WO2013183203A1

WO2013183203A1 - Infrared radiation element

Info

Publication number: WO2013183203A1
Application number: PCT/JP2013/001624
Authority: WO
Inventors: 吉祥永谷; 辻　幸司; 吉原　孝明; 植田　充彦; 桐原　昌男; 弘貴松浪
Original assignee: パナソニック株式会社
Priority date: 2012-06-04
Filing date: 2013-03-12
Publication date: 2013-12-12
Also published as: TWI498038B; TW201401917A; JP5884053B2; JPWO2013183203A1

Abstract

An infrared radiation element relating to the present invention is provided with: a substrate having one surface in the thickness direction; an opening that penetrates the substrate in the thickness direction; a first insulating layer disposed on the one surface of the substrate to cover the opening; a heat generating material layer, which is disposed on the first insulating layer such that the heat generating material layer is positioned inside of the opening within a reference plane parallel to the one surface; a second insulating layer, which is disposed on the first insulating layer such that the heat generating material layer is covered with the second insulating layer; and a current-carrying section, which is disposed on the second insulating layer, and which is electrically connected to the heat generating material layer. The opening has a shape having corners within the reference plane parallel to the one surface. The current-carrying section has a reinforcing portion that overlaps the corners of the opening in the thickness direction.

Description

Infrared radiation element

The present invention relates to an infrared radiation element.

Conventionally, an infrared radiation element manufactured using a manufacturing technology of MEMS (micro-electromechanical systems) has been researched and developed. This type of infrared radiation element can be used as an infrared light source (infrared light source) such as a gas sensor or an optical analyzer.

As this type of infrared radiating element, for example, an infrared radiating element 70 having the structure shown in FIGS. 4 and 5 has been proposed (Document 1 [Japanese Patent Publication No. 11-274553]).

The infrared radiation element 70 includes an element substrate 21 made of n-type silicon. The element substrate 21 is provided with a hole 22 penetrating in a trapezoidal shape from the one surface 21a side to the opposite surface 21b side. The infrared radiation element 70 is formed on the one surface 21 a side of the element substrate 21 so that a band-shaped diaphragm portion 23 made of a p-type semiconductor closes one opening surface of the hole 22. In the infrared radiation element 70, a heat generating portion 74 made of an n-type semiconductor is formed on the surface of the diaphragm portion 23, and first and

second electrodes

55 and 56 made of a metal material are provided at both ends of the surface of the heat generating portion 74. It has been.

In the infrared radiation element 70 described above, when a voltage is applied between the first electrode 55 and the second electrode 56, a current flows through the heat generating portion 74, the heat generating portion 74 generates heat, and emits infrared light.

In the infrared radiation element 70, the one surface 21a side of the element substrate 21 and the surface of the diaphragm part 23 are covered with a silicon oxide film 27 not only for the purpose of surface protection but also for promoting infrared radiation.

In the infrared radiation element 70 described above, the width of the central portion 74a of the heat generating portion 74 is widened, and the widths of both

end portions

74b and 74c are narrowed. Thereby, in the infrared radiation element 70, the region of the high temperature portion where the temperature is relatively high in the heat generating portion 74 is widened, and the infrared radiation density is increased.

By the way, when using an infrared radiation element as an infrared light source for a spectroscopic gas sensor, for example, the infrared radiation element is intermittently driven to emit infrared light intermittently, and the output of the light receiving element for detecting the infrared light is locked. It is known that the S / N ratio of the output of the gas sensor can be improved by amplifying with an in-amplifier.

Further, in the above-described infrared radiation element 70, stress is likely to be concentrated on the corner portion of the rectangular region overlapping the one opening surface of the hole 22 in the diaphragm portion 23 due to the thermal stress generated during operation. For this reason, in the infrared radiating element 70, when the output is increased or the chopping speed for intermittently emitting infrared rays is increased, the diaphragm 23 starts from the corner of the rectangular region of the diaphragm 23 as a starting point. There is a concern that it will break.

Further, in the above-described infrared radiation element 70, the diaphragm portion 23 is formed by ion-implanting boron into the one surface 21a side of the element substrate 21 for annealing. For this reason, in the infrared radiation element 70, it is assumed that the thermal conductivity of the diaphragm part 23 is equivalent to the thermal conductivity of the element substrate 21, the thermal resistance of the diaphragm part 23 is small, and it is difficult to further increase the output. It is inferred.

The present invention has been made in view of the above reasons, and an object of the present invention is to provide an infrared radiation element capable of increasing the output and improving the reliability. is there.

The infrared radiation element of the 1st form which concerns on this invention is equipped with a board | substrate, an opening part, a 1st insulating layer, a heat generating body layer, a 2nd insulating layer, and an electricity supply part. The substrate has one surface orthogonal to the thickness direction. The opening penetrates the substrate in the thickness direction. The first insulating layer is disposed on the one surface of the substrate so as to cover the opening. The heating element layer is disposed on the opposite side of the first insulating layer from the substrate so as to be positioned inside the opening with a reference plane parallel to the one surface. The second insulating layer is disposed on the opposite side of the first insulating layer from the substrate so as to cover the heating element layer. The energization portion is disposed on the opposite side of the second insulating layer from the substrate and is electrically connected to the heating element layer. The opening has a shape having an angle in a reference plane parallel to the one surface. The energizing part has a reinforcing part that overlaps the corner of the opening in the thickness direction.

In the infrared radiation element of the second form according to the present invention, in the first form, the first insulating layer, the second insulating layer, and the heating element layer have a tensile stress as a whole.

In the infrared radiating element according to the third aspect of the present invention, in the first or second aspect, the energizing section includes an electrode and a wiring. The electrode is disposed on the substrate so as to be located outside the opening in the reference plane. The wiring electrically connects the electrode to the heating element layer.

In the fourth aspect of the infrared radiation element according to the present invention, in the third aspect, the opening is rectangular or square having the four corners. The energization part has the four reinforcing parts respectively corresponding to the four corners.

In the infrared radiation element of the 5th form which concerns on this invention, in the 4th form, the said electricity supply part has four said wiring. Each of the four wirings includes four corresponding reinforcing portions.

In the sixth aspect of the infrared radiation element according to the present invention, in the fifth aspect, the electrode includes a first electrode and a second electrode. The first electrode and the second electrode are disposed on both sides of the opening in a predetermined direction along one side of the opening in the reference plane. The first electrode is connected to the wiring corresponding to two corners close to the first electrode among the four corners. The second electrode is connected to the wiring corresponding to two corners close to the second electrode among the four corners.

In an infrared radiation element according to a seventh aspect of the present invention, in the sixth aspect, the wiring has an end connected to the electrode. The end portion becomes wider as it gets closer to the electrode. The end portion is the reinforcing portion.

In the infrared radiation element of the 8th form which concerns on this invention, in the 7th form, the said edge part has the concave surface.

In the infrared radiating element according to the ninth aspect of the present invention, in any one of the fifth to eighth aspects, the heating element layer has a rectangular or square shape having four second corners on the reference plane. It is. The heating element layer has four sides parallel to the four sides of the opening on the reference plane. Each of the four wirings is formed in a straight line passing through the second corner of the heating element layer and the corner of the opening closest to the second corner on the reference plane.

In the infrared emitter of the tenth aspect according to the present invention, in the fourth aspect, the opening is rectangular or square having four corners. The electrode includes a first electrode and a second electrode. The first electrode and the second electrode are disposed on both sides of the opening in a predetermined direction along one side of the opening on the reference plane. The first electrode includes the reinforcing portions respectively corresponding to two corners close to the first electrode among the four corners. The second electrode includes the reinforcing portions respectively corresponding to two corners close to the second electrode among the four corners.

In the eleventh aspect of the infrared radiation element according to the present invention, in any one of the third to tenth aspects, the wiring is formed of a high melting point material.

In the infrared radiation element of the twelfth aspect according to the present invention, in the eleventh aspect, the heating element layer is formed of a material having a melting point higher than that of the high melting point material.

In the thirteenth aspect of the infrared radiation element according to the present invention, in the twelfth aspect, the wiring is made of tantalum. The heating element layer is formed of tantalum nitride.

In an infrared radiation element according to a fourteenth aspect of the present invention, in any one of the first to thirteenth aspects, the first insulating layer and the second insulating layer have thermal insulation and electrical insulation. . The heating element layer is configured to emit infrared rays when energized. The first insulating layer, the heating element layer, and the second insulating layer constitute a thin film structure. The thin film structure portion includes a diaphragm portion disposed on the opening, and a support portion disposed on the substrate and connected to the diaphragm portion.

(A) is a schematic plan view of the infrared radiation element of Embodiment 1, and (b) is a sectional view taken along line AA of (a). (A) is a schematic plan view of the infrared radiation element of Embodiment 2, (b) is a sectional view taken along line BB of (a). (A) is a schematic plan view of the infrared radiation element of Embodiment 3, (b) is a sectional view taken along the line CC of (a). It is a top view of the infrared rays radiating element of a prior art example. FIG. 5 is a cross-sectional view taken along the line GG in FIG. 4.

(Embodiment 1)
Below, the infrared radiation element 1 of this embodiment is demonstrated based on FIG.

The infrared radiation element 1 is formed on a substrate 2 and one surface (upper surface in FIG. 1B) 2b side of the substrate 2, and a laminated structure of a first insulating layer 3, a heating element layer 4, and a second insulating layer 5. And a thin film structure portion 6 having

The thin film structure 6 is laminated in the order of the first insulating layer 3, the heating element layer 4, and the second insulating layer 5 from the side close to the substrate 2.

In addition, the infrared radiation element 1 includes a pair of electrodes 9 (9A) that are penetrated in the thickness direction of the substrate 2 and have a rectangular opening shape (opening portion) 2a and electrically connected to the heating element layer 4. , 9 (9B) and wirings 8 (81 to 84) for electrically connecting each of the electrodes 9 and the heating element layer 4 to each other.

Further, in the infrared radiation element 1, the thin film structure portion 6 includes a rectangular diaphragm portion 6D facing the opening 2a and a frame-shaped support portion 6S surrounding the diaphragm portion 6D.

The diaphragm portion 6D has a laminated structure of the first insulating layer 3, the heating element layer 4, and the second insulating layer 5 in the central portion. The peripheral part of the diaphragm part 6 </ b> D and the support part 6 </ b> S have a laminated structure of the first insulating layer 3 and the second insulating layer 5.

That is, the first insulating layer 3, the heating element layer 4, and the second insulating layer 5 constitute a thin film structure portion 6. The thin film structure portion 6 includes a diaphragm portion 6D disposed on the opening 2a and a support portion 6S disposed on the substrate 2 and connected to the diaphragm portion 6D.

In addition, in the infrared radiation element 1, each electrode 9 is disposed on the support portion 6S, and an energization portion 11 including each wiring 8 and each electrode 9 is placed on each corner portion 60 (61 to 64) of the diaphragm portion 6D. Passing through.

The infrared radiation element 1 emits infrared rays from the heating element layer 4 by energizing the heating element layer 4.

Hereinafter, each component of the infrared radiation element 1 will be described in detail.

The substrate 2 has one surface (upper surface in FIG. 1 (b)) 2b and another surface (lower surface in FIG. 1 (b)) 2c which are both surfaces orthogonal to the thickness direction (vertical direction in FIG. 1 (b)). For example, the one surface 2b and the other surface 2c are flat surfaces. The substrate 2 is formed of a single crystal silicon substrate having a (100) plane on one surface 2b, but is not limited thereto, and may be formed of a single crystal silicon substrate having a (110) plane. The substrate 2 is not limited to a single crystal silicon substrate, but may be a polycrystalline silicon substrate or other than a silicon substrate. The material of the substrate 2 is preferably a material having a higher thermal conductivity and a larger heat capacity than the material of the first insulating layer 3.

The outer peripheral shape of the substrate 2 is rectangular. Although the external size of the board | substrate 2 is not specifically limited, For example, it is preferable to set to 10 mm □ or less (10 mm × 10 mm or less).

The opening 2a is formed so as to penetrate the substrate 2 in the thickness direction. The opening 2 a has a shape having an angle 20 in a reference plane parallel to the one surface 2 b of the substrate 2. For example, the opening 2a is rectangular or square having four corners 20 (21 to 24). In particular, in the present embodiment, the substrate 2 has a rectangular opening 2a.

The thin film structure 6 is formed on the one surface 2b of the substrate 2 so as to cover the opening 2a. Therefore, the four corners 60 (61 to 64) of the diaphragm 6D overlap with the corners 20 (21 to 24) of the opening 2a in the diaphragm 6D in the thickness direction (vertical direction in FIG. 1B). It is a part.

The opening 2a of the substrate 2 is formed in such a shape that the opening area on the other surface 2c side (the lower side in FIG. 1B) is larger than the one surface 2b side. Here, the opening 2 a of the substrate 2 is formed in a shape in which the opening area gradually increases as the distance from the first insulating layer 3 of the thin film structure 6 increases. The opening 2 a of the substrate 2 is formed by etching the substrate 2.

When a single crystal silicon substrate having one surface 2b of (100) is used as the substrate 2, the opening 2a of the substrate 2 may be formed by anisotropic etching using an alkaline solution as an etchant. it can.

In addition, in the infrared radiation element 1, when the mask layer for forming the opening 2a is made of an inorganic material at the time of manufacture, the mask layer may remain on the other surface 2c side of the substrate 2. As the mask layer, for example, a laminated film of a silicon oxide film and a silicon nitride film can be employed.

The first insulating layer 3 has thermal insulation and electrical insulation. The first insulating layer 3 is disposed on the one surface 2b of the substrate 2 so as to cover the opening 2a. The first insulating layer 3 is made of, for example, a silicon oxide film on the substrate 2 side and a silicon nitride film laminated on the opposite side of the silicon oxide film from the substrate 2 side.

The first insulating layer 3 preferably has a tensile stress (residual tensile stress). In other words, the first insulating layer 3 preferably has no compressive stress (residual compressive stress). Therefore, the first insulating layer 3 is formed to have a tensile stress. Note that a method for forming an insulating layer having a tensile stress is well known, and thus description thereof is omitted.

In particular, the first insulating layer 3, the second insulating layer 5, and the heating element layer 4 preferably have a tensile stress (residual tensile stress) as a whole. That is, it is preferable that the site | part comprised by the 1st insulating layer 3, the 2nd insulating layer 5, and the heat generating body layer 4 has a tensile stress.

For example, the first insulating layer 3, the second insulating layer 5, and the heating element layer 4 may each have a tensile stress. Note that it is not necessary for all of the first insulating layer 3, the second insulating layer 5, and the heating element layer 4 to have tensile stress. That is, any of the first insulating layer 3, the second insulating layer 5, and the heating element layer 4 can be used as long as the first insulating layer 3, the second insulating layer 5, and the heating element layer 4 have tensile stress as a whole. May have compressive stress or may not have compressive stress or tensile stress.

For example, even if the first insulating layer 3 has tensile stress, the second insulating layer 5 has no stress, and the heating element layer 4 has compressive stress, It is only necessary that the insulating layer 5 and the heating element layer 4 have a tensile stress as a whole.

The first insulating layer 3 is not limited to a laminated film of a silicon oxide film and a silicon nitride film, and may be a single layer structure of a silicon oxide film or a silicon nitride film, a single layer structure made of other materials, 2 A laminated structure of more than one layer may be used.

The first insulating layer 3 also has a function as an etching stopper layer when the opening 2a is formed by etching the substrate 2 from the other surface 2c side of the substrate 2 when the infrared radiation element 1 is manufactured.

The heating element layer 4 is configured to emit infrared rays when energized. The heating element layer 4 is on the opposite side of the first insulating layer 3 from the substrate 2 (upper side in FIG. 1B) so as to be positioned inside the opening 2a with a reference plane parallel to the one surface 2b of the substrate 2. Be placed. For example, the heating element layer 4 is disposed in the central portion of the opening 2a on the reference plane.

For example, the heating element layer 4 has a rectangular shape or a square shape having four corners (second corners) 40 (41 to 44) on the reference plane. The heating element layer 4 has four sides parallel to the four sides of the opening 2a on the reference plane. In the present embodiment, the heating element layer 4 has a rectangular planar shape.

The planar size of the heating element layer 4 is set smaller than the planar size of the surface of the first insulating layer 3 facing the opening 2a. That is, the planar size of the heating element layer 4 is set smaller than the planar size of the diaphragm portion 6D. Here, the planar size of the diaphragm portion 6D is not particularly limited, but is preferably set to 5 mm □ or less, for example.

The planar size of the heating element layer 4 is a radiation area excluding the contact area 4b that is interposed between the end portion (one end) 8a of the wiring 8 and the heating element layer 4 and that overlaps the contact portion 7 that electrically connects them. The plane size of 4a is preferably set to be 3 mm □ or less.

The material of the heating element layer 4 is tantalum nitride. That is, the heating element layer 4 is made of a tantalum nitride layer. The material of the heating element layer 4 is not limited to tantalum nitride, 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, and the like may be employed.

Further, as the material of the heating element layer 4, conductive polysilicon may be adopted. That is, the heating element layer 4 may be composed of a conductive polysilicon layer. The heating element layer 4 is preferably a tantalum nitride layer or a conductive polysilicon layer from the viewpoint of chemical stability at high temperatures and ease of design of sheet resistance.

The sheet resistance of the tantalum nitride layer can be changed by changing its composition.

The sheet resistance of the conductive polysilicon layer can be changed by changing the impurity concentration. The conductive polysilicon layer can be composed of an n-type polysilicon layer or a p-type polysilicon layer doped with an n-type impurity or a p-type impurity at a high concentration.

When the conductive polysilicon layer is an n-type polysilicon layer and phosphorus is used as the n-type impurity, the impurity concentration is, for example, in the range of about 1 × 10 ¹⁸ cm ⁻³ to 5 × 10 ²⁰ cm ^−3. What is necessary is just to set suitably.

Also, when the conductive polysilicon layer is a p-type polysilicon layer and boron is used as the p-type impurity, the impurity concentration is in the range of about 1 × 10 ¹⁸ cm ⁻³ to 1 × 10 ²⁰ cm ^−3. What is necessary is just to set suitably.

In addition, about the material of the heat generating body layer 4, from a viewpoint of preventing that the heat generating body layer 4 is destroyed by the thermal stress accompanying the linear expansion coefficient difference of the board | substrate 2 and the heat generating body layer 4, it is the board | substrate 2. A material having a small difference in linear expansion coefficient from the above material is preferable.

The peak wavelength λ of infrared rays emitted from the heating element layer 4 in the infrared radiation element 1 depends on the temperature of the heating element layer 4. Here, if the absolute temperature of the heating element layer 4 is T [K] and the peak wavelength is λ [μm], the peak wavelength λ is λ = 2898 / T, and the absolute temperature T of the heating element layer 4 and the heating element The relationship with the peak wavelength λ of infrared rays emitted from the layer 4 satisfies the Vienna displacement law. In short, in the infrared radiation element 1, the heating element layer 4 forms a black body. As a result, the infrared radiation element 1 is estimated that the total energy E radiated per unit time of the unit area of the heating element layer 4 is approximately proportional to T4 (that is, it is assumed that the Stefan-Boltzmann law is satisfied). )

The infrared radiation element 1 can change Joule heat generated in the heating element layer 4 by adjusting input power applied between the pair of

electrodes

9 and 9 from an external power source (not shown), for example. The temperature of can be changed. Therefore, the infrared radiation element 1 can change the temperature of the heating element layer 4 in accordance with the input power to the heating element layer 4, and can change the temperature of the heating element layer 4 from the heating element layer 4. The peak wavelength λ of the emitted infrared light can be changed.

Further, in the infrared radiation element 1 of the present embodiment, the amount of infrared radiation can be increased as the temperature of the heating element layer 4 is increased. For this reason, the infrared radiation element 1 can be used as a high-power infrared light source in a wide infrared wavelength range. For example, when the infrared radiation element 1 is used as an infrared light source of a gas sensor, a gas sensor is designed to transmit a plurality of infrared rays having different wavelengths by designing an optical filter of a detector that receives infrared rays so that a plurality of types of gases can be used. Can be detected.

The second insulating layer 5 has thermal insulation and electrical insulation. The second insulating layer 5 is disposed so as to cover the heating element layer 4 on the opposite side of the first insulating layer 3 from the substrate 2 (upper side in FIG. 1B). The second insulating layer 5 is made of, for example, a silicon nitride film. The second insulating layer 5 is not limited to this. For example, the second insulating layer 5 may be formed of a silicon oxide film, or may have a stacked structure of a silicon oxide film and a silicon nitride film. The second insulating layer 5 preferably has a high transmittance with respect to infrared rays of a desired wavelength or wavelength range radiated from the heating element layer 4 when the heating element layer 4 is energized, but it is essential that the transmittance is 100%. It is not something to do.

Incidentally, the heating element layer 4 has a sheet resistance set so as to suppress a decrease in infrared emissivity due to impedance mismatch with a gas (for example, air, nitrogen gas, etc.) with which the second insulating layer 5 is in contact. Is preferred.

For example, when tantalum nitride is employed as the material of the heating element layer 4, the sheet resistance of the heating element layer 4 is determined by the nitrogen gas used when the tantalum nitride layer that forms the basis of the heating element layer 4 is formed by reactive sputtering. It is possible to control by partial pressure. In short, when the infrared radiation element 1 employs tantalum nitride as the material of the heating element layer 4, the sheet resistance of the heating element layer 4 can be changed by changing the composition of the tantalum nitride layer.

In addition, when the infrared radiation element 1 employs conductive polysilicon as the material of the heating element layer 4, the heating element layer 4 can be changed by changing the impurity concentration of the conductive polysilicon layer that is the basis of the heating element layer 4. It is possible to change the sheet resistance. As a method of controlling the impurity concentration of the conductive polysilicon layer, there are a method of doping impurities after forming a non-doped polysilicon layer, a method of doping impurities during film formation, and the like.

In the environment where the second insulating layer 5 is in contact with air, which is a gas, the infrared radiation element 1 has an infrared emissivity by impedance matching with air if the sheet resistance is 189 Ω / □ (189 Ω / sq.). The maximum (50%) can be achieved.

Therefore, in order to suppress a decrease in emissivity and ensure emissivity of, for example, 40% or more, the sheet resistance of the heating element layer 4 may be set in the range of 73 to 493 Ω / □. If the sheet resistance at which the emissivity is maximized at a desired use temperature is referred to as a prescribed sheet resistance, the sheet resistance of the heating element layer 4 at the desired use temperature is within a range of the prescribed sheet resistance ± 10%. It is more preferable to set.

Further, the infrared radiation element 1 takes into account the stress balance of the sandwich structure composed of the first insulating layer 3, the heating element layer 4 and the second insulating layer 5, and the first insulating layer 3 and the second insulating layer 5. It is preferable to set each material and thickness. Thereby, the infrared radiation element 1 can improve the stress balance of the above-described sandwich structure, and can further suppress the warpage and breakage of the sandwich structure, thereby further improving the mechanical strength. Can be achieved.

The thickness of the heating element layer 4 is preferably 0.2 μm or less from the viewpoint of reducing the heat capacity of the heating element layer 4.

The total thickness of the thickness of the first insulating layer 3, the thickness of the heating element layer 4, and the thickness of the second insulating layer 5 is the laminated structure of the first insulating layer 3, the heating element layer 4, and the second insulating layer 5. From the viewpoint of reducing the heat capacity, for example, it is preferably set in the range of about 0.1 μm to 1 μm, more preferably 0.7 μm or less.

The infrared radiation element 1 further includes a contact portion 7 formed on the heating element layer 4 on the side opposite to the first insulating layer 3 (upper side in FIG. 1B). In particular, in the present embodiment, a pair of contact portions 7 is formed. The pair of contact portions 7 (7A) and 7 (7B) are formed on the one surface 2b side of the substrate 2 so as to be in contact with the peripheral portion of the heating element layer 4 (both left and right end portions in FIG. 1A). Yes. Each contact portion 7 is formed on the heating element layer 4 through a contact hole 5 a formed in the second insulating layer 5, and is electrically connected to the heating element layer 4. Here, each contact portion 7 is in ohmic contact with the heating element layer 4. That is, the contact portion 7 is formed so as to be in ohmic contact with the heating element layer 4.

In the infrared radiation element 1, the planar shape of the heating element layer 4 is rectangular, and the planar shape of the pair of

contact portions

7, 7 is a band-shaped shape along each of two parallel sides of the heating element layer 4. is there. More specifically, in the infrared radiation element 1, the planar shape of the pair of

contact portions

7, 7 is a band shape along each side orthogonal to the direction in which the pair of

electrodes

9, 9 are arranged.

As the material of each contact portion 7, a high melting point material is preferably used as will be described later. For example, the contact portion 7 is made of tantalum. The material of the contact portion 7 does not necessarily need to be a high melting point material, and may be aluminum or an aluminum alloy (for example, Al—Si, Al—Cu). The material of each contact part 7 is not specifically limited, For example, gold | metal | money, copper, etc. may be employ | adopted. Moreover, each contact part 7 should just be a material in which at least the part which contact | connects the heat generating body layer 4 can make ohmic contact with the heat generating body layer 4, and not only a single layer structure but a multilayered structure may be sufficient as it. For example, each contact portion 7 has a first layer in contact with the heating element layer 4 in the thickness direction as a three-layer structure in which a first layer, a second layer, and a third layer are stacked in order from the heating element layer 4 side. The material of the layer may be a refractory metal (such as chromium), the material of the second layer may be nickel, and the material of the third layer may be gold.

The electrode 9 includes a first electrode 9 (9A) and a second electrode 9 (9B). Each electrode 9 (9A, 9B) is arranged on the support portion 6S as described above. That is, the electrode 9 is disposed on the substrate 2 so as to be located outside the opening 2a on the reference plane. That is, the electrode 9 is disposed on the substrate 2 in a region that does not overlap with the opening 2a in the thickness direction (a region that overlaps with the support 6S and does not overlap with the diaphragm 6D).

The first electrode 9A and the second electrode 9B are arranged on both sides of the opening 2a in a predetermined direction along the one side of the opening 2a in the reference plane (the left-right direction in FIG. 1A). Each electrode 9 is formed in a strip shape (rectangular shape) having a longitudinal direction in a direction orthogonal to the direction in which both electrodes 9 are arranged in plan view. Each electrode 9 has a length dimension so as to cross two diagonal extensions of the diaphragm portion 6D.

The wiring 8 is formed so as to electrically connect the electrode 9 to the heating element layer 4. Two wirings 8 are provided between the heating element layer 4 and each electrode 9. That is, the energization unit 11 includes four wirings 8 (81 to 84). Each of the four wirings 8 is formed in a straight line passing through the second corner 40 of the heating element layer 4 and the corner (first corner) 20 of the opening 2a closest to the second corner 40 on the reference plane. . That is, the

wirings

81, 82, 83, 84 are respectively connected to the

second corners

41, 42, 43, 44 of the heating element layer 4 and the corner 21 of the opening 2 a closest to the

second corners

41, 41, 42, 43. , 22, 23, 24. In the present embodiment, the opening 2a and the heating element layer 4 have a similar shape, and the center positions are equal to each other. Therefore, the wiring 8 is arrange | positioned along the diagonal of diaphragm part 6D.

Each wiring 8 has one end (first end) 8a in the longitudinal direction connected to the contact portion 7 and the other end (second end) 8b connected to the electrode 9. That is, the wiring 8 is electrically connected to the heating element layer 4 through the contact portion 7.

The line width (width dimension) of the wiring 8 is constant. For example, the first end 8a of the wiring 81 is one end of the contact portion 7A (the upper end in FIG. 1A), and the first end 8a of the wiring 82 is the other end of the contact portion 7A (the lower end in FIG. 1A). ), Respectively. The first end 8a of the wiring 83 is at one end of the contact portion 7B (upper end in FIG. 1A), and the first end 8a of the wiring 84 is at the other end of the contact portion 7B (lower end in FIG. 1A). , Each connected.

As shown in FIG. 1A, the first electrode 9A is connected to wirings 81 and 82 corresponding to two

corners

21 and 22 close to the first electrode 9A among the four corners 20, respectively. The second electrode 9B is connected to the

wirings

83 and 84 corresponding to the two

corners

23 and 24 close to the second electrode 9B among the four corners 20, respectively. The wiring 8 corresponding to the corner 20 is defined as a wiring 8 passing over the corner 20 (wiring 8 overlapping the corner 20 in the thickness direction).

In the infrared radiation element 1 of the present embodiment, the energization section 11 composed of the wiring 8 and the electrode 9 passes over each corner of the diaphragm section 6D. Here, in the infrared radiation element 1 of the present embodiment, the other end portions (second end portions) 8b of the four wires 8 (81 to 84) extend over the four corner portions 60 (61 to 64) of the diaphragm portion 6D. Passing through.

As described above, the infrared radiation element 1 of the present embodiment is disposed on the opposite side of the second insulating layer 5 from the substrate 2 (upper side in FIG. 1B) and is electrically connected to the heating element layer 4. The unit 11 is provided. In the present embodiment, the second end portion 8b of the wiring 8 serves as a reinforcing portion that overlaps the corner 20 of the opening 2a (that is, the corner portion 60 of the diaphragm portion 6D) in the thickness direction. That is, the four wirings 8 each include four corresponding reinforcing portions (second end portions 8b). Accordingly, the energizing portion 11 has four reinforcing portions (second end portions 8b) respectively corresponding to the four corners 20 (21, 22, 23, 24).

Each wiring 8 and each electrode 9 are preferably made of the same material as each contact portion 7 and set to the same layer structure and the same thickness. Thereby, the infrared radiation element 1 can form each wiring 8 and each electrode 9 simultaneously with each contact part 7.

Each electrode 9 constitutes a pad. Therefore, the thickness of the electrode 9 is preferably set in the range of about 0.5 to 2 μm.

In manufacturing the infrared radiation element 1, for example, the first insulating layer 3, the heating element layer 4, and the second insulating layer 5 are sequentially formed on the one surface 2 b side of the substrate 2, and then the second insulating layer 5 is formed. The contact hole 5a is formed, then each contact portion 7, each wiring 8 and each electrode 9 are formed, and then the opening 2a is formed in the substrate 2.

As a method for forming the silicon oxide film of the first insulating layer 3, for example, a thin film forming technique such as a thermal oxidation method or a CVD (Chemical Vapor Deposition) method can be employed, and a thermal oxidation method is preferable. Further, as a method for forming the silicon nitride film of the first insulating layer 3, a thin film forming technique such as a CVD method can be used, and an LPCVD (Low Pressure Chemical Vapor Deposition) method is preferable.

As a method for forming the heating element layer 4, for example, a thin film forming technique such as a sputtering method, a vapor deposition method, or a CVD method, and a processing technique using a photolithography technique and an etching technique can be used.

As a method for forming the second insulating layer 5, for example, a thin film forming technique such as a CVD method and a processing technique using a photolithography technique and an etching technique can be used. As a CVD method for forming the second insulating layer 5, a plasma CVD method is preferable.

In forming the contact hole 5a, a photolithography technique and an etching technique may be used.

In forming each contact portion 7, each wiring 8, and each electrode 9, for example, thin film formation technology such as sputtering, vapor deposition, and CVD, and processing technology using photolithography technology and etching technology are used. can do.

In forming the opening 2a, the substrate 2 is etched from the other surface 2c side using a laminated film (not shown) of a silicon oxide film and a silicon nitride film on the other surface 2c side of the substrate 2 as a mask layer. May be formed.

In forming the mask layer, for example, first, a silicon oxide film serving as a base of the mask layer is formed on the other surface 2c side of the substrate 2 simultaneously with the formation of the silicon oxide film of the first insulating layer 3, and the first insulating layer is formed. The silicon nitride film is formed on the other surface 2c side of the substrate 2 simultaneously with the formation of the silicon nitride film 3. The patterning of the laminated film of the silicon oxide film and the silicon nitride film that is the basis of the mask layer may be performed using a photolithography technique and an etching technique.

In the manufacturing method of the infrared radiation element 1 of the present embodiment, it is possible to increase the accuracy of the thickness of the first insulating layer 3 by using the first insulating layer 3 as an etching stopper layer when forming the opening 2a. In addition, it is possible to prevent a part of the substrate 2 and residues from remaining on the opening 2a side of the first insulating layer 3. In this manufacturing method, it is possible to suppress variations in mechanical strength of the first insulating layer 3 and variations in the heat capacity of the entire diaphragm portion 6D of the first insulating layer 3 for each infrared radiation element 1.

In manufacturing the infrared radiation element 1 described above, the process until the formation of the opening 2a is completed at the wafer level, and after forming the opening 2a, the individual infrared radiation elements 1 may be separated. That is, in manufacturing the infrared radiation element 1, for example, a silicon wafer as a base of the substrate 2 is prepared, and a plurality of infrared detection elements 1 are formed on the silicon wafer according to the above-described manufacturing method. What is necessary is just to isolate | separate to the detection element 1. FIG.

As can be seen from the method for manufacturing the infrared radiating element 1 described above, the infrared radiating element 1 can be manufactured by using a MEMS manufacturing technique.

As described above, the infrared radiation element 1 of the present embodiment includes the substrate 2, the thin film structure 6 having the heating element layer 4, and the opening 2 a penetrating in the thickness direction of the substrate 2 and having a rectangular opening shape. A pair of

electrodes

9 and 9 electrically connected to the heating element layer 4 and a wiring 8 electrically connecting each of the electrodes 9 and the heating element layer 4 are provided. And the thin film structure part 6 is provided with the rectangular-shaped diaphragm part 6D which faces the opening part 2a, and the frame-shaped support part 6S surrounding the diaphragm part 6D. Further, in the infrared radiation element 1, the diaphragm portion 6D has a laminated structure of the first insulating layer 3, the heating element layer 4, and the second insulating layer 5 in the central portion, and the peripheral portion of the diaphragm portion 6D and the support portion 6S. Has a laminated structure of the first insulating layer 3 and the second insulating layer 5, each electrode 9 is disposed on the support portion 6S, and the energizing portion composed of each wiring 8 and each electrode 9 is a diaphragm portion. It passes over each corner of 6D.

In other words, the infrared radiation element 1 of the present embodiment has the following first feature. In the first feature, the infrared radiation element 1 includes a substrate 2, an opening 2 a, a first insulating layer 3, a heating element layer 4, a second insulating layer 5, and a current-carrying unit 11. The substrate 2 has one surface 2b orthogonal to the thickness direction (vertical direction in FIG. 1B). The opening 2a penetrates the substrate 2 in the thickness direction (vertical direction in FIG. 1B). The first insulating layer 3 is disposed on the one surface 2b of the substrate 2 so as to cover the opening 2a. The heating element layer 4 is on the opposite side of the first insulating layer 3 from the substrate 2 (upper side in FIG. 1B) so as to be positioned inside the opening 2a with a reference plane parallel to the one surface 2b of the substrate 2. Be placed. The second insulating layer 5 is disposed so as to cover the heating element layer 4 on the opposite side of the first insulating layer 3 from the substrate 2. The energizing portion 11 is disposed on the opposite side of the second insulating layer 5 from the substrate 2 and is electrically connected to the heating element layer 4. The opening 2a has a shape having an angle (first angle) 20 in a reference plane parallel to the one surface 2b. The energizing portion 11 has a reinforcing portion (in the present embodiment, the second end portion 8b of the wiring 8) that overlaps the corner 20 of the opening 2a in the thickness direction.

In addition to the first feature, the infrared radiation element 1 of the present embodiment has the following second to tenth features. The following second to tenth features are arbitrary features.

In the second feature, in the first feature, the first insulating layer 3, the heating element layer 4, and the second insulating layer 5 have a tensile stress as a whole.

In the third feature, in the first feature or the second feature, the energization unit 11 includes the electrode 9 and the wiring 8. The electrode 9 is disposed on the substrate 2 so as to be positioned outside the opening 2a on the reference plane. The wiring 8 electrically connects the electrode 9 to the heating element layer 4.

In the fourth feature, in the third feature, the opening 2a is rectangular or square having four corners 20 (21 to 24). The energizing portion 11 has four reinforcing portions (second end portions 8b of the wirings 81 to 84 in this embodiment) corresponding to the four corners 21 to 24, respectively.

In the fifth feature, in the fourth feature, the energizing section 11 has four wires 8 (81 to 84). The four wirings 81 to 84 each include four corresponding reinforcing portions (in the present embodiment, the second end portion 8b).

In the sixth feature, in the fifth feature, the electrode 9 includes a first electrode 9 (9A) and a second electrode 9 (9B). The first electrode 9A and the second electrode 9B are arranged on both sides of the opening 2a in a predetermined direction along the one side of the opening 2a in the reference plane (the left-right direction in FIG. 1A). The first electrode 9A is connected to wirings 81 and 82 corresponding to the two

corners

wirings

83 and 84 corresponding to the two

corners

23 and 24 close to the second electrode 9B among the four corners 20, respectively.

In the seventh feature, in the fifth or sixth feature, the heating element layer 4 is rectangular or square having four corners (second corners) 40 (41 to 44) on the reference plane. The heating element layer 4 has four sides parallel to the four sides of the opening 2a on the reference plane. Each of the four wirings 8 (81 to 84) is formed in a straight line passing through the second corner 40 of the heating element layer 4 and the corner 20 of the opening 2a closest to the second corner 40 on the reference plane. .

In the eighth feature, in any one of the first to seventh features, the wiring 8 is formed of a high melting point material.

In the ninth feature, in the eighth feature, the heating element layer 4 is formed of a material having a melting point higher than that of the high melting point material.

In the tenth feature, in the ninth feature, the wiring 8 is made of tantalum. The heating element layer 4 is formed of tantalum nitride.

In the eleventh feature, in any one of the first to tenth features, the first insulating layer 3 and the second insulating layer 5 have thermal insulation and electrical insulation. The heating element layer 4 is configured to emit infrared rays when energized. The first insulating layer 3, the heating element layer 4, and the second insulating layer 5 constitute a thin film structure portion 6. The thin film structure portion 6 includes a diaphragm portion 6D disposed on the opening 2a and a support portion 6S disposed on the substrate 2 and connected to the diaphragm portion 6D.

Thus, the infrared radiation element 1 according to the present embodiment has the heat generating layer 4 formed on the first insulating layer 3, so that the thermal insulation can be enhanced and the output can be increased. In addition, since the current-carrying part passes over each corner of the diaphragm part 6D, the diaphragm part 6D is reinforced by the current-carrying part, and the reliability can be improved. That is, in the infrared radiation element 1 of the present embodiment, it is possible to increase the output and to improve the reliability.

In addition, since the infrared radiation element 1 can reinforce the diaphragm portion 6D with the energizing portion 11, it is not necessary to separately form a reinforcing film in order to reinforce the diaphragm portion 6D, and the cost can be reduced. It becomes.

Further, the two wirings 8 that connect the electrode 7 and the pad 9 are respectively connected to both ends of the heating element layer 4 in a direction orthogonal to the direction in which the pair of

pads

9 and 9 are arranged in plan view. Thereby, since the infrared radiation element 1 of this embodiment is provided with two wirings 8 between each electrode 9, the heat generating body layer 4, and each electrode 9, compared with the case where the wiring 8 is one each. Thus, the current density of the current flowing through the heating element layer 4 can be made uniform.

Further, in the infrared radiation element 1, the diaphragm portion 6D is deformed as the heating element layer 4 expands and contracts, and mechanical stress is applied to each wiring 8 and the like. However, since the infrared radiation element 1 of the present embodiment includes two wirings 8 for connecting the heating element layer 4 and the electrode 9, it is used even if one of the two wirings 8 is disconnected. Therefore, it is possible to improve the reliability and extend the life.

Further, since the infrared radiation element 1 has the diaphragm portion 6D having a laminated structure of the first insulating layer 3, the heating element layer 4 and the second insulating layer 5, the heat capacity of the diaphragm portion 6D can be reduced, and the heating element. By setting the sheet resistance of the layer 4 as described above, it is possible to suppress a decrease in the emissivity of the heating element layer 4.

Therefore, in the infrared radiation element 1 of the present embodiment, it is possible to reduce the power consumption and the response speed. The infrared radiation element 1 speeds up the response of the temperature change of the heating element layer 4 to the voltage waveform applied between the pair of electrodes 9 by reducing the heat capacity of the laminated structure on the one surface side of the substrate 2. Therefore, the temperature of the heating element layer 4 is likely to rise, and it becomes possible to increase the output and the response speed.

Further, in the infrared radiation element 1, the substrate 2 is formed from a single crystal silicon substrate, and the first insulating layer 3 is composed of a silicon oxide film and a silicon nitride film. Accordingly, the infrared radiation element 1 has a larger heat capacity and thermal conductivity of the substrate 2 than the first insulating layer 3, and the substrate 2 has a function as a heat sink. Therefore, the infrared radiation element 1 is reduced in size and has a high response speed to input power. And stability of infrared radiation characteristics can be improved.

Further, in the infrared radiation element 1, tantalum nitride having a melting point higher than that of silicon is adopted as a material of the heating element layer 4, and a member that is not the heating element layer 4 constituting the diaphragm body (in the first embodiment, the first insulating layer). 3, the second insulating layer 5, the contact portion 7, and the wiring 8) have a melting point higher than that of the heating element layer 4, the temperature of the heating element layer 4 is set to the maximum use temperature of silicon constituting the substrate 2 (silicon The temperature can be increased to a temperature slightly lower than the melting point), and the amount of infrared radiation can be greatly increased as compared with the infrared light emitting diode.

In addition, the infrared radiation element 1 has the temperature of the heating element layer 4 as the material of each contact portion 7 as long as at least a portion in contact with the heating element layer 4 is formed of a metal having a melting point higher than that of silicon. It is possible to raise without restriction.

That is, a member (diaphragm portion 6D, second insulating layer 5, contact) that is not the heating element layer 4 constituting the diaphragm body (diaphragm portion 6D, heating element layer 4, second insulating layer 5, contact portion 7, and wiring 8). If a material having a melting point higher than that of the heating element layer 4 is used as the material of the part 7 and the wiring 8), the temperature of the heating element layer 4 can be raised to a temperature slightly lower than the melting point of the heating element layer 4. Here, the temperature of the heating element layer 4 refers to the temperature near the center (near the center of gravity) of the heating element layer 4.

When the heating element layer 4 is formed of a high melting point material (for example, tantalum nitride), the material of the other members constituting the diaphragm body (first insulating layer 3, second insulating layer 5, contact portion 7, wiring 8) Similarly, it is preferably formed of a high melting point material.

The high melting point material used for the first insulating layer 3 and the second insulating layer 5 is, for example, an insulator (silicon dioxide, silicon nitride) having a high melting point.

The high melting point material used for the contact portion 7 and the wiring 8 has, for example, a metal having a high melting point (tantalum, tungsten, molybdenum, etc.), a noble metal having a high melting point (platinum, ruthenium, iridium, etc.), and a high melting point. It is selected from conductive materials (single crystal silicon, polysilicon, single crystal germanium, conductive carbon). In particular, the wiring 8 is preferably formed of tantalum. The contact portion 7 is preferably formed of tantalum. When the wiring 8 is made of a noble metal having a high melting point, even when a part of the wiring 8 is exposed, the wiring 8 is oxidized when the temperature of the heating element layer 4 rises, and the electric resistance changes. Can be suppressed.

Note that the high melting point material only needs to have a higher melting point than the material of the substrate 2. For example, when the material of the substrate 2 is silicon, a material having a higher melting point than silicon is adopted as the high melting point material.

When a member that is not the heating element layer 4 among the members constituting the diaphragm body has a lower melting point than the heating element layer 4, the temperature of the heating element layer 4 (the temperature near the center of the heating element layer 4). Can be raised to a temperature slightly lower than the melting point of the material having the smallest melting point among the members constituting the diaphragm body.

Here, in the heating element layer 4, the heat radiation increases as the portion is closer to the periphery of the heating element layer 4. Further, the heating element layer 4 is more likely to dissipate heat as it is closer to the edge of the opening 2 a of the substrate 2. Therefore, the temperature of the peripheral portion of the heating element layer 4 is lower than the temperature at the center of the heating element layer 4. The contact portion 7 and the wiring 8 that are in contact with the peripheral portion of the heating element layer 4 have substantially the same temperature as that of the peripheral portion of the heating element layer 4 at or near the portion in contact with the heating element layer 4.

However, as described above, since the temperature of the peripheral portion of the heating element layer 4 is slightly lower than the temperature near the center of the heating element layer 4, the temperature near the center of the heating element layer 4 is changed to the material constituting the diaphragm body. Among them, if the temperature is set to be slightly lower than the melting point of the material having the lowest melting point, the infrared radiation element 1 can be used stably.

The infrared radiation element 1 is symmetrical with respect to the center line of the infrared radiation element 1 where the heating element layer 4, the contact portion 7, the wiring 8 and the electrode 9 are orthogonal to the direction in which the pair of

electrodes

9 and 9 are arranged in plan view. It is preferable to arrange | position. Thereby, the infrared radiation element 1 can further improve the mechanical strength, and can suppress the in-plane variation of the temperature of the heating element layer 4.

(Embodiment 2)
Below, the infrared radiation element 1 of this embodiment is demonstrated based on FIG. The infrared radiation element 1 of the present embodiment is different from the infrared radiation element 1 of the first embodiment in the shapes of the wiring 8 and the electrode 9. In addition, about the component similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The wiring 8 is formed in such a shape that the width of the other end portion 8b increases as the distance from the heating element layer 4 to the electrode 9 increases, and both side surfaces 10 become concave curved surfaces. That is, the width of the end portion (second end portion) 8 b of the wiring 8 increases as the distance from the electrode 9 increases. Further, the side surface 10 of the second end portion 8b of the wiring 8 is concave. In the present embodiment, both side surfaces 10 of the second end 8b are concave.

The other end 8 b of the wiring 8 passes over the corner 60 of the diaphragm 6. That is, the wiring 8 is arranged so that the other end 8b overlaps the corner 60 (the corner 20 of the opening 2a) of the diaphragm 6 in the thickness direction. An end portion (second end portion) 8b of the wiring 8 constitutes a reinforcing portion.

In addition, each electrode 9 has a strip-shaped pad portion 9a whose longitudinal direction is a direction orthogonal to the direction in which both electrodes 9 are arranged in a plan view, and the parallel direction from both ends in the longitudinal direction of the pad portion 9a. And two extending portions 9b extending to the front. Here, in the above-described wiring 8, one side surface of the other end portion is continuous with the pad portion 9a, and the other side surface is continuous with the extending portion 9b.

In the infrared radiation element 1 of the present embodiment described above, two wirings 8 are provided between the heating element layer 4 and each electrode 9 and are opposite to the one end portion 8a on the heating element layer 4 side. The other end portion 8b on the electrode 9 side is formed in a shape in which the width dimension increases as the distance from the heating element layer 4 approaches the electrode 9 and both side surfaces 10 become concave curved surfaces. It passes over the corner 60.

That is, the infrared radiation element 1 of the present embodiment has the following twelfth and thirteenth features in addition to the fourth feature. In the twelfth feature, the wiring 8 has an end (second end) 8 b connected to the electrode 9. The width of the end (second end) 8 b increases as it approaches the electrode 9. The end portion (second end portion) 8b is a reinforcing portion. In the thirteenth feature, in the eighth feature, the side surface 10 of the end portion (second end portion) 8b is concave. The thirteenth feature is an arbitrary feature. Further, the infrared radiation element 1 of the present embodiment may have at least one of the fifth to eleventh characteristics.

As described above, in the infrared radiation element 1 of the present embodiment, the width of the other end 8b of the wiring 8 increases as the distance from the heating element layer 4 and the approach to the electrode 9 increases, and both side surfaces 10 have concave curved shapes. The other end portion passes over the corner portion 60 of the diaphragm portion 6D.

Therefore, it is possible to disperse the stress in each of the corners 60 of the wiring 8 and the diaphragm portion 6D, and to improve the mechanical strength of each of the wiring 8 and the diaphragm portion 6D. Therefore, the infrared radiation element 1 can further improve the reliability.

(Embodiment 3)
Below, the infrared radiation element 1 of this embodiment is demonstrated based on FIG.

The infrared radiation element 1 of the present embodiment is different from the infrared radiation element 1 of the first embodiment in the arrangement of the wiring 8 and the shape of the electrode 9. In addition, about the component similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

In the infrared radiation element 1 of the present embodiment, the heating element layer 4 and each electrode 9 are connected by one wiring 8 (85, 86). That is, the electrode 9A is electrically connected to the heating element layer 4 by the wiring 85. The electrode 9 </ b> A is electrically connected to the heating element layer 4 by the wiring 85.

Here, each wiring 8 (85, 86) is arranged along the parallel arrangement direction of the pair of

electrodes

9A, 9B (the left-right direction in FIG. 3A). In addition, in the infrared radiation element 1, each wiring 8 (85, 86) is arranged so that a straight line connecting the two

wirings

85, 86 passes through the center of the heating element layer 4 in plan view.

The first electrode 9A and the second electrode 9B are disposed on both sides of the opening 2a in a predetermined direction along the one side of the opening 2a on the reference plane (the left-right direction in FIG. 3A). Each electrode 9 has a strip-shaped pad portion 9a whose longitudinal direction (vertical direction in FIG. 3A) is a direction perpendicular to the juxtaposed direction of the electrodes 9 (the predetermined direction) in plan view; Two extending portions 9b extending in the juxtaposed direction from each of both end portions in the longitudinal direction of the pad portion 9a are provided.

Here, each electrode 9 includes a triangular reinforcing portion 9c that continues to the pad portion 9a and the extending portion 9b and passes through the corner portion of the diaphragm portion 6D.

That is, the first electrode 9A includes, in addition to the pad portion 9a and the two extending portions 9b, reinforcing portions 9c (9c1, 9c1, 9c1, 9c1 and 9c2) corresponding to the two

corners

21 and 22 near the first electrode 9A among the four corners 20, respectively. 9c2). Similarly, in addition to the pad portion 9a and the two extending portions 9b, the second electrode 9B includes reinforcing portions 9c (9c3) corresponding to the two

corners

23 and 24 close to the second electrode 9B among the four corners 20, respectively. 9c4).

In addition to the third feature, the infrared radiation element 1 of the present embodiment described above has the following fourteenth feature. In the fourteenth feature, the opening 2a is rectangular or square having four corners 20 (21 to 24). The electrode 9 includes a first electrode 9A and a second electrode 9B. The first electrode 9A and the second electrode 9B have an opening 2a in a predetermined direction (left and right direction in FIG. 3A) along one side of the opening 2a on a reference plane (a surface parallel to the one surface 2b of the substrate 2). Arranged on both sides. The first electrode 9A includes reinforcing portions 9c1 and 9c2 respectively corresponding to two

corners

21 and 22 close to the first electrode 9A among the four corners 20 (21 to 24). The second electrode 9B includes reinforcing portions 9c3 and 9c4 corresponding to the two

corners

23 and 24 close to the second electrode 9B among the four corners 21 to 24, respectively. Note that the infrared radiation element 1 of the present embodiment may have at least one of the fourth to eleventh features.

Thus, the infrared radiation element 1 according to the present embodiment has the heat generating layer 4 formed on the first insulating layer 3, so that the thermal insulation can be enhanced and the output can be increased. In addition, since the energization section 11 passes over each corner 60 of the diaphragm section 6D, the diaphragm section 6D is reinforced by the energization section 11 and the reliability can be improved.

The infrared radiation element 1 of each embodiment is not limited to an infrared light source for a gas sensor, but can be used for an infrared light source for infrared light communication, an infrared light source for spectral analysis, and the like.

Claims

A substrate having one surface orthogonal to the thickness direction;
An opening that penetrates the substrate in the thickness direction;
A first insulating layer disposed on the one surface of the substrate so as to cover the opening;
A heating element layer disposed on a side opposite to the substrate in the first insulating layer so as to be located inside the opening in a reference plane parallel to the one surface;
A second insulating layer arranged to cover the heating element layer on the opposite side of the first insulating layer from the substrate;
A current-carrying part disposed on the opposite side of the second insulating layer from the substrate and electrically connected to the heating element layer;
With
The opening is a shape having a corner in the reference plane;
The current-carrying part includes a reinforcing part that overlaps the corner of the opening in the thickness direction.
The infrared radiation element according to claim 1, wherein the first insulating layer, the second insulating layer, and the heating element layer have tensile stress as a whole.
The energization part is
An electrode disposed on the substrate so as to be located outside the opening in the reference plane;
Wiring for electrically connecting the electrode to the heating element layer;
The infrared radiation element according to claim 1, comprising:
The opening is rectangular or square having the four corners,
The infrared radiation element according to claim 3, wherein the energization unit includes the four reinforcing portions respectively corresponding to the four corners.
The energization unit has four wirings,
The infrared radiation element according to claim 4, wherein each of the four wirings includes four corresponding reinforcing portions.
The electrode includes a first electrode and a second electrode,
The first electrode and the second electrode are disposed on both sides of the opening in a predetermined direction along one side of the opening in the reference plane,
The first electrode is connected to the wiring corresponding to two corners close to the first electrode among the four corners,
The infrared radiation element according to claim 5, wherein the second electrode is connected to the wiring corresponding to two of the four corners that are close to the second electrode.
The wiring has an end connected to the electrode,
The end portion increases in width as it approaches the electrode,
The infrared radiation element according to claim 6, wherein the end portion is the reinforcing portion.
The infrared radiation element according to claim 7, wherein the end portion has a concave side surface.
The heating element layer is rectangular or square having four second corners on the reference plane,
The heating element layer has four sides parallel to the four sides of the opening in the reference plane,
Each of the four wirings is formed in a straight line passing through the second corner of the heating element layer and the corner of the opening closest to the second corner on the reference plane. The infrared radiation element according to claim 5.
The opening is rectangular or square having the four corners,
The electrode includes a first electrode and a second electrode,
The first electrode and the second electrode are disposed on both sides of the opening in a predetermined direction along one side of the opening on the reference plane,
The first electrode includes the reinforcing portions respectively corresponding to two corners close to the first electrode among the four corners,
The infrared radiation element according to claim 3, wherein the second electrode includes the reinforcing portions respectively corresponding to two of the four corners close to the second electrode.
The wiring is formed of a high melting point material.
The infrared radiation element according to claim 3.
The infrared radiation element according to claim 11, wherein the heating element layer is formed of a material having a melting point equal to or higher than the high melting point material.
The wiring is formed of tantalum,
The infrared radiation element according to claim 12, wherein the heating element layer is made of tantalum nitride.
The first insulating layer and the second insulating layer have thermal insulation and electrical insulation,
The heating element layer is configured to emit infrared rays when energized,
The first insulating layer, the heating element layer, and the second insulating layer constitute a thin film structure,
The thin film structure is
A diaphragm portion disposed on the opening;
A support portion disposed on the substrate and connected to the diaphragm portion;
The infrared radiation element according to claim 1, wherein: