ELECTROMAGNETIC WAVE SENSOR

An electromagnetic wave sensor includes: a first wire which extends in a first direction; a second wire which extends in a second direction different from the first direction; and an electromagnetic wave detector which is electrically connected to the first wire and is electrically connected to the second wire, wherein the second wire is provided so as to leave an interval with respect to the first wire in a third direction orthogonal to the first direction and the second direction, and the second wire is disposed to three-dimensionally intersect the first wire. At least one wire of the first wire and the second wire includes a wide portion, which is wider than an average value of a width of a portion excluding an overlapping portion of the at least one wire, in the overlapping portion in which the first wire and the second wire overlap each other.

CROSS-REFERENCE TO RELATED APPLICATION

Priority is claimed on Japanese Patent Application No. 2022-180956, filed Nov. 11, 2022, the content of which is incorporated herein by reference.

BACKGROUND

The disclosure relates to an electromagnetic wave sensor.

For example, an electromagnetic wave sensor using an electromagnetic wave detector such as a thermistor element is known. The electrical resistance of a thermistor film of the thermistor element changes according to the temperature change of the thermistor film. In the electromagnetic wave sensor, infrared rays (electromagnetic waves) incident on the thermistor film are absorbed by the thermistor film or materials around the thermistor film, so that the temperature of the thermistor film changes. Accordingly, the thermistor element detects infrared rays.

Here, according to the Stefan-Boltzmann law, there is a correlation between the temperature of a measurement target and infrared rays (radiant heat) emitted from the measurement target by heat radiation. Thus, the temperature of the measurement target can be measured in a non-contact manner by detecting infrared rays emitted from the measurement target using the thermistor element.

Further, such thermistor elements are arranged in a two-dimensional array and are applied to electromagnetic wave sensors such as infrared imaging devices (infrared image sensors) that two-dimensionally detect (image) the temperature distribution of the measurement target (for example, see PCT International Publication No. WO 2019/171488).

SUMMARY

Incidentally, in the above-described electromagnetic wave sensor, it is required to keep the electrical resistance value of the lead wire electrically connected to the thermistor element low in order to obtain good detection accuracy of infrared rays.

The electrical resistance value of the lead wire can be reduced by increasing the width of the lead wire, but if the width of the entire lead wire is simply increased, the area of the lead wire becomes large in a plan view. Accordingly, the detection accuracy of infrared rays may deteriorate.

For example, when the area of the lead wire becomes large in the plan view, the influence of the heat radiation from the lead wire to the thermistor element increases and the detection accuracy of infrared rays may deteriorate. Further, for example, when the area of the lead wire in the plan view increases, the influence of the lead wire shielding the thermistor element from infrared rays of the measurement target increases and the detection accuracy of infrared rays deteriorates.

It is desirable to provide an electromagnetic wave sensor capable of obtaining good detection accuracy of electromagnetic waves.

The disclosure provides the following means.

An electromagnetic wave sensor including:a first wire which extends in a first direction;a second wire which extends in a second direction different from the first direction; andan electromagnetic wave detector which is electrically connected to the first wire and is electrically connected to the second wire,wherein the second wire is provided so as to leave an interval with respect to the first wire in a third direction orthogonal to the first direction and the second direction, and the second wire is disposed to three-dimensionally intersect the first wire, andwherein in a plan view from the third direction, at least one wire of the first wire and the second wire includes a wide portion, which is wider than an average value of a width of a portion excluding an overlapping portion of the at least one wire, in the overlapping portion in which the first wire and the second wire overlap each other.

DETAILED DESCRIPTION

Hereinafter, embodiments of the disclosure will be described in detail with reference to the drawings.

In addition, in the drawings used in the following description, in order to make each component easier to see, the scale of the dimensions may be changed depending on the component, and the dimensional ratio of each component may not necessarily be the same as the actual one. Further, the materials and the like provided in the following description are only exemplary examples, and the disclosure is not necessarily limited to them and can be implemented with appropriate modifications without changing the gist of the disclosure.

Further, in the drawings illustrated below, an XYZ orthogonal coordinate system is set, the X-axis direction is set as the first direction X within a specific plane of the electromagnetic wave sensor, the Y-axis direction is set as the second direction orthogonal to the first direction X within the specific plane of the electromagnetic wave sensor, and the Z-axis direction is set as the third direction Z orthogonal to the specific plane of the electromagnetic wave sensor. The third direction Z is a direction orthogonal to the first direction X and the second direction Y.

First Embodiment

First, an electromagnetic wave sensor1A, for example, illustrated inFIGS.1to8will be described as a first embodiment of the disclosure.

Additionally,FIG.1is a plan view illustrating a configuration of an electromagnetic wave sensor1A.FIG.2is an exploded perspective view illustrating a configuration of the electromagnetic wave sensor1A.FIG.3is a plan view illustrating a configuration of the electromagnetic wave sensor1A.FIG.4is a plan view illustrating a configuration of a structure20A of the electromagnetic wave sensor1A.FIG.5is a cross-sectional view of the structure20A taken along line segment A1-A1illustrated inFIG.4.FIG.6is a cross-sectional view of the structure20A taken along line segment B1-B1illustrated inFIG.4.FIG.7is a plan view illustrating another configuration example of the electromagnetic wave sensor1A.FIG.8is a plan view illustrating another configuration example of the electromagnetic wave sensor1A.

The electromagnetic wave sensor1A of this embodiment is obtained by applying the disclosure to an infrared imaging element (infrared image sensor) that two-dimensionally detects (images) the temperature distribution of the measurement target by detecting infrared rays emitted from the measurement target.

Infrared rays are electromagnetic waves with a wavelength of 0.75 μm or more and 1000 μm or less. Infrared image sensors are used as infrared cameras for indoor and outdoor night vision, and are also used as non-contact temperature sensors for measuring the temperature of people and objects.

Specifically, the electromagnetic wave sensor1A includes, as illustrated inFIGS.1to6, first and second substrates2and3which are arranged to face each other and thermistor elements4(not illustrated inFIGS.1and2) which are arranged between the first substrate2and the second substrate3.

The first substrate2and the second substrate3are silicon substrates having transparency with respect to electromagnetic waves of a certain wavelength, specifically, infrared rays IR having a wavelength band including a wavelength of 10 μm (in this embodiment, long wavelength infrared rays with wavelengths of 8 to 14 μm). Further, a germanium substrate or the like can be used as the substrate having transparency to infrared rays IR. The electromagnetic wave sensor1A of this embodiment is configured such that electromagnetic waves which are emitted from the measurement target and will be detected (infrared rays IR emitted from the measurement target) are incident from the side of the first substrate2.

The first substrate2and the second substrate3form an internal space K therebetween by sealing the periphery of the surfaces facing each other using a sealing material (not illustrated). Further, the internal space K is depressurized to a high vacuum.

Accordingly, in the electromagnetic wave sensor1A of this embodiment, the influence of heat due to convection in the internal space K is suppressed and the influence of heat other than infrared rays IR emitted from the measurement target with respect to a thermistor element4is eliminated.

Additionally, the electromagnetic wave sensor1A of this embodiment is not necessarily limited to a configuration in which the sealed internal space K is depressurized and may be configured to have the internal space K sealed or open under atmospheric pressure.

The thermistor element4is an electromagnetic wave detector which detects infrared rays IR, includes a thermistor film5which is a temperature sensing element, a pair of first electrodes6aand6bwhich are provided in contact with one surface of the thermistor film5, a second electrode6cwhich is provided in contact with the other surface of the thermistor film5, and insulating films7a,7b, and7cwhich are electromagnetic wave absorbers covering at least a portion (entirely in this embodiment) of the thermistor film5, and has a CPP (Current-Perpendicular-to-Plane) structure in which current flows in a direction orthogonal to the surface of the thermistor film5. The insulating film7bis provided on the side opposite to the side contacting the thermistor film5in the pair of first electrodes6aand6b.

That is, in the thermistor element4, current can flow from the first electrode6ato the second electrode6cin a direction orthogonal to the surface of the thermistor film5and current can flow from the second electrode6cto the first electrode6bin a direction orthogonal to the surface of the thermistor film5.

As the thermistor film5, for example, vanadium oxide, amorphous silicon, polycrystalline silicon, spinel crystal structure oxide containing manganese, titanium oxide, yttrium-barium-copper oxide, or the like can be used.

As the first electrodes6aand6band the second electrode6c, 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.

The insulating films7a,7b, and7cmay be provided to cover at least a part of the thermistor film5. In this embodiment, the insulating films7a,7b, and7care provided to cover both surfaces of the thermistor film5.

Additionally, the thermistor element4has the above-described CPP structure, but may have a CIP structure in which the second electrode6cis omitted.

The thermistor elements4are formed with the same size as each other. Further, the thermistor elements4are arranged in a two-dimensional array in a plane parallel to the first substrate2and the second substrate3(hereinafter, referred to as a “specific plane”). That is, the thermistor elements4are arranged in a matrix in a first direction X and a second direction Y that intersect each other (orthogonally in this embodiment) within the specific plane. Additionally, the first direction X and the second direction Y do not necessarily have to be orthogonal within the specific plane.

Further, the thermistor elements4are arranged side by side at regular intervals in the first direction X and the second direction Y on the assumption that the first direction X is the row direction and the second direction Y is the column direction.

Additionally, the number of rows and columns of the thermistor elements4is, for example, 640 rows×480 columns, 1024 rows×768 columns, or the like, but the disclosure is not limited to the number of matrices. That is, the number of matrices can be changed as appropriate.

A first insulator layer8, a wiring portion9which is electrically connected to a circuit portion15to be described later, and a first connection portion10which electrically connects each thermistor element4to the wiring portion9are provided on the side of the first substrate2.

The first insulator layer8is an insulating film formed on one surface of the first substrate2(the surface facing the second substrate3). 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, silicon boride, boron nitride, sialon (oxynitride of silicon and aluminum), and the like can be used.

The wiring portion9includes first lead wires (first wires)9aand second lead wires (second wires)9b. Each of the first lead wires9aand each of the second lead wires9bare made of, for example, a conductive film of copper or gold.

The first lead wires9aand the second lead wires9bare arranged at different positions in the third direction Z to intersect three-dimensionally. Among these, the first lead wires9aextend in the first direction X and are arranged side by side at regular intervals in the second direction Y. On the other hand, the second lead wires9bextend in the second direction Y and are arranged side by side at regular intervals in the first direction X.

That is, each of the first lead wires9ais provided so as to leave an interval with respect to each of the second lead wires9bin the third direction Z, and each of the first lead wires9ais disposed to three-dimensionally intersect each of the second lead wires9b. Further, each of the second lead wires9bis provided so as to leave an interval with respect to each of the first lead wires9ain the third direction Z, and each of the second lead wires9bis disposed to three-dimensionally intersect each of the first lead wires9a. A part of the first insulator layer8is disposed in a portion sandwiched between the first lead wire9aand the second lead wire9b.

Additionally, in this embodiment, the first lead wire9aand the second lead wire9bare located within the layer of the first insulator layer8, but at least the surface of at least one lead wire of the first lead wire9aand the second lead wire9bmay be exposed from the first insulator layer8.

Each thermistor element4is provided in each area E partitioned by the first lead wires9aand the second lead wires9bin a plan view in the third direction Z (hereinafter, simply referred to as “plan view”). A window portion W for transmitting infrared rays IR between the first substrate2and the thermistor film5exists in an area facing each thermistor film5and the first substrate2in the thickness direction (an overlapping area in the plan view).

The first connection portion10includes a pair of first connection members11aand11bwhich are provided to correspond to each of the thermistor elements4. In the electromagnetic wave sensor1A of this embodiment, each of the thermistor elements4is electrically connected to a corresponding one of the first lead wires9avia the first connection member11aand each of the thermistor elements4is electrically connected to the corresponding one of the second lead wires9bvia the first connection member11a.

Further, the pair of first connection members11aand11band one thermistor element4constitute one structure20A. Additionally, specific illustration of the structure20A is omitted inFIGS.1and2.

The pair of first connection members11aand11binclude a pair of arm portions12aand12band a pair of leg portions13aand13b.

Each of the arm portions12aand12bhas a linear shape. The arm portions12aand12binclude a linear wiring layer21which is electrically connected to the thermistor film5of the thermistor element4and protection layers22aand22bwhich are partially arranged on both surfaces of the wiring layer21. Each of the protection layers22aand22bhas a linear shape that matches the shape of the wiring layer21.

The wiring layer21of the arm portion12ais electrically connected to the thermistor film5via the first electrode6a. The wiring layer21of the arm portion12bis electrically connected to the thermistor film5via the first electrode6b. The wiring layer21is made of, for example, at least one selected from aluminum, gold, silver, copper, tungsten, titanium, tantalum, chromium, silicon, titanium nitride, tantalum nitride, chromium nitride, tungsten nitride, and zirconium nitride. If sufficient mechanical strength of the arm portions12aand12bcan be obtained only by the wiring layer21, the protection layers22aand22bmay not be provided on both surfaces of the wiring layer21.

The protection layers22aand22bare made of the insulating films7a,7b, and7ccovering the above-described thermistor film5. Among these, the protection layer (hereinafter, referred to as a “first protection layer”)22adisposed on one surface of the wiring layer21is composed of the insulating film7aand the protection layer (hereinafter, referred to as a “second protection layer”)22bdisposed on the other surface of the wiring layer21is composed of the insulating films7band7c.

The pair of arm portions12aand12bare located on both sides of the thermistor element4in the plan view in the third direction Z. Further, each of the arm portions12aand12bincludes at least a portion which extends along the periphery of the thermistor element4and a portion which is connected to the thermistor element4.

Specifically, the arm portions12aand12bof this embodiment have a structure in which portions (two portions in this embodiment) extending in the first direction X are arranged side by side in the second direction Y and one end and the other end adjacent to each other are folded back and connected through a portion extending in the second direction Y. Further, the pair of arm portions12aand12bare connected to the thermistor element4at positions sandwiching the thermistor element4through a portion extending in the second direction Y.

Each of the leg portions13aand13bis a contact plug electrically connected to the first lead wire9aor the second lead wire9b. Each of the leg portions13aand13bis made of a conductor pillar having a circular cross-section by plating with, for example, copper, gold, FeCoNi alloy, or NiFe alloy (permalloy). Each of the leg portions13aand13bextends in a direction including a component of the third direction Z (the third direction Z in this embodiment).

The first connection member11aincludes the arm portion12awhich is electrically connected to the first electrode6aand the leg portion13awhich electrically connects the arm portion12band the first lead wire9aand electrically connects the first electrode6aand the first lead wire9a. That is, the leg portion13ais electrically connected to the first lead wire9aand the thermistor element4(the thermistor film5).

The first connection member11bincludes the arm portion12bwhich is electrically connected to the first electrode6band the leg portion13bwhich electrically connects the arm portion12band the second lead wire9band electrically connects the first electrode6band the second lead wire9b. That is, the leg portion13bis electrically connected to the second lead wire9band the thermistor element4(the thermistor film5).

Accordingly, the thermistor element4is supported in a suspended state in the third direction Z by the pair of first connection members11aand11blocated diagonally in its plane. Further, a space G is provided between the thermistor element4and the first insulator layer8.

A second insulator layer14, the circuit portion15which detects a change in voltage output from the thermistor element4and converts the voltage into a brightness temperature, and a second connection portion16which electrically connects each thermistor element4and the circuit portion15are provided on the side of the second substrate3.

The second insulator layer14is an insulating film which is formed on one surface of the second substrate3(a surface facing the first substrate2). As the insulating film, the same insulating film provided as an exemplary example of the first insulator layer8can be used.

The circuit portion15includes a readout integrated circuit (ROIC), a regulator, an A/D converter (Analog-to-Digital Converter), a multiplexer, and the like and is provided within the layer of the second insulator layer14.

Further, connection terminals17acorresponding to the first lead wires9aand connection terminals17bcorresponding to the second lead wires9bare provided on the surface of the second insulator layer14. The connection terminals17aand17bare made of, for example, a conductive film of copper or gold.

The connection terminals17aare located on one side in the first direction X in the area around the circuit portion15and are arranged side by side at regular intervals in the second direction Y. The connection terminals17bare located on one side in the second direction Y in the area around the circuit portion15and are arranged side by side at regular intervals in the first direction X.

The second connection portion16includes second connection members18aprovided to correspond to the first lead wires9aand second connection members18bprovided to correspond to the second lead wires9b. The second connection members18aand18bare made of conductor pillars with a circular cross-section formed by plating with copper, gold, or the like. The second connection members18aand18bextend in a direction including a component of the third direction Z (the third direction Z in this embodiment).

The second connection member18aelectrically connects one end side of the first lead wire9aand the connection terminal17a. The second connection member18belectrically connects one end side of the second lead wire9band the connection terminal17b. Accordingly, the first lead wires9aand the circuit portion15are electrically connected via the second connection member18aand the connection terminal17a. Further, the second lead wires9band the circuit portion15are electrically connected via the second connection member18band the connection terminal17b.

An antireflection layer19is provided on the side of the surface facing the thermistor element4in the first substrate2. In this embodiment, the antireflection layer19is provided between the first substrate2and the first insulator layer8. At least a part of the antireflection layer19faces at least a part of the thermistor element4. The antireflection layer19allows infrared rays IR transmitted through the first substrate2to efficiently enter the thermistor film5by preventing the infrared rays IR from being reflected at the interface between the first substrate2and the space G until the infrared rays IR emitted from the measurement target pass through the window portion W from the first substrate2and enter the thermistor film5.

Further, the antireflection layer19may have a configuration in which films with different refractive indices are alternately laminated and the reflectance of infrared rays IR is reduced by utilizing the interference of waves reflected by each layer. In this case, as the antireflection layer19, in addition to the above materials, for example, a laminated film obtained by laminating 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, and the like can be used.

A hole portion8apenetrating the first insulator layer8is provided at a portion facing the thermistor element4in the first insulator layer8. In other words, the hole portion8apenetrating the first insulator layer8is provided between the antireflection layer19and the thermistor element4. The hole portion8ais provided at a portion facing the thermistor element4in the layer T provided with the first insulator layer8.

In the electromagnetic wave sensor1A of this embodiment with the above-described configuration, infrared rays IR emitted from the measurement target pass through the window portion W from the first substrate2and enter the thermistor element4.

In the thermistor element4, the temperature of the thermistor film5changes when infrared rays IR entering the insulating films7a,7b, and7cformed in the vicinity of the thermistor film5are absorbed by the insulating films7a,7b, and7cand infrared rays IR entering the thermistor film5are absorbed by the thermistor film5. Further, in the thermistor element4, the electrical resistance of the thermistor film5changes with the temperature change of the thermistor film5and hence the output voltage between the pair of first electrodes6aand6bchanges. In the electromagnetic wave sensor1A of this embodiment, the thermistor element4functions as a bolometer element.

In the electromagnetic wave sensor1A of this embodiment, when infrared rays IR emitted from the measurement target are two-dimensionally detected by the thermistor elements4and the electrical signal (voltage signal) output from each thermistor element4is converted into a brightness temperature, it is possible to two-dimensionally detect (image) the temperature distribution (temperature image) of the measurement target.

In the electromagnetic wave sensor1A of this embodiment, a constant current is applied to the thermistor film5and a change in voltage output from the thermistor film5is detected with respect to the temperature change of the thermistor film5. However, a configuration may be adopted in which a constant voltage is applied to the thermistor film5and a change in current flowing through the thermistor film5is detected with respect to the temperature change of the thermistor film5and is converted into a brightness temperature.

Incidentally, in the electromagnetic wave sensor1A of this embodiment, at least one lead wire (the second lead wire9bin this embodiment) of the first lead wire9aand the second lead wire9bincludes a wide portion31, which is wider than the average value of the width of a portion excluding an overlapping portion30of one lead wire (the second lead wire9b), in the overlapping portion30of the first lead wire9aand the second lead wire9bin the plan view from the third direction Z as illustrated inFIG.1.

That is, the wide portion31overlaps the other lead wire (the first lead wire9ain this embodiment) in the plan view and protrudes toward one side in the width direction of one lead wire (the second lead wire9b) in the plan view.

In the configuration illustrated inFIG.1, the wide portion31protrudes in the width direction with respect to a portion excluding the overlapping portion30of one lead wire (the second lead wire9b). Additionally, in the example illustrated inFIG.1, the width direction of the lead wire is a direction perpendicular to the extension direction of the lead wire in the plan view. That is, in the example illustrated inFIG.1, the width of the wide portion31in the first direction X is wider than the average value of the width of the first direction X in a portion excluding the overlapping portion30of the second lead wire9bextending in the second direction Y. In the example illustrated inFIG.1, the range of the wide portion31is the same as the range of the overlapping portion30of the second lead wire9b.

Further, the wide portion31may be formed over the outside of the overlapping portion30in the plan view instead of the range in which one lead wire (the second lead wire9b) overlaps the other lead wire (the first lead wire9a) in the plan view (the range of the overlapping portion30). The wide portion31preferably does not overlap the electromagnetic wave detector (the thermistor element4) in the plan view.

Further, the wide portion31may protrude toward both sides of the width direction of one lead wire (the second lead wire9b) in the plan view. Further, the shape of the wide portion31is also not particularly limited and the shape can be changed as appropriate.

In the electromagnetic wave sensor1A of this embodiment, since such a wide portion31is provided in the overlapping portion30, it is possible to widen the width of one lead wire (the second lead wire9b) in the wide portion31while suppressing an increase in the area of the lead wire in the plan view (the area including the first lead wire9aand the second lead wire9bin the plan view). Accordingly, it is possible to reduce the electrical resistance value of one lead wire (the second lead wire9b) while suppressing an increase in heat radiation from the lead wires9aand9b, which become a heat source when energized, to the electromagnetic wave detector (the thermistor element4).

Further, in the electromagnetic wave sensor1A of this embodiment, since the first lead wire9aand the second lead wire9bare arranged on the incident direction side of electromagnetic waves (infrared rays IR) of the measurement target when viewed from the electromagnetic wave detector (thermistor element4), it is conceived that a part of electromagnetic waves of the measurement target incident toward the electromagnetic wave detector (thermistor element4) is shielded by the overlapping portion with the electromagnetic wave detector (thermistor element4) in the plan view of the first lead wire9aand the second lead wire9b.

In the electromagnetic wave sensor1A of this embodiment, it is possible to widen the width of one lead wire (second lead wire9b) with respect to the wide portion31while suppressing an increase in the range in which the first lead wire9aand the second lead wire9boverlap the electromagnetic wave detector (thermistor element4) in the plan view. Accordingly, it is possible to reduce the electrical resistance value of one lead wire (second lead wire9b) while suppressing an increase in the influence of shielding the electromagnetic waves of the measurement target by the lead wires9aand9b.

Thus, in the electromagnetic wave sensor1A of this embodiment, it is possible to obtain good detection accuracy of electromagnetic waves (infrared rays IR).

Additionally, in the electromagnetic wave sensor1A, the wide portion31is provided in the second lead wire9bof the first lead wire9aand the second lead wire9b, for example, as illustrated inFIG.7, the wide portion31may be provided in the first lead wire9a. Further, specific illustration of the structure20A is omitted inFIG.7.

Specifically, in the configuration illustrated inFIG.7, the wide portion31, which is wider than the average value of the width of a portion excluding the overlapping portion30of the first lead wire9a, in the overlapping portion30in the plan view from the third direction Z is provided on the side of the first lead wire9a.

In the configuration illustrated inFIG.7, the wide portion31protrudes in the width direction in a portion excluding the overlapping portion30of the first lead wire9a. Further, in the example illustrated inFIG.7, the width direction of the lead wire is a direction perpendicular to the extension direction of the lead wire in the plan view. In the example illustrated inFIG.7, the width of the wide portion31in the second direction Y is wider than the average value of the width of the second direction Y in a portion excluding the overlapping portion30of the first lead wire9aextending in the first direction X. In the example illustrated inFIG.7, the range of the wide portion31is the same as the range of the overlapping portion30of the first lead wire9a.

That is, the wide portion31overlaps the second lead wire9bin the plan view and protrudes toward one side of the width direction of the first lead wire9ain the plan view. The wide portion31may protrude toward both sides of the width direction of the first lead wire9ain the plan view.

Further, in the electromagnetic wave sensor1A, for example, as illustrated inFIG.8, a first wide portion31amay be provided in the first lead wire9aand a second wide portion31bmay be provided in the second lead wire9b. Additionally, specific illustration of the structure20A is omitted inFIG.8.

Specifically, in the configuration illustrated inFIG.8, the first wide portion31a, which is wider than the average value of the width in a portion excluding the overlapping portion30of the first lead wire9a, in the overlapping portion30in the plan view from the third direction Z is provided in the first lead wire9aand the second wide portion31b, which is wider than the average value of the width in a portion excluding the overlapping portion30of the second lead wire9b, is provided in the second lead wire9b.

That is, the first wide portion31aoverlaps the second lead wire9bin the plan view and protrudes toward one side of the width direction of the first lead wire9ain the plan view. The first wide portion31amay protrude toward both sides of the width direction of the first lead wire9ain the plan view.

The second wide portion31boverlaps the first lead wire9ain the plan view and protrudes toward one side of the width direction of the second lead wire9bin the plan view. The second wide portion31bmay protrude toward both sides of the width direction of the second lead wire9bin the plan view.

In the configuration of the electromagnetic wave sensor1A illustrated inFIG.8, it is possible to reduce the electrical resistance values of both wires (the first lead wire9aand the second lead wire9b) while suppressing an increase in heat radiation from the lead wires9aand9b, which become a heat source when energized, to the electromagnetic wave detector (the thermistor element4). Further, in the configuration of the electromagnetic wave sensor1A illustrated inFIG.8, it is possible to reduce the electrical resistance values of both wires (the first lead wire9aand the second lead wire9b) while suppressing an increase in the influence of shielding the electromagnetic waves of the measurement target by the lead wires9aand9b.

Second Embodiment

Next, an electromagnetic wave sensor1B, for example, illustrated inFIGS.9to13will be described as a second embodiment of the disclosure.

Additionally,FIG.9is a plan view illustrating a configuration of an electromagnetic wave sensor1B.FIG.10is a plan view illustrating a configuration of a structure20B of the electromagnetic wave sensor1B.FIG.11is a cross-sectional view of the structure20B taken along line segment A2-A2illustrated inFIG.10.FIG.12is a cross-sectional view of the structure20B taken along line segment B2-B2illustrated inFIG.10.FIG.13is a plan view illustrating another configuration example of the electromagnetic wave sensor1B. Further, in the following description, description of parts equivalent to those of the electromagnetic wave sensor1A will be omitted and the same reference numerals will be given in the drawings.

The electromagnetic wave sensor1B of this embodiment includes the structure20B, for example, illustrated inFIGS.9to12instead of the structure20A. Further, in the electromagnetic wave sensor1B, the arrangement order of the first lead wire9aand the second lead wire9bis different from that in the electromagnetic wave sensor1A. As for the other configurations, the electromagnetic wave sensor1B basically has the same configuration as that of the electromagnetic wave sensor1A.

Specifically, in the electromagnetic wave sensor1B, each of the thermistor elements4is electrically connected to a corresponding one of the first lead wires9avia the first connection member11aand each of the thermistor elements4is electrically connected to the corresponding one of the second lead wires9bvia the first connection member11a.

Further, the pair of first connection members11aand11band one thermistor element4constitute one structure20B.

Specifically, the structure20B includes the pair of first connection members11aand11bincluding the pair of arm portions12aand12band the pair of leg portions13aand13band has a structure in which the thermistor element4is suspended from the first substrate2facing the thermistor element4through the pair of first connection members11aand11b.

Further, in the structure20B, the pair of arm portions12aand12bare arranged point-symmetrically with respect to the center of the thermistor element4in the plan view. In the structure20B, the connection position between the leg portion13band the second lead wire9bis different from that of the structure20A. As for the other configurations, the structure20B basically has the same configuration as that of the structure20A.

Further, in the electromagnetic wave sensor1B, the second lead wire9bis closer to the arm portions12aand12bin the third direction Z than the first lead wire9a. That is, in the electromagnetic wave sensor1B, the position of the second lead wire9bin the third direction Z is located between the position of the first lead wire9ain the third direction Z and the positions of the arm portions12aand12bin the third direction Z.

Incidentally, in the electromagnetic wave sensor1B of this embodiment, as illustrated inFIG.9, the wide portion31is provided in at least one lead wire (the second lead wire9bin this embodiment) of the first lead wire9aand the second lead wire9band one lead wire (the second lead wire9b) is electrically connected to one end side of the leg portion13bin the wide portion31.

That is, the wide portion31overlaps the other lead wire (the first lead wire9ain this embodiment) in the plan view and protrudes toward one side of the width direction of one lead wire (the second lead wire9b) in the plan view. Further, the end portion of the wide portion31has a rounded shape in the plan view.

Additionally, in this embodiment, one lead wire (the second lead wire9b) is electrically connected to one end side of the leg portion13bin a portion protruding in the width direction in the wide portion31. Further, in this embodiment, the wide portion31(a portion protruding in the width direction in the wide portion31) is directly connected to one end side of the leg portion13b.

Additionally, the wide portion31may be formed over the outside of the overlapping portion30in the plan view instead of the range in which one lead wire (the second lead wire9b) overlaps the other lead wire (the first lead wire9a) in the plan view (the range of the overlapping portion30). Further, the wide portion31preferably does not overlap the electromagnetic wave detector (the thermistor element4) in the plan view. Further, the wide portion31may protrude toward both sides of the width direction of one lead wire (the second lead wire9b) in the plan view.

Further, the shape of the wide portion31is not necessarily limited to the shape in which the end portions of the wide portion31are rounded in the plan view, and the shape can be changed as appropriate.

In the electromagnetic wave sensor1B of this embodiment, since such a wide portion31is provided in the overlapping portion30, it is possible to obtain good detection accuracy of electromagnetic waves (infrared rays IR) similarly to the electromagnetic wave sensor1A of the first embodiment.

Further, in the electromagnetic wave sensor1B of this embodiment, one lead wire (the second lead wire9b) is electrically connected to one end side of the leg portion13bin the wide portion31. Accordingly, it is possible to arrange the structures20B with good space efficiency. Further, it is possible to form the arm portion12aand the arm portion12bwith good symmetry. Furthermore, since the arm portions12aand12bformed with good symmetry are less likely to be distorted, high reliability of the electromagnetic wave sensor1B can be obtained.

Additionally, in the electromagnetic wave sensor1B, the wide portion31is provided in the second lead wire9bof the first lead wire9aand the second lead wire9band the second lead wire9bis electrically connected to one end side of the leg portion13bin the wide portion31. However, for example, as illustrated inFIG.13, the first wide portion31amay be provided in the first lead wire9a, the second wide portion31bmay be provided in the second lead wire9b, and the second lead wire9bmay be electrically connected to one end side of the leg portion13bin the second wide portion31b.

That is, the first wide portion31aoverlaps the second lead wire9bin the plan view and protrudes toward both sides of the width direction of the first lead wire9a. The first wide portion31amay protrude toward only one side of the width direction of the first lead wire9ain the plan view.

The second wide portion31boverlaps the first lead wire9ain the plan view and protrudes toward both sides of the width direction of the second lead wire9b. The second wide portion31bmay protrude toward only one side of the width direction of the second lead wire9bin the plan view.

Additionally, in the example illustrated inFIG.13, the second wide portion31bis directly connected to one end side of the leg portion13b. Further, in the example illustrated inFIG.13, the second lead wire9bis electrically connected to one end side of the leg portion13bin the second wide portion31b, but the first lead wire9amay be electrically connected to one end side of the leg portion13ain the first wide portion31a. Further, both configurations may be provided.

Third Embodiment

Next, an electromagnetic wave sensor1C, for example, illustrated inFIG.14will be described as a third embodiment of the disclosure.

Additionally,FIG.14is a plan view schematically illustrating a configuration of the electromagnetic wave sensor1C. Further, in the following description, description of parts equivalent to those of the electromagnetic wave sensors1A and1B will be omitted and the same reference numerals will be given in the drawings.

As illustrated inFIG.14, the electromagnetic wave sensor1C of this embodiment has a structure in which the thermistor elements4are arranged in a row.

That is, the electromagnetic wave sensor1C includes one second lead wire9band the first lead wires9a. Further, in the electromagnetic wave sensor1C, the thermistor elements4are arranged side by side in the second direction Y. Further, the first lead wires9aare arranged side by side in the second direction Y so that each of the thermistor elements4is electrically connected to a corresponding one of the first lead wires9a. Further, each of the thermistor elements4is electrically connected to one second lead wire9b.

The electromagnetic wave sensor1C includes a structure20C illustrated inFIG.14instead of the structure20A of the electromagnetic wave sensor1A. In the structure20C, the shape of the arm portion is slightly different from the arm portions12aand12bof the structure20A, but the other configurations are basically the same as those of the structure20A.

Similarly to the electromagnetic wave sensor1A of the first embodiment, in the electromagnetic wave sensor1C illustrated inFIG.14, at least one lead wire (the second lead wire9bin this embodiment) of the first lead wire9aand the second lead wire9bincludes the wide portion31, which is wider than the average value of the width of a portion excluding the overlapping portion30of one lead wire (the second lead wire9b), in the overlapping portion30in which the first lead wire9aand the second lead wire9boverlap each other in the plan view from the third direction Z.

That is, the wide portion31overlaps the other lead wire (the first lead wire9ain this embodiment) in the plan view and protrudes toward both sides of the width direction of one lead wire (the second lead wire9b) in the plan view.

Further, in the electromagnetic wave sensor1C of this embodiment, the wide portion31may protrude toward one side of the width direction of the lead wire (the second lead wire9b) in the plan view. Further, the electromagnetic wave sensor1C may have a configuration in which the wide portion is provided in the first lead wire9asimilarly to the electromagnetic wave sensor1A of the first embodiment. In this case, the wide portion provided in the first lead wire9amay protrude toward both sides of the width direction of the first lead wire9ain the plan view and may protrude toward one side of the width direction of the first lead wire9ain the plan view.

Further, in the electromagnetic wave sensor1C, the second lead wire9bmay be electrically connected to one end side of the leg portion13bin the wide portion31similarly to the electromagnetic wave sensor1B of the second embodiment.

In the electromagnetic wave sensor1C of this embodiment, since the overlapping portion30including such a wide portion31is provided, it is possible to obtain good detection accuracy of electromagnetic waves (infrared rays IR) similarly to the electromagnetic wave sensor1A of the first embodiment.

Fourth Embodiment

Next, an electromagnetic wave sensor1D, for example, illustrated inFIG.15will be described as a fourth embodiment of the disclosure.

Additionally,FIG.15is a cross-sectional view schematically illustrating a configuration of the electromagnetic wave sensor1D. For easy understanding,FIG.15is a schematic cross-sectional view combining cross-sections instead of one cross-section. Further, in the following description, description of parts equivalent to those of the electromagnetic wave sensors1A,1B, and1C will be omitted and the same reference numerals will be given in the drawings.

As illustrated inFIG.15, the electromagnetic wave sensor1D of this embodiment has a structure in which the thermistor elements4are suspended from the second substrate3facing the thermistor element4.

In this case, the wiring portion9is disposed on the side of the second substrate3. That is, the first lead wire9aand the second lead wire9bare arranged at different positions in the third direction Z on the side of the second substrate3to intersect three-dimensionally.

Specifically, in the electromagnetic wave sensor1D of this embodiment, the first lead wire9aand the second lead wire9bare located within the layer of the insulator layer formed on the second substrate3as in the case in which the first lead wire9aand the second lead wire9bare located within the layer of the first insulator layer8in the electromagnetic wave sensor1A of the first embodiment. Further, a part of the insulator layer is disposed in a portion sandwiched between the first lead wire9aand the second lead wire9b.

Further, at least the surface of at least one lead wire of the first lead wire9aand the second lead wire9bmay be exposed from the insulator layer formed on the second substrate3. In this embodiment, the wiring portion9(the first lead wire9aand the second lead wire9b) constitutes a part of the readout integrated circuit (ROIC) provided in the second substrate3. That is, the first connection members11aand11bare directly connected to the readout integrated circuit (ROIC) provided on the second substrate3.

Further, in the electromagnetic wave sensor1D of this embodiment, the thermistor elements4are arranged in the internal space K sealed by the first substrate2, the seal member23, and the second substrate3. On the other hand, the electrode pad24electrically connected to the readout integrated circuit (ROIC) is disposed outside the internal space K.

Further, in the electromagnetic wave sensor1D of this embodiment, it is possible to adopt the same configuration as the structures20A,20B, and20C of the electromagnetic wave sensors1A,1B, and1C as the structure including the first connection members11aand11band one thermistor element4.

Further, in the electromagnetic wave sensor1D of this embodiment, it is possible to adopt the same configuration as the first lead wire9aand the second lead wire9bof the electromagnetic wave sensors1A,1B, and1C as the first lead wire9aand the second lead wire9b.

That is, in the electromagnetic wave sensor1D of this embodiment, at least one lead wire (for example, the second lead wire9b) of the first lead wire9aand the second lead wire9bincludes the wide portion31, which is wider than the average value of the width of a portion excluding the overlapping portion30of one lead wire (for example, the second lead wire9b), in the overlapping portion30in which the first lead wire9aand the second lead wire9boverlap each other in the plan view from the third direction Z similarly to the electromagnetic wave sensors1A,1B, and1C.

Further, in the electromagnetic wave sensor1D of this embodiment, the first lead wire9amay include the wide portion31which is wider than the average value of the width of a portion excluding the overlapping portion30of the first lead wire9a, in the overlapping portion30, and the second lead wire9bmay include the wide portion31, which is wider than the average value of the width of a portion excluding the overlapping portion30of the second lead wire9b, in the overlapping portion30similarly to the electromagnetic wave sensors1A,1B, and1C.

In the electromagnetic wave sensor1D of this embodiment, since such a wide portion31is provided in the overlapping portion30, it is possible to reduce the electrical resistance value of one lead wire (for example, the second lead wire9b) or both wires (the first lead wire9aand the second lead wire9b) while suppressing an increase in heat radiation from the lead wires9aand9b, which become a heat source when energized, to the electromagnetic wave detector (the thermistor element4) similarly to the electromagnetic wave sensor1A of the first embodiment.

Thus, in the electromagnetic wave sensor1D of this embodiment, it is possible to obtain good detection accuracy of electromagnetic waves (infrared rays IR).

Additionally, the disclosure is not necessarily limited to the above-described embodiments and can be modified into various forms in the scope not departing from the spirit of the disclosure.

For example, the electromagnetic wave sensor that adopts the disclosure is not necessarily limited to the configuration of the infrared image sensor in which the thermistor elements4are arranged two-dimensionally or linearly, but the disclosure can be also applied to the electromagnetic wave sensor or the like using one thermistor element4.

Further, the electromagnetic wave sensor that adopts the disclosure is not necessarily limited to the one for detecting the infrared rays IR as electromagnetic waves, but the electromagnetic wave sensor may detect, for example, terahertz waves with a wavelength of 30 μm or more and 3 mm or less or visible light.

Further, the electromagnetic wave sensor that adopts the disclosure is not necessarily limited to the one that uses the thermistor element4as the electromagnetic wave detector and the one using a thermopile (thermocouple) type, pyroelectric type, or diode type temperature sensing element instead of the thermistor film5can be used as the electromagnetic wave detector. Instead of the thermistor element4, an element such as a photodiode that directly detects electromagnetic waves can be used as the electromagnetic wave detector.