ratio, the same Al / (Nb + Al) ratio, the same Al / (Mo + Al) ratio, the same Al / (Hf + Al) ratio, and the same Al / (Ta + Al) ratio. The reason why the B constant varies with respect to the same Al / (W + Al) ratio is that the amount of nitrogen in the crystal is different or the amount of lattice defects such as nitrogen defects is different.

The comparative examples 2 shown in Tables 1 to 5 were all in the region of Al / (M + Al) <0.65, and the crystal system was not a wurtzite type. In the case of Zr, it was cubic NaCl type.
Thus, in the region of Al / (M + Al) <0.65, the specific resistance value at 25 ° C. was less than 10 Ωcm, the B constant was less than 1200 K, and the region was low resistance and low B constant.
Each of Comparative Examples 1 shown in Tables 1 to 6 is a region where N / (M + Al + N) is less than 0.35, and the metal is in a crystal state in which nitriding is insufficient. This Comparative Example 1 was neither in the NaCl type nor in the wurtzite type, but in a state of very poor crystallinity. Further, in these comparative examples, it was found that both the B constant and the resistance value were very small and close to the metallic behavior.

(4) Thin film X-ray diffraction (identification of crystal phase)
The crystal phase of the thin film thermistor part 3 obtained by the reactive sputtering method was identified by grazing incidence X-ray diffraction (Grazing Incidence X-ray Diffraction). This thin film X-ray diffraction was a small angle X-ray diffraction experiment, and the measurement was performed in the range of 2θ = 20 to 130 degrees with Cu as the tube, the incident angle of 1 degree. Some samples were measured in the range of 2θ = 20 to 100 degrees with an incident angle of 0 degrees.

  As a result, in the region of Al / (M + Al) ≧ 0.65 (where M represents at least one of Zr, Nb, Mo, Hf, Ta and W), the wurtzite phase (hexagonal, AlN In the region of Al / (M + Al) <0.65, the crystal system was not a wurtzite type. In the case of Zr, it was a NaCl type phase (cubic, same phase as ZrN).

Thus, in the M-Al-N system (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W), the high resistance and high B constant region is Al / (M + Al )> Exists in the wurtzite phase of 0.65. In the examples of the present invention, the impurity phase is not confirmed, and is a wurtzite type single phase.
In Comparative Example 1 shown in Tables 1 to 6, the crystal phase was neither the wurtzite type phase nor the NaCl type phase as described above, and could not be identified in this test. Further, these comparative examples were materials with very poor crystallinity because the peak width of XRD was very wide. This is considered to be a metal phase with insufficient nitriding because it is close to a metallic behavior due to electrical characteristics.

  Next, all the examples of the present invention are films of wurtzite type phase, and since the orientation is strong, the a-axis orientation and the c-axis in the crystal axis in the direction perpendicular to the Si substrate S (film thickness direction). Which of the orientations is stronger was investigated using XRD. At this time, the peak intensity ratio of (100) (hkl index indicating a-axis orientation) and (002) (hkl index indicating c-axis orientation) was measured in order to investigate the orientation of crystal axes. The results are also shown in Tables 1 to 6.

  In addition, even if it formed into a film on the polyimide film on the same film-forming conditions, it confirmed that the wurtzite type single phase was formed similarly. Moreover, even if it forms into a film on a polyimide film on the same film-forming conditions, it has confirmed that orientation does not change.

An example of the XRD profile of the embodiment having a strong c-axis orientation is shown in FIGS. In the example of FIG. 22, Al / (Zr + Al) = 0.84 (wurtzite hexagonal crystal), and the incident angle was 1 degree. In the example of FIG. 23, Al / (Nb + Al) = 0.92 (wurtzite hexagonal crystal), and the incident angle was 1 degree. In the example of FIG. 24, Al / (Mo + Al) = 0.92 (wurtzite hexagonal crystal), and the incident angle was 1 degree. In the example of FIG. 25, Al / (Hf + Al) = 0.74 (wurtzite hexagonal crystal), and the incident angle was 1 degree. In the example of FIG. 26, Al / (Ta + Al) = 0.83 (wurtzite hexagonal crystal), and the incident angle was 1 degree. In the example of FIG. 27, Al / (W + Al) = 0.91 (wurtzite hexagonal crystal), and the incident angle was 1 degree.
As can be seen from these results, in these examples, the intensity of (002) is much stronger than (100).

  In the graph, (*) is a peak derived from the apparatus and from the Si substrate with a thermal oxide film, and it is confirmed that it is not the peak of the sample body or the peak of the impurity phase. Moreover, the incident angle was set to 0 degree, the symmetry measurement was implemented, it confirmed that the peak had disappeared, and it was checked that it is a peak derived from a device and a Si substrate with a thermal oxide film.

<Evaluation of crystal form>
Next, as an example showing the crystal form in the cross section of the thin film thermistor section 3, when M = Zr, an example (Al / (Zr + Al) = 0. FIG. 28 shows a cross-sectional SEM photograph of the thin film thermistor portion 3 of 94, wurtzite type hexagonal crystal and strong c-axis orientation.
In the case of M = Nb, a thin film of an example (Al / (Nb + Al) = 0.96, wurtzite hexagonal crystal, strong c-axis orientation) formed on a Si substrate S with a thermal oxide film to about 1110 nm A cross-sectional SEM photograph in the thermistor section 3 is shown in FIG.
In the case of M = Mo, a thin film of an example (Al / (Mo + Al) = 0.75, wurtzite hexagonal crystal, strong c-axis orientation) formed on a Si substrate S with a thermal oxide film to about 330 nm. A cross-sectional SEM photograph in the thermistor section 3 is shown in FIG.
In the case of M = Hf, the thin film of the example (Al / (Hf + Al) = 0.74, wurtzite hexagonal crystal, strong c-axis orientation) formed on the Si substrate S with thermal oxide film to about 245 nm A cross-sectional SEM photograph of the thermistor section 3 is shown in FIG.
In the case of M = Ta, a thin film of an example (Al / (Ta + Al) = 0.84, wurtzite hexagonal crystal, strong c-axis orientation) formed on a Si substrate S with a thermal oxide film about 330 nm. The cross-sectional SEM photograph in the thermistor part 3 is shown in FIG.
In the case of M = W, a thin film of an example (Al / (W + Al) = 0.91, wurtzite hexagonal crystal, strong c-axis orientation) formed on a Si substrate S with a thermal oxide film to about 325 nm. A cross-sectional SEM photograph of the thermistor section 3 is shown in FIG.
The samples of these examples are obtained by cleaving and breaking the Si substrate S. Moreover, it is the photograph which observed the inclination at an angle of 45 degrees.

As can be seen from these photographs, the examples of the present invention are formed of dense columnar crystals. That is, it has been observed that columnar crystals grow in a direction perpendicular to the substrate surface. Note that the breakage of the columnar crystal occurred when the Si substrate S was cleaved.
In addition, regarding the columnar crystal size in the figure, in the example of FIG. 28 where M = Zr, the particle diameter was 20 nmφ (± 10 nmφ) and the length was about 860 nm. In the example of FIG. 29 where M = Nb, the particle size was about 20 nmφ (± 10 nmφ) and the length was about 1110 nm. Further, in the example of FIG. 30 where M = Mo, the particle diameter was 20 nmφ (± 10 nmφ) and the length was about 330 nm. Further, in the example of FIG. 31 where M = Hf, the particle diameter was about 25 nmφ (± 15 nmφ) and the length was about 245 nm. Further, in the example of FIG. 32 where M = Ta, the particle size was about 20 nmφ (± 10 nmφ) and the length was about 330 nm. Further, in the example of FIG. 33 where M = W, the particle diameter was 15 nmφ (± 10 nmφ) and the length was 325 nm.

Here, the particle diameter is the diameter of the columnar crystal in the substrate surface, and the length is the length (film thickness) of the columnar crystal in the direction perpendicular to the substrate surface.
When the aspect ratio of the columnar crystal is defined as (length) / (grain size), this embodiment has a large aspect ratio of 10 or more. It is considered that the film is dense due to the small grain size of the columnar crystals.
In addition, even when each film is formed with a thickness of 200 nm, 500 nm, and 1000 nm on the Si substrate S with a thermal oxide film, it is confirmed that the film is formed with dense columnar crystals as described above.

<Evaluation of heat resistance test>
In some examples and comparative examples shown in Tables 1 to 6, resistance values and B constants before and after a heat resistance test at 125 ° C. and 1000 h in the air were evaluated. The results are shown in Table 7. In addition, the comparative example by the Ta-Al-N type material which is not a conventional wurtzite type was also evaluated similarly.
As can be seen from these results, although the Al concentration and the nitrogen concentration are different, when compared with an example having a B constant of the same amount as that of a comparative example that is a Ta-Al-N system that is not a conventional wurtzite type, Wurtz The ore-type M-Al-N system (where M is at least one of Zr, Nb, Mo, Hf, Ta, and W) has a smaller resistance value increase rate and B constant increase rate, and is heat resistant. The wurtzite type M-Al-N system is superior in heat resistance when viewed in terms of changes in electrical characteristics before and after the test.
From the above results, it is considered that good results were obtained in heat resistance by taking a wurtzite type single phase.
When M = Ta and M = W (Ta-Al-N, W-Al-N), the B constant for the same resistance value is larger than that of the Ti-AI-N system.

  The technical scope of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Film type thermistor sensor, 2 ... Insulating film, 3 ... Thin film thermistor part, 4,124 ... Pattern electrode

Claims (4)

A metal nitride material used for the thermistor,
General formula: M _x Al _y N _z (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W. 0.65 ≦ y / (x + y) ≦ 0.98, 0.35 ≦ z ≦ 0.5, x + y + z = 1)
A metal nitride material for a thermistor characterized in that its crystal structure is a hexagonal wurtzite type single phase. The thermistor metal nitride material according to claim 1,
Formed into a film,
A metal nitride material for a thermistor, wherein the metal nitride material is a columnar crystal extending in a direction perpendicular to the surface of the film. An insulating film;
A thin film thermistor portion formed of the metal nitride material for a thermistor according to claim 1 or 2 on the insulating film;
A film type thermistor sensor comprising at least a pair of pattern electrodes formed above or below the thin film thermistor section. A method for producing a metal nitride material for a thermistor according to claim 1 or 2,
Film-forming process for forming a film by reactive sputtering in a nitrogen-containing atmosphere using an M-Al alloy sputtering target (where M represents at least one of Zr, Nb, Mo, Hf, Ta, and W). A method for producing a metal nitride material for a thermistor, comprising: