WO2013145540A1 - Infrared radiation element and method for manufacturing same - Google Patents

Infrared radiation element and method for manufacturing same Download PDF

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Publication number
WO2013145540A1
WO2013145540A1 PCT/JP2013/001051 JP2013001051W WO2013145540A1 WO 2013145540 A1 WO2013145540 A1 WO 2013145540A1 JP 2013001051 W JP2013001051 W JP 2013001051W WO 2013145540 A1 WO2013145540 A1 WO 2013145540A1
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Prior art keywords
substrate
infrared radiation
radiation element
layer
opening
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PCT/JP2013/001051
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French (fr)
Japanese (ja)
Inventor
桐原　昌男
辻　幸司
吉祥 永谷
弘貴 松浪
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パナソニック株式会社
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Publication of WO2013145540A1 publication Critical patent/WO2013145540A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0256—Compact construction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
    • G01J3/108—Arrangements of light sources specially adapted for spectrometry or colorimetry for measurement in the infrared range
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment

Definitions

  • the present invention relates to an infrared emitting element and a method of manufacturing the same.
  • an infrared radiation element an infrared radiation element manufactured using a semiconductor process or the like has been researched and developed.
  • This type of infrared radiation element can be used as an infrared source such as a gas sensor or an optical analyzer.
  • an infrared radiation element of this type for example, an infrared light source 100 having a configuration shown in FIGS. 8A and 8B is known (Japanese Patent Application Publication No. 2005-207891: Patent Document 1).
  • the infrared light source 100 includes a substrate 110, a membrane 120 provided on the substrate 110 as a thin portion including the resistor 115, and a condensing lens 130 provided on the surface of the membrane 120 as a condensing member. It is done.
  • the substrate 110 is a semiconductor substrate made of silicon, and has a hollow portion 111 corresponding to the formation region of the membrane 120.
  • the membrane 120 including the resistor 115 is formed in a floating state on the hollow portion 111 with respect to the substrate 110, and is formed to be thinner than other portions of the infrared light source 100.
  • a silicon nitride film 112 is provided on the lower surface of the substrate 110, and an insulating film 113 (for example, a silicon nitride film) is provided on the upper surface of the substrate 110. Then, a silicon oxide film 114 is provided on the insulating film 113.
  • a resistor 115 made of a polycrystalline silicon film is provided in a predetermined shape.
  • a wiring portion 117 electrically connecting the resistor 115 and the pad portion 117a is connected to the resistor 115 via an interlayer insulating film 116 made of BPSG (boron-doped phospho-silicate glass).
  • a protective film 118 (for example, a silicon nitride film) is provided on the wiring portion 117 excluding the pad portion 117a. Therefore, in the infrared light source 100, the membrane 120 is configured by the insulating film 113, the silicon oxide film 114, the resistor 115, the interlayer insulating film 116, the wiring portion 117, and the protective film 118 on the hollow portion 111 of the substrate 110.
  • the infrared light source 100 is a condensing lens as a condensing member that condenses infrared radiation emitted by causing the resistor 115 to generate heat on the protective film 118 in the formation region of the membrane 120. 130 are provided.
  • the condensing lens 130 is a concave lens formed by processing a silicon oxide film so that the upper surface 130 a facing the surface in contact with the protective film 118 has a concave shape having a predetermined radius as shown in FIG. 8B. is there.
  • the infrared light source 100 since the upper surface 130a that emits infrared light to the infrared sensor has a concave shape having a predetermined R, the infrared light emitted from the condensing lens 130 is condensed to the infrared sensor Be done.
  • the infrared light source 100 is provided such that the optical axis of the condenser lens 130 substantially coincides with the center position of the resistor 115.
  • Patent Document 1 describes that the condensing lens 130 is formed using a semiconductor process. That is, in Patent Document 1, a silicon oxide film is formed, for example, by the CVD method in the formation region of the membrane 120 on the protective film 118, and the silicon oxide film is processed using photolithography technology and etching technology. Thus, it is described that the condenser lens 130 is formed.
  • the infrared radiation element is intermittently driven by intermittently driving the infrared radiation element to lock the output of the light receiving element for detecting the infrared ray. It is known that the S / N ratio of the output of the infrared type gas sensor can be improved by amplifying with an amplifier.
  • the thickness of the silicon oxide film that is the source of the condensing lens 130 is limited based on R of the upper surface 130a of the condensing lens 130.
  • the present invention has been made in view of the above-described problems, and an object thereof is to provide an infrared radiation element capable of improving directivity and capable of achieving high output and a method of manufacturing the same.
  • the infrared radiation element of the present invention comprises a substrate, a thin film portion provided on one surface side of the substrate, and a heating element layer provided on the thin film portion on the opposite side of the substrate side, the heat generation It is an infrared radiation element in which infrared rays are emitted from the heat generating body layer by energization to a body layer, and in the substrate, the thickness of the opening portion which exposes the surface of the thin film portion opposite to the heat generating body layer side
  • the thin film portion is provided in the peripheral portion of the opening portion on the one surface side of the substrate, the diaphragm portion separating the opening portion from the heating element layer, and the diaphragm A supporting portion for supporting a portion, and the diaphragm portion includes a recess having a recess on the side of the opening and the inner surface being a concave surface, and the heat generating body layer is formed at least along the inner surface of the recess It is characterized by
  • the concave surface is preferably in the form of a rotational quadric surface.
  • the diaphragm portion is provided with a plurality of the concave portions in an array.
  • the outer peripheral shape of the diaphragm portion is circular.
  • the outer peripheral shape of the diaphragm portion is rectangular.
  • a method of manufacturing an infrared radiation element is the method of manufacturing the infrared radiation element, wherein a first step of forming a recess for forming a recess of the diaphragm on the one surface side of the substrate; A second step of forming a thin film portion on the one surface side of the substrate after the first step; a third step of forming the heating element layer on the thin film portion after the second step; Forming a diaphragm portion provided with the concave portion by etching the formation scheduled region of the opening in the substrate from the other surface side of the substrate after the third step; I assume.
  • the directivity can be improved and the output can be increased.
  • an infrared radiation element of the present invention it is possible to provide an infrared radiation element capable of improving directivity and capable of achieving high output.
  • FIG. 1A is a schematic plan view of the infrared radiation element of Embodiment 1.
  • FIG. 1B is a schematic cross-sectional view of the infrared radiation element of Embodiment 1.
  • 2A to 2E are main process cross-sectional views for explaining the method of manufacturing the infrared radiation element of Embodiment 1.
  • FIG. 3 is an operation explanatory view of the infrared radiation element of the first embodiment.
  • FIG. 4 is an operation explanatory view of the infrared ray emitting element of the comparative example.
  • FIG. 5A is a schematic plan view of the infrared radiation element of Embodiment 2.
  • FIG. 5B is a schematic cross-sectional view of the infrared radiation element of Embodiment 2.
  • FIG. 6A to 6E are main process cross-sectional views for explaining the method of manufacturing the infrared radiation device of the second embodiment.
  • FIG. 7 is an operation explanatory view of the infrared radiation element of the second embodiment.
  • FIG. 8A is a plan view of a conventional infrared light source.
  • FIG. 8B is a cross-sectional view taken along line AA of FIG. 8A.
  • the infrared radiation element 1 comprises a substrate 2, a thin film portion 5 provided on one surface side of the substrate 2, and a heating element layer 3 provided on the thin film portion 5 opposite to the substrate 2 side. There is.
  • infrared radiation element 1 infrared rays are emitted from the heat generating body layer 3 by energization to the heat generating body layer 3.
  • an opening 2 a for exposing the surface of the thin film portion 5 on the opposite side to the heating element layer 3 side is penetrated in the thickness direction.
  • the thin film portion 5 is a diaphragm 51 separating the opening 2 a from the heating element layer 3, and a support 52 provided on the periphery of the opening 2 a on the one surface side of the substrate 2 and supporting the diaphragm 51. And have.
  • the diaphragm part 51 is provided with the recessed part 53 indented to the opening part 2a side.
  • the inner surface 53a is a concave surface.
  • the heating element layer 3 is formed along the inner surface 53 a of the recess 53.
  • the heating element layer 3 may be formed along at least the inner surface 53 a of the recess 53.
  • the infrared radiation element 1 is provided with a pair of pads 7 formed so as to be partially in contact with the heating element layer 3 on the one surface side of the substrate 2.
  • the infrared radiation element 1 may be provided with a wire between each of the pads 7 and the heating element layer 3.
  • the substrate 2 is formed of a single crystal silicon substrate of which the one surface is a (100) plane, but is not limited to this, and may be formed of a single crystal silicon substrate of a (110) plane. Further, the substrate 2 is not limited to a single crystal silicon substrate, and may be a polycrystalline silicon substrate or may be other than a silicon substrate.
  • the material of the substrate 2 is preferably a material having a larger thermal conductivity and a larger heat capacity than the material of the thin film portion 5.
  • the outer peripheral shape of the substrate 2 is rectangular.
  • the outer size of the substrate 2, that is, the chip size is not particularly limited, but is preferably set to, for example, 10 mm ⁇ 10 mm or less.
  • the substrate 2 has a circular shape in the opening 2a.
  • the opening 2a of the substrate 2 is formed in a shape such that the opening area is substantially constant from the one surface side of the substrate 2 to the other surface side.
  • the opening 2a of the substrate 2 can be formed, for example, by etching using an inductive coupling plasma type dry etching apparatus.
  • the infrared radiation element 1 may have a mask layer on the other surface side of the substrate 2 when the opening 2 a is formed. Note that, for example, a stacked film of a silicon oxide film and a silicon nitride film can be used as the mask layer.
  • the thin film portion 5 is provided on the peripheral portion of the opening portion 2a on the one surface side of the substrate 2 with the diaphragm portion 51 separating the opening portion 2a and the heating element layer 3 from each other. And a supporting portion 52 for supporting.
  • the diaphragm portion 51 has a circular outer peripheral shape. That is, as described above, the infrared radiation element 1 has a circular opening shape of the opening 2a, and the diaphragm 51 viewed from the other surface side of the substrate 2 has a circular shape.
  • the thin film portion 5 can be constituted of, for example, a silicon oxide film on the side of the substrate 2 and a silicon nitride film stacked on the opposite side of the silicon oxide film to the side of the substrate 2.
  • the laminated structure of the thin film portion 5 is not particularly limited.
  • the layer structure of the thin film portion 5 is not limited to the laminated structure of a silicon oxide film and a silicon nitride film, but may be a single layer structure of a silicon oxide film or a silicon nitride film, or a single layer structure made of other materials It may be a laminated structure of layers or more.
  • the thin film portion 5 also has a function as an etching stopper layer when forming the opening 2 a by etching the substrate 2 from the other surface side of the substrate 2 at the time of manufacturing the infrared radiation element 1.
  • the diaphragm portion 51 is provided with the concave portion 53 whose concave inner surface 53a is a concave surface on the side of the opening 2a. It is preferable that the concave curved surface which comprises the inner surface 53a of the recessed part 53 is rotation quadric surface shape.
  • the concave surface forming the inner surface 53a of the concave portion 53 is a concave surface having a substantially constant radius of curvature, but may be, for example, a paraboloid of revolution, as long as it is a shape of a rotational quadric surface.
  • the concave surface forming the inner surface 53a of the concave portion 53 may be configured to be a part of an aspheric surface whose curvature changes continuously, and is not limited to the paraboloid of revolution, for example, a hyperboloid It may be in the form of
  • the heat generating layer 3 has a rectangular outer peripheral shape. That is, the heat generating layer 3 has a rectangular shape in a plan view.
  • the plan view shape of the heat generating layer 3 is not limited to the rectangular shape, and may be, for example, a circular shape or a polygonal shape.
  • the heat generating body layer 3 is formed in the magnitude
  • the heat generating body layer 3 may be smaller than the outer peripheral shape of the diaphragm portion 51 in plan view, and in this case, a wire made of a metal film electrically connecting the heat generating body layer 3 and each of the pads 7 is provided. Just do it.
  • the central axis (not shown) along the thickness direction of the substrate 2 in the heating element layer 3 is aligned with the central axis along the thickness direction of the substrate 2 in the diaphragm portion 51
  • the heating element layer 3 is designed in a pattern.
  • the surface of the portion of the heat generating layer 3 stacked in the recess 53 has a concave surface (for example, a rotational quadratic surface) along the inner surface 53 a of the recess 53.
  • the film thickness of the heating element layer 3 is set.
  • tantalum nitride is used as a material of the heat generating body layer 3, it is not limited thereto.
  • the material of the heating element layer 3 is, for example, titanium nitride, nickel chromium, tungsten, titanium, thorium, platinum, zirconium, chromium, vanadium, rhodium, hafnium, ruthenium, boron, iridium, niobium, molybdenum, tantalum, osmium, rhenium, Nickel, holmium, cobalt, erbium, yttrium, iron, scandium, thulium, palladium, lutetium or the like may be employed.
  • a material of the heat generating layer 3 conductive polysilicon, conductive amorphous silicon or the like may be employed.
  • the material of the heat generating body layer 3 the material of the substrate 2 from the viewpoint of preventing the heat generating body layer 3 from being broken due to the thermal stress caused by the difference in linear expansion coefficient between the substrate 2 and the heat generating body layer 3.
  • a material having a small difference in coefficient of linear expansion with is preferable.
  • the total thickness of the thickness of the thin film portion 5 and the thickness of the heating element layer 3 is preferably set, for example, in the range of about 0.1 ⁇ m to 10 ⁇ m.
  • the pair of pads 7 is formed such that parts of both ends (left and right ends in FIGS. 1A and 1B) of the heating element layer 3 are in contact with each other on the one surface side of the substrate 2. Each pad 7 is in ohmic contact with the heating element layer 3.
  • each pad 7 As a material of each pad 7, Al-Si which is a kind of aluminum alloy is adopted.
  • the material of each pad 7 is not particularly limited, and, for example, an aluminum alloy other than Al-Si, gold, copper or the like may be adopted.
  • Each pad 7 may be made of any material that allows at least a portion in contact with the heat generating layer 3 to be in ohmic contact with the heat generating layer 3, and is not limited to a single layer structure, and may be a multilayer structure.
  • each pad 7 has a three-layer structure in which a first layer, a second layer, and a third layer are sequentially stacked from the heat generating body layer 3 side, and the material of the first layer in contact with the heat generating body layer 3 is a high melting point metal
  • the material of the second layer may be nickel, and the material of the third layer may be gold.
  • the thickness of each pad 7 is preferably set in the range of about 0.5 to 2 ⁇ m.
  • a substrate 2 made of a single crystal silicon substrate having a (100) plane is prepared (see FIG. 2A).
  • a first step of forming a recess 23 for forming the recess 53 of the diaphragm 51 on the one surface side of the substrate 2 is performed to obtain a structure shown in FIG. 2B.
  • a first silicon oxide film 21 is formed on the one surface side of the substrate 2 by a thermal oxidation method, a CVD (Chemical Vapor Deposition) method or the like, and a second silicon oxide film on the other surface side.
  • the first silicon oxide film 21 is patterned using photolithography technology and etching technology.
  • the substrate 2 is isotropically etched from the one surface side to form a recess 23.
  • the first silicon oxide film 21 and the second silicon oxide film 22 are removed by etching, and then the second step of forming the thin film portion 5 on the one surface side of the substrate 2 is performed. , The structure shown to FIG. 2C is obtained.
  • a CVD method or the like can be employed as a method of forming the thin film portion 5.
  • the third step of forming the heating element layer 3 on the thin film portion 5 is performed.
  • a method of forming the heat generating body layer 3 a sputtering method, a vapor deposition method, a CVD method or the like can be adopted.
  • each pad 7 After the third step, after each pad 7 is formed (see FIG. 2D), a region including the opening 2a in the substrate 2 is etched from the other surface side of the substrate 2 to etch the diaphragm 53 having the recess 53. By performing the fourth step of forming the portion 51, the infrared radiation element 1 having the structure shown in FIG. 2E is obtained.
  • a thin film formation technique such as a sputtering method, an evaporation method, a CVD method, etc., and a photolithography technique and an etching technique can be used.
  • a mask material layer formed of a laminated film (not shown) of a silicon oxide film and a silicon nitride film is formed on the other surface side of the substrate 2 by the CVD method or the like. Thereafter, the mask material layer is patterned using photolithography technology and etching technology to form a mask layer, and then the substrate 2 is etched from the other surface side to form the opening 2a.
  • the opening 2a of the substrate 2 can be formed, for example, by etching using an inductive coupling plasma type dry etching apparatus.
  • the thin film portion 5 can be used as an etching stopper layer at the time of forming the opening portion 2 a, so that the thickness accuracy of the thin film portion 5 can be enhanced. It is possible to prevent a part or residue of the substrate 2 from remaining on the side of the opening 2a. Further, in the method of manufacturing the infrared radiation element 1, by using the thin film portion 5 as an etching stopper layer at the time of forming the opening portion 2a, it becomes possible to increase the accuracy of the thickness of the thin film portion 5 It is possible to suppress the variation of the mechanical strength of the thin film portion 5 and the variation of the heat capacity of the diaphragm portion 51 for each unit.
  • the process until the formation of the opening 2a is completed may be performed at the wafer level to form the opening 2a, and then the infrared radiation element 1 may be separated. That is, in the manufacture of the infrared radiation element 1, for example, a silicon wafer to be a base of the substrate 2 is prepared, and a plurality of infrared detection elements 1 are formed on this silicon wafer according to the above manufacturing method. It may be separated into the detection element 1.
  • the peak wavelength ⁇ of the infrared ray emitted from the heat generating layer 3 in the infrared emitting element 1 depends on the temperature of the heat generating layer 3.
  • the peak wavelength ⁇ is ⁇ [ ⁇ m] and the absolute temperature of the heat generating body layer 3 is T [K]
  • the relationship between the absolute temperature T of the heat generating body layer 3 and the peak wavelength ⁇ of the infrared ray emitted from the heat generating body layer 3 satisfies the Wien's displacement law.
  • the heating element layer 3 constitutes a pseudo black body.
  • the infrared radiation element 1 can change the Joule heat generated in the heating element layer 3 by, for example, adjusting the input power to be applied between the pair of pads 7 and 7 from an external power supply (not shown). Can change the temperature of the Therefore, the infrared radiation element 1 can change the temperature of the heat generating layer 3 in accordance with the maximum input power to the heat generating layer 3, and changes the temperature of the heat generating layer 3.
  • the infrared radiation element 1 can be used as a high output infrared source in a wide range of infrared wavelength range.
  • the infrared radiation element 1 when used as an infrared source of a gas sensor, it is preferable to set the peak wavelength ⁇ of infrared radiation emitted from the heating element layer 3 to about 4 ⁇ m, and the temperature of the heating element layer 3 is about 800 K do it.
  • the heating element layer 3 constitutes a pseudo black body as described above.
  • the infrared radiation element 1 is considered to assume that the total energy E emitted per unit time of the heating element layer 3 is substantially proportional to T 4 (that is, satisfying the Stefan-Boltzmann's law) I guess).
  • the infrared radiation element 1 of the present embodiment described above includes a substrate 2, a thin film portion 5 provided on one surface side of the substrate 2, and a heating element provided on the thin film portion 5 opposite to the substrate 2 side. And a layer 3.
  • an opening 2a for exposing the surface of the thin film 5 on the opposite side to the heating element layer 3 is formed in the substrate 2
  • the thin film 5 is an opening A diaphragm 51 for separating the heat generating body layer 3 from each other and a support 52 provided on the periphery of the opening 2 a on the one surface side of the substrate 2 and supporting the diaphragm 51 are provided.
  • the diaphragm portion 51 is provided with a recess 53 which is recessed toward the opening 2a, and the inner surface 53a of the recess 53 is a concave surface.
  • the heating element layer 3 is formed along the inner surface 53 a of the recess 53.
  • the concave curved surface which comprises the inner surface 53a of the recessed part 53 is rotation quadric surface shape. As a result, the infrared radiation element 1 can improve the directivity in the front direction (the upper direction in FIG. 1B).
  • FIG. 3 is a diagram for explaining the operation of the infrared radiation element 1, in which the radiation direction of the infrared radiation emitted from the heating element layer 3 when energized between the pair of pads 7 is schematically shown by a solid line with an arrow. is there.
  • FIG. 4 is an operation explanatory view of the infrared ray emitting element 1 ′ of the comparative example in which the diaphragm portion 51 is flat and the surface of the heat generating layer 3 is flat.
  • the radiation direction of the infrared rays emitted from the heating element layer 3 is schematically shown by a solid line with an arrow.
  • FIG. 4 is an operation explanatory view of the infrared ray emitting element 1 ′ of the comparative example in which the diaphragm portion 51 is flat and the surface of the heat generating layer 3 is flat.
  • the radiation direction of the infrared rays emitted from the heating element layer 3 is schematically shown by a solid line with an arrow.
  • the irradiation unit 10 is, for example, a light receiving element that receives infrared light.
  • the surface of the portion of the heating element layer 3 stacked on the diaphragm portion 51 has a concave surface.
  • the infrared radiation element 1 emits radiation as shown in FIG. 3 as compared with the non-directional one in which infrared rays are radiated isotropically as in the infrared radiation element 1 ′ of the comparative example shown in FIG.
  • the irradiation unit 10 is a light receiving element, it is possible to improve the light receiving efficiency of the light receiving element.
  • the infrared radiation element 1 of the present embodiment is a laminated including the diaphragm portion 51 as compared with the infrared light source 100 having the condensing lens 130 as in the conventional example shown in FIGS. 8A and 8B while improving the directivity. It is possible to reduce the heat capacity of the entire structure. Therefore, since the infrared radiation element 1 can accelerate the response of the temperature change of the heat generating body layer 3 to the voltage waveform applied between the pair of pads 7, the temperature of the heat generating body layer 3 tends to rise. It is possible to achieve high output and high response speed.
  • the substrate 2 is formed of a single crystal silicon substrate, and the thin film portion 5 is configured of a silicon oxide film and a silicon nitride film.
  • the infrared radiation element 1 has a large thermal capacity and thermal conductivity of the substrate 2 as compared to the thin film portion 5 and the substrate 2 has a function as a heat sink. It is possible to improve the stability of the radiation characteristics.
  • the temperature of the heating body layer 3 is the maximum use temperature of silicon (from the melting point of silicon It is possible to raise the temperature to a somewhat lower temperature), and it is possible to significantly increase the amount of infrared radiation as compared to the infrared light emitting diode.
  • the infrared radiation element 1 is formed of a metal having a melting point higher than that of silicon, at least a portion of each pad 7 in contact with the heating element layer 3, the temperature of the heating element layer 3 is restricted by the material of each pad 7. Can be raised without
  • directivity can be improved by including the above-described first step, second step, third step and fourth step. It is possible to provide an infrared radiation element 1 which is capable of achieving high output.
  • the infrared rays radiating element 1 of this embodiment is demonstrated based on FIG. 5A and 5B.
  • symbol is attached
  • the plurality of concave portions 53 are provided in the diaphragm portion 51 in an array (in the illustrated example, a two-dimensional array). That is, the diaphragm unit 51 is provided with a plurality of concave portions 53. As in the first embodiment, each recess 53 is recessed toward the opening 2 a, and the inner surface 53 a is a concave surface.
  • the infrared radiation elements 1 be arranged such that, for example, the recesses 53 have a two-dimensional periodic structure in a two-dimensional plane orthogonal to the thickness direction of the substrate 2. In the example shown in FIGS.
  • each recess 53 is located at each lattice point of a virtual two-dimensional square lattice having a square unit cell, but the invention is not limited thereto.
  • a unit lattice The center of each recess 53 may be located at each grid point of a virtual two-dimensional triangular grid of an equilateral triangle.
  • the infrared radiation element 1 may have, for example, a configuration in which a plurality of concave portions 53 are spaced apart in the circumferential direction on one virtual circle.
  • the infrared radiation element 1 may have, for example, a configuration in which a plurality of concave portions 53 are spaced apart on a virtual spiral having a spiral shape in a two-dimensional surface.
  • the diaphragm part 51 makes the magnitude
  • the plurality of recesses 53 are preferably arranged in line symmetry with the center line of the heat generating layer 3 along the direction in which the pair of pads 7 and 7 are arranged and the direction orthogonal to the thickness direction of the substrate 2 as a symmetry axis. .
  • the infrared radiation element 1 suppresses the in-plane variation of the temperature of the heat generating layer 3 compared to the case where the plurality of recesses 53 are not arranged in line symmetry with the center line of the heat generating layer 3 as a symmetry axis. It becomes possible.
  • the substrate 2 has a rectangular shape in the opening 2a.
  • the opening 2 a of the substrate 2 is formed in a shape in which the opening area on the other surface side is larger than that of the one surface side of the substrate 2.
  • the opening 2 a of the substrate 2 is formed in such a shape that the opening area gradually increases as the distance from the thin film portion 5 in the thickness direction of the substrate 2 increases.
  • the opening 2 a of the substrate 2 is formed by etching the substrate 2.
  • the opening 2a of the substrate 2 can be formed by anisotropic etching using an alkaline solution as an etching solution, for example, when the substrate 2 is a (100) plane single crystal silicon substrate.
  • the heat generating layer 3 has a rectangular outer peripheral shape. That is, the heat generating layer 3 has a rectangular shape in a plan view.
  • the planar shape is rectangular, it is not particularly limited to the rectangular, and may be, for example, circular or polygonal.
  • the thin film portion 5 is provided on the peripheral portion of the opening 2 a on the one surface side of the substrate 2, the diaphragm 51 separating the opening 2 a from the heating element layer 3. And a support portion 52 for supporting the The diaphragm portion 51 has a rectangular outer peripheral shape. That is, in the infrared radiation element 1, as described above, the opening shape of the opening 2a is rectangular, and the shape of the diaphragm 51 viewed from the other surface side of the substrate 2 is rectangular.
  • the heat generating layer 3 has a rectangular outer peripheral shape. That is, the heat generating layer 3 has a rectangular shape in a plan view.
  • the plan view shape of the heat generating layer 3 is not limited to the rectangular shape, and may be, for example, a circular shape or a polygonal shape.
  • the surface of the portion of the heat generating layer 3 stacked in the recess 53 has a concave surface (for example, a rotational quadratic surface) along the inner surface 53 a of the recess 53. It is preferable to set the film thickness of the heating element layer 3.
  • a substrate 2 made of a single crystal silicon substrate having a (100) plane is prepared (see FIG. 6A).
  • a first step of forming a plurality of depressions 23 for forming each of the recesses 53 of the diaphragm 51 on the one surface side of the substrate 2 is performed.
  • the first silicon oxide film 21 is formed on the one surface side of the substrate 2 by the thermal oxidation method, the CVD method or the like, and the second silicon oxide film 22 is formed on the other surface side.
  • the first silicon oxide film 21 is patterned using photolithography technology and etching technology.
  • the substrate 2 is isotropically etched from the one surface side to form a plurality of depressions 23.
  • the first silicon oxide film 21 and the second silicon oxide film 22 are removed by etching, and then the second step of forming the thin film portion 5 on the one surface side of the substrate 2 is performed. , The structure shown in FIG. 6C is obtained.
  • a CVD method or the like can be employed as a method of forming the thin film portion 5.
  • the third step of forming the heating element layer 3 on the thin film portion 5 is performed.
  • a method of forming the heat generating body layer 3 a sputtering method, a vapor deposition method, a CVD method or the like can be adopted.
  • each pad 7 After the third step, after each pad 7 is formed (see FIG. 6D), a plurality of recessed portions 53 are provided by etching the formation planned region of the opening 2a in the substrate 2 from the other surface side of the substrate 2
  • the fourth step of forming the diaphragm portion 51 By performing the fourth step of forming the diaphragm portion 51, the infrared radiation element 1 having the structure shown in FIG. 6E is obtained.
  • a thin film formation technique such as a sputtering method, an evaporation method, a CVD method, etc., and a photolithography technique and an etching technique can be used.
  • a mask material layer formed of a laminated film (not shown) of a silicon oxide film and a silicon nitride film is formed on the other surface side of the substrate 2 by the CVD method or the like. Thereafter, the mask material layer is patterned using photolithography technology and etching technology to form a mask layer, and then the substrate 2 is etched from the other surface side to form the opening 2a.
  • the opening 2a of the substrate 2 may be formed by anisotropic etching using an alkaline solution as an etching solution.
  • the thin film portion 5 can be used as an etching stopper layer at the time of forming the opening portion 2 a, so that the thickness accuracy of the thin film portion 5 can be enhanced. It is possible to prevent a part or residue of the substrate 2 from remaining on the side of the opening 2a.
  • the thin film portion 5 by using the thin film portion 5 as an etching stopper layer when forming the opening portion 2 a, it becomes possible to increase the accuracy of the thickness of the thin film portion 5. It is possible to suppress the dispersion of the mechanical strength of the thin film portion 5 and the dispersion of the heat capacity of the diaphragm portion 51.
  • the diaphragm portion 51 is provided with a plurality of recessed portions 53 which are recessed toward the opening 2 a side, and the inner surface 53 a of each recessed portion 53 is a concave surface.
  • the heating element layer 3 is formed along the inner surface 53 a of each recess 53.
  • the directivity can be improved by the heating element layer 3 being formed along the inner surface 53 a of each recess 53.
  • the concave surface which comprises each inner surface 53a of each recessed part 53 is rotation quadric surface shape.
  • FIG. 7 is an operation explanatory view of the infrared radiation element 1, schematically showing the radiation direction of infrared radiation emitted from the heating element layer 3 when energized between the pair of pads 7 and 7 by a solid line with an arrow. is there. Further, FIG. 7 schematically shows a desired irradiation unit 10 to which the infrared radiation emitted from the infrared radiation element 1 is emitted.
  • the irradiation unit 10 is, for example, a light receiving element that receives infrared light.
  • the surface of each portion of the heating element layer 3 which is stacked in each of the concave portions 53 of the diaphragm portion 51 has a concave curved surface.
  • the infrared radiation element 1 emits radiation as shown in FIG. 7 as compared to the non-directional one in which the infrared radiation is isotropically emitted like the infrared radiation element 1 ′ of the comparative example shown in FIG.
  • the size of the irradiation unit 10 is the same. It becomes possible to improve the irradiation efficiency to the irradiation part 10, and it becomes possible to reduce the loss of the emitted infrared rays.
  • the irradiation unit 10 is a light receiving element, it is possible to improve the light receiving efficiency of the light receiving element.
  • the infrared radiation element 1 of the present embodiment is a laminated including the diaphragm portion 51 as compared with the infrared light source 100 having the condensing lens 130 as in the conventional example shown in FIGS. 8A and 8B while improving the directivity. It is possible to reduce the heat capacity of the entire structure. Therefore, since the infrared radiation element 1 can accelerate the response of the temperature change of the heat generating body layer 3 to the voltage waveform applied between the pair of pads 7, the temperature of the heat generating body layer 3 tends to rise. It is possible to achieve high output and high response speed.
  • directivity can be improved by including the above-described first step, second step, third step and fourth step. It is possible to provide an infrared radiation element 1 which is capable of achieving high output.
  • the infrared radiation element 1 of each embodiment is not limited to an infrared source for a gas sensor, and may be used, for example, for an infrared source for flame detection, an infrared source for infrared light communication, an infrared source for spectral analysis, etc. Is possible.

Abstract

This infrared radiation element is provided with a substrate, a thin film section that is provided on one surface side of the substrate, and a heat generating material layer that is provided on the thin film section side opposite to the substrate side. The infrared radiation element radiates infrared rays from the heat generating material layer when electricity is carried to the heat generating material layer. The substrate has an opening penetrating in the thickness direction, said opening exposing the thin film section surface on the side opposite to the heat generating material layer side. The thin film section is provided with: a diaphragm section, which isolates the opening and the heat generating material layer from each other; and a supporting section, which is provided on the circumference portion of the opening, said portion being on the one surface side of the substrate, and which supports the diaphragm section. The diaphragm section is provided with a concave section, which is concaved to the opening side. The concave section has a concave inner surface. The heat generating material layer is formed along the inner surface of the concave section.

Description

赤外線放射素子およびその製造方法Infrared radiation element and method of manufacturing the same
　本発明は、赤外線放射素子およびその製造方法に関するものである。 The present invention relates to an infrared emitting element and a method of manufacturing the same.
　従来から、赤外線放射素子としては、半導体プロセスなどを利用して製造される赤外線放射素子が研究開発されている。この種の赤外線放射素子は、ガスセンサや光学分析装置などの赤外線源として使用することができる。 Conventionally, as an infrared radiation element, an infrared radiation element manufactured using a semiconductor process or the like has been researched and developed. This type of infrared radiation element can be used as an infrared source such as a gas sensor or an optical analyzer.
　この種の赤外線放射素子としては、例えば、図８Ａ、８Ｂに示す構成の赤外線光源１００が知られている（日本国特許出願公開番号２００５－２０７８９１号：特許文献１）。 As an infrared radiation element of this type, for example, an infrared light source 100 having a configuration shown in FIGS. 8A and 8B is known (Japanese Patent Application Publication No. 2005-207891: Patent Document 1).
　この赤外線光源１００は、基板１１０と、この基板１１０に設けられ、抵抗体１１５を含む薄肉部としてのメンブレン１２０と、このメンブレン１２０表面に設けられた集光部材としての集光レンズ１３０とにより構成されている。 The infrared light source 100 includes a substrate 110, a membrane 120 provided on the substrate 110 as a thin portion including the resistor 115, and a condensing lens 130 provided on the surface of the membrane 120 as a condensing member. It is done.
　基板１１０は、シリコンからなる半導体基板であり、メンブレン１２０の形成領域に対応した空洞部１１１を有している。抵抗体１１５を含むメンブレン１２０は、基板１１０に対して空洞部１１１上に浮いた状態に形成されており、赤外線光源１００の他の部位と比べて膜厚が薄く形成されている。 The substrate 110 is a semiconductor substrate made of silicon, and has a hollow portion 111 corresponding to the formation region of the membrane 120. The membrane 120 including the resistor 115 is formed in a floating state on the hollow portion 111 with respect to the substrate 110, and is formed to be thinner than other portions of the infrared light source 100.
　また、基板１１０の下面には、窒化シリコン膜１１２が設けられ、基板１１０の上面には、絶縁膜１１３（例えば窒化シリコン膜）が設けられている。そして、絶縁膜１１３上には、酸化シリコン膜１１４が設けられている。 In addition, a silicon nitride film 112 is provided on the lower surface of the substrate 110, and an insulating film 113 (for example, a silicon nitride film) is provided on the upper surface of the substrate 110. Then, a silicon oxide film 114 is provided on the insulating film 113.
　酸化シリコン膜１１４上のメンブレン１２０の形成領域内には、多結晶シリコン膜からなる抵抗体１１５が所定形状で設けられている。そして、抵抗体１１５には、ＢＰＳＧ（Boron－doped Phospho－Silicate Glass）からなる層間絶縁膜１１６を介して、抵抗体１１５とパッド部１１７ａとを電気的に繋ぐ配線部１１７が接続されている。 In the formation region of the membrane 120 on the silicon oxide film 114, a resistor 115 made of a polycrystalline silicon film is provided in a predetermined shape. A wiring portion 117 electrically connecting the resistor 115 and the pad portion 117a is connected to the resistor 115 via an interlayer insulating film 116 made of BPSG (boron-doped phospho-silicate glass).
　また、パッド部１１７ａを除いた配線部１１７上には、保護膜１１８（例えば窒化シリコン膜）が設けられている。したがって、赤外線光源１００は、基板１１０の空洞部１１１上における絶縁膜１１３、酸化シリコン膜１１４、抵抗体１１５、層間絶縁膜１１６、配線部１１７及び保護膜１１８によりメンブレン１２０が構成されている。 A protective film 118 (for example, a silicon nitride film) is provided on the wiring portion 117 excluding the pad portion 117a. Therefore, in the infrared light source 100, the membrane 120 is configured by the insulating film 113, the silicon oxide film 114, the resistor 115, the interlayer insulating film 116, the wiring portion 117, and the protective film 118 on the hollow portion 111 of the substrate 110.
　そして、赤外線光源１００は、メンブレン１２０の形成領域内における保護膜１１８上に、抵抗体１１５を発熱させることにより放射される赤外線を、赤外線センサに対して集光させる集光部材としての集光レンズ１３０が設けられている。集光レンズ１３０は、保護膜１１８と接する面に対向する上面１３０ａが、図８Ｂに示すような所定のＲをもった凹形状となるように、酸化シリコン膜を加工して形成された凹レンズである。赤外線光源１００は、赤外線センサに対して赤外線を放射する上面１３０ａが、所定のＲをもった凹形状を有しているので、集光レンズ１３０から放射される赤外線が赤外線センサに対して集光される。 Then, the infrared light source 100 is a condensing lens as a condensing member that condenses infrared radiation emitted by causing the resistor 115 to generate heat on the protective film 118 in the formation region of the membrane 120. 130 are provided. The condensing lens 130 is a concave lens formed by processing a silicon oxide film so that the upper surface 130 a facing the surface in contact with the protective film 118 has a concave shape having a predetermined radius as shown in FIG. 8B. is there. In the infrared light source 100, since the upper surface 130a that emits infrared light to the infrared sensor has a concave shape having a predetermined R, the infrared light emitted from the condensing lens 130 is condensed to the infrared sensor Be done.
　赤外線光源１００は、集光レンズ１３０の光軸が抵抗体１１５の中心位置と略一致するように設けられている。 The infrared light source 100 is provided such that the optical axis of the condenser lens 130 substantially coincides with the center position of the resistor 115.
　特許文献１には、集光レンズ１３０を、半導体プロセスを用いて形成することが記載されている。すなわち、特許文献１には、保護膜１１８上のメンブレン１２０の形成領域内に、例えばＣＶＤ法により酸化シリコン膜を成膜し、この酸化シリコン膜をフォトリソグラフィ技術およびエッチング技術を利用して加工することで集光レンズ１３０を形成する旨が記載されている。 Patent Document 1 describes that the condensing lens 130 is formed using a semiconductor process. That is, in Patent Document 1, a silicon oxide film is formed, for example, by the CVD method in the formation region of the membrane 120 on the protective film 118, and the silicon oxide film is processed using photolithography technology and etching technology. Thus, it is described that the condenser lens 130 is formed.
　ところで、赤外線放射そしを例えば赤外線式ガスセンサ用の赤外線源として用いる場合には、赤外線放射素子を間欠的に駆動することで赤外線を間欠的に放射させ、赤外線を検出する受光素子の出力をロックインアンプにより増幅することで、赤外線式ガスセンサの出力のＳ／Ｎ比を向上できることが知られている。 By the way, when using an infrared radiation source as an infrared source for, for example, an infrared type gas sensor, the infrared radiation element is intermittently driven by intermittently driving the infrared radiation element to lock the output of the light receiving element for detecting the infrared ray. It is known that the S / N ratio of the output of the infrared type gas sensor can be improved by amplifying with an amplifier.
　しかしながら、上述の赤外線光源１００では、集光レンズ１３０の熱容量に起因して、抵抗体１１５へ与える電圧波形に対する抵抗体１１５の温度変化の応答が遅くなって、抵抗体１１５の温度が上昇しにくくなり、高出力化および応答速度の高速化が難しい。 However, in the above-described infrared light source 100, due to the heat capacity of the condenser lens 130, the response of the temperature change of the resistor 115 to the voltage waveform applied to the resistor 115 is delayed, and the temperature of the resistor 115 does not easily increase. It is difficult to achieve high output and high response speed.
　そこで、上述の赤外線光源１００では、集光レンズ１３０の熱容量を小さくするために、集光レンズ１３０の元となる酸化シリコン膜の厚さを薄くすることが考えられる。しかしながら、上述の赤外線光源１００では、集光レンズ１３０の元となる酸化シリコン膜の厚さが、集光レンズ１３０の上面１３０ａのＲに基づいて制限されてしまう。 Therefore, in the above-described infrared light source 100, in order to reduce the heat capacity of the condensing lens 130, it is conceivable to reduce the thickness of the silicon oxide film that is the source of the condensing lens 130. However, in the above-described infrared light source 100, the thickness of the silicon oxide film that is the source of the condensing lens 130 is limited based on R of the upper surface 130a of the condensing lens 130.
　本発明は上記事由に鑑みて為されたものであり、その目的は、指向性を向上させることが可能であり且つ高出力化が可能な赤外線放射素子およびその製造方法を提供することにある。 The present invention has been made in view of the above-described problems, and an object thereof is to provide an infrared radiation element capable of improving directivity and capable of achieving high output and a method of manufacturing the same.
　本発明の赤外線放射素子は、基板と、前記基板の一表面側に設けられた薄膜部と、前記薄膜部における前記基板側とは反対側に設けられた発熱体層と、を備え、前記発熱体層への通電により前記発熱体層から赤外線が放射される赤外線放射素子であって、前記基板は、前記薄膜部における前記発熱体層側とは反対側の表面を露出させる開孔部が厚み方向に貫設されてなり、前記薄膜部は、前記開孔部と前記発熱体層とを隔離するダイヤフラム部と、前記基板の前記一表面側で前記開孔部の周部に設けられ前記ダイヤフラム部を支持する支持部と、を備え、前記ダイヤフラム部は、前記開孔部側に窪み内面が凹曲面である凹部を備え、前記発熱体層は、少なくとも前記凹部の前記内面に沿って形成されてなることを特徴とする。 The infrared radiation element of the present invention comprises a substrate, a thin film portion provided on one surface side of the substrate, and a heating element layer provided on the thin film portion on the opposite side of the substrate side, the heat generation It is an infrared radiation element in which infrared rays are emitted from the heat generating body layer by energization to a body layer, and in the substrate, the thickness of the opening portion which exposes the surface of the thin film portion opposite to the heat generating body layer side The thin film portion is provided in the peripheral portion of the opening portion on the one surface side of the substrate, the diaphragm portion separating the opening portion from the heating element layer, and the diaphragm A supporting portion for supporting a portion, and the diaphragm portion includes a recess having a recess on the side of the opening and the inner surface being a concave surface, and the heat generating body layer is formed at least along the inner surface of the recess It is characterized by
　この赤外線放射素子において、前記凹曲面は、回転２次曲面状であることが好ましい。 In the infrared radiation element, the concave surface is preferably in the form of a rotational quadric surface.
　この赤外線放射素子において、前記ダイヤフラム部は、複数の前記凹部がアレイ状に設けられてなることが好ましい。 In the infrared radiation element, preferably, the diaphragm portion is provided with a plurality of the concave portions in an array.
　この赤外線放射素子において、前記ダイヤフラム部は、外周形状が円形状であることが好ましい。 In the infrared radiation element, preferably, the outer peripheral shape of the diaphragm portion is circular.
　この赤外線放射素子において、前記ダイヤフラム部は、外周形状が矩形状であることが好ましい。 In the infrared radiation element, preferably, the outer peripheral shape of the diaphragm portion is rectangular.
　本発明の赤外線放射素子の製造方法は、前記赤外線放射素子の製造方法であって、前記基板の上記一表面側に前記ダイヤフラム部の凹部を形成するための窪み部を形成する第１工程と、前記第１工程の後で前記基板の前記一表面側に薄膜部を形成する第２工程と、前記第２工程の後で前記薄膜部上に前記発熱体層を形成する第３工程と、前記第３工程の後で前記基板における前記開孔部の形成予定領域を前記基板の他表面側からエッチングすることで前記凹部を備えた前記ダイヤフラム部を形成する第４工程と、を備えることを特徴とする。 A method of manufacturing an infrared radiation element according to the present invention is the method of manufacturing the infrared radiation element, wherein a first step of forming a recess for forming a recess of the diaphragm on the one surface side of the substrate; A second step of forming a thin film portion on the one surface side of the substrate after the first step; a third step of forming the heating element layer on the thin film portion after the second step; Forming a diaphragm portion provided with the concave portion by etching the formation scheduled region of the opening in the substrate from the other surface side of the substrate after the third step; I assume.
　本発明の赤外線放射素子においては、指向性を向上させることが可能であり且つ高出力化が可能となる。 In the infrared radiation element of the present invention, the directivity can be improved and the output can be increased.
　本発明の赤外線放射素子の製造方法においては、指向性を向上させることが可能であり且つ高出力化が可能な赤外線放射素子を提供することが可能となる。 According to the method of manufacturing an infrared radiation element of the present invention, it is possible to provide an infrared radiation element capable of improving directivity and capable of achieving high output.
図１Ａは、実施形態１の赤外線放射素子の概略平面図である。図１Ｂは、実施形態１の赤外線放射素子の概略断面図である。FIG. 1A is a schematic plan view of the infrared radiation element of Embodiment 1. FIG. FIG. 1B is a schematic cross-sectional view of the infrared radiation element of Embodiment 1. 図２Ａ～２Ｅは、実施形態１の赤外線放射素子の製造方法を説明するための主要工程断面図である。2A to 2E are main process cross-sectional views for explaining the method of manufacturing the infrared radiation element of Embodiment 1. FIG. 図３は、実施形態１の赤外線放射素子の動作説明図である。FIG. 3 is an operation explanatory view of the infrared radiation element of the first embodiment. 図４は、比較例の赤外線放射素子の動作説明図である。FIG. 4 is an operation explanatory view of the infrared ray emitting element of the comparative example. 図５Ａは、実施形態２の赤外線放射素子の概略平面図である。図５Ｂは、実施形態２の赤外線放射素子の概略断面図である。FIG. 5A is a schematic plan view of the infrared radiation element of Embodiment 2. FIG. FIG. 5B is a schematic cross-sectional view of the infrared radiation element of Embodiment 2. 図６Ａ～６Ｅは、実施形態２の赤外線放射素子の製造方法を説明するための主要工程断面図である。6A to 6E are main process cross-sectional views for explaining the method of manufacturing the infrared radiation device of the second embodiment. 図７は、実施形態２の赤外線放射素子の動作説明図である。FIG. 7 is an operation explanatory view of the infrared radiation element of the second embodiment. 図８Ａは、従来の赤外線光源の平面図である。図８Ｂは、図８ＡのＡ－Ａ断面図である。FIG. 8A is a plan view of a conventional infrared light source. FIG. 8B is a cross-sectional view taken along line AA of FIG. 8A.
　（実施形態１）
　以下では、本実施形態の赤外線放射素子１について図１Ａ、１Ｂに基づいて説明する。 (Embodiment 1)
Below, the infrared rays radiating element 1 of this embodiment is demonstrated based on FIG. 1A and 1B.
　赤外線放射素子１は、基板２と、この基板２の一表面側に設けられた薄膜部５と、薄膜部５における基板２側とは反対側に設けられた発熱体層３と、を備えている。この赤外線放射素子１は、発熱体層３への通電により発熱体層３から赤外線が放射される。 The infrared radiation element 1 comprises a substrate 2, a thin film portion 5 provided on one surface side of the substrate 2, and a heating element layer 3 provided on the thin film portion 5 opposite to the substrate 2 side. There is. In the infrared radiation element 1, infrared rays are emitted from the heat generating body layer 3 by energization to the heat generating body layer 3.
　基板２は、薄膜部５における発熱体層３側とは反対側の表面を露出させる開孔部２ａが厚み方向に貫設されている。 In the substrate 2, an opening 2 a for exposing the surface of the thin film portion 5 on the opposite side to the heating element layer 3 side is penetrated in the thickness direction.
　薄膜部５は、開孔部２ａと発熱体層３とを隔離するダイヤフラム部５１と、基板２の上記一表面側で開孔部２ａの周部に設けられダイヤフラム部５１を支持する支持部５２と、を備えている。 The thin film portion 5 is a diaphragm 51 separating the opening 2 a from the heating element layer 3, and a support 52 provided on the periphery of the opening 2 a on the one surface side of the substrate 2 and supporting the diaphragm 51. And have.
　ダイヤフラム部５１は、開孔部２ａ側に窪む凹部５３を備えている。凹部５３は、内面５３ａが凹曲面である。 The diaphragm part 51 is provided with the recessed part 53 indented to the opening part 2a side. In the recess 53, the inner surface 53a is a concave surface.
　発熱体層３は、凹部５３の内面５３ａに沿って形成されている。発熱体層３は、少なくとも凹部５３の内面５３ａに沿って形成されていればよい。 The heating element layer 3 is formed along the inner surface 53 a of the recess 53. The heating element layer 3 may be formed along at least the inner surface 53 a of the recess 53.
　また、赤外線放射素子１は、基板２の上記一表面側で発熱体層３に一部が接するように形成された一対のパッド７、７を備えている。なお、赤外線放射素子１は、各パッド７、７の各々と発熱体層３との間に配線を設けてもよい。 In addition, the infrared radiation element 1 is provided with a pair of pads 7 formed so as to be partially in contact with the heating element layer 3 on the one surface side of the substrate 2. The infrared radiation element 1 may be provided with a wire between each of the pads 7 and the heating element layer 3.
　赤外線放射素子１の各構成要素については、以下に詳細に説明する。 Each component of the infrared radiation element 1 will be described in detail below.
　基板２は、上記一表面が（１００）面の単結晶のシリコン基板により形成されているが、これに限らず、（１１０）面の単結晶のシリコン基板により形成してもよい。また、基板２は、単結晶のシリコン基板に限らず、多結晶のシリコン基板でもよいし、シリコン基板以外でもよい。基板２の材料は、薄膜部５の材料よりも熱伝導率が大きく且つ熱容量が大きな材料が好ましい。 The substrate 2 is formed of a single crystal silicon substrate of which the one surface is a (100) plane, but is not limited to this, and may be formed of a single crystal silicon substrate of a (110) plane. Further, the substrate 2 is not limited to a single crystal silicon substrate, and may be a polycrystalline silicon substrate or may be other than a silicon substrate. The material of the substrate 2 is preferably a material having a larger thermal conductivity and a larger heat capacity than the material of the thin film portion 5.
　基板２の外周形状は、矩形状である。基板２の外形サイズ、すなわち、チップサイズは、特に限定するものではないが、例えば、１０ｍｍ×１０ｍｍ以下に設定するのが好ましい。また、基板２は、開孔部２ａの開口形状を円形状としてある。また、基板２の開孔部２ａは、基板２の上記一表面側から上記他表面側にかけて開口面積が略一定となる形状に形成されている。この場合、基板２の開孔部２ａは、例えば、誘導結合プラズマ型のドライエッチング装置を用いたエッチングにより形成することができる。赤外線放射素子１は、基板２の上記他表面側に、開孔部２ａを形成する際のマスク層が残っていてもよい。なお、マスク層としては、例えば、シリコン酸化膜とシリコン窒化膜との積層膜などを用いることができる。 The outer peripheral shape of the substrate 2 is rectangular. The outer size of the substrate 2, that is, the chip size is not particularly limited, but is preferably set to, for example, 10 mm × 10 mm or less. Further, the substrate 2 has a circular shape in the opening 2a. The opening 2a of the substrate 2 is formed in a shape such that the opening area is substantially constant from the one surface side of the substrate 2 to the other surface side. In this case, the opening 2a of the substrate 2 can be formed, for example, by etching using an inductive coupling plasma type dry etching apparatus. The infrared radiation element 1 may have a mask layer on the other surface side of the substrate 2 when the opening 2 a is formed. Note that, for example, a stacked film of a silicon oxide film and a silicon nitride film can be used as the mask layer.
　薄膜部５は、上述のように、開孔部２ａと発熱体層３とを隔離するダイヤフラム部５１と、基板２の上記一表面側で開孔部２ａの周部に設けられダイヤフラム部５１を支持する支持部５２とを備えている。ダイヤフラム部５１は、外周形状が円形状である。すなわち、赤外線放射素子１は、上述のように開孔部２ａの開口形状を円形状としてあり、基板２の上記他表面側から見たダイヤフラム部５１の形状が円形状となっている。 As described above, the thin film portion 5 is provided on the peripheral portion of the opening portion 2a on the one surface side of the substrate 2 with the diaphragm portion 51 separating the opening portion 2a and the heating element layer 3 from each other. And a supporting portion 52 for supporting. The diaphragm portion 51 has a circular outer peripheral shape. That is, as described above, the infrared radiation element 1 has a circular opening shape of the opening 2a, and the diaphragm 51 viewed from the other surface side of the substrate 2 has a circular shape.
　薄膜部５は、例えば、基板２側のシリコン酸化膜と、このシリコン酸化膜における基板２側とは反対側に積層されたシリコン窒化膜と、で構成することができる。薄膜部５の積層構造は特に限定するものではない。また、薄膜部５の層構造は、シリコン酸化膜とシリコン窒化膜の積層構造に限らず、シリコン酸化膜やシリコン窒化膜の単層構造でもよいし、その他の材料からなる単層構造や、２層以上の積層構造でもよい。薄膜部５は、赤外線放射素子１の製造時において基板２の上記他表面側から基板２をエッチングして開孔部２ａを形成する際のエッチングストッパ層としての機能も有している。 The thin film portion 5 can be constituted of, for example, a silicon oxide film on the side of the substrate 2 and a silicon nitride film stacked on the opposite side of the silicon oxide film to the side of the substrate 2. The laminated structure of the thin film portion 5 is not particularly limited. The layer structure of the thin film portion 5 is not limited to the laminated structure of a silicon oxide film and a silicon nitride film, but may be a single layer structure of a silicon oxide film or a silicon nitride film, or a single layer structure made of other materials It may be a laminated structure of layers or more. The thin film portion 5 also has a function as an etching stopper layer when forming the opening 2 a by etching the substrate 2 from the other surface side of the substrate 2 at the time of manufacturing the infrared radiation element 1.
　ダイヤフラム部５１は、上述のように、開孔部２ａ側に窪み内面５３ａが凹曲面である凹部５３を備えている。凹部５３の内面５３ａを構成する凹曲面は、回転２次曲面状であることが好ましい。凹部５３の内面５３ａを構成する凹曲面は、曲率半径が略一定の凹曲面としてあるが、回転２次曲面状の形状であれば、例えば、回転放物面状などの形状としてもよい。要するに、凹部５３の内面５３ａを構成する凹曲面は、曲率が連続的に変化する非球面の一部からなるように構成してもよく、回転放物面状に限らず、例えば、双曲面状の形状としてもよい。 As described above, the diaphragm portion 51 is provided with the concave portion 53 whose concave inner surface 53a is a concave surface on the side of the opening 2a. It is preferable that the concave curved surface which comprises the inner surface 53a of the recessed part 53 is rotation quadric surface shape. The concave surface forming the inner surface 53a of the concave portion 53 is a concave surface having a substantially constant radius of curvature, but may be, for example, a paraboloid of revolution, as long as it is a shape of a rotational quadric surface. In short, the concave surface forming the inner surface 53a of the concave portion 53 may be configured to be a part of an aspheric surface whose curvature changes continuously, and is not limited to the paraboloid of revolution, for example, a hyperboloid It may be in the form of
　発熱体層３は、外周形状を矩形状としてある。すなわち、発熱体層３は、平面視形状を矩形状としてある。発熱体層３の平面視形状は、矩形状に限定するものではなく、例えば、円形状や多角形状などでもよい。また、発熱体層３は、平面視においてダイヤフラム部５１全体を覆う大きさに形成されている。発熱体層３は、平面視においてダイヤフラム部５１の外周形状よりも小さくしてもよく、この場合、発熱体層３と各パッド７の各々とを電気的に接続する金属膜からなる配線を設ければよい。いずれにしても、赤外線放射素子１は、発熱体層３における基板２の厚み方向に沿った中心軸（図示せず）が、ダイヤフラム部５１における基板２の厚み方向に沿った中心軸と揃うように、発熱体層３をパターン設計することが好ましい。また、赤外線放射素子１は、発熱体層３のうち凹部５３に積層されている部分の表面が、凹部５３の内面５３ａに沿った凹曲面（例えば、回転２次曲面状）の形状となるように、発熱体層３の膜厚を設定することが好ましい。 The heat generating layer 3 has a rectangular outer peripheral shape. That is, the heat generating layer 3 has a rectangular shape in a plan view. The plan view shape of the heat generating layer 3 is not limited to the rectangular shape, and may be, for example, a circular shape or a polygonal shape. Moreover, the heat generating body layer 3 is formed in the magnitude | size which covers the diaphragm part 51 whole in planar view. The heat generating body layer 3 may be smaller than the outer peripheral shape of the diaphragm portion 51 in plan view, and in this case, a wire made of a metal film electrically connecting the heat generating body layer 3 and each of the pads 7 is provided. Just do it. In any case, in the infrared radiation element 1, the central axis (not shown) along the thickness direction of the substrate 2 in the heating element layer 3 is aligned with the central axis along the thickness direction of the substrate 2 in the diaphragm portion 51 Preferably, the heating element layer 3 is designed in a pattern. Further, in the infrared radiation element 1, the surface of the portion of the heat generating layer 3 stacked in the recess 53 has a concave surface (for example, a rotational quadratic surface) along the inner surface 53 a of the recess 53. Preferably, the film thickness of the heating element layer 3 is set.
　発熱体層３の材料としては、窒化タンタルを採用しているが、これに限らない。発熱体層３の材料は、例えば、窒化チタン、ニッケルクロム、タングステン、チタン、トリウム、白金、ジルコニウム、クロム、バナジウム、ロジウム、ハフニウム、ルテニウム、ボロン、イリジウム、ニオブ、モリブデン、タンタル、オスミウム、レニウム、ニッケル、ホルミウム、コバルト、エルビウム、イットリウム、鉄、スカンジウム、ツリウム、パラジウム、ルテチウムなどを採用してもよい。また、発熱体層３の材料としては、導電性のポリシリコンや導電性のアモルファスシリコンなどを採用してもよい。発熱体層３の材料について、基板２と発熱体層３との線膨張係数差に伴う熱応力に起因して発熱体層３が破壊されるのを防止するという観点からは、基板２の材料との線膨張係数差が小さい材料が好ましい。 Although tantalum nitride is used as a material of the heat generating body layer 3, it is not limited thereto. The material of the heating element layer 3 is, for example, titanium nitride, nickel chromium, tungsten, titanium, thorium, platinum, zirconium, chromium, vanadium, rhodium, hafnium, ruthenium, boron, iridium, niobium, molybdenum, tantalum, osmium, rhenium, Nickel, holmium, cobalt, erbium, yttrium, iron, scandium, thulium, palladium, lutetium or the like may be employed. Further, as a material of the heat generating layer 3, conductive polysilicon, conductive amorphous silicon or the like may be employed. With respect to the material of the heat generating body layer 3, the material of the substrate 2 from the viewpoint of preventing the heat generating body layer 3 from being broken due to the thermal stress caused by the difference in linear expansion coefficient between the substrate 2 and the heat generating body layer 3. A material having a small difference in coefficient of linear expansion with is preferable.
　薄膜部５の厚さと発熱体層３の厚さとの合計厚さは、例えば、０．１μｍ～１０μｍ程度の範囲で設定することが好ましい。 The total thickness of the thickness of the thin film portion 5 and the thickness of the heating element layer 3 is preferably set, for example, in the range of about 0.1 μm to 10 μm.
　一対のパッド７、７は、基板２の上記一表面側において、発熱体層３の両端部（図１Ａ、１Ｂにおける左右両端部）それぞれと各々の一部が接する形で形成されている。各パッド７は、発熱体層３とオーミック接触をなしている。 The pair of pads 7 is formed such that parts of both ends (left and right ends in FIGS. 1A and 1B) of the heating element layer 3 are in contact with each other on the one surface side of the substrate 2. Each pad 7 is in ohmic contact with the heating element layer 3.
　各パッド７の材料としては、アルミニウム合金の一種であるＡｌ－Ｓｉを採用している。各パッド７の材料は、特に限定するものではなく、例えば、Ａｌ－Ｓｉ以外のアルミニウム合金や、金、銅などを採用してもよい。また、各パッド７は、少なくとも、発熱体層３と接する部分が発熱体層３とオーミック接触が可能な材料であればよく、単層構造に限らず、多層構造でもよい。例えば、各パッド７は、発熱体層３側から順に、第１層、第２層、第３層が積層された３層構造として、発熱体層３に接する第１層の材料を高融点金属（例えば、クロムなど）とし、第２層の材料をニッケルとし、第３層の材料を金としてもよい。各パッド７の厚さは、０．５～２μｍ程度の範囲で設定することが好ましい。 As a material of each pad 7, Al-Si which is a kind of aluminum alloy is adopted. The material of each pad 7 is not particularly limited, and, for example, an aluminum alloy other than Al-Si, gold, copper or the like may be adopted. Each pad 7 may be made of any material that allows at least a portion in contact with the heat generating layer 3 to be in ohmic contact with the heat generating layer 3, and is not limited to a single layer structure, and may be a multilayer structure. For example, each pad 7 has a three-layer structure in which a first layer, a second layer, and a third layer are sequentially stacked from the heat generating body layer 3 side, and the material of the first layer in contact with the heat generating body layer 3 is a high melting point metal The material of the second layer may be nickel, and the material of the third layer may be gold. The thickness of each pad 7 is preferably set in the range of about 0.5 to 2 μm.
　以下では、本実施形態の赤外線放射素子１の製造方法の一例について図２Ａ～２Ｅを参照しながら説明する。 Hereinafter, an example of a method of manufacturing the infrared radiation element 1 of the present embodiment will be described with reference to FIGS. 2A to 2E.
　赤外線放射素子１を製造するにあたっては、まず、上記一表面が（１００）面の単結晶のシリコン基板などからなる基板２を準備する（図２Ａ参照）。 In order to manufacture the infrared radiation element 1, first, a substrate 2 made of a single crystal silicon substrate having a (100) plane is prepared (see FIG. 2A).
　基板２を準備した後には、基板２の上記一表面側にダイヤフラム部５１の凹部５３を形成するための窪み部２３を形成する第１工程を行うことによって、図２Ｂに示す構造を得る。第１工程では、まず、熱酸化法やＣＶＤ（Chemical Vapor Deposition）法などによって、基板２の上記一表面側に第１のシリコン酸化膜２１を形成するとともに他表面側に第２のシリコン酸化膜２２を形成する。その後には、フォトリソグラフィ技術およびエッチング技術を利用して、第１のシリコン酸化膜２１をパターニングする。その後には、第１のシリコン酸化膜２１および第２のシリコン酸化膜２２をマスクとして、基板２を上記一表面側から等方性エッチングすることで窪み部２３を形成する。 After the substrate 2 is prepared, a first step of forming a recess 23 for forming the recess 53 of the diaphragm 51 on the one surface side of the substrate 2 is performed to obtain a structure shown in FIG. 2B. In the first step, first, a first silicon oxide film 21 is formed on the one surface side of the substrate 2 by a thermal oxidation method, a CVD (Chemical Vapor Deposition) method or the like, and a second silicon oxide film on the other surface side. Form 22 Thereafter, the first silicon oxide film 21 is patterned using photolithography technology and etching technology. Thereafter, using the first silicon oxide film 21 and the second silicon oxide film 22 as a mask, the substrate 2 is isotropically etched from the one surface side to form a recess 23.
　第１工程の後には、第１のシリコン酸化膜２１および第２のシリコン酸化膜２２をエッチングにより除去した後、基板２の上記一表面側に薄膜部５を形成する第２工程を行うことによって、図２Ｃに示す構造を得る。薄膜部５の形成方法は、例えば、ＣＶＤ法などを採用することができる。 After the first step, the first silicon oxide film 21 and the second silicon oxide film 22 are removed by etching, and then the second step of forming the thin film portion 5 on the one surface side of the substrate 2 is performed. , The structure shown to FIG. 2C is obtained. For example, a CVD method or the like can be employed as a method of forming the thin film portion 5.
　第２工程の後には、薄膜部５上に発熱体層３を形成する第３工程を行う。発熱体層３の形成方法は、スパッタ法や蒸着法やＣＶＤ法などを採用することができる。 After the second step, the third step of forming the heating element layer 3 on the thin film portion 5 is performed. As a method of forming the heat generating body layer 3, a sputtering method, a vapor deposition method, a CVD method or the like can be adopted.
　第３工程の後には、各パッド７を形成した後（図２Ｄ参照）、基板２における開孔部２ａの形成予定領域を基板２の上記他表面側からエッチングすることで凹部５３を備えたダイヤフラム部５１を形成する第４工程を行うことによって、図２Ｅに示す構造の赤外線放射素子１を得る。各パッド７の形成にあたっては、例えば、スパッタ法や蒸着法やＣＶＤ法などの薄膜形成技術と、フォトリソグラフィ技術およびエッチング技術とを利用することができる。また、開孔部２ａの形成にあたっては、例えば、基板２の上記他表面側にシリコン酸化膜とシリコン窒化膜との積層膜（図示せず）からなるマスク材料層をＣＶＤ法などにより形成し、その後、フォトリソグラフィ技術およびエッチング技術を利用してマスク材料層をパターニングすることでマスク層を形成し、その後、基板２を上記他表面側からエッチングすることで開孔部２ａを形成すればよい。基板２の開孔部２ａは、例えば、誘導結合プラズマ型のドライエッチング装置を用いたエッチングにより形成することができる。赤外線放射素子１の製造方法では、開孔部２ａの形成時に、薄膜部５をエッチングストッパ層として利用することにより、薄膜部５の厚さの精度を高めることが可能となるとともに、薄膜部５における開孔部２ａ側に基板２の一部や残渣が残るのを防止することが可能となる。また、赤外線放射素子１の製造方法では、開孔部２ａの形成時に、薄膜部５をエッチングストッパ層として利用することにより、薄膜部５の厚さの精度を高めることが可能となり、赤外線放射素子１ごとの、薄膜部５の機械的強度のばらつきや、ダイヤフラム部５１の熱容量のばらつきを抑制することが可能となる。 After the third step, after each pad 7 is formed (see FIG. 2D), a region including the opening 2a in the substrate 2 is etched from the other surface side of the substrate 2 to etch the diaphragm 53 having the recess 53. By performing the fourth step of forming the portion 51, the infrared radiation element 1 having the structure shown in FIG. 2E is obtained. In forming each pad 7, for example, a thin film formation technique such as a sputtering method, an evaporation method, a CVD method, etc., and a photolithography technique and an etching technique can be used. Further, in forming the opening 2a, for example, a mask material layer formed of a laminated film (not shown) of a silicon oxide film and a silicon nitride film is formed on the other surface side of the substrate 2 by the CVD method or the like. Thereafter, the mask material layer is patterned using photolithography technology and etching technology to form a mask layer, and then the substrate 2 is etched from the other surface side to form the opening 2a. The opening 2a of the substrate 2 can be formed, for example, by etching using an inductive coupling plasma type dry etching apparatus. In the method of manufacturing the infrared radiation element 1, the thin film portion 5 can be used as an etching stopper layer at the time of forming the opening portion 2 a, so that the thickness accuracy of the thin film portion 5 can be enhanced. It is possible to prevent a part or residue of the substrate 2 from remaining on the side of the opening 2a. Further, in the method of manufacturing the infrared radiation element 1, by using the thin film portion 5 as an etching stopper layer at the time of forming the opening portion 2a, it becomes possible to increase the accuracy of the thickness of the thin film portion 5 It is possible to suppress the variation of the mechanical strength of the thin film portion 5 and the variation of the heat capacity of the diaphragm portion 51 for each unit.
　赤外線放射素子１の製造にあたっては、開孔部２ａの形成が終了するまでのプロセスを、ウェハレベルで行い、開孔部２ａを形成した後、個々の赤外線放射素子１に分離すればよい。つまり、赤外線放射素子１の製造にあたっては、例えば、基板２の基礎となるシリコンウェハを準備して、このシリコンウェハに複数の赤外線検出素子１を上述の製造方法に従って形成し、その後、個々の赤外線検出素子１に分離すればよい。 When the infrared radiation element 1 is manufactured, the process until the formation of the opening 2a is completed may be performed at the wafer level to form the opening 2a, and then the infrared radiation element 1 may be separated. That is, in the manufacture of the infrared radiation element 1, for example, a silicon wafer to be a base of the substrate 2 is prepared, and a plurality of infrared detection elements 1 are formed on this silicon wafer according to the above manufacturing method. It may be separated into the detection element 1.
　ところで、赤外線放射素子１において発熱体層３から放射される赤外線のピーク波長λは、発熱体層３の温度に依存する。ここで、ピーク波長をλ〔μｍ〕、発熱体層３の絶対温度をＴ〔Ｋ〕とすれば、ピーク波長λは、
λ＝２８９８／Ｔ
となり、発熱体層３の絶対温度Ｔと発熱体層３から放射される赤外線のピーク波長λとの関係がウィーンの変位則を満足している。要するに、赤外線放射素子１では、発熱体層３が擬似黒体を構成している。赤外線放射素子１は、例えば、図示しない外部電源から一対のパッド７、７間に与える入力電力を調整することにより、発熱体層３に発生するジュール熱を変化させることができ、発熱体層３の温度を変化させることができる。したがって、赤外線放射素子１は、発熱体層３への最大入力電力に応じて発熱体層３の温度を変化させることができ、また、発熱体層３の温度を変化させることで発熱体層３から放射される赤外線のピーク波長λを変化させることができる。また、本実施形態の赤外線放射素子１では、発熱体層３の温度を高くするほど赤外線の放射量を増大させることが可能となる。このため、赤外線放射素子１は、広範囲の赤外線波長域において高出力の赤外線源として用いることが可能となる。例えば、赤外線放射素子１をガスセンサの赤外線源として使用する場合には、発熱体層３から放射される赤外線のピーク波長λを４μｍ程度にするのが好ましく、発熱体層３の温度を８００Ｋ程度とすればよい。ここにおいて、本実施形態の赤外線放射素子１では、発熱体層３が上述のように擬似黒体を構成している。これにより、赤外線放射素子１は、発熱体層３の単位面積が単位時間に放射する全エネルギＥがＴ4に略比例するものと推考される（つまり、シュテファン－ボルツマンの法則を満足するものと推考される）。 The peak wavelength λ of the infrared ray emitted from the heat generating layer 3 in the infrared emitting element 1 depends on the temperature of the heat generating layer 3. Here, assuming that the peak wavelength is λ [μm] and the absolute temperature of the heat generating body layer 3 is T [K], the peak wavelength λ is
λ = 2898 / T
The relationship between the absolute temperature T of the heat generating body layer 3 and the peak wavelength λ of the infrared ray emitted from the heat generating body layer 3 satisfies the Wien's displacement law. In short, in the infrared radiation element 1, the heating element layer 3 constitutes a pseudo black body. The infrared radiation element 1 can change the Joule heat generated in the heating element layer 3 by, for example, adjusting the input power to be applied between the pair of pads 7 and 7 from an external power supply (not shown). Can change the temperature of the Therefore, the infrared radiation element 1 can change the temperature of the heat generating layer 3 in accordance with the maximum input power to the heat generating layer 3, and changes the temperature of the heat generating layer 3. The peak wavelength λ of the infrared radiation emitted from Further, in the infrared radiation element 1 of the present embodiment, it is possible to increase the radiation amount of infrared rays as the temperature of the heat generating layer 3 is increased. For this reason, the infrared radiation element 1 can be used as a high output infrared source in a wide range of infrared wavelength range. For example, when the infrared radiation element 1 is used as an infrared source of a gas sensor, it is preferable to set the peak wavelength λ of infrared radiation emitted from the heating element layer 3 to about 4 μm, and the temperature of the heating element layer 3 is about 800 K do it. Here, in the infrared radiation element 1 of the present embodiment, the heating element layer 3 constitutes a pseudo black body as described above. As a result, the infrared radiation element 1 is considered to assume that the total energy E emitted per unit time of the heating element layer 3 is substantially proportional to T 4 (that is, satisfying the Stefan-Boltzmann's law) I guess).
　以上説明した本実施形態の赤外線放射素子１は、基板２と、この基板２の一表面側に設けられた薄膜部５と、薄膜部５における基板２側とは反対側に設けられた発熱体層３と、を備えている。ここで、赤外線放射素子１は、基板２に、薄膜部５における発熱体層３側とは反対側の表面を露出させる開孔部２ａが貫設されており、薄膜部５が、開孔部２ａと発熱体層３とを隔離するダイヤフラム部５１と、基板２の上記一表面側で開孔部２ａの周部に設けられダイヤフラム部５１を支持する支持部５２と、を備えている。また、赤外線放射素子１は、ダイヤフラム部５１が、開孔部２ａ側に窪む凹部５３を備え、凹部５３の内面５３ａが凹曲面である。そして、赤外線放射素子１は、発熱体層３が凹部５３の内面５３ａに沿って形成されている。しかして、赤外線放射素子１においては、発熱体層３が凹部５３の内面５３ａに沿って形成されていることにより、指向性を向上させることが可能である。凹部５３の内面５３ａを構成する凹曲面は、回転２次曲面状であることが好ましい。これにより、赤外線放射素子１は、正面方向（図１Ｂの上方向）の指向性を向上させることが可能となる。図３は、赤外線放射素子１の動作説明図であり、一対のパッド７、７間に通電したときに発熱体層３から放射される赤外線の放射方向を矢印付きの実線で模式的に示してある。一方、図４は、ダイヤフラム部５１が平板状であり発熱体層３の表面が平面である比較例の赤外線放射素子１’の動作説明図であり、一対のパッド７、７間に通電したときに発熱体層３から放射される赤外線の放射方向を矢印付きの実線で模式的に示してある。また、図３、４には、赤外線放射素子１、１’から放射された赤外線が照射される所望の照射部１０を模式的に示してある。この照射部１０は、例えば、赤外線を受光する受光素子などである。 The infrared radiation element 1 of the present embodiment described above includes a substrate 2, a thin film portion 5 provided on one surface side of the substrate 2, and a heating element provided on the thin film portion 5 opposite to the substrate 2 side. And a layer 3. Here, in the infrared radiation element 1, an opening 2a for exposing the surface of the thin film 5 on the opposite side to the heating element layer 3 is formed in the substrate 2, and the thin film 5 is an opening A diaphragm 51 for separating the heat generating body layer 3 from each other and a support 52 provided on the periphery of the opening 2 a on the one surface side of the substrate 2 and supporting the diaphragm 51 are provided. Further, in the infrared radiation element 1, the diaphragm portion 51 is provided with a recess 53 which is recessed toward the opening 2a, and the inner surface 53a of the recess 53 is a concave surface. In the infrared radiation element 1, the heating element layer 3 is formed along the inner surface 53 a of the recess 53. Thus, in the infrared radiation element 1, the directivity can be improved by the heating element layer 3 being formed along the inner surface 53a of the recess 53. It is preferable that the concave curved surface which comprises the inner surface 53a of the recessed part 53 is rotation quadric surface shape. As a result, the infrared radiation element 1 can improve the directivity in the front direction (the upper direction in FIG. 1B). FIG. 3 is a diagram for explaining the operation of the infrared radiation element 1, in which the radiation direction of the infrared radiation emitted from the heating element layer 3 when energized between the pair of pads 7 is schematically shown by a solid line with an arrow. is there. On the other hand, FIG. 4 is an operation explanatory view of the infrared ray emitting element 1 ′ of the comparative example in which the diaphragm portion 51 is flat and the surface of the heat generating layer 3 is flat. The radiation direction of the infrared rays emitted from the heating element layer 3 is schematically shown by a solid line with an arrow. Moreover, in FIG. 3, 4, the desired irradiation part 10 to which the infrared rays radiated | emitted from the infrared rays radiating element 1 and 1 'is irradiated is shown typically. The irradiation unit 10 is, for example, a light receiving element that receives infrared light.
　赤外線放射素子１は、発熱体層３においてダイヤフラム部５１に積層されている部分の表面が、凹曲面となっている。これにより、赤外線放射素子１は、図４に示した比較例の赤外線放射素子１’のように赤外線が等方的に放射される無指向性のものに比べて、図３に示すように放射する赤外線の指向性を強くすることができる。つまり、赤外線放射素子１では、正面方向（図３の上方向）への指向性が向上し、例えば、図４の比較例と入力電力を同じとし、照射部１０の大きさを同じとした場合、照射部１０への照射効率を向上させることが可能となり、放射された赤外線の損失を低減することが可能となる。ここで、照射部１０が受光素子の場合には、この受光素子の受光効率を向上させることが可能となる。 In the infrared radiation element 1, the surface of the portion of the heating element layer 3 stacked on the diaphragm portion 51 has a concave surface. Thereby, the infrared radiation element 1 emits radiation as shown in FIG. 3 as compared with the non-directional one in which infrared rays are radiated isotropically as in the infrared radiation element 1 ′ of the comparative example shown in FIG. Can make the directivity of infrared rays stronger. That is, in the infrared radiation element 1, the directivity in the front direction (the upper direction in FIG. 3) is improved, for example, when the input power is the same as in the comparative example of FIG. It becomes possible to improve the irradiation efficiency to the irradiation part 10, and it becomes possible to reduce the loss of the emitted infrared rays. Here, when the irradiation unit 10 is a light receiving element, it is possible to improve the light receiving efficiency of the light receiving element.
　本実施形態の赤外線放射素子１は、指向性を向上させながらも、図８Ａ、８Ｂに示した従来例のように集光レンズ１３０を備えた赤外線光源１００に比べて、ダイヤフラム部５１を含む積層構造全体の熱容量を低減することが可能となる。よって、赤外線放射素子１は、一対のパッド７、７間へ与える電圧波形に対する発熱体層３の温度変化の応答を速くすることが可能となるから、発熱体層３の温度が上昇しやすくなり、高出力化および応答速度の高速化を図ることが可能となる。 The infrared radiation element 1 of the present embodiment is a laminated including the diaphragm portion 51 as compared with the infrared light source 100 having the condensing lens 130 as in the conventional example shown in FIGS. 8A and 8B while improving the directivity. It is possible to reduce the heat capacity of the entire structure. Therefore, since the infrared radiation element 1 can accelerate the response of the temperature change of the heat generating body layer 3 to the voltage waveform applied between the pair of pads 7, the temperature of the heat generating body layer 3 tends to rise. It is possible to achieve high output and high response speed.
　また、本実施形態の赤外線放射素子１では、基板２を単結晶のシリコン基板から形成し、薄膜部５をシリコン酸化膜とシリコン窒化膜とで構成してある。これにより、赤外線放射素子１は、薄膜部５に比べて基板２の熱容量および熱伝導率それぞれが大きく、基板２がヒートシンクとしての機能を有するので、小型で入力電力に対する応答速度が速く且つ赤外線の放射特性の安定性を向上させることが可能となる。また、本実施形態の赤外線放射素子１では、発熱体層３の材料として、シリコンよりも高融点の窒化タンタルを採用すれば、発熱体層３の温度をシリコンの最高使用温度（シリコンの融点よりもやや低い温度）まで上昇させることが可能となり、赤外線発光ダイオードに比べて赤外線の放射量を大幅に増大させることが可能となる。また、赤外線放射素子１は、各パッド７において少なくとも発熱体層３に接する部位がシリコンよりも高融点の金属により形成されていれば、発熱体層３の温度を各パッド７の材料に制約されることなく上昇させることが可能となる。 Further, in the infrared radiation element 1 of the present embodiment, the substrate 2 is formed of a single crystal silicon substrate, and the thin film portion 5 is configured of a silicon oxide film and a silicon nitride film. As a result, the infrared radiation element 1 has a large thermal capacity and thermal conductivity of the substrate 2 as compared to the thin film portion 5 and the substrate 2 has a function as a heat sink. It is possible to improve the stability of the radiation characteristics. Further, in the infrared radiation element 1 of the present embodiment, if tantalum nitride having a melting point higher than that of silicon is employed as the material of the heating body layer 3, the temperature of the heating body layer 3 is the maximum use temperature of silicon (from the melting point of silicon It is possible to raise the temperature to a somewhat lower temperature), and it is possible to significantly increase the amount of infrared radiation as compared to the infrared light emitting diode. Further, if the infrared radiation element 1 is formed of a metal having a melting point higher than that of silicon, at least a portion of each pad 7 in contact with the heating element layer 3, the temperature of the heating element layer 3 is restricted by the material of each pad 7. Can be raised without
　また、本実施形態の赤外線放射素子１の製造方法によれば、上述の第１工程、第２工程、第３工程および第４工程を備えていることにより、指向性を向上させることが可能であり且つ高出力化が可能な赤外線放射素子１を提供することが可能となる。 Further, according to the method of manufacturing the infrared radiation element 1 of the present embodiment, directivity can be improved by including the above-described first step, second step, third step and fourth step. It is possible to provide an infrared radiation element 1 which is capable of achieving high output.
　（実施形態２）
　以下では、本実施形態の赤外線放射素子１について図５Ａ、５Ｂに基づいて説明する。なお、実施形態１の赤外線放射素子１と同様の構成要素には同一の符号を付して説明を適宜省略する。 Second Embodiment
Below, the infrared rays radiating element 1 of this embodiment is demonstrated based on FIG. 5A and 5B. In addition, the same code | symbol is attached | subjected to the component similar to the infrared rays radiating element 1 of Embodiment 1, and description is abbreviate | omitted suitably.
　本実施形態の赤外線放射素子１では、ダイヤフラム部５１に、複数の凹部５３がアレイ状（図示例では、２次元アレイ状）に設けられている。すなわち、ダイヤフラム部５１は、複数の凹部５３を備えている。各凹部５３は、実施形態１と同様、開孔部２ａ側に窪んでおり、内面５３ａが凹曲面となっている。ここで、赤外線放射素子１は、例えば、基板２の厚み方向に直交する２次元面内で凹部５３が２次元的な周期構造を有するように配列されていることが好ましい。図５Ａ、５Ｂに示した例では、単位格子が正方形の仮想的な２次元正方格子の各格子点の各々に各凹部５３の中心が位置しているが、これに限らず、例えば、単位格子が正三角形の仮想的な２次元三角格子の各格子点の各々に各凹部５３の中心が位置しているようにしてもよい。また、赤外線放射素子１は、例えば、複数の凹部５３が、１つの仮想円上で円周方向に離間して配列された構成としてもよい。また、赤外線放射素子１は、例えば、複数の凹部５３が、２次元面内の形状が渦巻き状である仮想渦巻き上で離間して配列された構成としてもよい。ダイヤフラム部５１は、各凹部５３の大きさを同じとしてあるが、必ずしも同じ大きさでなくてもよい。 In the infrared radiation element 1 of the present embodiment, the plurality of concave portions 53 are provided in the diaphragm portion 51 in an array (in the illustrated example, a two-dimensional array). That is, the diaphragm unit 51 is provided with a plurality of concave portions 53. As in the first embodiment, each recess 53 is recessed toward the opening 2 a, and the inner surface 53 a is a concave surface. Here, it is preferable that the infrared radiation elements 1 be arranged such that, for example, the recesses 53 have a two-dimensional periodic structure in a two-dimensional plane orthogonal to the thickness direction of the substrate 2. In the example shown in FIGS. 5A and 5B, the center of each recess 53 is located at each lattice point of a virtual two-dimensional square lattice having a square unit cell, but the invention is not limited thereto. For example, a unit lattice The center of each recess 53 may be located at each grid point of a virtual two-dimensional triangular grid of an equilateral triangle. Further, the infrared radiation element 1 may have, for example, a configuration in which a plurality of concave portions 53 are spaced apart in the circumferential direction on one virtual circle. Further, the infrared radiation element 1 may have, for example, a configuration in which a plurality of concave portions 53 are spaced apart on a virtual spiral having a spiral shape in a two-dimensional surface. Although the diaphragm part 51 makes the magnitude | size of each recessed part 53 the same, it is not necessary to necessarily be the same size.
　複数の凹部５３は、一対のパッド７、７の並ぶ方向および基板２の厚み方向に直交する方向に沿った発熱体層３の中心線を対称軸として、線対称に配置されていることが好ましい。これにより、赤外線放射素子１は、複数の凹部５３が発熱体層３の中心線を対称軸として線対称に配置されていない場合に比べて、発熱体層３の温度の面内ばらつきを抑制することが可能となる。 The plurality of recesses 53 are preferably arranged in line symmetry with the center line of the heat generating layer 3 along the direction in which the pair of pads 7 and 7 are arranged and the direction orthogonal to the thickness direction of the substrate 2 as a symmetry axis. . Thereby, the infrared radiation element 1 suppresses the in-plane variation of the temperature of the heat generating layer 3 compared to the case where the plurality of recesses 53 are not arranged in line symmetry with the center line of the heat generating layer 3 as a symmetry axis. It becomes possible.
　基板２は、開孔部２ａの開口形状を矩形状としてある。基板２の開孔部２ａは、基板２の上記一表面側に比べて他表面側での開口面積が大きくなる形状に形成されている。この基板２の開孔部２ａは、基板２の厚み方向において薄膜部５から離れるほど開口面積が徐々に大きくなる形状に形成されている。基板２の開孔部２ａは、基板２をエッチングすることにより形成されている。基板２の開孔部２ａは、例えば、基板２が（１００）面の単結晶のシリコン基板の場合には、アルカリ系溶液をエッチング液として用いた異方性エッチングにより形成することができる。 The substrate 2 has a rectangular shape in the opening 2a. The opening 2 a of the substrate 2 is formed in a shape in which the opening area on the other surface side is larger than that of the one surface side of the substrate 2. The opening 2 a of the substrate 2 is formed in such a shape that the opening area gradually increases as the distance from the thin film portion 5 in the thickness direction of the substrate 2 increases. The opening 2 a of the substrate 2 is formed by etching the substrate 2. The opening 2a of the substrate 2 can be formed by anisotropic etching using an alkaline solution as an etching solution, for example, when the substrate 2 is a (100) plane single crystal silicon substrate.
　発熱体層３は、外周形状を矩形状としてある。すなわち、発熱体層３は、平面視形状を矩形状としてある。平面形状を矩形状としてあるが、特に矩形状に限定するものではなく、例えば、円形状や多角形状などでもよい。 The heat generating layer 3 has a rectangular outer peripheral shape. That is, the heat generating layer 3 has a rectangular shape in a plan view. Although the planar shape is rectangular, it is not particularly limited to the rectangular, and may be, for example, circular or polygonal.
　薄膜部５は、実施形態１と同様、開孔部２ａと発熱体層３とを隔離するダイヤフラム部５１と、基板２の上記一表面側で開孔部２ａの周部に設けられダイヤフラム部５１を支持する支持部５２と、を備えている。ダイヤフラム部５１は、外周形状が矩形状である。すなわち、赤外線放射素子１は、上述のように開孔部２ａの開口形状を矩形状としてあり、基板２の上記他表面側から見たダイヤフラム部５１の形状が矩形状となっている。 As in the first embodiment, the thin film portion 5 is provided on the peripheral portion of the opening 2 a on the one surface side of the substrate 2, the diaphragm 51 separating the opening 2 a from the heating element layer 3. And a support portion 52 for supporting the The diaphragm portion 51 has a rectangular outer peripheral shape. That is, in the infrared radiation element 1, as described above, the opening shape of the opening 2a is rectangular, and the shape of the diaphragm 51 viewed from the other surface side of the substrate 2 is rectangular.
　発熱体層３は、外周形状を矩形状としてある。すなわち、発熱体層３は、平面視形状を矩形状としてある。発熱体層３の平面視形状は、矩形状に限定するものではなく、例えば、円形状や多角形状などでもよい。赤外線放射素子１は、発熱体層３のうち凹部５３に積層されている部分の表面が、凹部５３の内面５３ａに沿った凹曲面（例えば、回転２次曲面状）の形状となるように、発熱体層３の膜厚を設定することが好ましい。 The heat generating layer 3 has a rectangular outer peripheral shape. That is, the heat generating layer 3 has a rectangular shape in a plan view. The plan view shape of the heat generating layer 3 is not limited to the rectangular shape, and may be, for example, a circular shape or a polygonal shape. In the infrared radiation element 1, the surface of the portion of the heat generating layer 3 stacked in the recess 53 has a concave surface (for example, a rotational quadratic surface) along the inner surface 53 a of the recess 53. It is preferable to set the film thickness of the heating element layer 3.
　以下では、本実施形態の赤外線放射素子１の製造方法の一例について図６Ａ～６Ｅを参照しながら説明する。 Hereinafter, an example of a method of manufacturing the infrared radiation element 1 of the present embodiment will be described with reference to FIGS. 6A to 6E.
　赤外線放射素子１を製造するにあたっては、まず、上記一表面が（１００）面の単結晶のシリコン基板などからなる基板２を準備する（図６Ａ参照）。 In order to manufacture the infrared radiation element 1, first, a substrate 2 made of a single crystal silicon substrate having a (100) plane is prepared (see FIG. 6A).
　基板２を準備した後には、基板２の上記一表面側にダイヤフラム部５１の各凹部５３の各々を形成するための複数の窪み部２３を形成する第１工程を行うことによって、図６Ｂに示す構造を得る。第１工程では、まず、熱酸化法やＣＶＤ法などによって、基板２の上記一表面側に第１のシリコン酸化膜２１を形成するとともに他表面側に第２のシリコン酸化膜２２を形成する。その後には、フォトリソグラフィ技術およびエッチング技術を利用して、第１のシリコン酸化膜２１をパターニングする。その後には、第１のシリコン酸化膜２１および第２のシリコン酸化膜２２をマスクとして、基板２を上記一表面側から等方性エッチングすることで複数の窪み部２３を形成する。 As shown in FIG. 6B, after the substrate 2 is prepared, a first step of forming a plurality of depressions 23 for forming each of the recesses 53 of the diaphragm 51 on the one surface side of the substrate 2 is performed. Get the structure. In the first step, first, the first silicon oxide film 21 is formed on the one surface side of the substrate 2 by the thermal oxidation method, the CVD method or the like, and the second silicon oxide film 22 is formed on the other surface side. Thereafter, the first silicon oxide film 21 is patterned using photolithography technology and etching technology. Thereafter, using the first silicon oxide film 21 and the second silicon oxide film 22 as a mask, the substrate 2 is isotropically etched from the one surface side to form a plurality of depressions 23.
　第１工程の後には、第１のシリコン酸化膜２１および第２のシリコン酸化膜２２をエッチングにより除去した後、基板２の上記一表面側に薄膜部５を形成する第２工程を行うことによって、図６Ｃに示す構造を得る。薄膜部５の形成方法は、例えば、ＣＶＤ法などを採用することができる。 After the first step, the first silicon oxide film 21 and the second silicon oxide film 22 are removed by etching, and then the second step of forming the thin film portion 5 on the one surface side of the substrate 2 is performed. , The structure shown in FIG. 6C is obtained. For example, a CVD method or the like can be employed as a method of forming the thin film portion 5.
　第２工程の後には、薄膜部５上に発熱体層３を形成する第３工程を行う。発熱体層３の形成方法は、スパッタ法や蒸着法やＣＶＤ法などを採用することができる。 After the second step, the third step of forming the heating element layer 3 on the thin film portion 5 is performed. As a method of forming the heat generating body layer 3, a sputtering method, a vapor deposition method, a CVD method or the like can be adopted.
　第３工程の後には、各パッド７を形成した後（図６Ｄ参照）、基板２における開孔部２ａの形成予定領域を基板２の上記他表面側からエッチングすることで複数の凹部５３を備えたダイヤフラム部５１を形成する第４工程を行うことによって、図６Ｅに示す構造の赤外線放射素子１を得る。各パッド７の形成にあたっては、例えば、スパッタ法や蒸着法やＣＶＤ法などの薄膜形成技術と、フォトリソグラフィ技術およびエッチング技術とを利用することができる。また、開孔部２ａの形成にあたっては、例えば、基板２の上記他表面側にシリコン酸化膜とシリコン窒化膜との積層膜（図示せず）からなるマスク材料層をＣＶＤ法などにより形成し、その後、フォトリソグラフィ技術およびエッチング技術を利用してマスク材料層をパターニングすることでマスク層を形成し、その後、基板２を上記他表面側からエッチングすることで開孔部２ａを形成すればよい。基板２の開孔部２ａは、例えば、基板２が（１００）面の単結晶のシリコン基板の場合、アルカリ系溶液をエッチング液として用いた異方性エッチングにより形成すればよい。赤外線放射素子１の製造方法では、開孔部２ａの形成時に、薄膜部５をエッチングストッパ層として利用することにより、薄膜部５の厚さの精度を高めることが可能となるとともに、薄膜部５における開孔部２ａ側に基板２の一部や残渣が残るのを防止することが可能となる。赤外線放射素子１の製造方法では、開孔部２ａの形成時に、薄膜部５をエッチングストッパ層として利用することにより、薄膜部５の厚さの精度を高めることが可能となり、赤外線放射素子１ごとの、薄膜部５の機械的強度のばらつきや、ダイヤフラム部５１の熱容量のばらつきを抑制することが可能となる。 After the third step, after each pad 7 is formed (see FIG. 6D), a plurality of recessed portions 53 are provided by etching the formation planned region of the opening 2a in the substrate 2 from the other surface side of the substrate 2 By performing the fourth step of forming the diaphragm portion 51, the infrared radiation element 1 having the structure shown in FIG. 6E is obtained. In forming each pad 7, for example, a thin film formation technique such as a sputtering method, an evaporation method, a CVD method, etc., and a photolithography technique and an etching technique can be used. Further, in forming the opening 2a, for example, a mask material layer formed of a laminated film (not shown) of a silicon oxide film and a silicon nitride film is formed on the other surface side of the substrate 2 by the CVD method or the like. Thereafter, the mask material layer is patterned using photolithography technology and etching technology to form a mask layer, and then the substrate 2 is etched from the other surface side to form the opening 2a. For example, in the case where the substrate 2 is a (100) plane single crystal silicon substrate, the opening 2a of the substrate 2 may be formed by anisotropic etching using an alkaline solution as an etching solution. In the method of manufacturing the infrared radiation element 1, the thin film portion 5 can be used as an etching stopper layer at the time of forming the opening portion 2 a, so that the thickness accuracy of the thin film portion 5 can be enhanced. It is possible to prevent a part or residue of the substrate 2 from remaining on the side of the opening 2a. In the method of manufacturing the infrared radiation element 1, by using the thin film portion 5 as an etching stopper layer when forming the opening portion 2 a, it becomes possible to increase the accuracy of the thickness of the thin film portion 5. It is possible to suppress the dispersion of the mechanical strength of the thin film portion 5 and the dispersion of the heat capacity of the diaphragm portion 51.
　本実施形態の赤外線放射素子１は、ダイヤフラム部５１が、開孔部２ａ側に窪む複数の凹部５３を備え、各凹部５３の各々の内面５３ａが凹曲面である。そして、赤外線放射素子１は、発熱体層３が各凹部５３の各々の内面５３ａに沿って形成されている。しかして、本実施形態の赤外線放射素子１においては、発熱体層３が各凹部５３の各々の内面５３ａに沿って形成されていることにより、指向性を向上させることが可能である。各凹部５３の各々の内面５３ａを構成する凹曲面は、回転２次曲面状であることが好ましい。これにより、赤外線放射素子１は、正面方向（図５Ｂの上方向）の指向性を向上させることが可能となる。図７は、赤外線放射素子１の動作説明図であり、一対のパッド７、７間に通電したときに発熱体層３から放射される赤外線の放射方向を矢印付きの実線で模式的に示してある。また、図７には、赤外線放射素子１から放射された赤外線が照射される所望の照射部１０を模式的に示してある。この照射部１０は、例えば、赤外線を受光する受光素子などである。 In the infrared radiation element 1 of the present embodiment, the diaphragm portion 51 is provided with a plurality of recessed portions 53 which are recessed toward the opening 2 a side, and the inner surface 53 a of each recessed portion 53 is a concave surface. In the infrared radiation element 1, the heating element layer 3 is formed along the inner surface 53 a of each recess 53. Thus, in the infrared radiation element 1 of the present embodiment, the directivity can be improved by the heating element layer 3 being formed along the inner surface 53 a of each recess 53. It is preferable that the concave surface which comprises each inner surface 53a of each recessed part 53 is rotation quadric surface shape. Thus, the infrared radiation element 1 can improve the directivity in the front direction (the upper direction in FIG. 5B). FIG. 7 is an operation explanatory view of the infrared radiation element 1, schematically showing the radiation direction of infrared radiation emitted from the heating element layer 3 when energized between the pair of pads 7 and 7 by a solid line with an arrow. is there. Further, FIG. 7 schematically shows a desired irradiation unit 10 to which the infrared radiation emitted from the infrared radiation element 1 is emitted. The irradiation unit 10 is, for example, a light receiving element that receives infrared light.
　赤外線放射素子１は、発熱体層３においてダイヤフラム部５１の各凹部５３の各々に積層されている各部分の表面が凹曲面となっている。これにより、赤外線放射素子１は、図４に示した比較例の赤外線放射素子１’のように赤外線が等方的に放射される無指向性のものに比べて、図７に示すように放射する赤外線の指向性を強くすることができる。つまり、赤外線放射素子１では、正面方向（図７の上方向）への指向性が向上し、例えば、図４の比較例と入力電力を同じとし、照射部１０の大きさを同じとした場合、照射部１０への照射効率を向上させることが可能となり、放射された赤外線の損失を低減することが可能となる。ここで、照射部１０が受光素子の場合には、この受光素子の受光効率を向上させることが可能となる。 In the infrared radiation element 1, the surface of each portion of the heating element layer 3 which is stacked in each of the concave portions 53 of the diaphragm portion 51 has a concave curved surface. Thus, the infrared radiation element 1 emits radiation as shown in FIG. 7 as compared to the non-directional one in which the infrared radiation is isotropically emitted like the infrared radiation element 1 ′ of the comparative example shown in FIG. Can make the directivity of infrared rays stronger. That is, in the infrared radiation element 1, the directivity in the front direction (the upper direction in FIG. 7) is improved, for example, when the input power is the same as the comparative example of FIG. 4 and the size of the irradiation unit 10 is the same. It becomes possible to improve the irradiation efficiency to the irradiation part 10, and it becomes possible to reduce the loss of the emitted infrared rays. Here, when the irradiation unit 10 is a light receiving element, it is possible to improve the light receiving efficiency of the light receiving element.
　本実施形態の赤外線放射素子１は、指向性を向上させながらも、図８Ａ、８Ｂに示した従来例のように集光レンズ１３０を備えた赤外線光源１００に比べて、ダイヤフラム部５１を含む積層構造全体の熱容量を低減することが可能となる。よって、赤外線放射素子１は、一対のパッド７、７間へ与える電圧波形に対する発熱体層３の温度変化の応答を速くすることが可能となるから、発熱体層３の温度が上昇しやすくなり、高出力化および応答速度の高速化を図ることが可能となる。 The infrared radiation element 1 of the present embodiment is a laminated including the diaphragm portion 51 as compared with the infrared light source 100 having the condensing lens 130 as in the conventional example shown in FIGS. 8A and 8B while improving the directivity. It is possible to reduce the heat capacity of the entire structure. Therefore, since the infrared radiation element 1 can accelerate the response of the temperature change of the heat generating body layer 3 to the voltage waveform applied between the pair of pads 7, the temperature of the heat generating body layer 3 tends to rise. It is possible to achieve high output and high response speed.
　また、本実施形態の赤外線放射素子１の製造方法によれば、上述の第１工程、第２工程、第３工程および第４工程を備えていることにより、指向性を向上させることが可能であり且つ高出力化が可能な赤外線放射素子１を提供することが可能となる。 Further, according to the method of manufacturing the infrared radiation element 1 of the present embodiment, directivity can be improved by including the above-described first step, second step, third step and fourth step. It is possible to provide an infrared radiation element 1 which is capable of achieving high output.
　なお、各実施形態の赤外線放射素子１は、ガスセンサ用の赤外線源に限らず、例えば、炎検知用の赤外線源、赤外光通信用の赤外線源、分光分析用の赤外線源などに使用することが可能である。 The infrared radiation element 1 of each embodiment is not limited to an infrared source for a gas sensor, and may be used, for example, for an infrared source for flame detection, an infrared source for infrared light communication, an infrared source for spectral analysis, etc. Is possible.

Claims (6)

  1. 　基板と、前記基板の一表面側に設けられた薄膜部と、前記薄膜部における前記基板側とは反対側に設けられた発熱体層と、
    を備え、
    　前記発熱体層への通電により前記発熱体層から赤外線が放射される赤外線放射素子であって、
    　前記基板は、前記薄膜部における前記発熱体層側とは反対側の表面を露出させる開孔部が厚み方向に貫設されてなり、
    　前記薄膜部は、前記開孔部と前記発熱体層とを隔離するダイヤフラム部と、
    　前記基板の前記一表面側で前記開孔部の周部に設けられ前記ダイヤフラム部を支持する支持部と、
    を備え、
    　前記ダイヤフラム部は、前記開孔部側に窪み内面が凹曲面である凹部を備え、
    　前記発熱体層は、少なくとも前記凹部の前記内面に沿って形成されてなる
    　ことを特徴とする赤外線放射素子。     A substrate, a thin film portion provided on one surface side of the substrate, and a heating element layer provided on the thin film portion opposite to the substrate side;
    Equipped with
    It is an infrared rays radiating element by which infrared rays are emitted from the heating element layer by energization to the heating element layer,
    In the substrate, an opening that exposes the surface of the thin film portion on the opposite side to the heating element layer side is provided in the thickness direction.
    The thin film portion is a diaphragm portion that separates the opening portion from the heating element layer;
    A supporting portion provided on a peripheral portion of the opening on the one surface side of the substrate and supporting the diaphragm;
    Equipped with
    The diaphragm portion is provided with a recess on the side of the opening portion, the inner surface of which is a concave surface,
    The infrared ray emitting element, wherein the heating element layer is formed at least along the inner surface of the recess.
  2. 　前記凹曲面は、回転２次曲面状である
    　ことを特徴とする請求項１記載の赤外線放射素子。     The infrared radiation element according to claim 1, wherein the concave surface is in the form of a rotational quadric surface.
  3. 　前記ダイヤフラム部は、複数の前記凹部がアレイ状に設けられてなる
    　ことを特徴とする請求項１又は２記載の赤外線放射素子。     The infrared radiation element according to claim 1 or 2, wherein the diaphragm portion is provided with a plurality of the concave portions in an array.
  4. 　前記ダイヤフラム部は、外周形状が円形状である
    　ことを特徴とする請求項１ないし３のいずれか１項に記載の赤外線放射素子。     The infrared radiation element according to any one of claims 1 to 3, wherein an outer peripheral shape of the diaphragm portion is circular.
  5. 　前記ダイヤフラム部は、外周形状が矩形状である
    　ことを特徴とする請求項１ないし３のいずれか１項に記載の赤外線放射素子。     The infrared radiation element according to any one of claims 1 to 3, wherein an outer peripheral shape of the diaphragm portion is rectangular.
  6. 　請求項１ないし５のいずれか１項に記載の赤外線放射素子の製造方法であって、
    　前記基板の上記一表面側に前記ダイヤフラム部の凹部を形成するための窪み部を形成する第１工程と、
    　前記第１工程の後で前記基板の前記一表面側に薄膜部を形成する第２工程と、
    　前記第２工程の後で前記薄膜部上に前記発熱体層を形成する第３工程と、
    　前記第３工程の後で前記基板における前記開孔部の形成予定領域を前記基板の他表面側からエッチングすることで前記凹部を備えた前記ダイヤフラム部を形成する第４工程と、
    　を備える
    　ことを特徴とする赤外線放射素子の製造方法。     A method of manufacturing an infrared radiation element according to any one of claims 1 to 5, wherein
    A first step of forming a recess for forming a recess of the diaphragm on the one surface side of the substrate;
    Forming a thin film portion on the one surface side of the substrate after the first step;
    A third step of forming the heating element layer on the thin film portion after the second step;
    A fourth step of forming the diaphragm portion provided with the concave portion by etching the formation planned region of the opening in the substrate from the other surface side of the substrate after the third step;
    A method of manufacturing an infrared radiation element comprising:
PCT/JP2013/001051 2012-03-30 2013-02-25 Infrared radiation element and method for manufacturing same WO2013145540A1 (en)

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