Thermistor element and electromagnetic wave sensor

Abstract

The thermistor element of the present application includes: a thermistor film; a pair of first electrodes disposed in contact with one face of the thermistor film; an insulating film disposed on the side opposite to the side of the pair of first electrodes in contact with the thermistor film; and at least one or more opening portions located in the region overlapping the pair of first electrodes respectively in plan view, penetrating the insulating film, the first electrode having: a first portion located in the region overlapping the opening portion in plan view; and a second portion located outside the region overlapping the opening portion in plan view, and disposed in contact with one face of the thermistor film throughout between the first portion and the second portion.

Description

Technical Field

[0001] This invention relates to thermistor elements and electromagnetic wave sensors. Background Technology

[0002] For example, there are temperature sensors that use thermistor elements (see, for example, Patent Document 1 below). Additionally, there are electromagnetic wave sensors that use thermistor elements (see, for example, Patent Document 2 below).

[0003] A thermistor element has a thermistor film that changes temperature according to the thermistor film. In an electromagnetic wave sensor, infrared radiation (electromagnetic waves) incident on the thermistor film is absorbed by the thermistor film or the material surrounding the thermistor film, thereby causing a change in the temperature of the thermistor film. Thus, the thermistor element detects the infrared radiation (electromagnetic waves).

[0004] Here, according to the Stefan-Boltzmann rule, there is a correlation between the temperature of the object being measured and the infrared radiation (radiative heat) emitted from the object through thermal radiation. Therefore, by using a thermistor element to detect the infrared radiation emitted from the object, the temperature of the object can be measured non-contactly.

[0005] In addition, such thermistor elements are arranged in an array of multiple and are used in electromagnetic wave sensors such as infrared imaging elements (infrared image sensors) to detect (capture) the temperature distribution of a measured object in two dimensions.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-156274

[0009] Patent Document 2: International Publication No. 2019 / 171488 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, the element structures of the aforementioned thermistor element include the CIP (Current-In-Plane) structure, in which current flows in the in-plane direction of the thermistor film, and the CPP (Current-Perpendicular-to-Plane) structure, in which current flows in the normal direction of the thermistor film.

[0012] In the CIP structure, the resistance of the thermistor film increases. On the other hand, in the CPP structure, the thermistor film can have a lower resistance than in the CIP structure.

[0013] However, for example, in the thermistor element described in Patent Document 1 above, the electrode contacts the thermistor film through an opening that penetrates the insulating film. In this case, the contact area between the electrode and the thermistor film cannot be sufficiently obtained, which poses a reliability problem.

[0014] The present invention is made in view of this existing situation, and its object is to provide a thermistor element that can increase the contact area between the electrode and the thermistor film, and an electromagnetic wave sensor that can improve reliability by having such a thermistor element.

[0015] Technical solutions for solving the problem

[0016] To achieve the above objectives, the present invention provides the following technical solutions.

[0017] [1] A thermistor element, characterized in that,

[0018] have:

[0019] Thermistor film;

[0020] A pair of first electrodes are disposed in contact with one side of the thermistor film;

[0021] An insulating film is disposed on the opposite side of the pair of first electrodes that is in contact with the thermistor film; and

[0022] At least one opening, located in the region that overlaps with the pair of first electrodes when viewed from above, penetrates the insulating film.

[0023] The first electrode has: a first portion located in a region that overlaps with the opening when viewed from above; and a second portion located outside the region that overlaps with the opening when viewed from above, and is disposed in contact with one side of the thermistor film, extending between the first portion and the second portion.

[0024] [2] The thermistor element according to [1] above is characterized in that,

[0025] It includes: a wiring layer, electrically connected to the first electrode.

[0026] The wiring layer is disposed in contact with the first portion.

[0027] [3] The thermistor element according to [2] above is characterized in that,

[0028] The wiring layer is composed of at least one material selected from aluminum, tungsten, titanium, tantalum, titanium nitride, tantalum nitride, chromium nitride, and zirconium nitride.

[0029] [4] The thermistor element according to any one of [1] to [3] above, characterized in that,

[0030] It includes: a second electrode, which is disposed in contact with the other side of the thermistor film.

[0031] [5] The thermistor element according to any one of [1] to [4] above, characterized in that,

[0032] When viewed from above, the area of ​​the opening is smaller than the area of ​​the second part.

[0033] [6] An electromagnetic wave sensor, characterized in that,

[0034] The thermistor element is provided with any one of the above [1] to [5].

[0035] [7] The electromagnetic wave sensor according to claim [6], characterized in that,

[0036] The thermistor elements are arranged in an array of multiple units.

[0037] The effects of the invention

[0038] According to the present invention, a thermistor element capable of increasing the contact area between the electrode and the thermistor film can be provided, as well as an electromagnetic wave sensor whose reliability can be improved by having such a thermistor element. Attached Figure Description

[0039] Figure 1 This is a top view showing the structure of an electromagnetic wave sensor according to one embodiment of the present invention.

[0040] Figure 2 It means Figure 1 The diagram shows an exploded three-dimensional view of the structure of the electromagnetic wave sensor.

[0041] Figure 3 It means Figure 1 The diagram shows a cross-sectional view of the structure of the electromagnetic wave sensor.

[0042] Figure 4 This is a top view showing the structure of the thermistor element in an electromagnetic wave sensor.

[0043] Figure 5 It is by Figure 4 The cross-sectional view of the thermistor element shown is taken by line segment AA.

[0044] Figures 6A to 6C This is a top view showing a modified example of an opening.

[0045] Figure 7 It is used to explain in sequence. Figure 4The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0046] Figure 8 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0047] Figure 9 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0048] Figure 10 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0049] Figure 11 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0050] Figure 12 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0051] Figure 13 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0052] Figure 14 It is used to explain in sequence. Figure 4 The diagram shows a cross-sectional view of the manufacturing process of the thermistor element.

[0053] Figure 15 This is a cross-sectional view showing another structure of a thermistor element.

[0054] Figure 16 This is a cross-sectional view showing another structure of a thermistor element. Detailed Implementation

[0055] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0056] Furthermore, in the accompanying drawings used in the following description, the dimensions of each component are sometimes shown at different scales to facilitate observation, and are not limited to being the same as the actual dimensions of each component. Also, the materials exemplified in the following description are examples, and the present invention is not necessarily limited thereto; it can be implemented with appropriate modifications without changing its essence.

[0057] Furthermore, in the accompanying drawings shown below, an XYZ orthogonal coordinate system is established, with the X-axis direction set as the first direction X within a specific plane of the electromagnetic wave sensor, the Y-axis direction set as the second direction Y orthogonal to the first direction X within the specific plane of the electromagnetic wave sensor, and the Z-axis direction set as the third direction Z orthogonal to the specific plane of the electromagnetic wave sensor.

[0058] [Electromagnetic wave sensor]

[0059] First, as one embodiment of the present invention, for example, regarding... Figures 1-3 The electromagnetic wave sensor 1 shown will be explained.

[0060] also, Figure 1 This is a top view showing the structure of electromagnetic wave sensor 1. Figure 2 This is an exploded three-dimensional view showing the structure of electromagnetic wave sensor 1. Figure 3 This is a cross-sectional view showing the structure of electromagnetic wave sensor 1.

[0061] The electromagnetic wave sensor 1 of this embodiment applies the electromagnetic wave sensor of the present invention in an infrared imaging element (infrared image sensor) that detects (captures) the temperature distribution of the object being measured in two dimensions by detecting infrared rays (electromagnetic waves) emitted from the object being measured.

[0062] Infrared radiation consists of electromagnetic waves with wavelengths between 0.75 μm and 1000 μm. Infrared image sensors, used in infrared cameras for indoor and outdoor low-light observation, are also used as non-contact temperature sensors for measuring the temperature of people or objects.

[0063] Specifically, such as Figures 1-3 As shown, the electromagnetic wave sensor 1 includes a first substrate 2 and a second substrate 3 arranged opposite to each other, and a plurality of thermistor elements 4 disposed between these first substrate 2 and second substrate 3.

[0064] The first substrate 2 and the second substrate 3 are made of silicon substrates that are transmissive to electromagnetic waves with a specific wavelength (in this embodiment, long-wavelength infrared radiation with a wavelength of 8 to 14 μm, hereinafter referred to as "infrared radiation") IR. Alternatively, germanium substrates or the like can be used as substrates that are transmissive to infrared radiation IR.

[0065] The first substrate 2 and the second substrate 3 form a sealed internal space K by sealing the perimeter of their opposing surfaces with a sealing material (not shown). Furthermore, the internal space K is depressurized to a high vacuum. Thus, in the electromagnetic wave sensor 1, the influence of heat generated by convection in the internal space K is suppressed, and the influence of heat other than infrared radiation (IR) emitted from the object being measured on the thermistor element 4 is eliminated.

[0066] Furthermore, the electromagnetic wave sensor 1 in this embodiment is not necessarily limited to a structure that depressurizes the aforementioned sealed internal space K, but may also be a structure that has an internal space K that is sealed or open under atmospheric pressure.

[0067] The thermistor element 4 comprises a thermistor film 5 for detecting infrared (IR), a pair of first electrodes 6a and 6b disposed in contact with one side of the thermistor film 5, a second electrode 6c disposed in contact with the other side of the thermistor film 5, and insulating films 7a, 7b, and 7c covering the thermistor film 5. It has a CPP (Current-Perpendicular-to-Plane) structure that allows current to flow in the normal direction of the thermistor film 5. The insulating film 7b is disposed on the side opposite to the side of the thermistor film 5 that contacts the pair of first electrodes 6a and 6b.

[0068] That is, in this thermistor element 4, current can flow from one first electrode 6a toward the second electrode 6c in the normal direction of the thermistor film 5, and current can flow from the second electrode 6c toward the other first electrode 6b in the normal direction of the thermistor film 5.

[0069] As the thermistor film 5, materials such as vanadium oxide, amorphous silicon, polycrystalline silicon, oxides with a spinel-type crystal structure containing manganese, titanium oxide, or yttrium-barium-copper oxide can be used.

[0070] Conductive films made of materials such as platinum (Pt), gold (Au), palladium (Pd), ruthenium (Ru), silver (Ag), radium (Rh), iridium (Ir), and cesium (Os) can be used as the first electrodes 6a and 6b and the second electrode 6c.

[0071] As insulating films 7a, 7b, and 7c, materials such as aluminum nitride, silicon nitride, aluminum oxide, silicon oxide, magnesium oxide, tantalum oxide, niobium oxide, hafnium oxide, zirconium oxide, germanium oxide, yttrium oxide, tungsten oxide, bismuth oxide, calcium oxide, aluminum oxynitride, silicon oxynitride, magnesium aluminum oxide, silicon boride, boron nitride, or silon (oxynitrides of silicon and aluminum) can be used.

[0072] The insulating films 7a, 7b, and 7c can be configured to cover at least a portion of the thermistor film 5. In this embodiment, the insulating films 7a, 7b, and 7c are provided to cover both sides of the thermistor film 5.

[0073] Multiple thermistor elements 4 are formed to be the same size when viewed from above. Furthermore, the multiple thermistor elements 4 are arranged in an array within a plane parallel to the first substrate 2 and the second substrate 3 (hereinafter referred to as "specific plane"). That is, these multiple thermistor elements 4 are arranged in a matrix configuration in a first direction X and a second direction Y that intersect (orthogonal in this embodiment) each other within the specific plane.

[0074] In addition, each thermistor element 4 is arranged at a certain interval in the first direction X and in the second direction Y, with the first direction X as the row direction and the second direction Y as the column direction.

[0075] Furthermore, the matrix number of the aforementioned thermistor element 4 can be, for example, 640 rows × 480 columns, 1024 rows × 768 columns, etc., but it is not necessarily limited to these matrix numbers and can be appropriately changed.

[0076] A first insulating layer 8, a wiring section 9 electrically connected to the circuit section 15 (described later), and a first connection section 10 electrically connecting each thermistor element 4 and the wiring section 9 are provided on the first substrate 2 side.

[0077] The first insulating layer 8 is composed of an insulating film laminated on one side of the first substrate 2 (the side opposite to the second substrate 3). As the insulating film, materials such as aluminum nitride, silicon nitride, aluminum oxide, silicon oxide, magnesium oxide, tantalum oxide, niobium oxide, hafnium oxide, zirconium oxide, germanium oxide, yttrium oxide, tungsten oxide, bismuth oxide, calcium oxide, aluminum oxynitride, silicon oxynitride, magnesium aluminum oxide, silicon boride, boron nitride, or silon (oxynitride of silicon and aluminum) can be used.

[0078] The wiring section 9 has a plurality of first leads 9a and a plurality of second leads 9b. The first leads 9a and the second leads 9b are made of conductive films such as copper or gold.

[0079] A plurality of first leads 9a and a plurality of second leads 9b are configured to be located in different layers in a third direction Z of the first insulating layer 8 and to intersect three-dimensionally. The plurality of first leads 9a extend in the first direction X and are arranged at certain intervals in the second direction Y. Conversely, the plurality of second leads 9b extend in the second direction Y and are arranged at certain intervals in the first direction X.

[0080] Each thermistor element 4 is provided in each region divided by a plurality of first leads 9a and a plurality of second leads 9b when viewed from above. In the regions opposite each thermistor film 5 and the first substrate 2 in the thickness direction (the regions that overlap when viewed from above), there is a window W between the first substrate 2 and the thermistor film 5 that allows infrared IR to pass through.

[0081] The first connecting portion 10 has a pair of first connecting members 11a, 11b provided corresponding to each of the plurality of thermistor elements 4. In addition, the pair of first connecting members 11a, 11b has a pair of arm portions 12a, 12b and a pair of leg portions 13a, 13b.

[0082] Each arm 12a, 12b is made of at least one material selected from aluminum, tungsten, titanium, tantalum, titanium nitride, tantalum nitride, chromium nitride, and zirconium nitride. Each arm 12a, 12b is a wiring layer electrically connected to the first electrode 6a or the first electrode 6b, and is formed by a bent-line conductor pattern formed around the thermistor film 5 when viewed from above, and a conductor portion formed at a position overlapping the thermistor film 5 when viewed from above and connected to one first electrode 6a or the other first electrode 6b. Each leg 13a, 13b serves as a contact plug electrically connected to the first lead 9a or the second lead 9b, and is formed by plating, for example, copper, gold, FeCoNi alloy, or NiFe alloy (permalloy), with a conductor post extending in the third direction Z forming a circular cross-section.

[0083] A first connecting member 11a has an arm 12a electrically connected to a first electrode 6a, and a leg 13a electrically connecting the arm 12a to a first lead 9a, and electrically connecting the first electrode 6a and the first lead 9a.

[0084] Another first connecting member 11b has another arm 12b electrically connected to another first electrode 6b, and another leg 13b electrically connecting the other arm 12b to the second lead 9b, and electrically connecting the other first electrode 6b and the second lead 9b.

[0085] Thus, the thermistor element 4 is supported in a third direction Z by a pair of first connecting members 11a and 11b located diagonally within its plane. Furthermore, a space G is provided between the thermistor element 4 and the first insulating layer 8.

[0086] A plurality of selection transistors (not shown) for selecting one thermistor element 4 from a plurality of thermistor elements 4 are provided on one side of the first substrate 2 (the side opposite to the second substrate 3). The plurality of selection transistors are disposed at corresponding positions on the first substrate 2 for each of the plurality of thermistor elements 4. In addition, each selection transistor is disposed at a position that avoids the aforementioned window portion W in order to prevent diffuse reflection of infrared IR and reduction of incident efficiency.

[0087] A second insulating layer 14, a circuit section 15 for detecting changes in voltage output from the thermistor element 4 and converting them into brightness temperature, and a second connection section 16 for electrically connecting each thermistor element 4 and the circuit section 15 are provided on the side of the second substrate 3.

[0088] The second insulating layer 14 is composed of an insulating film laminated on one side of the second substrate 3 (the side opposite to the first substrate 2). As the insulating film, the same insulating film exemplified in the first insulating layer 8 described above can be used.

[0089] The circuit component 15 consists of a read-out integrated circuit (ROIC), a regulator, an A / D converter, a multiplexer, etc., and is disposed within the second insulating layer 14.

[0090] Furthermore, a plurality of connection terminals 17a, 17b corresponding to each of the plurality of first leads 9a and the plurality of second leads 9b are provided on the surface of the second insulating layer 14. The connection terminals 17a, 17b are made of conductive films such as copper or gold.

[0091] One connection terminal 17a is located in a region surrounding the circuit section 15 on one side in the first direction X, and is arranged at certain intervals in the second direction Y. Another connection terminal 17b is located in a region surrounding the circuit section 15 on one side in the second direction Y, and is arranged at certain intervals in the first direction X.

[0092] The second connection portion 16 has a plurality of second connection members 18a, 18b respectively corresponding to a plurality of first leads 9a and a plurality of second leads 9b. The plurality of second connection members 18a, 18b are constructed of conductor posts with a circular cross-section formed by extending in the third direction Z through, for example, copper or gold plating.

[0093] A second connecting member 18a electrically connects one end of the first lead 9a to a connecting terminal 17a. Another second connecting member 18b electrically connects one end of the second lead 9b to another connecting terminal 17b. Thus, the plurality of first leads 9a and the circuit section 15 are electrically connected via a second connecting member 18a and a connecting terminal 17a. Furthermore, the plurality of second leads 9b and the circuit section 15 are electrically connected via another second connecting member 18b and another connecting terminal 17b.

[0094] In the electromagnetic wave sensor 1 of this embodiment having the above-described structure, infrared rays IR emitted from the object being measured are incident on the thermistor element 4 through the window W from the first substrate 2 side.

[0095] In the thermistor element 4, infrared radiation IR incident on the insulating films 7a, 7b, and 7c formed near the thermistor film 5 is absorbed by the insulating films 7a, 7b, and 7c, and infrared radiation IR incident on the thermistor film 5 is also absorbed by the thermistor film 5, thereby causing a change in the temperature of the thermistor film 5. Furthermore, in the thermistor element 4, because the resistance of the thermistor film 5 changes relative to its temperature, the output voltage between the pair of first electrodes 6a and 6b changes. In the electromagnetic wave sensor 1 of this embodiment, the thermistor element 4 functions as a calorimeter element.

[0096] In the electromagnetic wave sensor 1 of this embodiment, after the infrared radiation IR emitted from the object being measured is detected planarly by a plurality of thermistor elements 4, the electrical signal (voltage signal) output from each thermistor element 4 is converted into brightness temperature, thereby enabling two-dimensional detection (capturing) of the temperature distribution (temperature image) of the object being measured.

[0097] Furthermore, in the thermistor element 4, when a constant voltage is applied to the thermistor film 5, the change in current flowing to the thermistor film 5 can be detected relative to the temperature change of the thermistor film 5 and converted into brightness temperature.

[0098] [Thermistor element]

[0099] Next, as an embodiment of the present invention, for example, regarding... Figure 4 as well as Figure 5 The thermistor element 4 shown will be explained.

[0100] also, Figure 4 This is a top view showing the structure of the thermistor element 4. Figure 5 It is by Figure 4 The cross-sectional view of the thermistor element 4 cut by line segment AA is shown.

[0101] like Figure 4 and Figure 5 As shown, the thermistor element 4 in this embodiment has a thermistor film 5 and a side of the thermistor film 5 ( Figure 5 A pair of first electrodes 6a and 6b are disposed in contact with the lower surface of the thermistor film 5, and the other side of the thermistor film 5 is in contact with the lower surface of the thermistor film 5. Figure 5 The CPP structure of the second electrode 6c (with the upper surface in the middle) is in contact with the ground.

[0102] In the thermistor element 4 of this embodiment, for example, an oxide containing cobalt, manganese, and nickel spinel-type crystal structure (hereinafter referred to as "Co-Mn-Ni oxide") is used as the thermistor film 5, and platinum (Pt) is used as the first electrode 6a, 6b and the second electrode 6c. This thermistor element 4 is an element whose resistance decreases as the temperature, known as NTC (Negative Temperature Coefficient), increases.

[0103] In the thermistor element 4 of this embodiment having the above structure, current can flow from one first electrode 6a toward the second electrode 6c in the normal direction of the thermistor film 5, and current can flow from the second electrode 6c toward the other first electrode 6b in the normal direction of the thermistor film 5.

[0104] The resistance value of the thermistor film 5 in the CPP structure depends on the thickness of the thermistor film 5 and the relative areas of the first electrodes 6a, 6b and the second electrode 6c. Therefore, by adopting the above-described CPP structure, it is possible to achieve low resistance in the thermistor film 5.

[0105] However, in the thermistor element 4 of this embodiment, a pair of openings 20a and 20b are provided, which are located in the regions that overlap with the pair of first electrodes 6a and 6b respectively when viewed from above, and an insulating film 7b penetrates between them and the arm portions 12a and 12b that form the wiring layer. Specifically, in this embodiment, rectangular openings 20a and 20b are respectively provided in the approximate central portion of the regions that overlap with the first electrodes 6a and 6b respectively when viewed from above.

[0106] The first electrodes 6a and 6b each have a first portion 61 located within the region overlapping the openings 20a and 20b when viewed from above, and a second portion 62 located outside the region overlapping the openings 20a and 20b when viewed from above. In each of the first electrodes 6a and 6b, the first portion 61 and the second portion 62 are electrically connected. Thus, the first electrodes 6a and 6b are disposed between the first portion 61 and the second portion 62, in contact with one side of the thermistor film 5.

[0107] Therefore, in the thermistor element 4 of this embodiment, the contact area between the first electrodes 6a and 6b and the thermistor film 5 can be increased, and the reliability of the thermistor element 4 can be improved. Furthermore, in the CPP structure of the thermistor element 4 of this embodiment, since the relative area between the first electrodes 6a and 6b and the second electrode 6c can be increased, it is possible to prevent the resistance value of the thermistor film 5 between one first electrode 6a and the second electrode 6c, and the resistance value of the thermistor film 5 between the second electrode 6c and the other first electrode 6b, from becoming excessively high.

[0108] Furthermore, in the thermistor element 4 of this embodiment, each arm 12a, 12b (wiring layer) is in contact with the first portion 61 of each first electrode 6a, 6b. On the other hand, the second portion 62 of each first electrode 6a, 6b is sandwiched between the insulating film 7b disposed on each arm 12a, 12b (wiring layer) and one side of the thermistor film 5.

[0109] Furthermore, in the thermistor element 4 of this embodiment, such as Figure 4 As shown, when viewed from above, the area of ​​the openings 20a and 20b (first part 61) is smaller than the area of ​​the second part 62. The portion of the thermistor film 5 that overlaps with the openings 20a and 20b when viewed from above tends to have deteriorated film quality. However, in the thermistor element 4 of this embodiment, since the area of ​​the openings 20a and 20b (first part 61) is smaller than the area of ​​the second part 62 when viewed from above, the thermistor film 5 can be formed with good film quality.

[0110] Furthermore, in the thermistor element 4 of this embodiment, such as Figure 4 As shown, when viewed from above, there are regions where a pair of first electrodes 6a and 6b are in contact with the thermistor film 5 in the area where the second electrode 6c is in contact with the thermistor film 5.

[0111] Therefore, in the thermistor element 4 of this embodiment, even if there is a deviation in the in-plane arrangement of the first electrodes 6a and 6b, since the relative areas of the first electrodes 6a and 6b and the second electrode 6c remain unchanged, the deviation in the resistance value of the thermistor film 5 can be suppressed.

[0112] Furthermore, in this embodiment, the thermistor film 5, the pair of first electrodes 6a, 6b and the second electrode 6c are shown to be roughly rectangular when viewed from above, but the shapes of these thermistor films 5, the pair of first electrodes 6a, 6b and the second electrode 6c can be appropriately changed.

[0113] Furthermore, the openings 20a and 20b are not necessarily limited to the above-described structure; for example, they can also be... Figures 6A to 6C The structure shown can be adapted to change its shape, configuration, quantity, etc.

[0114] Specifically, in Figure 6A In the structure shown, openings 20a and 20b are provided near the ends of the regions that overlap with the first electrodes 6a and 6b respectively in the length direction when viewed from above.

[0115] On the other hand, Figure 6B In the structure shown, in the regions that overlap with the first electrodes 6a and 6b when viewed from above, a plurality of openings 20a and 20b are arranged respectively (3 in this embodiment).

[0116] On the other hand, Figure 6C In the structure shown, long openings 20a and 20b are provided in most of the area that overlaps with the first electrodes 6a and 6b when viewed from above.

[0117] Next, refer to Figures 7-14 The manufacturing process of the thermistor element 4 described above is explained.

[0118] also, Figures 7-14 This is a cross-sectional view used to illustrate the manufacturing process of the thermistor element 4.

[0119] In manufacturing the aforementioned thermistor element 4, firstly, as... Figure 7 As shown, an insulating film 7a, composed of, for example, Al2O3, is formed over the entire surface of the organic material layer 30.

[0120] Next, as Figure 8 As shown, after a conductive film 52 made of, for example, Ti is formed over the entire surface of the film, a pattern is created using photolithography to form a pair of arms 12a and 12b.

[0121] Next, as Figure 9 As shown, an insulating film 7b, made of, for example, Al2O3, is formed over a pair of arms 12a and 12b and covers the entire surface.

[0122] Next, as Figure 10 As shown, by using photolithography, openings 20a and 20b, which are formed through an insulating film 7b, are formed on a pair of arms 12a and 12b.

[0123] Next, as Figure 11 As shown, after a conductive film 53 made of, for example, Pt is formed over the entire surface of the electrode, it is patterned using photolithography to form the first electrodes 6a and 6b.

[0124] Next, as Figure 12 As shown, after a thermistor material film 54 composed of, for example, Co-Mn-Ni oxide is formed over its entire surface, a conductive film 55 composed of, for example, Pt is formed over its entire surface.

[0125] Next, as Figure 13 As shown, a second electrode 6c and a thermistor film 5 with identical shapes are formed by using photolithography. Then, a thermal (annealing) treatment is performed in oxygen.

[0126] Next, as Figure 14 As shown, an insulating film 7c, composed of, for example, SiO2, is formed over the entire surface. Then, the organic material layer 30 is removed by ashing. Through the above steps, the aforementioned thermistor element 4 can be fabricated.

[0127] Furthermore, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0128] For example, in the thermistor element 4 described above, the insulating film 7b surrounding the openings 20a and 20b is composed of a surface perpendicular to the film surface. However, for example, as... Figure 15 As shown, the insulating film 7b surrounding the openings 20a and 20b can also be formed by an inclined surface 70.

[0129] In this case, the contact area between the first electrodes 6a and 6b and the thermistor film 5 can be increased, which can improve the reliability of the thermistor element 4. In addition, it can prevent the resistance value of the thermistor film 5 between one first electrode 6a and the second electrode 6c, and the resistance value of the thermistor film 5 between the second electrode 6c and the other first electrode 6b, from becoming too large.

[0130] Furthermore, in the aforementioned thermistor element 4, the thickness of the first portion 61 of the first electrodes 6a and 6b is smaller than the thickness of the insulating film 7b surrounding the openings 20a and 20b. In contrast, as... Figure 16 As shown, it can also be configured such that the thickness of the first portion 61 of the first electrodes 6a and 6b is greater than the thickness of the insulating film 7b surrounding the openings 20a and 20b.

[0131] Furthermore, the aforementioned thermistor element 4 has a CPP structure, and conversely, it can also have a CIP structure with the second electrode 6c omitted. In this case, the contact area between the first electrodes 6a and 6b and the thermistor film 5 can be increased, thereby improving the reliability of the thermistor element 4.

[0132] Furthermore, the electromagnetic wave sensor employing the present invention is not necessarily limited to the structure of an infrared image sensor in which the plurality of thermistor elements 4 are arranged in an array. The present invention can also be applied to electromagnetic wave sensors that use a single thermistor element 4, or to electromagnetic wave sensors in which a plurality of thermistor elements 4 are arranged in a linear parallel arrangement. In addition, the thermistor element 4 can also be used as a temperature sensor for measuring temperature.

[0133] Furthermore, the electromagnetic wave sensor using the present invention is not necessarily limited to the aforementioned infrared sensor that detects electromagnetic waves. For example, it can also be a sensor that detects terahertz waves with wavelengths of 30 μm or more and 3 mm or less.

[0134] Symbol Explanation

[0135] 1…Electromagnetic wave sensor; 2…First substrate; 3…Second substrate; 4, 4A, 4B…Thermistor element; 5…Thermistor film; 6a, 6b…First electrode; 6c…Second electrode; 7a, 7b, 7c…Insulating film; 8…First insulating layer; 9…Wiring section; 9a…First lead; 9b…Second lead; 10…First connection section; 11a, 11b…First connecting member; 12a, 12b…Arm (wiring layer); 13a, 13b…Leg; 14…Second insulating layer; 15…Circuit section; 16…Second connection section; 17a, 17b…Connecting terminal; 18a, 18b…Second connecting member; 20a, 20b…Opening; 61…First part; 62…Second part; IR…Infrared (electromagnetic wave); G…Space.

Claims

1. A thermistor element characterized by comprising: a thermistor film; a pair of first electrodes provided in contact with one face of the thermistor film; an insulating film provided on the side opposite to the side in contact with the thermistor film of the pair of first electrodes; and at least one or more opening portions penetrating the insulating film in a region overlapping with the pair of first electrodes respectively when viewed from above. The first electrode has: a first portion in a region overlapping with the opening portion when viewed from above; and a second portion outside the region overlapping with the opening portion when viewed from above, and is provided in contact with the one face of the thermistor film throughout between the first portion and the second portion. The first electrode is a single layer respectively. A portion of each of the first electrodes is formed in the opening portion.

2. The thermistor element according to claim 1, characterized by comprising: a wiring layer electrically connected to the first electrode, the wiring layer being provided in contact with the first portion.

3. The thermistor element according to claim 2, characterized in that the wiring layer is composed of at least one selected from the group consisting of aluminum, tungsten, titanium, tantalum, titanium nitride, tantalum nitride, chromium nitride, and zirconium nitride.

4. The thermistor element according to any one of claims 1 to 3, characterized by comprising: a second electrode provided in contact with the other face of the thermistor film.

5. The thermistor element according to any one of claims 1 to 4, characterized in that the area of the opening portion is smaller than the area of the second portion when viewed from above.

6. An electromagnetic wave sensor characterized by comprising the thermistor element according to any one of claims 1 to 5.

7. The electromagnetic wave sensor according to claim 6, characterized in that a plurality of the thermistor elements are arranged in an array. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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