Electromagnetic wave sensor

Abstract

The present application provides an electromagnetic wave sensor with improved detection accuracy of electromagnetic waves by a thermistor element. It includes: a substrate (2) having permeability to electromagnetic waves (IR) of a certain wavelength; an insulator layer (8) provided on one surface side of the substrate (2); a thermistor film (5) arranged in a manner that a space (G) is provided between one surface of the substrate (2); and a wiring portion (9) provided inside or on the surface of the insulator layer (8) and electrically connected to the thermistor film (5), in the layer (T) provided with the insulator layer (8), the permeability of electromagnetic waves (IR) of the portion opposite to the thermistor film (5) is relatively higher than that of the portion provided with the wiring portion (9).

Description

TECHNICAL FIELD

[0001] The present application relates to an electromagnetic wave sensor. BACKGROUND

[0002] For example, there is an electromagnetic wave sensor that uses a thermistor element. The thermistor element has a thermistor film whose resistance changes in correspondence with a change in temperature of the thermistor film. In the electromagnetic wave sensor, infrared rays (electromagnetic waves) that are incident on the thermistor film are absorbed by the thermistor film or a material of the periphery of the thermistor film, whereby the temperature of the thermistor film changes. Thus, the thermistor element detects the infrared rays (electromagnetic waves).

[0003] Here, according to the Stefan-Boltzmann law, there is a correlation between the temperature of a measurement object and infrared rays (radiant heat) that are emitted from the measurement object by thermal radiation. Therefore, by detecting the infrared rays that are emitted from the measurement object using the thermistor element, it is possible to measure the temperature of the measurement object by non-contact measurement.

[0004] In addition, such a thermistor element is applied to an electromagnetic wave sensor such as an infrared camera element (infrared image sensor) that detects (photographs) a temperature distribution of a measurement object two-dimensionally by arranging a plurality of them in an array (for example, refer to Patent Literature 1 below).

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: International Publication No. 2019 / 171488 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, in the electromagnetic wave sensor described above, in order to improve the detection accuracy of the thermistor element with respect to infrared rays (electromagnetic waves), it is required to suppress the absorption of infrared rays by a portion other than the thermistor film as much as possible during a period from when the infrared rays are emitted from the measurement object to when the infrared rays are incident on the thermistor film.

[0010] The present application has been made in view of such a prior art, and an object thereof is to provide an electromagnetic wave sensor in which the detection accuracy of a thermistor element with respect to electromagnetic waves is improved.

[0011] MEANS FOR SOLVING THE PROBLEMS

[0012] In order to achieve the above object, the present application provides the following means.

[0013] (1) An electromagnetic wave sensor characterized by comprising:

[0014] a substrate which is permeable to electromagnetic waves of a certain wavelength;

[0015] an insulator layer provided on one surface side of the substrate;

[0016] a thermistor film disposed so as to have a space from one surface of the substrate; and

[0017] a wiring portion provided inside or on a surface of the insulator layer and electrically connected to the thermistor film,

[0018] the permeability of the electromagnetic waves in a portion of the layer in which the insulator layer is provided, which opposes the thermistor film, is relatively higher than the permeability of the electromagnetic waves in a portion in which the wiring portion is provided.

[0019] (2) The electromagnetic wave sensor according to the above (1), wherein a hole portion which penetrates the insulator layer is provided in the portion opposing the thermistor film.

[0020] (3) The electromagnetic wave sensor according to the above (1), wherein a recess portion which recesses the insulator layer is provided in the portion opposing the thermistor film.

[0021] (4) The electromagnetic wave sensor according to any one of the above (1) to (3), wherein a layer in which the permeability of the electromagnetic waves per unit thickness is higher than the insulator layer in the portion in which the wiring portion is provided is provided in the portion opposing the thermistor film.

[0022] (5) The electromagnetic wave sensor according to any one of the above (1) to (4), wherein an anti-reflection film is provided between the substrate and the insulator layer.

[0023] (6) The electromagnetic wave sensor according to any one of the above (1) to (5), wherein the insulator layer has a laminated film of a silicon oxide film and an aluminum oxide film provided between the substrate and the silicon oxide film.

[0024] (7) The electromagnetic wave sensor according to any one of the above (1) to (6), wherein a dielectric film which covers at least a portion of the thermistor film is provided.

[0025] (8) The electromagnetic wave sensor according to any one of the above (1) to (7), wherein

[0026] a connection portion which electrically connects the thermistor film and the wiring portion,

[0027] The connecting portion has a leg portion configured to extend in a direction having a thickness direction component of the substrate, and an arm portion configured at a position not overlapping the thermistor film in the thickness direction of the substrate,

[0028] The arm portion is located between the thermistor film and the leg portion in the connecting portion,

[0029] The leg portion is located between the wiring portion and the arm portion in the connecting portion,

[0030] The transmittance of the electromagnetic wave in a portion opposite to the arm portion is relatively lower than the transmittance of the electromagnetic wave in a portion opposite to the thermistor film in a layer in which the insulator layer is provided.

[0031] (9) The electromagnetic wave sensor according to any one of (1) to (8) above, characterized in that

[0032] a reference thermistor film different from the thermistor film is included,

[0033] The transmittance of the electromagnetic wave in a portion opposite to the thermistor film is relatively higher than the transmittance of the electromagnetic wave in a portion opposite to the reference thermistor film in a layer in which the insulator layer is provided.

[0034] (10) An electromagnetic wave sensor, characterized by comprising:

[0035] a substrate that is transmissive to electromagnetic waves of a certain wavelength;

[0036] an insulator layer provided on one face side of the substrate;

[0037] a thermistor film configured with a space from one face of the substrate; and

[0038] a wiring portion provided inside or on a surface of the insulator layer and electrically connected to the thermistor film,

[0039] a hole portion that penetrates the insulator layer or a recess portion that recesses the insulator layer is provided between the substrate and the thermistor film.

[0040] (11) The electromagnetic wave sensor according to any one of (1) to (10) above, characterized in that the thermistor film is arranged in an array.

[0041] Effects of the Invention

[0042] As described above, according to the present application, it is possible to provide an electromagnetic wave sensor in which the detection accuracy of a thermistor element with respect to electromagnetic waves is improved. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a plan view showing the structure of the electromagnetic wave sensor of the first embodiment of the present application.

[0044] Figure 2 is a plan view showing the structure of the electromagnetic wave sensor of the first embodiment of the present application. Figure 1 is an exploded perspective view showing the structure of the electromagnetic wave sensor shown in Fig. 1.

[0045] Figure 3 is a plan view showing the structure of the electromagnetic wave sensor shown in Fig. 1. Figure 1 is a sectional view showing the unit structure of the electromagnetic wave sensor shown in Fig. 1.

[0046] Figure 4 is a plan view showing the unit structure of the electromagnetic wave sensor shown in Fig. 1. Figure 1 is a plan view showing the unit structure of the electromagnetic wave sensor shown in Fig. 1.

[0047] Figure 5 is a sectional view showing the unit structure of the electromagnetic wave sensor of the second embodiment of the present application.

[0048] Figure 6 is a sectional view for sequentially explaining the process of forming a hole portion on the first insulator layer.

[0049] Figure 7 is a sectional view for sequentially explaining the process of forming a hole portion on the first insulator layer.

[0050] Figure 8 is a sectional view for sequentially explaining the process of forming a hole portion on the first insulator layer.

[0051] Figure 9 is a sectional view for sequentially explaining the process of forming a hole portion on the first insulator layer.

[0052] Figure 10 is a sectional view showing the unit structure of the electromagnetic wave sensor of the third embodiment of the present application.

[0053] Figure 11 is a sectional view showing the unit structure of the electromagnetic wave sensor of the fourth embodiment of the present application.

[0054] Figure 12 is a sectional view showing the unit structure of the electromagnetic wave sensor of the fifth embodiment of the present application.

[0055] Explanation of Reference Numerals

[0056] 1A, 1B, 1C, 1D, 1E electromagnetic wave sensor; 2 first substrate; 3 second substrate; 4 thermistor element; 4A thermistor element for measurement; 4B thermistor element for reference; 5 thermistor film; 6a first electrode; 6b second electrode; 7 dielectric film; 8 first insulator layer; 8a silicon oxide film; 8b aluminum oxide film; 9 wiring portion; 9a first lead wiring; 9b second lead wiring; 10 first connecting portion; 11a, 11b first connecting member; 12a, 12b arm portion; 13a, 13b leg portion; 14 second insulator layer; 15 circuit portion; 16 second connecting portion; 17a, 17b connecting terminal; 18a, 18b second connecting member; 21 hole portion; 22 anti-reflection film; 23 recessed portion; 24 high-transmittance layer; IR infrared ray (electromagnetic wave); G space; K internal space. DETAILED DESCRIPTION

[0057] Hereinafter, an embodiment of the present application will be described in detail with reference to the drawings.

[0058] Further, in the drawings used in the following description, in order to easily observe each constituent element, the scale of the size is sometimes represented differently according to the constituent element, and the size ratio and the like of each constituent element are not limited to be the same as the actual. In addition, the materials and the like exemplified in the following description are one example, and the present application is not necessarily limited thereto, and can be implemented by being appropriately changed within a range not changing the gist thereof.

[0059] Further, in the drawings shown below, an XYZ orthogonal coordinate system is set, the X-axis direction is set as a first direction X in a specific plane of the electromagnetic wave sensor, the Y-axis direction is set as a second direction Y in the specific plane of the electromagnetic wave sensor orthogonal to the first direction X, and the Z-axis direction is set as a third direction Z orthogonal to the specific plane of the electromagnetic wave sensor, and each is represented.

[0060] (First Embodiment)

[0061] First, as the first embodiment of the present application, the electromagnetic wave sensor 1A shown in FIG. 1A, for example, will be described. Figures 1-4

[0062] Further, FIG. 1B is a plan view showing the structure of the electromagnetic wave sensor 1A. Figure 1 is a plan view showing the structure of the electromagnetic wave sensor 1A. Figure 2 is a perspective view showing the structure of the electromagnetic wave sensor 1A. Figure 3 is a sectional view showing the unit structure of the electromagnetic wave sensor 1A. Figure 4 is a plan view showing the unit structure of the electromagnetic wave sensor 1A.

[0063] ​The electromagnetic wave sensor 1A of this embodiment applies the present invention to an infrared imaging element (infrared image sensor) that detects (captures) the temperature distribution of a measured object in two dimensions by detecting infrared light (electromagnetic waves) emitted from the measured object.

[0064] Infrared radiation consists of electromagnetic waves with wavelengths between 0.75 μm and 1000 μm. Besides being used as infrared cameras for indoor and outdoor night vision, infrared image sensors are also used as non-contact temperature sensors for measuring the temperature of people or objects.

[0065] Specifically, such as Figures 1-4 As shown, the electromagnetic wave sensor 1A includes a first substrate 2 and a second substrate 3 arranged opposite to each other, and a plurality of thermistor elements 4 disposed between the first substrate 2 and the second substrate 3.

[0066] The first substrate 2 and the second substrate 3 are made of silicon substrates that are transparent to electromagnetic waves of a specific wavelength (in this embodiment, long-wavelength infrared light with a wavelength of 8 to 14 μm) (hereinafter referred to as "infrared light") IR. Alternatively, germanium substrates or the like can be used as substrates that are transparent to infrared light IR.

[0067] The first substrate 2 and the second substrate 3 form a sealed internal space K by sealing the periphery 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 heat effect caused by convection in the internal space K is suppressed, and the influence of heat other than infrared radiation (IR) emitted from the measured object on the thermistor element 4 is eliminated.

[0068] Furthermore, the electromagnetic wave sensor 1A of this embodiment is not necessarily limited to the structure that depressurizes the sealed internal space K as described above, but may also be a structure that has an internal space K that is sealed or open under atmospheric pressure.

[0069] The thermistor element 4 includes a thermistor film 5 for detecting infrared IR, a first electrode 6a disposed in contact with one side of the thermistor film 5, a pair of second electrodes 6b disposed in contact with the other side of the thermistor film 5, and a dielectric film 7 covering the thermistor film 5, and has a CPP (Current-Perpendicular-to-Plane) structure that allows current to flow in a direction perpendicular to the thermistor film 5.

[0070] That is, in this thermistor element 4, current can flow from one second electrode 6b to the first electrode 6a in the vertical direction of the thermistor film 5, and current can flow from the first electrode 6a to the other second electrode 6b in the vertical direction of the thermistor film 5.

[0071] As the thermistor film 5, for example, a vanadium oxide film, amorphous silicon, polycrystal silicon, an oxide having a spinel crystal structure containing manganese, titanium oxide, or yttrium-barium-copper oxide, or the like can be used.

[0072] As the first electrode 6a and the second electrode 6b, for example, a conductive film of platinum (Pt), gold (Au), palladium (Pd), ruthenium (Ru), silver (Ag), rhodium (Rh), iridium (Ir), osmium (Os), or the like can be used.

[0073] As the dielectric film 7, for example, 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 sialon (silicon-aluminum oxynitride), or the like can be used.

[0074] The dielectric film 7 is a structure provided at least to cover at least a portion of the thermistor film 5. In the present embodiment, the dielectric film 7 is provided to cover both surfaces of the thermistor film 5.

[0075] The plurality of thermistor elements 4 are formed to be the same size as each other and rectangular (in the present embodiment, square) in plan view. In addition, the plurality of thermistor elements 4 are arranged in an array in a plane parallel to the first substrate 2 and the second substrate 3 (hereinafter referred to as "a specific plane").

[0076] In addition, each thermistor element 4 is arranged in a certain interval in the first direction X and in a certain interval in the second direction Y with the first direction X as a row direction and the second direction Y as a column direction.

[0077] In addition, as the number of rows and columns of the above-described thermistor elements 4, for example, 640 rows x 480 columns, 1024 rows x 768 columns, or the like can be given, but is not necessarily limited to these numbers of rows and columns and can be appropriately changed.

[0078] The first insulator layer 8, a wiring portion 9 electrically connected to a circuit portion 15 described later, and a first connection portion 10 electrically connecting each thermistor element 4 and the wiring portion 9 are provided on the first substrate 2 side.

[0079] The first insulator layer 8 is composed of an insulating film layered on one surface (a surface opposite to the second substrate 3) of the first substrate 2. As the insulating film, for example, 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, boron silicon, boron nitride, or sialon (silicon-aluminum oxynitride), or the like can be used.

[0080] The wiring portion 9 has a plurality of first lead wirings 9a and a plurality of second lead wirings 9b. The first lead wirings 9a and the second lead wirings 9b are composed of, for example, a conductive film of copper, gold, or the like. The wiring portion 9 is provided inside or on the surface of the first insulator layer 8.

[0081] The plurality of first lead wirings 9a and the plurality of second lead wirings 9b are arranged in a three-dimensional manner so as to be located in different layers in the third direction Z of the first insulator layer 8. Among them, the plurality of first lead wirings 9a extend in the first direction X and are arranged at a certain interval in the second direction Y. On the other hand, the plurality of second lead wirings 9b extend in the second direction Y and are arranged at a certain interval in the first direction X.

[0082] Each thermistor element 4 is provided in each region divided by the plurality of first lead wirings 9a and the plurality of second lead wirings 9b when viewed from above. In the region (a region overlapping when viewed from above) opposite to each thermistor film 5 in the thickness direction of the first substrate 2, a window portion W that transmits infrared rays IR is present between the first substrate 2 and the thermistor film 5.

[0083] The first connection portion 10 has a pair of first connection members 11a, 11b provided corresponding to each of the plurality of thermistor elements 4. In addition, the pair of first connection members 11a, 11b has a pair of arm portions 12a, 12b and a pair of leg portions 13a, 13b.

[0084] Each arm portion 12a, 12b is composed of, for example, a bent line-shaped conductor pattern formed along the periphery of the thermistor element 4 by a thin film of titanium, titanium nitride, or the like. Each leg portion 13a, 13b is composed of, for example, a cross-sectional circular-shaped conductor pillar formed so as to extend in the third direction Z by electroplating of copper, gold, FeCoNi alloy, or NiFe alloy (ferroperm), or the like.

[0085] One first connection member 11a has one arm portion 12a electrically connected to one second electrode 6b, and one leg portion 13a electrically connecting the one arm portion 12a and the first lead wiring 9a, electrically connecting one side of the thermistor element 4 and the first lead wiring 9a.

[0086] The other first connecting member 11b has the other arm portion 12b electrically connected to the other second electrode 6b, and the other leg portion 13b electrically connecting between the other arm portion 12c and the second lead wiring 9b, and electrically connecting between the other side of the thermistor element 4 and the second lead wiring 9b.

[0087] Thus, the thermistor element 4 is supported by the pair of first connecting members 11a, 11b in the diagonal direction on the face thereof in a state of being suspended in the third direction Z. Further, a space G is provided between the thermistor element 4 and the first insulator layer 8, and the thermistor film 5 is arranged so as to have the space G between one face of the first substrate 2 (a face opposite to the second substrate 3).

[0088] Although omitted from the illustration, a plurality of selection transistors (not illustrated) for selecting one thermistor element 4 from among the plurality of thermistor elements 4 are provided on the one face of the first substrate 2 (a face opposite to the second substrate 3). The plurality of selection transistors are provided at positions corresponding to the plurality of thermistor elements 4 of the first substrate 2, respectively. Further, in order to prevent diffuse reflection of infrared rays IR or reduction in incidence efficiency, each selection transistor is provided at a position avoiding the above-described window portion W.

[0089] The second insulator layer 14, a circuit portion 15 that detects a change in voltage output from the thermistor element 4 and converts it into a luminance temperature, and a second connecting portion 16 that electrically connects between each thermistor element 4 and the circuit portion 15 are provided on the second substrate 3 side.

[0090] The second insulator layer 14 is composed of an insulating film laminated on the one face of the second substrate 3 (a face opposite to the first substrate 2). As the insulating film, the same insulating film as that exemplified in the above-described first insulator layer 8 can be used.

[0091] The circuit portion 15 is composed of a readout integrated circuit (ROIC), or a regulator, an A / D converter, a multiplexer, or the like, and is provided in a layer of the second insulator layer 14.

[0092] Further, a plurality of connection terminals 17a, 17b corresponding to the plurality of first lead wirings 9a and the plurality of second lead wirings 9b, respectively, are provided on the face of the second insulator layer 14. The connection terminals 17a, 17b are composed of, for example, a conductive film of copper, gold, or the like.

[0093] One connection terminal 17a is arranged in a region on one side in the first direction X around the circuit portion 15, and is arranged at a certain interval in the second direction Y. The other connection terminal 17b is arranged in a region on one side in the second direction Y around the circuit portion 15, and is arranged at a certain interval in the first direction X.

[0094] The second connecting portion 16 has a plurality of second connecting members 18a, 18b arranged corresponding to the plurality of first lead wirings 9a and the plurality of second lead wirings 9b, respectively. The plurality of second connecting members 18a, 18b are constituted of, for example, conductor posts of a circular cross-sectional shape formed extending in the third direction Z by electroplating of copper or gold, or the like.

[0095] One second connecting member 18a electrically connects between one end side of the first lead wiring 9a and one connection terminal 17a. The other second connecting member 18b electrically connects between one end side of the second lead wiring 9b and the other connection terminal 17b. Thus, the plurality of first lead wirings 9a and the circuit portion 15 are electrically connected via one second connecting member 18a and one connection terminal 17a. In addition, the plurality of second lead wirings 9b and the circuit portion 15 are electrically connected via the other second connecting member 18b and the other connection terminal 17b.

[0096] In the electromagnetic wave sensor 1 of the present embodiment having the above structure, the infrared rays IR emitted from the measurement object enter the thermistor element 4 from the first substrate 2 side through the window portion W.

[0097] In the thermistor element 4, the infrared rays IR incident to the dielectric film 7 formed in the vicinity of the thermistor film 5 are absorbed by the dielectric film 7, and the infrared rays IR incident to the thermistor film 5 are absorbed by the thermistor film 5, whereby the temperature of the thermistor film 5 changes. In addition, in the thermistor element 4, in response to the temperature change of the thermistor film 5, the resistance of the thermistor film 5 changes, whereby the output voltage between the pair of second electrodes 6 changes. In the electromagnetic wave sensor 1 of the present embodiment, the thermistor element 4 functions as a bolometer element.

[0098] In the electromagnetic wave sensor 1 of the present embodiment, after the infrared rays IR emitted from the measurement object are detected planarly by the plurality of thermistor elements 4, the temperature distribution (temperature image) of the measurement object can be detected (photographed) two-dimensionally by converting the electric signals (voltage signals) output from the respective thermistor elements 4 into luminance temperatures.

[0099] In addition, in the thermistor element 4, in the case where a constant voltage is applied to the thermistor film 5, in response to the temperature change of the thermistor film 5, the change in the current flowing through the thermistor film 5 can also be detected and converted into a luminance temperature.

[0100] However, as Figure 3 and Figure 4 shown, the electromagnetic wave sensor 1A of the present embodiment has a structure in which several reference thermistor elements 4B are arranged in a region outside a region in which the measurement thermistor elements 4A are periodically arranged. Alternatively, a structure in which several reference thermistor elements 4B are arranged in a region inside a region in which the measurement thermistor elements 4A are periodically arranged can also be employed.

[0101] In the electromagnetic wave sensor 1A of the present embodiment, by using the difference between the signal detected by the measurement thermistor elements 4A and the signal detected by the reference thermistor elements 4B, the influence of the temperature of the surroundings of the thermistor film 5 can be suppressed, and thus the temperature of the measurement object can be detected with high accuracy.

[0102] In the electromagnetic wave sensor 1A of the present embodiment, in the measurement thermistor elements 4A, the transmittance of the infrared rays IR at the portion opposing the thermistor film 5 is relatively higher than the transmittance of the infrared rays IR at the portion in which the wiring portion 9 is provided in the layer T in which the first insulator layer 8 is provided.

[0103] Specifically, in the thermistor element 4A, a hole portion 21 that penetrates the first insulator layer 8 is provided at the portion opposing the thermistor film 5. In other words, the hole portion 21 that penetrates the first insulator layer 8 is provided between the first substrate 2 and the thermistor film 5. Due to this, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared rays IR is highest at the position at which the hole portion 21 is provided.

[0104] The first connection portion 10 has leg portions 13a, 13b that are arranged in a manner extending in a direction having a thickness direction component of the first substrate 2, and arm portions 12a, 12b that are arranged at positions not overlapping the thermistor film 5 in the thickness direction of the first substrate 2.

[0105] The arm portions 12a, 12b are located between the thermistor film 5 and the leg portions 13a, 13b in the first connection portion 10. The leg portions 13a, 13b are located between the wiring portion 9 and the arm portions 12a, 12b in the first connection portion 10. The first insulator layer 8 is provided between the first substrate 2 and the arm portions 12a, 12b.

[0106] Due to this, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared rays IR at the portion opposing the arm portions 12a, 12b is relatively lower than the transmittance of the infrared rays IR at the portion opposing the thermistor film 5. Due to this, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared rays IR is highest at the portion opposing the thermistor film 5.

[0107] Therefore, in the electromagnetic wave sensor 1A of the present embodiment, in the measurement thermistor element 4A, during a period from when the infrared ray IR emitted from the measurement target passes through the window portion W from the first substrate 2 side to when it reaches the vicinity of the thermistor film 5, the absorption of the infrared ray IR by the portion other than the thermistor film 5 and its vicinity is suppressed to be lower.

[0108] Further, in the electromagnetic wave sensor 1A of the present embodiment, in the measurement thermistor element 4A, the transmittance of the infrared ray IR at the portion of the layer T of the first insulator layer 8 opposing the arm portions 12a, 12b is lower than the transmittance of the infrared ray IR at the portion opposing the thermistor film 5. Therefore, the infrared ray IR irradiated to the arm portions 12a, 12b can be suppressed, and the influence of the infrared ray IR irradiated to the arm portions 12a, 12b on the thermistor film 5 can be suppressed.

[0109] On the other hand, in the reference thermistor element 4B, the first insulator layer 8 is provided between the first substrate 2 and the thermistor film 5. That is, the reference thermistor element 4B is a structure in which the portion opposing the thermistor film 5 in the layer T of the first insulator layer 8 is not provided with the hole portion 21 penetrating the first insulator layer 8. Therefore, in the reference thermistor element 4B, during a period from when the infrared ray IR emitted from the measurement target passes through the window portion W from the first substrate 2 side to when it reaches the thermistor film 5, the infrared ray IR is absorbed by the first insulator layer 8.

[0110] Therefore, in the layer T of the first insulator layer 8, the transmittance of the infrared ray IR at the portion opposing the thermistor film 5 constituting the measurement thermistor element 4A is relatively higher than the transmittance of the infrared ray IR at the portion opposing the thermistor film 5 constituting the reference thermistor element 4B.

[0111] Thus, in the electromagnetic wave sensor 1A of the present embodiment, the infrared ray IR emitted from the measurement target is suppressed from being incident on the thermistor film 5 of the reference thermistor element 4B, so by utilizing the difference between the signal detected by the measurement thermistor element 4A described above and the signal detected by the reference thermistor element 4B, the influence of the temperature of the surroundings of the thermistor film 5 can be suppressed, and the temperature of the measurement target can be detected with high accuracy.

[0112] As described above, in the electromagnetic wave sensor 1A of the present embodiment, the detection accuracy of the infrared ray IR by the measurement thermistor element 4A described above can be improved, and the temperature distribution (temperature image) of the measurement target can be detected (photographed) with high accuracy.

[0113] (Second Embodiment)

[0114] Next, as the second embodiment of the present application, the electromagnetic wave sensor IB shown in FIG. 6, for example, will be described. Figure 5

[0115] Further, Figure 5 is a cross-sectional view showing the unit structure of the electromagnetic wave sensor IB. In the following description, for parts equivalent to the above-described electromagnetic wave sensor 1A, the description will be omitted and the same reference numerals will be marked in the drawings.

[0116] As shown in FIG. 6, the electromagnetic wave sensor IB of the present embodiment is a structure in which an anti-reflection film 22 is provided between the first substrate 2 and the first insulator layer 8. Other than this, it has substantially the same structure as the above-described electromagnetic wave sensor 1A. Figure 5

[0117] The anti-reflection film 22 functions to prevent the infrared rays IR from being reflected at the interface between the first substrate 2 and the space G during the period from when the infrared rays IR emitted from the measurement object pass through the window portion W from the first substrate 2 side to when they reach the thermistor film 5, and to cause the infrared rays IR that have passed through the first substrate 2 to be efficiently incident to the thermistor film 5 side.

[0118] As the anti-reflection film 22, for example, zinc sulfide, yttrium fluoride, chalcogenide glass, germanium, silicon, zinc selenide, gallium arsenide, or the like can be used.

[0119] Further, the anti-reflection film 22 can also be a structure in which films having different refractive indexes are alternately laminated, and the reflectance of the infrared rays IR is reduced by interference of the waves reflected at the respective layers. In this case, as the anti-reflection film 22, in addition to the above-described materials, for example, a laminated film in which an oxide film, a nitride film, a sulfide film, a fluoride film, a boride film, a bromide film, a chloride film, a selenide film, a Ge film, a diamond film, a chalcogenide film, a Si film, or the like is laminated can be used.

[0120] In the electromagnetic wave sensor IB of the present embodiment, as with the above-described electromagnetic wave sensor 1A, in the measurement thermistor element 4A, a hole portion 21 that penetrates the first insulator layer 8 is provided at a portion opposite the thermistor film 5. That is, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared rays IR is highest at the position at which the hole portion 21 is provided.

[0121] Thus, in the measurement thermistor element 4A, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared rays IR is relatively high at the portion opposite the thermistor film 5, as compared with the transmittance of the infrared rays IR at the portion at which the wiring portion 9 is provided.

[0122] ​​Therefore, in the electromagnetic wave sensor 1B of the present embodiment, in the thermistor element 4A for measurement, during a period from when the infrared ray IR emitted from the measurement target enters the vicinity of the thermistor film 5 from the side of the first substrate 2 through the window portion W, it is possible to suppress the case where the infrared ray IR is absorbed by a portion other than the thermistor film 5 and its vicinity to be lower.

[0123] Therefore, in the electromagnetic wave sensor 1B of the present embodiment, even in the case where the antireflection film 22 is provided between the first substrate 2 and the first insulator layer 8, in the thermistor element 4A for measurement, during a period from when the infrared ray IR emitted from the measurement target enters the vicinity of the thermistor film 5, it is possible to suppress the case where the infrared ray IR is absorbed by a portion other than the thermistor film 5 and its vicinity to be lower.

[0124] As described above, in the electromagnetic wave sensor 1B of the present embodiment, it is possible to improve the detection accuracy of the thermistor element 4A for infrared ray IR described above, and to detect (capture) the temperature distribution (temperature image) of the measurement target with high accuracy.

[0125] However, in the electromagnetic wave sensor 1A of the first embodiment and the electromagnetic wave sensor 1B of the second embodiment, the hole portion 21 that penetrates the first insulator layer 8 is provided. In the case of such a structure, the first insulator layer 8 is preferably composed of a laminated film of a silicon oxide film 8a and an aluminum oxide film 8b provided between the first substrate 2 and the silicon oxide film 8a.

[0126] Here, reference is made to Figures 6-9 The process of forming the hole portion 21 in the first insulator layer 8 will be described.

[0127] In addition, Figures 6-9 is a cross-sectional view for sequentially describing the process of forming the hole portion 21 on the first insulator layer 8. In addition, here, the electromagnetic wave sensor 1B of the second embodiment is exemplified and described.

[0128] When the hole portion 21 is formed in the first insulator layer 8, first, as shown in Figure 6 , the antireflection film 22, the aluminum oxide film 8b, and the silicon oxide film 8a that constitute the first insulator layer 8 are sequentially laminated on one face of the first substrate 2. In addition, on the face of the first insulator layer 8, the mask layer 30 having the opening portion 30a at a position corresponding to the hole portion 21 is formed. The mask layer 30 is composed of a photoresist.

[0129] Next, as shown in Figure 7As shown, reactive ion etching (RIE) using chlorine-based gases is performed. At this time, the aluminum oxide film 8b is used as an etching stopper, and the silicon oxide film 8a is patterned into a shape corresponding to the opening 30a while being removed until the aluminum oxide film 8b is exposed.

[0130] Next, as Figure 8 As shown, alkaline etching is used to remove the aluminum oxide film 8b by patterning it into a shape corresponding to the opening 30a until the anti-reflective film 22 is exposed.

[0131] Next, as Figure 9 As shown, the mask layer 30 is removed from the surface of the first insulating layer 8. As a result, the hole 21 can be formed in the first insulating layer 8 with high precision.

[0132] (Third Implementation)

[0133] Next, as a third embodiment of the present invention, for example, regarding... Figure 10 The electromagnetic wave sensor 1C shown is described below.

[0134] also, Figure 10 This is a cross-sectional view showing the unit structure of the electromagnetic wave sensor 1C. Furthermore, in the following description, parts equivalent to those in the electromagnetic wave sensor 1A described above are omitted, and the same reference numerals are used in the accompanying drawings.

[0135] like Figure 10 As shown, the electromagnetic wave sensor 1C of this embodiment is configured such that, in the thermistor element 4A for measurement, in the portion of the layer T where the first insulating layer 8 is provided, opposite to the thermistor film 5, a recess 23 is provided to recess the first insulating layer 8 instead of the aforementioned hole 21 penetrating the first insulating layer 8. The recess 23 is provided between the first substrate 2 and the thermistor film 5.

[0136] That is, in layer T where the first insulating layer 8 is provided, the infrared (IR) transmittance is highest at the location where the recess 23 is provided. Apart from this, it has a structure that is essentially the same as the electromagnetic wave sensor 1A described above.

[0137] Therefore, in the thermistor element 4A for measurement, in the layer T where the first insulating layer 8 is provided, the infrared IR transmittance at the portion opposite to the thermistor film 5 is relatively higher than the infrared IR transmittance at the portion where the wiring portion 9 is provided.

[0138] Therefore, in the electromagnetic wave sensor 1C of the present embodiment, in the thermistor element 4A for measurement, during a period from when the infrared ray IR emitted from the measurement object passes through the window portion W from the first substrate 2 side to when it reaches the vicinity of the thermistor film 5, it is possible to suppress the case where the infrared ray IR is absorbed by the portion other than the thermistor film 5 and its vicinity to be lower.

[0139] As described above, in the electromagnetic wave sensor 1C of the present embodiment, it is possible to improve the detection accuracy of the thermistor element 4A for infrared ray IR, and to detect (capture) the temperature distribution (temperature image) of the measurement object with high accuracy.

[0140] (4th Embodiment)

[0141] Next, as the 4th embodiment of the present application, for example, the electromagnetic wave sensor 1D shown in FIG. 12 is described. Figure 11

[0142] Further, Figure 11 is a cross-sectional view showing the unit structure of the electromagnetic wave sensor 1D. In addition, in the following description, for the same parts as those of the above-described electromagnetic wave sensors 1B and 1C, the description is omitted, and the same reference numerals are marked in the drawings.

[0143] As shown in FIG. 12, the electromagnetic wave sensor 1D of the present embodiment is a structure in which the antireflection film 22 is provided between the first substrate 2 and the first insulator layer 8. Other than this, it has substantially the same structure as that of the above-described electromagnetic wave sensor 1C. Figure 11 In the electromagnetic wave sensor 1D of the present embodiment, as with the above-described electromagnetic wave sensor 1C, in the thermistor element 4A for measurement, the portion opposite to the thermistor film 5 in the layer T in which the first insulator layer 8 is provided is provided with the recessed portion 23 in which the first insulator layer 8 is recessed.

[0144] Thereby, in the thermistor element 4A for measurement, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared ray IR at the portion opposite to the thermistor film 5 is relatively higher than that at the portion in which the wiring portion 9 is provided.

[0145] Therefore, in the electromagnetic wave sensor 1D of the present embodiment, in the thermistor element 4A for measurement, during a period from when the infrared ray IR emitted from the measurement object passes through the window portion W from the first substrate 2 side to when it reaches the vicinity of the thermistor film 5, it is possible to suppress the case where the infrared ray IR is absorbed by the portion other than the thermistor film 5 and its vicinity to be lower.

[0146]

[0147] ​​As described above, in the electromagnetic wave sensor 1D of the present embodiment, the detection accuracy of the thermistor element 4A with respect to the infrared rays IR can be improved, and the temperature distribution (temperature image) of the measurement target can be detected (captured) with high accuracy.

[0148] (5th Embodiment)

[0149] Next, as the 5th embodiment of the present application, for example, the electromagnetic wave sensor 1E shown in FIG. 17 will be described. Figure 12

[0150] Further, Figure 12 is a cross-sectional view showing the unit structure of the electromagnetic wave sensor 1E. In the following description, for parts equivalent to those of the electromagnetic wave sensor 1A described above, the description will be omitted, and the same reference numerals will be marked in the drawings.

[0151] As shown in FIG. 17, the electromagnetic wave sensor 1E of the present embodiment is a structure in which the high-transmittance layer 24 is buried inside the hole portion 21 in the measurement thermistor element 4A. Other than this, it has substantially the same structure as the electromagnetic wave sensor 1A described above. Figure 12

[0152] The high-transmittance layer 24 is provided in the layer T in which the first insulator layer 8 is provided, at a portion opposite to the thermistor film 5. The high-transmittance layer 24 is a layer in which the transmittance of the infrared rays IR per unit thickness is higher than that of the first insulator layer 8 in which the wiring portion 9 is provided.

[0153] In the measurement thermistor element 4A, in the layer T in which the first insulator layer 8 is provided, the transmittance of the infrared rays IR is highest at the positions where the hole portion 21 and the high-transmittance layer 24 are provided.

[0154] Therefore, in the electromagnetic wave sensor 1E of the present embodiment, in the measurement thermistor element 4A, during the period in which the infrared rays IR emitted from the measurement target pass through the high-transmittance layer 24 from the first substrate 2 side to the vicinity of the thermistor film 5, the absorption of the infrared rays IR by the thermistor film 5 and the portions other than the vicinity thereof can be suppressed to be lower.

[0155] Therefore, in the electromagnetic wave sensor 1E of the present embodiment, in the measurement thermistor element 4A, during the period in which the infrared rays IR emitted from the measurement target pass through the high-transmittance layer 24 from the first substrate 2 side to the vicinity of the thermistor film 5, the absorption of the infrared rays IR by the thermistor film 5 and the portions other than the vicinity thereof can be suppressed to be lower.

[0156] ​​The high-transmittance layer 24 can function as an antireflection layer, for example. In this case, as the material of the high-transmittance layer 24, zinc sulfide, yttrium fluoride, a chalcogenide glass, germanium, silicon, zinc selenide, gallium arsenide, or the like can be used. These materials are materials having a high transmittance of infrared IR per unit thickness compared to the materials exemplified in the above-mentioned first insulator layer 8.

[0157] In the case where the high-transmittance layer 24 functions as an antireflection layer, during the period from when the infrared IR emitted from the measurement object passes through the high-transmittance layer 24 to when it is incident on the thermistor film 5, the infrared IR is prevented from being reflected at the interface between the first substrate 2 and the space G, and the infrared IR that has transmitted through the first substrate 2 is efficiently incident on the thermistor film 5 side.

[0158] As described above, in the electromagnetic wave sensor 1E of the present embodiment, the detection accuracy of the above-mentioned thermistor element 4A with respect to infrared IR can be improved, and the temperature distribution (temperature image) of the measurement object can be detected (photographed) with high accuracy.

[0159] Furthermore, the present application is not necessarily limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present application.

[0160] For example, with respect to the above-mentioned antireflection film 22, not only a structure provided on the one face (the face opposite to the second substrate 3) side of the first substrate 2, but also a structure provided on the other face (the face opposite to the face of the one face side) side of the first substrate 2 can be adopted.

[0161] In addition, the above-mentioned reference thermistor element 4B is not necessarily an essential structure, and can be omitted as appropriate.

[0162] Furthermore, in the case where only the antireflection film 22 is provided as the above-mentioned first insulator layer 8, depending on the material of the antireflection film 22, it can sometimes be difficult to apply the semiconductor process of the related art to the process for forming the above-mentioned hole portion 21 or recess portion 23. Therefore, in the electromagnetic wave sensor 1B of the second embodiment and the electromagnetic wave sensor 1D of the fourth embodiment, the hole portion 21 or recess portion 23 is not provided in the above-mentioned antireflection film 22, but is provided in the first insulator layer 8 to which the semiconductor process of the related art can be easily applied.

[0163] Furthermore, the electromagnetic wave sensor to which the present application is applied is not necessarily limited to an infrared image sensor configured by arranging a plurality of the above-mentioned thermistor elements 4 in an array, and the present application can be applied to an electromagnetic wave sensor in which the thermistor element 4 is used as a single body, or an electromagnetic wave sensor in which a plurality of thermistor elements 4 are arranged in a line, or the like.

[0164] In addition, the electromagnetic wave sensor to which the present application is applied is not necessarily limited to detecting the above-described infrared rays as electromagnetic waves, and, for example, can also detect terahertz waves having a wavelength of 30 μm or more and 3 mm or less.

Claims

1. An electromagnetic wave sensor characterized by comprising: a first substrate that is permeable to electromagnetic waves of a certain wavelength; an insulator layer provided on one surface side of the first substrate; a thermistor film disposed with a space from one surface of the first substrate; a wiring portion provided inside or on a surface of the insulator layer and electrically connected to the thermistor film; and a second substrate provided with a circuit portion electrically connected to the wiring portion, the thermistor film is disposed between the first substrate and the second substrate, the permeability of the electromagnetic waves in a portion of the layer provided with the insulator layer, which opposes the thermistor film, is relatively higher than the permeability of the electromagnetic waves in a portion provided with the wiring portion.

2. The electromagnetic wave sensor according to claim 1, characterized by: a hole portion that penetrates the insulator layer is provided in the portion opposing the thermistor film.

3. The electromagnetic wave sensor according to claim 1, characterized by: a recess portion that recesses the insulator layer is provided in the portion opposing the thermistor film.

4. The electromagnetic wave sensor according to any one of claims 1 to 3, characterized by: a layer having a higher permeability of the electromagnetic waves per unit thickness than the insulator layer in the portion provided with the wiring portion is provided in the portion opposing the thermistor film.

5. The electromagnetic wave sensor according to any one of claims 1 to 4, characterized by: an antireflection film is provided between the first substrate and the insulator layer.

6. The electromagnetic wave sensor according to any one of claims 1 to 5, characterized by: the insulator layer has a laminated film of a silicon oxide film and an aluminum oxide film provided between the first substrate and the silicon oxide film.

7. The electromagnetic wave sensor according to any one of claims 1 to 6, characterized by: a dielectric film that covers at least a portion of the thermistor film is provided.

8. The electromagnetic wave sensor according to any one of claims 1 to 7, characterized by: comprising a connection portion that electrically connects between the thermistor film and the wiring portion, the connection portion has a leg portion disposed in a manner extending in a direction having a thickness direction component of the first substrate, and an arm portion disposed at a position not overlapping with the thermistor film in the thickness direction of the first substrate, the arm portion is located between the thermistor film and the leg portion in the connection portion, the leg portion is located between the wiring portion and the arm portion in the connection portion, the permeability of the electromagnetic waves in a portion of the layer provided with the insulator layer, which opposes the arm portion, is relatively lower than the permeability of the electromagnetic waves in a portion opposing the thermistor film.

9. The electromagnetic wave sensor according to any one of claims 1 to 8, characterized by: comprising a reference thermistor film that is different from the thermistor film, the permeability of the electromagnetic waves in a portion of the layer provided with the insulator layer, which opposes the thermistor film, is relatively higher than the permeability of the electromagnetic waves in a portion opposing the reference thermistor film.

10. An electromagnetic wave sensor characterized by ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprise: a first substrate which is transparent to electromagnetic waves of a certain wavelength; an insulator layer provided on one surface side of the first substrate; a thermistor film which is arranged with a space from one surface of the first substrate; a wiring portion which is provided inside or on a surface of the insulator layer and is electrically connected to the thermistor film; and a second substrate which is provided with a circuit portion electrically connected to the wiring portion, the thermistor film is arranged between the first substrate and the second substrate, a hole portion which penetrates the insulator layer or a recess portion which recesses the insulator layer is provided between the first substrate and the thermistor film.

11. The electromagnetic wave sensor according to any one of claims 1 to 10, wherein: the thermistor film is arranged in an array shape with a plurality of thermistor films.

Images