WO2020158156A1 - Method for forming detection element and detection device - Google Patents

Method for forming detection element and detection device Download PDF

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Publication number
WO2020158156A1
WO2020158156A1 PCT/JP2019/046785 JP2019046785W WO2020158156A1 WO 2020158156 A1 WO2020158156 A1 WO 2020158156A1 JP 2019046785 W JP2019046785 W JP 2019046785W WO 2020158156 A1 WO2020158156 A1 WO 2020158156A1
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Prior art keywords
thermocouple
row
forming
substrate
detection device
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PCT/JP2019/046785
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French (fr)
Japanese (ja)
Inventor
隆 笠井
幸志 桃谷
優 中野
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オムロン株式会社
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Publication of WO2020158156A1 publication Critical patent/WO2020158156A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
    • G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
    • G01F1/692—Thin-film arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching

Definitions

  • the present invention relates to a method for forming a detection element and a detection device.
  • a detection device in which a cavity having an opening is formed on a surface of a substrate made of a semiconductor, and a detection element is arranged so as to face the opening of the cavity on the surface of the substrate (for example, Patent Document 1). -4).
  • a method for forming a cavity in a substrate a technique is disclosed in which a portion of the substrate to be a cavity is formed of a silicon oxide film and the silicon oxide film is etched and removed by corrosion to form the cavity (for example, a non-patent document). Reference 1).
  • an etching hole is formed in a portion of the surface of the substrate which becomes an opening of the cavity, and a corrosive agent for corroding and removing the substrate is supplied from the etching hole. It is possible.
  • the substrate has a single crystal structure, it is considered that the progress of corrosion is anisotropic. Therefore, it is considered that it is difficult to control the area to be removed by corrosion, and it is necessary to strictly consider the installation location of the etching hole in order to provide the cavity in the desired area.
  • Non-Patent Document 1 In the method of creating a cavity disclosed in Non-Patent Document 1, it is not necessary to provide an etching hole. However, in the case of such a cavity forming method, the depth of the cavity corresponds to the film thickness of the oxide film. Then, the cavity is formed shallowly, and the heat in the cavity moves to the substrate through the bottom of the cavity. Therefore, this method is applied to the heat (distribution) detection device, and the detection element is applied to the opening of the cavity. When arranged, there is a disadvantage that the sensitivity to heat (distribution) decreases.
  • the present inventor has found that, in the prior art, the degree of freedom of the installation location of the etching hole for supplying the corrosive agent is lowered, or the sensitivity of the heat (distribution) detection device is lowered.
  • the present invention in one aspect, has been made in view of such circumstances, and an object thereof is to improve the degree of freedom of an installation place of an etching hole for supplying a corrosive agent and to prevent heat (distribution). It is an object of the present invention to provide a technique for forming a detection device having higher sensitivity.
  • the present invention adopts the following configurations in order to solve the above problems.
  • the method for forming a detection element comprises a step of forming a sacrificial layer film which is a thin film made of a polycrystalline semiconductor on the surface of a substrate made of a single crystal semiconductor, and the sacrificial layer film, A step of forming an element thin film layer having a function as a detection element, and partially corroding and removing the element thin film layer to penetrate the element thin film layer and connect the outside of the system to the surface of the sacrificial layer film.
  • the sacrificial layer film is corroded by the predetermined corrosive liquid. Further, the predetermined corrosive liquid that has penetrated into the sacrificial layer film also permeates into the substrate, and the substrate is corroded. Therefore, it is possible to match the shape of the opening of the cavity provided in the substrate with the shape of the sacrificial layer film. And the detection element in which the thermocouple exists in the said opening part is formed.
  • the corrosive liquid supplied from the holes corrodes and removes the sacrificial layer film regardless of the position of the corrosive liquid supply holes. Based on this, it is possible to further corrode and remove the substrate. That is, according to the above-described method of forming the detection element, the degree of freedom of the installation location of the hole is improved. As a result, according to this method, it is possible to flexibly change the installation location of the thermocouple and the hole in order to improve the performance of the detection element.
  • the corrosion of the substrate progresses by adding a predetermined amount or more of a predetermined corrosive liquid, and it is possible to form a cavity having a depth of a predetermined film thickness or more. Therefore, heat transfer to the substrate through the bottom of the cavity is suppressed. Therefore, the decrease in the detection sensitivity of the thermocouple with respect to the change in heat is suppressed.
  • the method it is possible to suppress the variation in the dimension of the cavity as compared with the case where the opening is formed on the back surface side of the substrate. Therefore, variations in heat distribution are suppressed, and variations in thermocouple output are suppressed.
  • a cavity opening can be formed on the front side of the substrate. Therefore, it is possible to generate a substrate having higher rigidity than a substrate having a cavity in which the front side and the back side of the substrate are open.
  • the step of forming the sacrificial layer film, the step of forming an insulating film on the surface of the substrate, the step of removing a part of the insulating film may include the step of forming the sacrificial layer film on a surface of an exposed portion where the insulating film is removed and the substrate is exposed, and a surface of an edge of the insulating film that surrounds the exposed portion.
  • the sacrificial layer film provided in the portion where the insulating film is removed is corroded. Further, the substrate located below the sacrifice layer film is also corroded.
  • the corrosion of the substrate varies.
  • corrosion of the sacrificial layer film provided on the surface of the edge of the insulating film surrounding the part where the insulating film is removed proceeds isotropically. That is, even if the dimensions of the cavity vary due to the variation in the corrosion of the substrate, the variation in the area of the element thin film layer exposed in the cavity is suppressed. Therefore, the variation in the degree of transfer of heat distributed in the cavity to the thermocouple through the film is suppressed. Therefore, variations in the sensitivity of the thermocouple are suppressed.
  • the detection element has a first hot junction and a first thermocouple having a first cold junction connected in series and arranged in a direction perpendicular to the longitudinal direction.
  • Arranging the first thermocouple row and the second thermocouple row such that the first hot junction row and the second hot junction row face each other with a linear electric heater interposed therebetween.
  • the hole is a detection element formed by that, in the region where the first thermocouple row and the second thermocouple row are arranged, the alignment direction of the first thermocouple and the second thermocouple It may be characterized in that it is provided on both sides of.
  • the heat contained in the element thin film layer is suppressed from moving to the substrate due to the existence of the holes. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. That is, the sensitivity of the thermocouple is increased.
  • the holes it is possible to arrange the holes as one opening. That is, it becomes easy to increase the size of the hole. Therefore, when a predetermined corrosive liquid that corrodes the substrate is added from the hole to form a cavity in the substrate, it is easy to add a large amount of the predetermined corrosive liquid. That is, the progress of corrosion is accelerated.
  • thermocouple not only the element thin film layer is exposed on the front side of the substrate, but also inside the cavity. Therefore, changes in the external environment are easily transmitted to the element thin film layer. Therefore, the sensitivity of the thermocouple is improved.
  • the fluid flowing outside the cavity through the hole flows into the cavity. Therefore, the movement of heat around the thermocouple is promoted. Therefore, the sensitivity of the thermocouple for detecting a change in heat is improved as compared with the case where the fluid does not flow into the inside of the cavity.
  • the outside of the system and the cavity are communicated by the existence of the holes. Therefore, when the fluid exists inside the cavity, the characteristic of the fluid is prevented from changing due to the cavity being sealed. Therefore, it is possible to prevent the detection result of the thermocouple from changing due to the change of the characteristic of the fluid and the deterioration of the detection accuracy.
  • thermocouple row the second thermocouple row depending on whether the fluid flows or not. That is, according to this configuration, the flow rate of the fluid can be calculated based on the difference between the output of the first thermocouple string and the output of the second thermocouple string.
  • thermocouple heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the response speed of the output of the first thermocouple array and the output of the second thermocouple array to changes in the distributed heat is improved as compared with the case where heat is transferred to the thermocouple through air.
  • thermocouple heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the amount of heat transferred to the thermocouple is larger than that transferred to the thermocouple via air. Therefore, the output of the first thermocouple string and the output of the second thermocouple string are increased, and the influence of noise contained in the output of the first thermocouple string and the output of the second thermocouple string is relatively reduced. In addition, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
  • the hole is a region in which the first thermocouple row and the second thermocouple row are arranged, of the first thermocouple and the second thermocouple. It may be characterized in that it is provided in two places on both sides in the arranging direction with the electrothermal heater interposed therebetween.
  • the heat contained in the element thin film layer is suppressed from moving to the substrate. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. That is, the sensitivity of the thermocouple is increased.
  • the hole is further provided in a region where the first thermocouple row and the second thermocouple row are arranged, the first thermocouple and the second thermocouple. It may be characterized in that it is provided so as to sandwich the electrothermal heater in at least a part of the arranging direction of the pair.
  • thermocouple the amount of heat generated by the electric heater transferred through air increases. Therefore, the sensitivity of the thermocouple to the flow velocity of the fluid flowing near the surface of the element thin film layer increases.
  • thermocouple when the fluid flows near the surface of the element thin film layer, the amount of the fluid flowing near the surface of the element thin film layer flows into the cavity through the holes increases. Therefore, the movement of heat around the thermocouple when the flow rate of the fluid changes is promoted. That is, the sensitivity of the thermocouple is improved.
  • At least a part of the holes may be formed as a set of minute dot-shaped minute holes.
  • the rigidity of the element thin film layer is increased as compared with the case where one hole having the same area as the total area of the micropores is opened.
  • a detection device having a detection element formed by the method for forming a detection element according to the one aspect, wherein the detection element is a series of first thermocouples having a first hot junction and a first cold junction. In the direction perpendicular to the longitudinal direction by connecting the first thermocouple row connected in the direction perpendicular to the longitudinal direction and the second thermocouple having the second hot junction and the second cold junction in series.
  • thermocouple row arranged, the first thermocouple row and the second thermocouple row, the first hot junction row and the second hot junction row are linear Is a detection element formed by arranging so as to face each other across the electrothermal heater, the hole, in the region in which the first thermocouple row and the second thermocouple row is arranged, the first The thermocouple and the second thermocouple may be provided on both sides in the arranging direction.
  • the heat contained in the element thin film layer is suppressed from moving to the substrate due to the existence of the holes. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. Therefore, the sensitivity of the thermocouple is increased.
  • a hole as one opening. That is, it becomes easy to increase the size of the hole. Therefore, when a predetermined corrosive liquid that corrodes the substrate is added from the hole to form a cavity in the substrate, it is easy to add a large amount of the predetermined corrosive liquid. That is, the progress of corrosion is accelerated.
  • thermocouple not only the element thin film layer is exposed on the front side of the substrate, but also exposed inside the cavity. Therefore, changes in the external environment are easily transmitted to the element thin film layer. Therefore, the sensitivity of the thermocouple is improved.
  • the fluid flowing outside the cavity through the hole flows into the inside of the cavity. Therefore, the movement of heat around the thermocouple is promoted. Therefore, the sensitivity of the thermocouple for detecting a change in heat is improved as compared with the case where the fluid does not flow into the inside of the cavity.
  • the outside of the system communicates with the cavity due to the existence of the holes. Therefore, when the fluid exists inside the cavity, the characteristic of the fluid is prevented from changing due to the cavity being sealed. Therefore, it is possible to prevent the detection result of the thermocouple from changing due to the change of the characteristic of the fluid and the deterioration of the detection accuracy.
  • thermocouple row the second thermocouple row depending on whether the fluid flows or not. That is, according to this configuration, the flow rate of the fluid can be calculated based on the difference between the output of the first thermocouple string and the output of the second thermocouple string.
  • thermocouple the heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the response speed of the output of the first thermocouple array and the output of the second thermocouple array to changes in the distributed heat is improved as compared with the case where heat is transferred to the thermocouple through air.
  • the heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the amount of heat transferred to the thermocouple is larger than that transferred to the thermocouple via air. Therefore, the output of the first thermocouple string and the output of the second thermocouple string are increased, and the influence of noise contained in the output of the first thermocouple string and the output of the second thermocouple string is relatively reduced. In addition, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
  • the hole is a region in which the first thermocouple row and the second thermocouple row are arranged, in a direction in which the first thermocouple and the second thermocouple are arranged. It may be characterized in that it is provided at two places on both sides with the electric heater interposed therebetween.
  • thermocouple According to the configuration, heat contained in the element thin film layer is suppressed from moving to the substrate. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. Therefore, the sensitivity of the thermocouple is increased.
  • the hole is further arranged in a region where the first thermocouple row and the second thermocouple row are arranged, in which the first thermocouple and the second thermocouple are arranged.
  • the electrothermal heater may be sandwiched in at least a part of the direction.
  • thermocouple the amount of heat generated by the electric heater transferred through air increases. Therefore, the sensitivity of the thermocouple to the flow velocity of the fluid flowing near the surface of the element thin film layer increases.
  • thermocouple when the fluid flows near the surface of the element thin film layer, the amount of the fluid flowing near the surface of the element thin film layer flows into the cavity through the holes increases. Therefore, the movement of heat around the thermocouple when the flow rate of the fluid changes is promoted. That is, the sensitivity of the thermocouple is improved.
  • At least a part of the holes may be formed as a set of minute dot-shaped minute holes.
  • the rigidity of the element thin film layer is increased as compared with the case where one hole having the same area as the total area of the micro holes is opened.
  • the present invention it is possible to provide a technique for forming a detection device having higher sensitivity to heat (distribution) while improving the degree of freedom of the installation place of the etching hole for supplying the corrosive agent.
  • FIG. 1 schematically illustrates an example of the outline of the detection device according to the embodiment.
  • FIG. 2A schematically illustrates an example of temperature distribution when a fluid is not flowing.
  • FIG. 2B schematically illustrates an example of temperature distribution when a fluid is flowing.
  • FIG. 3 is a flowchart illustrating an example of a method for forming the detection device according to the embodiment.
  • FIG. 4 schematically illustrates one step of the method for forming the detection device.
  • FIG. 5 schematically illustrates one step of the method for forming the detection device.
  • FIG. 6 schematically illustrates one step of the method for forming the detection device.
  • FIG. 7 schematically illustrates one step of the method for forming the detection device.
  • FIG. 8 schematically illustrates one step of the method for forming the detection device.
  • FIG. 1 schematically illustrates an example of the outline of the detection device according to the embodiment.
  • FIG. 2A schematically illustrates an example of temperature distribution when a fluid is not flowing.
  • FIG. 2B schematic
  • FIG. 9 schematically illustrates one step of the method for forming the detection device.
  • FIG. 10 schematically illustrates an example of the outline of a conventional detection device.
  • FIG. 11A schematically illustrates an outline of a cavity formed when a rectangular etching hole is provided in a substrate.
  • FIG. 11B schematically illustrates the outline of the cavity formed when the substrate is provided with an elliptical etching hole.
  • FIG. 11C schematically illustrates an outline of a cavity formed when a slit-shaped etching hole is provided in the substrate.
  • FIG. 12 schematically illustrates an outline of a cavity formed when a plurality of etching holes is provided in a substrate.
  • FIG. 13A schematically illustrates an example of an outline of a detection device in which an etching hole is formed by a plurality of small holes.
  • FIG. 13B schematically illustrates an example of the outline of the detection device in which the etching hole is formed of a plurality of small holes and a part of the holes is provided between the heater and the thermopile.
  • FIG. 13C schematically exemplifies an example of the outline of a detection device in which the etching hole provided between the heater and the thermopile is formed of a plurality of small holes.
  • FIG. 14A schematically illustrates an example of an outline of a top view of a detection device according to a modified example of the embodiment.
  • FIG. 14A schematically illustrates an example of an outline of a top view of a detection device according to a modified example of the embodiment.
  • FIG. 14B schematically illustrates an example of an outline of a cross-sectional view of a detection device according to a modified example of the embodiment.
  • FIG. 15 schematically illustrates an example of the outline of the detection device when the silicon oxide film located above the cavity is removed by the corrosion of the hydrofluoric acid aqueous solution.
  • this embodiment an embodiment according to one aspect of the present invention (hereinafter, also referred to as “this embodiment”) will be described with reference to the drawings.
  • the present embodiment described below is merely an example of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. That is, in implementing the present invention, a specific configuration according to the embodiment may be appropriately adopted.
  • FIG. 1 schematically illustrates an example of the outline of the detection device 1 according to the present embodiment.
  • FIG. 1 shows an example of an outline of a top view of the detection device 1.
  • the detection device 1 includes a heater 2 in the central portion. Further, the detection device 1 includes thermopiles 3A and 3B that are symmetrically provided about the heater 2.
  • the heater 2 is an example of the “electrothermal heater” of the present invention.
  • the thermopiles 3A and 3B have a plurality of thermocouples connected in series.
  • the thermopile 3A corresponds to the "first thermocouple string" of the present invention
  • the thermopile 3B corresponds to the "second thermocouple string” of the present invention.
  • thermopiles 3A and 3B are arranged is, for example, the direction in which the fluid flowing near the heater 2 flows. Further, the thermopiles 3A and 3B respectively include hot contacts 5A and 5B and cold contacts 6A and 6B.
  • the hot junction 5A is an example of the "first hot junction” in the present invention.
  • the cold junction 6A is an example of the "first cold junction” in the present invention.
  • the hot junction 5B is an example of the "second hot junction” in the present invention.
  • the cold junction 6B is an example of the "second cold junction” in the present invention.
  • the detection device 1 also includes a substrate 10 on which the heater 2 and the thermopiles 3A and 3B are arranged.
  • the substrate 10 is formed of single crystal silicon.
  • the substrate 10 also has a cavity 11 and an opening 12 at the top of the cavity 11.
  • the cavity 11 and the opening 12 have a symmetrical shape with respect to the surface direction of the substrate 10 with the center portion as the center.
  • the detection device 1 also includes silicon oxide films 8 and 13 (described later) and a silicon nitride film 9.
  • the opening 12 is covered with the silicon oxide film 8, and the heater 2 and the thermopiles 3A and 3B are formed on the silicon oxide film 8.
  • the silicon oxide film 13 covers the surface of the substrate 10 other than the openings 12.
  • the silicon nitride film 9 covers the heater 2 and the thermopiles 3A and 3B from the upper surface.
  • the detection device 1 has an etching hole 14 which is lateral to the thermopiles 3A and 3B and penetrates the silicon oxide film 8 and the silicon nitride film 9 at the edge of the opening 12 to communicate the outside of the system with the opening 12.
  • the heater 2 is arranged in the central portion of the opening 12.
  • the hot contact 5A and the cold contact 6A of the thermopile 3A are provided so as to straddle the edge of the opening 12. That is, the hot contact 5A of the thermopile 3A is arranged inside the opening 12 in the top view shown in FIG. 1, and the cold contact 6A of the thermopile 3A is arranged outside the opening 12.
  • the hot contact 5B and the cold contact 6B of the thermopile 3B are provided so as to straddle the edge of the opening 12. That is, the hot contact 5B of the thermopile 3B is arranged inside the opening 12, and the cold contact 6B of the thermopile 3B is arranged outside the opening 12.
  • FIG. 2A and 2B schematically illustrate the principle of flow rate detection using the detection device 1.
  • FIG. 2A schematically exemplifies an example of the temperature distribution when the heater 2 is energized in a state where no fluid is flowing.
  • FIG. 2B schematically illustrates an example of the temperature distribution when the heater 2 is energized while the fluid is flowing.
  • the heat from the heater 2 diffuses symmetrically around the heater 2. Therefore, the temperature difference between the temperature of the hot junction 5A and the temperature of the cold junction 6A is the same as the temperature difference between the temperature of the hot junction 5B and the temperature of the cold junction 6B.
  • thermopile 3A there is no difference between the output of the thermopile 3A and the output of the thermopile 3B.
  • the heat from the heater 2 is affected by the flow of the fluid, does not spread symmetrically around the heater 2, and diffuses further to the downstream thermopile 3B side. Therefore, the temperature difference between the temperature of the hot junction 5A and the temperature of the cold junction 6A is different from the temperature difference between the temperature of the hot junction 5B and the temperature of the cold junction 6B. That is, there is a difference between the output of the thermopile 3A and the output of the thermopile 3B. Further, the larger the flow rate of the fluid, the larger the difference between the outputs of the thermopile 3A and the thermopile 3B.
  • thermopiles 3A and 3B The relationship between the flow rate of the fluid and the difference between the outputs of the thermopiles 3A and 3B is expressed by the following mathematical expression 1, for example.
  • ⁇ V represents the difference between the output of the thermopile 3A and the output of the thermopile 3B
  • V L represents the output value of the thermopile 3B
  • V U represents the output value of the thermopile 3A.
  • R f is the flow velocity of the fluid. Based on the above equation, the flow rate of the fluid can be calculated from the outputs of the thermopiles 3A and 3B.
  • FIG. 3 is a flowchart illustrating an example of a method for forming the detection device 1 according to this embodiment. Note that the processing procedure described below is merely an example, and each processing may be changed as much as possible. Further, in the processing procedure described below, steps can be omitted, replaced, and added as appropriate according to the embodiment.
  • FIG. 4 schematically illustrates an example of the outline of the process in step S101.
  • FIG. 4 is an example of a cross-sectional view showing one side of the detection device 1.
  • the substrate 10 is prepared.
  • the substrate 10 is made of, for example, single crystal silicon.
  • the silicon oxide film 13 is formed on the entire surface of the substrate 10. After that, a predetermined portion of the silicon oxide film 13 is removed by photolithography, etching or the like.
  • the silicon oxide film 13 is an example of the “element thin film layer” of the present invention and an example of the “insulating film” of the present invention.
  • Forming the silicon oxide film 13 on the entire surface of the substrate 10 is an example of the “step of forming an insulating film on the surface of the substrate” in the present invention. Further, removing a predetermined portion of the silicon oxide film 13 means “partially corroding and removing the element thin film layer" of the present invention and “the step of removing a part of the insulating film” of the present invention. This is an example.
  • FIG. 5 schematically illustrates an example of the outline of the process in step S102.
  • a polysilicon layer 15 (hereinafter referred to as a sacrifice layer Poly-Si layer 15) is formed in the portion where the silicon oxide film 13 is removed.
  • the sacrificial layer Poly-Si layer 15 includes a polycrystal of silicon.
  • the sacrificial layer Poly-Si layer 15 is formed so as to extend to the surface portion 16 of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 is removed.
  • the sacrificial layer Poly-Si layer 15 is an example of the “sacrificial layer film” in the present invention.
  • the surface portion 16 is an example of the “surface of the edge of the insulating film surrounding the exposed portion” in the present invention.
  • Step S102 is an example of the "step of forming a sacrificial layer film, which is a thin film made of a polycrystalline semiconductor, on the surface of the substrate made of a single crystal semiconductor" of the present invention.
  • Step S102 is an example of the "step of forming the sacrificial layer film on the surface of the exposed portion where the insulating film is removed and the substrate is exposed and on the surface of the edge of the insulating film surrounding the exposed portion” of the present invention.
  • FIG. 6 schematically illustrates an example of the outline of the process in step S103.
  • the silicon oxide film 8 is formed on the substrate 10 to insulate the substrate 10 from the outside of the system. Further, a polysilicon layer 7 is formed on the silicon oxide film 8. Then, the heater 2 is formed on the polysilicon layer 7. Further, the thermopiles 3A and 3B are formed on the polysilicon layer 7.
  • the silicon oxide film 8 is an example of a film forming the "element thin film layer" of the present invention.
  • FIG. 7 schematically illustrates an example of the outline of the process in step S104.
  • the polysilicon layer 7 and the heater 2 and the thermopiles 3A and 3B formed thereon are covered with the silicon oxide film 8 and the silicon nitride film 9.
  • an etching hole 14 is provided which penetrates the silicon oxide film 8 and the silicon nitride film 9 and connects the outside of the system to the sacrificial layer Poly-Si layer 15.
  • the silicon nitride film 9 is an example of a film forming the “element thin film layer” of the present invention.
  • the etching hole 14 is an example of the "hole" in the present invention.
  • Steps S103 and S104 are an example of the "step of forming an element thin film layer having a function as a detection element on the sacrificial layer film" of the present invention.
  • Providing the etching hole 14 is an example of the "step of forming a hole that penetrates the element thin film layer and connects the outside of the system to the surface of the sacrificial layer film" of the present invention.
  • FIG. 8 schematically illustrates an example of the outline of the process in step S105.
  • a corrosive liquid that corrodes the sacrificial layer Poly-Si layer 15 and the substrate 10 is supplied from the etching hole 14.
  • the corrosive liquid is, for example, TMAH (Tetramethylammonium hydroxide) liquid.
  • TMAH Tetramethylammonium hydroxide
  • the TMAH liquid is an example of the "predetermined corrosive liquid" of the present invention.
  • the sacrificial layer Poly-Si layer 15 contains a polycrystal of silicon, it has a property that corrosion proceeds isotropically by the TMAH solution. That is, the sacrificial layer Poly-Si layer 15 isotropically corrodes in the mounting surface direction of the substrate 10. Further, the TMAH liquid also penetrates into the substrate 10 via the sacrificial layer Poly-Si layer 15. Then, the substrate 10 is also corroded.
  • FIG. 9 schematically illustrates an example of the outline of the process in step S106.
  • the TMAH solution is corroded by corroding the sacrificial layer Poly-Si layer 15 existing on the surface portion 16 of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 is removed in the step S102, and the gap 17 is formed. Until the formation of. Then, the substrate 10 is corroded to a desired depth, and the cavity 11 is formed in the substrate 10. Then, the supply of the TMAH liquid from the etching hole 14 is stopped.
  • step S106 and step S107 are an example of the "step of removing the sacrificial layer film by isotropically corroding and removing the sacrificial layer film by supplying the corrosive liquid from the hole" of the present invention.
  • steps S106 and S107 are performed by supplying the corrosive liquid through the space from which the sacrificial layer film is removed to corrode the substrate, so that the substrate is provided with respect to the element thin film layer. It is an example of a "process of forming a cavity that opens.”
  • FIG. 10 shows an example of an outline of a top view of the conventional detection device 30 formed by the forming process of the conventional detection device 30.
  • the sacrificial layer Poly-Si layer 15 is not provided on the substrate 10A.
  • the etching hole 34 is not provided so as to penetrate the silicon oxide film 8 and the silicon nitride film 9.
  • the etching hole 34 is provided in the substrate 10A.
  • the conventional detection device 30 includes a plurality of etching holes 34 in the central portion of the substrate 10A.
  • 11A, 11B, and 11C show an example of a cavity formed when an etching hole is provided in the substrate and the TMAH liquid is introduced from the etching hole.
  • 11A shows the case where the etching hole 14F is rectangular
  • FIG. 11B shows the case where the etching hole 14F is elliptical
  • FIG. 11C shows the case where the etching hole 14F is slit-shaped.
  • FIGS. 11A, 11B, and 11C when the substrate 10A is a standard silicon substrate ((100) substrate, XY axes are in the ⁇ 110> direction), the maximum lateral width of the etching hole in the X axis direction. And a rectangular cavity 11G having the maximum vertical width in the Y-axis direction is formed.
  • FIG. 12 shows an example of a cavity 11G formed when a plurality of etching holes 14G are provided in the substrate 10A. As shown in FIG. 12, when a plurality of etching holes 14G are provided and the TMAH liquid is introduced from each etching hole 14G, a cavity 11G having a size larger than the etching hole 14G can be produced.
  • the corrosive liquid for corroding the substrate 10A is introduced from the plurality of etching holes 34, so that the substrate 10A is corroded. Then, the cavity 41 is formed in the central portion of the substrate 10A. Then, the heater 2 and the thermopiles 3A and 3B are formed on the surface of the substrate.
  • the conventional detection device 30 is formed by such a forming process.
  • the substrate 10A is anisotropically corroded than the sacrificial layer Poly-Si layer 15 when corroded by the corrosive liquid. Therefore, in the case of the conventional corrosion method, the dimensions of the cavity 41 and the opening 42 vary. Further, if the positions and the number of the etching holes are not properly set, the cavities 41 and the openings 42 cannot be formed into desired shapes and sizes.
  • the sacrificial layer Poly-Si layer 15 includes a polycrystalline silicon body. Therefore, the corrosion of the sacrificial layer Poly-Si layer 15 proceeds isotropically. In other words, regardless of the position of the etching hole 14 for supplying the TMAH solution, the TMAH solution supplied from the etching hole 14 corrodes and removes the sacrificial layer Poly-Si layer 15. It is possible to further corrode and remove the substrate 10 based on the formed area. That is, according to the method for forming the detection device 1 described above, the degree of freedom of the installation location of the etching hole is improved.
  • thermopiles 3A and 3B the degree of freedom of the installation location of the thermopiles 3A and 3B is also improved. That is, according to the method, it is possible to flexibly change the installation locations of the thermopiles 3A and 3B and the etching hole 14 in order to improve the performance of the detection device 1.
  • the corrosion of the substrate 10 progresses according to the amount of the TMAH liquid added. Therefore, the cavity 11 having a depth equal to or larger than a predetermined film thickness can be formed. Therefore, heat transfer to the substrate 10 via the bottom of the cavity 11 is suppressed. Therefore, it is possible to prevent the detection sensitivity of the thermopiles 3A and 3B from decreasing due to heat change.
  • thermopiles 3A and 3B are suppressed.
  • the opening 12 of the cavity 11 can be formed on the front side of the substrate 10. Therefore, it is possible to generate the substrate 10 having higher rigidity than that of the substrate having the cavities whose front and back sides are open.
  • the sacrificial layer Poly-Si layer 15 provided in the portion where the silicon oxide film 13 is removed is corroded. Further, the substrate 10 located below the sacrifice layer Poly-Si layer 15 is also corroded. Here, it is considered that the corrosion of the substrate 10 varies. However, even in such a case, the sacrificial layer Poly-Si layer 15 provided on the surface of the edge of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 has been removed corrodes isotropically. .. Then, a predetermined gap 17 is formed. That is, even when the dimensions of the cavity 11 vary due to the variation in the corrosion of the substrate 10, the variation in the dimension of the gap 17 is suppressed.
  • thermopiles 3A and 3B are suppressed.
  • heating by the heater 2 causes a symmetrical heat distribution about the heater 2. Then, for example, when the fluid flows from the thermopile 3A to the thermopile 3B in the vicinity of the surface of the silicon nitride film 9, the heat distribution changes. Therefore, a difference occurs between the output of the thermopile 3A and the output of the thermopile 3B depending on whether the fluid flows or not. Then, the flow rate of the fluid can be calculated based on the above equation 1.
  • the heat contained in the silicon oxide film 8 or the silicon nitride film 9 is suppressed from moving to the substrate 10 due to the existence of the etching hole 14. Therefore, a decrease in the amount of heat distributed around the silicon oxide film 8 or the silicon nitride film 9 is suppressed. Therefore, when the fluid flows from the thermopile 3A to the thermopile 3B in the vicinity of the surface of the silicon oxide film 8 or the silicon nitride film 9, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. Therefore, the sensitivity of the thermopiles 3A and 3B is improved. In addition, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
  • thermopiles 3A and 3B are improved.
  • the fluid flowing outside the cavity 11 flows into the cavity 11 through the etching hole 14. Therefore, the movement of heat around the thermopiles 3A and 3B is promoted.
  • the etching hole 14 is provided on the side of the thermopiles 3A and 3B and at the edge of the opening 12. That is, the place where the etching hole 14 is provided is a place where the heater 2 and other parts do not exist, and the etching hole 14 can be provided as a large opening. Therefore, it becomes easy to increase the amount of fluid flowing into the inside of the cavity 11. Therefore, the sensitivities of the thermopiles 3A and 3B for detecting changes in heat distribution are improved as compared with the case where the fluid does not flow into the cavity 11. Further, since the etching hole 14 is provided with a large size, it becomes easy to add a large amount of TMAH liquid. Therefore, the progress of corrosion is accelerated.
  • the existence of the etching hole 14 allows the outside of the system to communicate with the cavity 11. Therefore, when the fluid is present inside the cavity 11, the inside of the cavity 11 is sealed while being heated, so that the characteristics such as the pressure of the fluid are prevented from changing. Therefore, changes in the degree of heat transfer to the thermopiles 3A and 3B due to changes in the characteristics of the fluid are suppressed. That is, it is possible to prevent the detection results of the thermopiles 3A and 3B from changing and the detection accuracy from decreasing.
  • the etching hole 14 is provided on the side of the thermopile 3A, 3B, and is not provided between the heater 2 and the thermopile 3A or 3B. Therefore, the heat generated by the heater 2 is transmitted to the thermopiles 3A and 3B through the silicon oxide film 8 or the silicon nitride film 9. Therefore, the response speed of the thermopile 3A, 3B to the change of the distributed heat is improved as compared with the case where the heat is transferred to the thermopile 3A, 3B via air.
  • the heat generated by the heater 2 is transmitted to the thermopiles 3A and 3B via the silicon oxide film 8 or the silicon nitride film 9. Therefore, the amount of heat transferred to the thermopiles 3A and 3B is larger than that when transferred to the thermopiles 3A and 3B via air. Therefore, the outputs of the thermopiles 3A and 3B are increased, and the influence of noise contained in the outputs of the thermopiles 3A and 3B is relatively reduced. Further, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
  • FIG. 13A, FIG. 13B, and FIG. 13C show an example of an outline of a detection device according to a modified example of this embodiment.
  • FIG. 13A shows an example of the outline of the detection device 1A in which the etching hole 14A is formed by a plurality of small holes. The plurality of small holes are provided at substantially equal intervals.
  • the rigidity of the silicon oxide film 8 and the silicon nitride film 9 is increased as compared with the case where one etching hole having the same area as the sum of the opening areas of the plurality of holes is opened.
  • FIG. 13B shows an example of the outline of the detection device 1B in which the etching hole 14B is formed by a plurality of small holes, and a part of these holes is provided between the heater 2 and the thermopiles 3A, 3B.
  • thermopiles 3A and 3B the amount of heat generated by the heater 2 moving through air increases. Therefore, the sensitivity of the thermopiles 3A and 3B to the flow velocity of the fluid flowing near the surface of the silicon oxide film 8 or the silicon nitride film 9 is increased.
  • thermopiles 3A and 3B when the fluid flows near the surface of the silicon oxide film 8 or the silicon nitride film 9, the fluid flowing near the surface of the silicon oxide film 8 or the silicon nitride film 9 causes the etching hole 14B to flow.
  • the amount flowing into the inside of the cavity 11 through the inside increases. Therefore, the movement of heat around the thermopiles 3A and 3B when the flow rate of the fluid changes is promoted. That is, the decrease in sensitivity of the thermopiles 3A and 3B is suppressed.
  • FIG. 13C shows an example of an outline of a detection device 1C in which an etching hole 14C provided between the heater 2 and the thermopiles 3A and 3B is formed by a plurality of small holes. Further, the detection device 1C has a portion in which the etching hole 14D is provided on the side of the thermopile 3A, 3B, communicates with the edge of the opening 12, and is formed by one large hole.
  • Such a detection device 1C has a configuration in which, in addition to the configuration of the detection device 1B, etching holes provided on the sides of the thermopiles 3A and 3B are large openings. Therefore, when the TMAH liquid that corrodes the substrate 10 is added from the etching hole 14D to form the cavity 11 in the substrate 10, a large amount of the TMAH liquid can be added, and the progress of the corrosion is accelerated.
  • the heat contained in the silicon oxide film 8 or the silicon nitride film 9 is suppressed from moving to the substrate 10 due to the presence of the etching hole 14D. Therefore, a decrease in the amount of heat distributed around the silicon oxide film 8 or the silicon nitride film 9 is suppressed. Therefore, even when the fluid flows from the thermopile 3A to the thermopile 3B in the vicinity of the surface of the silicon oxide film 8 or the silicon nitride film 9, even if the flow velocity of the fluid is high and heat is easily removed by the fluid. , The flow rate of the fluid can be detected.
  • thermopiles 3A and 3B when the fluid flows near the surface of the silicon oxide film 8 or the silicon nitride film 9, the fluid flowing outside the cavity 11 flows into the cavity 11 through the etching hole 14D. To do. Therefore, the movement of heat around the thermopiles 3A and 3B is promoted. Further, the size of the etching hole 14D is easily expanded, and it is easy to increase the amount of fluid flowing into the inside of the cavity 11. Therefore, the sensitivity of the thermopiles 3A and 3B for detecting a change in heat is improved as compared with the case where the fluid does not flow into the cavity 11.
  • FIG. 14A and 14B show an example of an outline of a detection device according to a modified example of this embodiment.
  • FIG. 14A shows an example of an outline of a top view of the detection device 1D.
  • FIG. 14B has shown the AA arrow sectional view in FIG. 14A.
  • the detection device 1D does not include the heater 2.
  • the etching hole 14E of the detection device 1D is a portion located laterally of the thermopiles 3A and 3B, and is provided so that the outside of the system and the edge of the opening 12 communicate with each other. Further, the etching hole 14E is provided in a slit shape.
  • the surface of the silicon nitride film 9 may be coated with a film that absorbs infrared rays.
  • the film that absorbs infrared rays is formed of, for example, titanium nitride or gold. According to such a detection device 1D, the infrared absorption efficiency is improved.
  • step S107 the hydrofluoric acid aqueous solution is introduced from the etching hole 14, so that the cavity 11 is formed above the cavity 11.
  • the silicon oxide film 8 located may be corroded.
  • FIG. 15 shows an example of the outline of the detection device when the silicon oxide film 8 located above the cavity 11 is removed by the corrosion of the hydrofluoric acid aqueous solution. According to the forming process of the detecting device including such steps, the silicon oxide film 8 located above the cavity 11 is eliminated.
  • thermopile 3A, 3B becomes thin, and the speed at which the heat in the cavity 11 moves to the thermopile 3A, 3B via the film covering the thermopile 3A, 3B increases. Therefore, the sensitivity of the outputs of the thermopiles 3A and 3B to changes in the flow rate of the fluid is improved.
  • thermopiles 3A and 3B are arranged is not limited to the direction in which the fluid flows, and may be arranged, for example, in a direction that blocks the direction in which the fluid flows.
  • the sacrificial layer Poly-Si layer 15 may not be formed to extend to the surface portion 16 of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 is removed. That is, the gap 17 may not be formed.
  • the position of the etching hole 14 is not limited to the position illustrated above, and may be any position where the sacrificial layer Poly-Si layer 15 and the substrate 10 can be corroded.
  • the etching hole 14D of the detection device 1D does not have to be slit-shaped, and may be formed of a plurality of small holes provided at substantially equal intervals, and the surface area of the silicon nitride film 9 that absorbs infrared energy. It suffices that the shape is such that the narrowing is suppressed.
  • the plurality of small holes forming the etching holes 14A and the like may be formed so as to increase the rigidity of the silicon oxide film 8 and the silicon nitride film 9. Therefore, the plurality of small holes may not be provided at equal intervals. The diameters of the plurality of small holes may be the same or different.
  • ⁇ Appendix 1> A step of forming a sacrificial layer film (15), which is a thin film made of a polycrystalline semiconductor, on the surface of a substrate (10) made of a single crystal semiconductor; A step of forming an element thin film layer (8, 9, 13) having a function as a detection element on the sacrificial layer film (15); By partially corroding and removing the element thin film layer (8, 9, 13), the element thin film layer (8, 9, 13) is penetrated and the outside of the system and the surface of the sacrificial layer film (15) are separated.
  • a method of forming a detection element comprising: ⁇ Appendix 2>
  • the step of forming the sacrificial layer film (15) includes A step of forming an insulating film (13) on the surface of the substrate (10), A step of removing a part of the insulating film (13), The sacrificial layer film (15) is formed on the surface of the exposed portion where the insulating film (13) is removed and the substrate (10) is exposed, and on the edge surface (16) of
  • the detection element is A first thermocouple row (3A) in which a first thermocouple having a first hot junction (5A) and a first cold junction (5B) is connected in series and arranged in a direction perpendicular to the longitudinal direction; A second thermocouple row (3B) in which a second thermocouple having a second hot junction (6A) and a second cold junction (6B) is connected in series and arranged in a direction perpendicular to the longitudinal direction, Have, The first thermocouple row (3A) and the second thermocouple row (3B) have a linear shape between the first hot junction (5A) row and the second hot junction (6A) row.
  • the holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple.
  • the holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple. 4.
  • the method for forming a detection element according to appendix 3 characterized in that the detection element is provided in two places on both sides in the direction of arrangement of the thermocouples with the electrothermal heater (2) interposed therebetween.
  • the holes (14B, 14C) further include the first thermocouple and the second thermocouple in a region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged.
  • the method for forming a detection element according to appendix 4 characterized in that the detection element is provided so as to sandwich the electrothermal heater (2) in at least a part of the arrangement direction.
  • thermocouple row (3A) in which a first thermocouple having a first hot junction (5A) and a first cold junction (5B) is connected in series and arranged in a direction perpendicular to the longitudinal direction;
  • a second thermocouple row (3B) in which a second thermocouple having a second hot junction (6A) and a second cold junction (6B) is connected in series and arranged in a direction perpendicular to the longitudinal direction, Have,
  • the first thermocouple row (3A) and the second thermocouple row (3B) have a linear shape between the first hot junction (5A) row and the second hot
  • the holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple.
  • the holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple.
  • the detection device (1, 1A, 1B, 1D) according to appendix 7, characterized in that the detection device (1, 1A, 1B, 1D) is provided in two places on both sides in the direction of arrangement of the thermocouples with the electrothermal heater (2) interposed therebetween.
  • the holes (14B, 14C) further include the first thermocouple and the second thermocouple in a region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged.
  • the detection device (1B, 1C) according to appendix 8, wherein the detection device (1B, 1C) is provided so as to sandwich the electrothermal heater (2) in at least a part of the arranging direction.
  • Detection device 1A Detection device 1B: Detection device 1C: Detection device 1D: Detection device 2: Heater 3A: Thermopile 3B: Thermopile 5A: Hot junction 5B: Hot junction 6A: Cold junction 6B: Cold junction 7: Polysilicon layer 8: Silicon oxide film 9: Silicon nitride film 10: Substrate 10A: Substrate 11: Cavity 11G: Cavity 12: Opening 13: Silicon oxide film 14: Etching hole 14A: Etching hole 14B: Etching hole 14C: Etching hole 14D: Etching hole 14D 14E: Etching hole 14F: Etching hole 14G: Etching hole 15: Sacrificial layer Poly-Si layer 16: Surface portion 17: Gap 30: Detector 34: Etching hole 41: Cavity 42: Opening

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Abstract

The present invention is a method for forming a detection element, the method including: a step for forming, on a surface of a substrate comprising a single crystal semiconductor, a sacrifice layer film which is a thin film comprising a polycrystalline semiconductor; a step for forming, on the sacrifice layer film, an element thin film layer that includes the function of a detection element; a step for partially eroding and removing the element thin film layer to form a hole that penetrates through the element thin film layer and connects the outside of the system with a surface of the sacrifice layer film; a step for supplying an etchant from the hole to isotropically erode and remove the sacrifice layer film; and further, a step for supplying the etchant via the space formed due to removal of the sacrifice layer to erode the substrate so as to form a cavity that opens toward the element thin film layer in the substrate.

Description

検出素子の形成方法及び検出装置Detecting element forming method and detecting device
　本発明は、検出素子の形成方法及び検出装置に関する。 The present invention relates to a method for forming a detection element and a detection device.
　半導体からなる基板に、当該基板の表面に開口を有する空洞を形成し、さらに、基板表面における空洞の開口に対向するように検出素子が配置される検出装置が開示されている（例えば特許文献１―４）。また、基板の空洞の形成方法として、空洞となる基板の部分をシリコン酸化膜で形成し、当該シリコン酸化膜をエッチングにより腐食除去することによって空洞を形成する技術が開示されている（例えば非特許文献１）。 There is disclosed a detection device in which a cavity having an opening is formed on a surface of a substrate made of a semiconductor, and a detection element is arranged so as to face the opening of the cavity on the surface of the substrate (for example, Patent Document 1). -4). Further, as a method for forming a cavity in a substrate, a technique is disclosed in which a portion of the substrate to be a cavity is formed of a silicon oxide film and the silicon oxide film is etched and removed by corrosion to form the cavity (for example, a non-patent document). Reference 1).
特許第５５３４１９３号公報Japanese Patent No. 5534193 特許第４７４２９７２号公報Japanese Patent No. 4742972 特許第４０５０８５７号公報Japanese Patent No. 4050857 米国特許出願公開第２０１５／００２０５８７号明細書US Patent Application Publication No. 2015/0020587
　特許文献１‐４に開示される基板の空洞を形成する方法として、基板表面の空洞の開口となる部分にエッチングホールを形成し、このエッチングホールから基板を腐食除去するための腐食剤を供給することが考えられる。 As a method for forming a cavity of a substrate disclosed in Patent Documents 1 to 4, an etching hole is formed in a portion of the surface of the substrate which becomes an opening of the cavity, and a corrosive agent for corroding and removing the substrate is supplied from the etching hole. It is possible.
　しかしながら、基板が単結晶構造により形成される場合、腐食の進行に異方性があると考えられる。従って、腐食除去する領域の制御が困難で、所望の領域に空洞を設けるためにはエッチングホールの設置場所を厳密に検討する必要があると考えられる。 However, when the substrate has a single crystal structure, it is considered that the progress of corrosion is anisotropic. Therefore, it is considered that it is difficult to control the area to be removed by corrosion, and it is necessary to strictly consider the installation location of the etching hole in order to provide the cavity in the desired area.
　一方、非特許文献１に開示される空洞の作成方法の場合、エッチングホールを設けずに済む。しかしながら、このような空洞の作成方法の場合、空洞の深さは、酸化膜の膜厚に相当するものとなる。そうすると、空洞が浅く形成され、空洞内の熱は空洞の底部を介して基板へ移動してしまうため、本作成方法を熱（分布）の検出装置に適用し、検出素子が空洞の開口部分に配置される場合には、熱（分布）に対する感度が低下する不都合がある。 On the other hand, in the method of creating a cavity disclosed in Non-Patent Document 1, it is not necessary to provide an etching hole. However, in the case of such a cavity forming method, the depth of the cavity corresponds to the film thickness of the oxide film. Then, the cavity is formed shallowly, and the heat in the cavity moves to the substrate through the bottom of the cavity. Therefore, this method is applied to the heat (distribution) detection device, and the detection element is applied to the opening of the cavity. When arranged, there is a disadvantage that the sensitivity to heat (distribution) decreases.
　本発明者は、従来技術においては、腐食剤を供給するエッチングホールの設置場所の自由度が低くなり、あるいは、熱（分布）の検出装置における感度が低下することを見出した。 The present inventor has found that, in the prior art, the degree of freedom of the installation location of the etching hole for supplying the corrosive agent is lowered, or the sensitivity of the heat (distribution) detection device is lowered.
　本発明は、一側面では、このような実情を鑑みてなされたものであり、その目的は、腐食剤を供給するエッチングホールの設置場所の自由度を向上させつつ、熱（分布）に対してより高い感度を有する検出装置を形成する技術を提供することである。 The present invention, in one aspect, has been made in view of such circumstances, and an object thereof is to improve the degree of freedom of an installation place of an etching hole for supplying a corrosive agent and to prevent heat (distribution). It is an object of the present invention to provide a technique for forming a detection device having higher sensitivity.
　本発明は、上述した課題を解決するために、以下の構成を採用する。 The present invention adopts the following configurations in order to solve the above problems.
　すなわち本発明の一側面に係る検出素子の形成方法は、単結晶半導体からなる基板の表面に、多結晶半導体からなる薄膜である犠牲層膜を形成する工程と、前記犠牲層膜の上に、検出素子としての機能を含む素子薄膜層を形成する工程と、前記素子薄膜層を部分的に腐食除去することで、該素子薄膜層を貫通し、系外と前記犠牲層膜の表面とを繋ぐ孔を形成する工程と、前記孔から腐食液を供給することで、前記犠牲層膜を等方的に腐食させて除去する工程と、さらに、前記犠牲層膜が除去された空間を介して腐食液を供給して前記基板を腐食させることで、前記基板に、前記素子薄膜層に対して開口する空洞を形成する工程と、を有する、検出素子の形成方法である。 That is, the method for forming a detection element according to one aspect of the present invention comprises a step of forming a sacrificial layer film which is a thin film made of a polycrystalline semiconductor on the surface of a substrate made of a single crystal semiconductor, and the sacrificial layer film, A step of forming an element thin film layer having a function as a detection element, and partially corroding and removing the element thin film layer to penetrate the element thin film layer and connect the outside of the system to the surface of the sacrificial layer film. A step of forming a hole, a step of isotropically corroding and removing the sacrificial layer film by supplying a corrosive liquid from the hole, and further a step of corroding through the space where the sacrificial layer film is removed. A step of forming a cavity opening to the element thin film layer in the substrate by supplying a liquid to corrode the substrate.
　当該方法によれば、所定の腐食液が孔へ供給される場合、所定の腐食液による犠牲層膜の腐食が進行する。また、犠牲層膜に浸透した所定の腐食液が基板へも浸透し、基板の腐食が進行する。よって、基板に設けられた空洞の開口の形状を、犠牲層膜の形状に合わせることが可能となる。そして、当該開口部分に熱電対が存在する検出素子が形成される。 According to the method, when the predetermined corrosive liquid is supplied to the holes, the sacrificial layer film is corroded by the predetermined corrosive liquid. Further, the predetermined corrosive liquid that has penetrated into the sacrificial layer film also permeates into the substrate, and the substrate is corroded. Therefore, it is possible to match the shape of the opening of the cavity provided in the substrate with the shape of the sacrificial layer film. And the detection element in which the thermocouple exists in the said opening part is formed.
　また、当該方法によれば、腐食液を供給する孔の位置が何れの位置であっても、孔から供給された腐食液は犠牲層膜を腐食除去し、このように腐食除去された領域に基づいて、さらに基板を腐食除去することが可能となる。すなわち、上記の検出素子の形成方法によれば、孔の設置場所の自由度は向上する。その結果、当該方法によれば、検出素子の性能を向上させるために熱電対及び孔の設置場所を柔軟に変更することができる。 According to the method, the corrosive liquid supplied from the holes corrodes and removes the sacrificial layer film regardless of the position of the corrosive liquid supply holes. Based on this, it is possible to further corrode and remove the substrate. That is, according to the above-described method of forming the detection element, the degree of freedom of the installation location of the hole is improved. As a result, according to this method, it is possible to flexibly change the installation location of the thermocouple and the hole in order to improve the performance of the detection element.
　また、当該方法によれば、所定の腐食液を所定量以上入れることにより、基板の腐食が進行し、所定の膜厚以上の深さの空洞を形成することができる。よって、空洞の底を介して熱が基板へ移動することは抑制される。よって、熱の変化に対する熱電対の検出感度が低下することは抑制される。 In addition, according to the method, the corrosion of the substrate progresses by adding a predetermined amount or more of a predetermined corrosive liquid, and it is possible to form a cavity having a depth of a predetermined film thickness or more. Therefore, heat transfer to the substrate through the bottom of the cavity is suppressed. Therefore, the decrease in the detection sensitivity of the thermocouple with respect to the change in heat is suppressed.
　また、当該方法によれば、基板の裏面側に開口が形成される場合と比較し、空洞の寸法のばらつきを抑制することができる。よって、熱の分布のばらつきは抑制され、熱電対の出力がばらつくことは抑制される。 Also, according to the method, it is possible to suppress the variation in the dimension of the cavity as compared with the case where the opening is formed on the back surface side of the substrate. Therefore, variations in heat distribution are suppressed, and variations in thermocouple output are suppressed.
　また、当該方法によれば、基板の表側に空洞の開口を形成することができる。よって、基板の表側と裏側とが開口している空洞を有する基板よりも、剛性の高い基板を生成することができる。 Also, according to this method, a cavity opening can be formed on the front side of the substrate. Therefore, it is possible to generate a substrate having higher rigidity than a substrate having a cavity in which the front side and the back side of the substrate are open.
　上記一側面に係る検出素子の形成方法において、前記犠牲層膜が形成される工程は、前記基板の表面に絶縁膜が形成される工程と、前記絶縁膜の一部が除去される工程と、前記絶縁膜が除去され前記基板が露出した露出部分の表面と、前記露出部分を囲む前記絶縁膜の縁の表面に前記犠牲層膜が形成される工程を含んでもよい。 In the method for forming a detection element according to the one aspect, the step of forming the sacrificial layer film, the step of forming an insulating film on the surface of the substrate, the step of removing a part of the insulating film, The method may include the step of forming the sacrificial layer film on a surface of an exposed portion where the insulating film is removed and the substrate is exposed, and a surface of an edge of the insulating film that surrounds the exposed portion.
　当該方法によれば、絶縁膜が除去された部分に設けられる犠牲層膜が腐食される。また、当該犠牲層膜の下方に位置する基板も腐食される。ここで、基板の腐食にばらつきが生じることが考えられる。しかしながら、このような場合であっても、絶縁膜が除去された部分を囲む絶縁膜の縁の表面に設けられた犠牲層膜の腐食は等方的に進行する。すなわち、基板の腐食がばらつくことにより空洞の寸法にばらつきが生じる場合であっても、空洞に露出する素子薄膜層の面積のばらつきは抑制される。よって、空洞内に分布する熱が膜を介して熱電対へ伝わる度合いのばらつきは抑制される。よって、熱電対の感度のばらつきは抑制される。 According to this method, the sacrificial layer film provided in the portion where the insulating film is removed is corroded. Further, the substrate located below the sacrifice layer film is also corroded. Here, it is considered that the corrosion of the substrate varies. However, even in such a case, corrosion of the sacrificial layer film provided on the surface of the edge of the insulating film surrounding the part where the insulating film is removed proceeds isotropically. That is, even if the dimensions of the cavity vary due to the variation in the corrosion of the substrate, the variation in the area of the element thin film layer exposed in the cavity is suppressed. Therefore, the variation in the degree of transfer of heat distributed in the cavity to the thermocouple through the film is suppressed. Therefore, variations in the sensitivity of the thermocouple are suppressed.
　上記一側面に係る検出素子の形成方法において、前記検出素子は、第一の温接点、及び第一の冷接点を有する第一の熱電対を直列に繋げて長手方向と垂直な方向に並べた第一熱電対列と、第二の温接点、及び第二の冷接点を有する第二の熱電対を直列に繋げて長手方向と垂直な方向に並べた第二熱電対列と、を有し、前記第一熱電対列と前記第二熱電対列とを、前記第一の温接点の列と前記第二の温接点の列とが直線状の電熱ヒータを挟んで対向するように配置することで形成された検出素子であり、前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側に設けられることを特徴としてもよい。 In the method for forming a detection element according to the one aspect, the detection element has a first hot junction and a first thermocouple having a first cold junction connected in series and arranged in a direction perpendicular to the longitudinal direction. A first thermocouple array and a second thermocouple array in which a second thermocouple having a second hot junction and a second cold junction is connected in series and arranged in a direction perpendicular to the longitudinal direction. Arranging the first thermocouple row and the second thermocouple row such that the first hot junction row and the second hot junction row face each other with a linear electric heater interposed therebetween. The hole is a detection element formed by that, in the region where the first thermocouple row and the second thermocouple row are arranged, the alignment direction of the first thermocouple and the second thermocouple It may be characterized in that it is provided on both sides of.
　当該方法によれば、孔の存在により、素子薄膜層に含まれる熱が基板へ移動することは抑制される。よって、素子薄膜層の周辺に分布する熱量の低下は抑制される。よって、素子薄膜層の周辺を流体が流れる場合、流体の流速の変化に対する熱の分布の変化の感度は高まる。すなわち、熱電対の感度は高まる。 According to the method, the heat contained in the element thin film layer is suppressed from moving to the substrate due to the existence of the holes. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. That is, the sensitivity of the thermocouple is increased.
　また、当該方法によれば、孔を１つの開口として配置することが可能である。すなわち、孔の大きさを拡大することは容易となる。よって、基板に空洞を形成するために、孔から基板を腐食させる所定の腐食液を入れる場合、所定の腐食液を多く入れることは容易に行うことができる。すなわち、腐食の進行は促進される。 Also, according to the method, it is possible to arrange the holes as one opening. That is, it becomes easy to increase the size of the hole. Therefore, when a predetermined corrosive liquid that corrodes the substrate is added from the hole to form a cavity in the substrate, it is easy to add a large amount of the predetermined corrosive liquid. That is, the progress of corrosion is accelerated.
　また、当該方法によれば、素子薄膜層が基板の表側に露出するだけではなく、空洞の内部へも露出する。よって、外部環境の変化が素子薄膜層に伝わりやすくなる。よって、熱電対の感度が向上する。 According to this method, not only the element thin film layer is exposed on the front side of the substrate, but also inside the cavity. Therefore, changes in the external environment are easily transmitted to the element thin film layer. Therefore, the sensitivity of the thermocouple is improved.
　また、当該方法によれば、孔を介して空洞の外側を流れる流体が空洞の内部へ流入する。よって、熱電対の周辺の熱の移動が促進される。よって、空洞の内部に流体が流入しない場合と比較して、熱の変化を検出する熱電対の感度は向上する。 Also, according to the method, the fluid flowing outside the cavity through the hole flows into the cavity. Therefore, the movement of heat around the thermocouple is promoted. Therefore, the sensitivity of the thermocouple for detecting a change in heat is improved as compared with the case where the fluid does not flow into the inside of the cavity.
　また、当該方法によれば、孔の存在により系外と空洞とは通じている。よって、空洞の内部に流体が存在する場合、空洞が密閉されることにより、流体の特性が変化することは抑制される。よって、流体の特性が変化することにより、熱電対の検出結果が変化し、検出の正確性が低下することは抑制される。 Also, according to the method, the outside of the system and the cavity are communicated by the existence of the holes. Therefore, when the fluid exists inside the cavity, the characteristic of the fluid is prevented from changing due to the cavity being sealed. Therefore, it is possible to prevent the detection result of the thermocouple from changing due to the change of the characteristic of the fluid and the deterioration of the detection accuracy.
　また、当該方法によれば、電熱ヒータによる加熱により、電熱ヒータを中心として対称に熱の分布が生じる。そして、熱の分布が生じている場所に流体が流れる場合、当該熱の分布に変化が生じる。よって、流体が流れる場合と流れない場合とによって第一熱電対列及び第二熱電対列からの出力に差が生じる。すなわち、当該構成によれば、第一熱電対列の出力及び第二熱電対列の出力の差に基づき流体の流量は算出可能となる。 In addition, according to the method, heat is generated symmetrically around the electric heater by heating with the electric heater. When the fluid flows to the place where the heat distribution is generated, the heat distribution changes. Therefore, there is a difference in output from the first thermocouple row and the second thermocouple row depending on whether the fluid flows or not. That is, according to this configuration, the flow rate of the fluid can be calculated based on the difference between the output of the first thermocouple string and the output of the second thermocouple string.
　また、当該方法によれば、電熱ヒータによって生成された熱が素子薄膜層を介して熱電対へ伝わる。よって、熱が空気を介して熱電対へ伝わる場合よりも分布する熱の変化に対する第一熱電対列の出力及び第二熱電対列の出力の応答速度は向上する。 Also, according to the method, heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the response speed of the output of the first thermocouple array and the output of the second thermocouple array to changes in the distributed heat is improved as compared with the case where heat is transferred to the thermocouple through air.
　また、当該方法によれば、電熱ヒータによって生成された熱が素子薄膜層を介して熱電対へ伝わる。よって、空気を介して熱電対へ伝わる場合よりも熱電対へ伝わる熱量は多くなる。よって、第一熱電対列の出力及び第二熱電対列の出力は大きくなり、第一熱電対列の出力及び第二熱電対列の出力に含まれるノイズの影響は相対的に低減される。また、流体の流速が速く、熱が流体によって奪われやすい状態であっても、流体の流量は検出可能となる。 Also, according to the method, heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the amount of heat transferred to the thermocouple is larger than that transferred to the thermocouple via air. Therefore, the output of the first thermocouple string and the output of the second thermocouple string are increased, and the influence of noise contained in the output of the first thermocouple string and the output of the second thermocouple string is relatively reduced. In addition, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
　上記一側面に係る検出素子の形成方法において、前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側において、其々前記電熱ヒータを挟んで二箇所ずつ設けられることを特徴としてもよい。 In the method for forming a detection element according to the one aspect, the hole is a region in which the first thermocouple row and the second thermocouple row are arranged, of the first thermocouple and the second thermocouple. It may be characterized in that it is provided in two places on both sides in the arranging direction with the electrothermal heater interposed therebetween.
　当該方法によれば、素子薄膜層に含まれる熱が基板へ移動することは抑制される。よって、素子薄膜層の周辺に分布する熱量の低下は抑制される。よって、素子薄膜層の周辺を流体が流れる場合、流体の流速の変化に対する熱の分布の変化の感度は高まる。すなわち、熱電対の感度は高まる。 According to this method, the heat contained in the element thin film layer is suppressed from moving to the substrate. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. That is, the sensitivity of the thermocouple is increased.
　上記一側面に係る検出素子の形成方法において、前記孔は、さらに、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の少なくとも一部において、前記電熱ヒータを挟んで設けられることを特徴としてもよい。 In the method for forming a detection element according to the one aspect, the hole is further provided in a region where the first thermocouple row and the second thermocouple row are arranged, the first thermocouple and the second thermocouple. It may be characterized in that it is provided so as to sandwich the electrothermal heater in at least a part of the arranging direction of the pair.
　当該方法によれば、電熱ヒータによって生じた熱が空気を介して移動する量が多くなる。よって、素子薄膜層の表面近傍を流れる流体の流速に対する熱電対の感度が高まる。 According to this method, the amount of heat generated by the electric heater transferred through air increases. Therefore, the sensitivity of the thermocouple to the flow velocity of the fluid flowing near the surface of the element thin film layer increases.
　また、当該方法によれば、素子薄膜層の表面近傍を流体が流れる場合、素子薄膜層の表面近傍を流れる流体が孔を介して空洞の内部へ流入する量は増大する。よって、流体の流量が変化した場合の熱電対の周囲の熱の移動が促進される。すなわち、熱電対の感度は向上する。 Also, according to the method, when the fluid flows near the surface of the element thin film layer, the amount of the fluid flowing near the surface of the element thin film layer flows into the cavity through the holes increases. Therefore, the movement of heat around the thermocouple when the flow rate of the fluid changes is promoted. That is, the sensitivity of the thermocouple is improved.
　上記一側面に係る検出素子の形成方法において、前記孔の少なくとも一部は、微小な点状の微小孔の集合として形成されることを特徴としてもよい。 In the method for forming a detection element according to the above-mentioned one aspect, at least a part of the holes may be formed as a set of minute dot-shaped minute holes.
　当該方法によれば、微小孔の開孔面積の総和と同じ面積を有する１つの孔が開けられる場合と比較し、素子薄膜層の剛性は高められる。 According to the method, the rigidity of the element thin film layer is increased as compared with the case where one hole having the same area as the total area of the micropores is opened.
　上記一側面に係る検出素子の形成方法によって形成された検出素子を有する検出装置であって、前記検出素子は、第一の温接点、及び第一の冷接点を有する第一の熱電対を直列に繋げて長手方向と垂直な方向に並べた第一熱電対列と、第二の温接点、及び第二の冷接点を有する第二の熱電対を直列に繋げて長手方向と垂直な方向に並べた第二熱電対列と、を有し、前記第一熱電対列と前記第二熱電対列とを、前記第一の温接点の列と前記第二の温接点の列とが直線状の電熱ヒータを挟んで対向するように配置することで形成された検出素子であり、前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側に設けられることを特徴としてもよい。 A detection device having a detection element formed by the method for forming a detection element according to the one aspect, wherein the detection element is a series of first thermocouples having a first hot junction and a first cold junction. In the direction perpendicular to the longitudinal direction by connecting the first thermocouple row connected in the direction perpendicular to the longitudinal direction and the second thermocouple having the second hot junction and the second cold junction in series. A second thermocouple row arranged, the first thermocouple row and the second thermocouple row, the first hot junction row and the second hot junction row are linear Is a detection element formed by arranging so as to face each other across the electrothermal heater, the hole, in the region in which the first thermocouple row and the second thermocouple row is arranged, the first The thermocouple and the second thermocouple may be provided on both sides in the arranging direction.
　当該構成によれば、孔の存在により、素子薄膜層に含まれる熱が基板へ移動することは抑制される。よって、素子薄膜層の周辺に分布する熱量の低下は抑制される。よって、素子薄膜層の周辺を流体が流れる場合、流体の流速の変化に対する熱の分布の変化の感度は高まる。よって、熱電対の感度は高まる。 According to this configuration, the heat contained in the element thin film layer is suppressed from moving to the substrate due to the existence of the holes. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. Therefore, the sensitivity of the thermocouple is increased.
　また、当該構成によれば、孔を１つの開口として配置することが可能である。すなわち、孔の大きさを拡大することは容易となる。よって、基板に空洞を形成するために、孔から基板を腐食させる所定の腐食液を入れる場合、所定の腐食液を多く入れることは容易に行うことができる。すなわち、腐食の進行は促進される。 Moreover, according to the said structure, it is possible to arrange a hole as one opening. That is, it becomes easy to increase the size of the hole. Therefore, when a predetermined corrosive liquid that corrodes the substrate is added from the hole to form a cavity in the substrate, it is easy to add a large amount of the predetermined corrosive liquid. That is, the progress of corrosion is accelerated.
　また、当該構成によれば、素子薄膜層が基板の表側に露出するだけではなく、空洞の内部へも露出する。よって、外部環境の変化が素子薄膜層に伝わりやすくなる。よって、熱電対の感度が向上する。 Also, according to the configuration, not only the element thin film layer is exposed on the front side of the substrate, but also exposed inside the cavity. Therefore, changes in the external environment are easily transmitted to the element thin film layer. Therefore, the sensitivity of the thermocouple is improved.
　また、当該構成によれば、孔を介して空洞の外側を流れる流体が空洞の内部へ流入する。よって、熱電対の周辺の熱の移動が促進される。よって、空洞の内部に流体が流入しない場合と比較して、熱の変化を検出する熱電対の感度は向上する。 Also, according to the configuration, the fluid flowing outside the cavity through the hole flows into the inside of the cavity. Therefore, the movement of heat around the thermocouple is promoted. Therefore, the sensitivity of the thermocouple for detecting a change in heat is improved as compared with the case where the fluid does not flow into the inside of the cavity.
　また、当該構成によれば、孔の存在により系外と空洞とは通じている。よって、空洞の内部に流体が存在する場合、空洞が密閉されることにより、流体の特性が変化することは抑制される。よって、流体の特性が変化することにより、熱電対の検出結果が変化し、検出の正確性が低下することは抑制される。 Also, according to the configuration, the outside of the system communicates with the cavity due to the existence of the holes. Therefore, when the fluid exists inside the cavity, the characteristic of the fluid is prevented from changing due to the cavity being sealed. Therefore, it is possible to prevent the detection result of the thermocouple from changing due to the change of the characteristic of the fluid and the deterioration of the detection accuracy.
　また、当該構成によれば、電熱ヒータによる加熱により、電熱ヒータを中心として対称に熱の分布が生じる。そして、熱の分布が生じている場所に流体が流れる場合、当該熱の分布に変化が生じる。よって、流体が流れる場合と流れない場合とによって第一熱電対列及び第二熱電対列からの出力に差が生じる。すなわち、当該構成によれば、第一熱電対列の出力及び第二熱電対列の出力の差に基づき流体の流量は算出可能となる。 In addition, according to the configuration, heating by the electric heater causes a symmetrical heat distribution around the electric heater. When the fluid flows to the place where the heat distribution is generated, the heat distribution changes. Therefore, there is a difference in output from the first thermocouple row and the second thermocouple row depending on whether the fluid flows or not. That is, according to this configuration, the flow rate of the fluid can be calculated based on the difference between the output of the first thermocouple string and the output of the second thermocouple string.
　また、当該構成によれば、電熱ヒータによって生成された熱が素子薄膜層を介して熱電対へ伝わる。よって、熱が空気を介して熱電対へ伝わる場合よりも分布する熱の変化に対する第一熱電対列の出力及び第二熱電対列の出力の応答速度は向上する。 Also, according to the configuration, the heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the response speed of the output of the first thermocouple array and the output of the second thermocouple array to changes in the distributed heat is improved as compared with the case where heat is transferred to the thermocouple through air.
　また、当該構成によれば、電熱ヒータによって生成された熱が素子薄膜層を介して熱電対へ伝わる。よって、空気を介して熱電対へ伝わる場合よりも熱電対へ伝わる熱量は多くなる。よって、第一熱電対列の出力及び第二熱電対列の出力は大きくなり、第一熱電対列の出力及び第二熱電対列の出力に含まれるノイズの影響は相対的に低減される。また、流体の流速が速く、熱が流体によって奪われやすい状態であっても、流体の流量は検出可能となる。 Also, according to the configuration, the heat generated by the electric heater is transferred to the thermocouple through the element thin film layer. Therefore, the amount of heat transferred to the thermocouple is larger than that transferred to the thermocouple via air. Therefore, the output of the first thermocouple string and the output of the second thermocouple string are increased, and the influence of noise contained in the output of the first thermocouple string and the output of the second thermocouple string is relatively reduced. In addition, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
　上記一側面に係る検出装置において、前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側において、其々前記電熱ヒータを挟んで二箇所ずつ設けられることを特徴としてもよい。 In the detection device according to the above-mentioned one aspect, the hole is a region in which the first thermocouple row and the second thermocouple row are arranged, in a direction in which the first thermocouple and the second thermocouple are arranged. It may be characterized in that it is provided at two places on both sides with the electric heater interposed therebetween.
　当該構成によれば、素子薄膜層に含まれる熱が基板へ移動することは抑制される。よって、素子薄膜層の周辺に分布する熱量の低下は抑制される。よって、素子薄膜層の周辺を流体が流れる場合、流体の流速の変化に対する熱の分布の変化の感度は高まる。よって、熱電対の感度が高まる。 According to the configuration, heat contained in the element thin film layer is suppressed from moving to the substrate. Therefore, the decrease in the amount of heat distributed around the element thin film layer is suppressed. Therefore, when the fluid flows around the element thin film layer, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. Therefore, the sensitivity of the thermocouple is increased.
　上記一側面に係る検出装置において、前記孔は、さらに、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の少なくとも一部において、前記電熱ヒータを挟んで設けられることを特徴としてもよい。 In the detection device according to the one aspect, the hole is further arranged in a region where the first thermocouple row and the second thermocouple row are arranged, in which the first thermocouple and the second thermocouple are arranged. The electrothermal heater may be sandwiched in at least a part of the direction.
　当該構成によれば、電熱ヒータによって生じた熱が空気を介して移動する量が多くなる。よって、素子薄膜層の表面近傍を流れる流体の流速に対する熱電対の感度が高まる。 According to this configuration, the amount of heat generated by the electric heater transferred through air increases. Therefore, the sensitivity of the thermocouple to the flow velocity of the fluid flowing near the surface of the element thin film layer increases.
　また、当該構成によれば、素子薄膜層の表面近傍を流体が流れる場合、素子薄膜層の表面近傍を流れる流体が孔を介して空洞の内部へ流入する量は増大する。よって、流体の流量が変化した場合の熱電対の周囲の熱の移動が促進される。すなわち、熱電対の感度は向上する。 In addition, according to the configuration, when the fluid flows near the surface of the element thin film layer, the amount of the fluid flowing near the surface of the element thin film layer flows into the cavity through the holes increases. Therefore, the movement of heat around the thermocouple when the flow rate of the fluid changes is promoted. That is, the sensitivity of the thermocouple is improved.
　上記一側面に係る検出装置において、前記孔の少なくとも一部は、微小な点状の微小孔の集合として形成されることを特徴としてもよい。 In the detection device according to the above-mentioned one aspect, at least a part of the holes may be formed as a set of minute dot-shaped minute holes.
　当該構成によれば、微小孔の開孔面積の総和と同じ面積を有する１つの孔が開けられる場合と比較し、素子薄膜層の剛性は高められる。 According to the configuration, the rigidity of the element thin film layer is increased as compared with the case where one hole having the same area as the total area of the micro holes is opened.
　本発明によれば、腐食剤を供給するエッチングホールの設置場所の自由度を向上させつつ、熱（分布）に対してより高い感度を有する検出装置を形成する技術を提供することができる。 According to the present invention, it is possible to provide a technique for forming a detection device having higher sensitivity to heat (distribution) while improving the degree of freedom of the installation place of the etching hole for supplying the corrosive agent.
図１は、実施形態に係る検出装置の概要の一例を模式的に例示する。FIG. 1 schematically illustrates an example of the outline of the detection device according to the embodiment. 図２Ａは、流体が流れていない場合の温度分布の一例を模式的に例示する。FIG. 2A schematically illustrates an example of temperature distribution when a fluid is not flowing. 図２Ｂは、流体が流れている場合の温度分布の一例を模式的に例示する。FIG. 2B schematically illustrates an example of temperature distribution when a fluid is flowing. 図３は、実施形態に係る検出装置の形成方法の一例を例示するフローチャートである。FIG. 3 is a flowchart illustrating an example of a method for forming the detection device according to the embodiment. 図４は、検出装置の形成方法の一工程を模式的に例示する。FIG. 4 schematically illustrates one step of the method for forming the detection device. 図５は、検出装置の形成方法の一工程を模式的に例示する。FIG. 5 schematically illustrates one step of the method for forming the detection device. 図６は、検出装置の形成方法の一工程を模式的に例示する。FIG. 6 schematically illustrates one step of the method for forming the detection device. 図７は、検出装置の形成方法の一工程を模式的に例示する。FIG. 7 schematically illustrates one step of the method for forming the detection device. 図８は、検出装置の形成方法の一工程を模式的に例示する。FIG. 8 schematically illustrates one step of the method for forming the detection device. 図９は、検出装置の形成方法の一工程を模式的に例示する。FIG. 9 schematically illustrates one step of the method for forming the detection device. 図１０は、従来の検出装置の概要の一例を模式的に例示する。FIG. 10 schematically illustrates an example of the outline of a conventional detection device. 図１１Ａは、基板に矩形のエッチングホールを設けた場合に形成される空洞の概要を模式的に例示する。FIG. 11A schematically illustrates an outline of a cavity formed when a rectangular etching hole is provided in a substrate. 図１１Ｂは、基板に楕円形のエッチングホールを設けた場合に形成される空洞の概要を模式的に例示する。FIG. 11B schematically illustrates the outline of the cavity formed when the substrate is provided with an elliptical etching hole. 図１１Ｃは、基板にスリット状のエッチングホールを設けた場合に形成される空洞の概要を模式的に例示する。FIG. 11C schematically illustrates an outline of a cavity formed when a slit-shaped etching hole is provided in the substrate. 図１２は、基板に複数のエッチングホールが設けられる場合に、形成される空洞の概要を模式的に例示する。FIG. 12 schematically illustrates an outline of a cavity formed when a plurality of etching holes is provided in a substrate. 図１３Ａは、エッチングホールが、複数の小さな孔から形成される検出装置の概要の一例を模式的に例示する。FIG. 13A schematically illustrates an example of an outline of a detection device in which an etching hole is formed by a plurality of small holes. 図１３Ｂは、エッチングホールが、複数の小さな孔から形成され、さらにそれらの孔の一部がヒータとサーモパイルとの間に設けられる検出装置の概要の一例を模式的に例示する。FIG. 13B schematically illustrates an example of the outline of the detection device in which the etching hole is formed of a plurality of small holes and a part of the holes is provided between the heater and the thermopile. 図１３Ｃは、ヒータとサーモパイルとの間に設けられるエッチングホールが、複数の小さな孔から形成される検出装置の概要の一例を模式的に例示する。FIG. 13C schematically exemplifies an example of the outline of a detection device in which the etching hole provided between the heater and the thermopile is formed of a plurality of small holes. 図１４Ａは、実施形態の変形例に係る検出装置の上面図の概要の一例を模式的に例示する。FIG. 14A schematically illustrates an example of an outline of a top view of a detection device according to a modified example of the embodiment. 図１４Ｂは、実施形態の変形例に係る検出装置の断面図の概要の一例を模式的に例示する。FIG. 14B schematically illustrates an example of an outline of a cross-sectional view of a detection device according to a modified example of the embodiment. 図１５は、空洞の上部に位置するシリコン酸化膜がフッ酸水溶液の腐食により除去された場合の検出装置の概要の一例を模式的に例示する。FIG. 15 schematically illustrates an example of the outline of the detection device when the silicon oxide film located above the cavity is removed by the corrosion of the hydrofluoric acid aqueous solution.
　以下、本発明の一側面に係る実施の形態（以下、「本実施形態」とも表記する）を、図面に基づいて説明する。ただし、以下で説明する本実施形態は、あらゆる点において本発明の例示に過ぎない。本発明の範囲を逸脱することなく種々の改良や変形を行うことができることは言うまでもない。つまり、本発明の実施にあたって、実施形態に応じた具体的構成が適宜採用されてもよい。 Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “this embodiment”) will be described with reference to the drawings. However, the present embodiment described below is merely an example of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. That is, in implementing the present invention, a specific configuration according to the embodiment may be appropriately adopted.
　§１　構成例 §1 configuration example
　図１は、本実施形態に係る検出装置１の概要の一例を模式的に例示する。図１は、検出装置１の上面図の概要の一例を示している。検出装置１は、中央部分にヒータ２を備える。また、検出装置１は、ヒータ２を中心として対称に設けられるサーモパイル３Ａ、３Ｂを備える。ここで、ヒータ２は、本発明の「電熱ヒータ」の一例である。サーモパイル３Ａ、３Ｂは、複数の熱電対が直列に接続されるものである。また、サーモパイル３Ａが本発明の「第一の熱電対列」、サーモパイル３Ｂが本発明の「第二の熱電対列」の夫々に対応する。サーモパイル３Ａ、３Ｂが並ぶ方向は、例えばヒータ２の近傍を流れる流体の流れる向きである。また、サーモパイル３Ａ、３Ｂは、夫々温接点５Ａ、５Ｂ、及び冷接点６Ａ、６Ｂを備える。ここで、温接点５Ａは、本発明の「第一の温接点」の一例である。また、冷接点６Ａは、本発明の「第一の冷接点」の一例である。また、温接点５Ｂは、本発明の「第二の温接点」の一例である。また、冷接点６Ｂは、本発明の「第二の冷接点」の一例である。 FIG. 1 schematically illustrates an example of the outline of the detection device 1 according to the present embodiment. FIG. 1 shows an example of an outline of a top view of the detection device 1. The detection device 1 includes a heater 2 in the central portion. Further, the detection device 1 includes thermopiles 3A and 3B that are symmetrically provided about the heater 2. Here, the heater 2 is an example of the “electrothermal heater” of the present invention. The thermopiles 3A and 3B have a plurality of thermocouples connected in series. The thermopile 3A corresponds to the "first thermocouple string" of the present invention, and the thermopile 3B corresponds to the "second thermocouple string" of the present invention. The direction in which the thermopiles 3A and 3B are arranged is, for example, the direction in which the fluid flowing near the heater 2 flows. Further, the thermopiles 3A and 3B respectively include hot contacts 5A and 5B and cold contacts 6A and 6B. Here, the hot junction 5A is an example of the "first hot junction" in the present invention. The cold junction 6A is an example of the "first cold junction" in the present invention. The hot junction 5B is an example of the "second hot junction" in the present invention. The cold junction 6B is an example of the "second cold junction" in the present invention.
　また、検出装置１は、ヒータ２及びサーモパイル３Ａ、３Ｂが配置される基板１０を備える。基板１０は、単結晶のシリコンにより形成される。また、基板１０は、空洞１１を有し、空洞１１の上部に開口１２を有する。空洞１１及び開口１２は、その中央部分を中心として基板１０の表面方向に対称な形状をしている。また、検出装置１は、シリコン酸化膜８、１３（後述する）、及びシリコン窒化膜９を備える。開口１２は、シリコン酸化膜８によって覆われ、シリコン酸化膜８の上にヒータ２及びサーモパイル３Ａ，３Ｂが形成される。また、シリコン酸化膜１３は、開口１２以外の基板１０の表面を覆う。シリコン窒化膜９は、ヒータ２、及びサーモパイル３Ａ、３Ｂを上面から覆う。また、検出装置１は、サーモパイル３Ａ及び３Ｂの側方であって、開口１２の縁に、シリコン酸化膜８及びシリコン窒化膜９を貫通し、系外と開口１２とを連通させるエッチングホール１４を備える。 The detection device 1 also includes a substrate 10 on which the heater 2 and the thermopiles 3A and 3B are arranged. The substrate 10 is formed of single crystal silicon. The substrate 10 also has a cavity 11 and an opening 12 at the top of the cavity 11. The cavity 11 and the opening 12 have a symmetrical shape with respect to the surface direction of the substrate 10 with the center portion as the center. The detection device 1 also includes silicon oxide films 8 and 13 (described later) and a silicon nitride film 9. The opening 12 is covered with the silicon oxide film 8, and the heater 2 and the thermopiles 3A and 3B are formed on the silicon oxide film 8. The silicon oxide film 13 covers the surface of the substrate 10 other than the openings 12. The silicon nitride film 9 covers the heater 2 and the thermopiles 3A and 3B from the upper surface. In addition, the detection device 1 has an etching hole 14 which is lateral to the thermopiles 3A and 3B and penetrates the silicon oxide film 8 and the silicon nitride film 9 at the edge of the opening 12 to communicate the outside of the system with the opening 12. Prepare
　ここで、ヒータ２は、開口１２の中央部分に配置される。そして、サーモパイル３Ａの温接点５Ａと冷接点６Ａとは、開口１２の縁を跨ぐように設けられる。すなわち、サーモパイル３Ａの温接点５Ａは、図１に示す上面視において開口１２の内側に配置され、サーモパイル３Ａの冷接点６Ａは、開口１２の外側に配置される。同様にして、サーモパイル３Ｂの温接点５Ｂと冷接点６Ｂとは、開口１２の縁を跨ぐように設けられる。すなわち、サーモパイル３Ｂの温接点５Ｂは、開口１２の内側に配置され、サーモパイル３Ｂの冷接点６Ｂは、開口１２の外側に配置される。 Here, the heater 2 is arranged in the central portion of the opening 12. The hot contact 5A and the cold contact 6A of the thermopile 3A are provided so as to straddle the edge of the opening 12. That is, the hot contact 5A of the thermopile 3A is arranged inside the opening 12 in the top view shown in FIG. 1, and the cold contact 6A of the thermopile 3A is arranged outside the opening 12. Similarly, the hot contact 5B and the cold contact 6B of the thermopile 3B are provided so as to straddle the edge of the opening 12. That is, the hot contact 5B of the thermopile 3B is arranged inside the opening 12, and the cold contact 6B of the thermopile 3B is arranged outside the opening 12.
　§２　流量測定原理
　次に、検出装置１を用いた流量検出の原理を説明する。図２Ａ及び図２Ｂは、検出装置１を用いた流量検出の原理を模式的に例示する。図２Ａは、流体が流れていない状態でヒータ２が通電している場合の温度分布の一例を模式的に例示する。一方、図２Ｂは、流体が流れている状態でヒータ２を通電している場合の温度分布の一例を模式的に例示する。流体が流れていない場合、ヒータ２からの熱は、ヒータ２を中心として対称に拡散する。よって、温接点５Ａの温度と冷接点６Ａの温度との温度差と、温接点５Ｂの温度と冷接点６Ｂの温度との温度差とは同一となる。すなわち、サーモパイル３Ａの出力とサーモパイル３Ｂの出力との間には差は生じない。一方、流体が流れている場合、ヒータ２からの熱は、流体の流れの影響を受け、ヒータ２を中心として対称に広がらず、下流のサーモパイル３Ｂ側へ、より拡散していく。よって、温接点５Ａの温度と冷接点６Ａの温度との温度差と、温接点５Ｂの温度と冷接点６Ｂの温度との温度差とは異なる。すなわち、サーモパイル３Ａの出力とサーモパイル３Ｂの出力との間には差が生じる。また、流体の流量が多いほど、サーモパイル３Ａとサーモパイル３Ｂの出力の差は大きくなる。上記の流体の流量とサーモパイル３Ａと３Ｂの出力の差との関係は、例えば下記の数１のように表される。
Figure JPOXMLDOC01-appb-M000001
 　ここで、ΔＶはサーモパイル３Ａの出力とサーモパイル３Ｂの出力との差、ＶＬはサーモパイル３Ｂの出力値、ＶＵはサーモパイル３Ａの出力値を表す。また、Ｒｆは流体の流速である。上記の式に基づき、サーモパイル３Ａ、３Ｂの出力から流体の流量は算出可能となる。 §2 Flow rate measurement principle Next, the principle of flow rate detection using the detection device 1 will be described. 2A and 2B schematically illustrate the principle of flow rate detection using the detection device 1. FIG. 2A schematically exemplifies an example of the temperature distribution when the heater 2 is energized in a state where no fluid is flowing. On the other hand, FIG. 2B schematically illustrates an example of the temperature distribution when the heater 2 is energized while the fluid is flowing. When the fluid is not flowing, the heat from the heater 2 diffuses symmetrically around the heater 2. Therefore, the temperature difference between the temperature of the hot junction 5A and the temperature of the cold junction 6A is the same as the temperature difference between the temperature of the hot junction 5B and the temperature of the cold junction 6B. That is, there is no difference between the output of the thermopile 3A and the output of the thermopile 3B. On the other hand, when the fluid is flowing, the heat from the heater 2 is affected by the flow of the fluid, does not spread symmetrically around the heater 2, and diffuses further to the downstream thermopile 3B side. Therefore, the temperature difference between the temperature of the hot junction 5A and the temperature of the cold junction 6A is different from the temperature difference between the temperature of the hot junction 5B and the temperature of the cold junction 6B. That is, there is a difference between the output of the thermopile 3A and the output of the thermopile 3B. Further, the larger the flow rate of the fluid, the larger the difference between the outputs of the thermopile 3A and the thermopile 3B. The relationship between the flow rate of the fluid and the difference between the outputs of the thermopiles 3A and 3B is expressed by the following mathematical expression 1, for example.
Figure JPOXMLDOC01-appb-M000001
 Here, ΔV represents the difference between the output of the thermopile 3A and the output of the thermopile 3B, V L represents the output value of the thermopile 3B, and V U represents the output value of the thermopile 3A. Further, R f is the flow velocity of the fluid. Based on the above equation, the flow rate of the fluid can be calculated from the outputs of the thermopiles 3A and 3B.
　§３　検出装置１の形成方法
　次に、本実施形態に係る検出装置１の形成方法を説明する。図３は、本実施形態に係る検出装置１の形成方法の一例を例示するフローチャートである。なお、以下で説明する処理手順は一例に過ぎず、各処理は可能な限り変更されてよい。また、以下で説明する処理手順について、実施の形態に応じて、適宜、ステップの省略、置換、及び追加が可能である。 §3 Method of Forming Detection Device 1 Next, a method of forming the detection device 1 according to the present embodiment will be described. FIG. 3 is a flowchart illustrating an example of a method for forming the detection device 1 according to this embodiment. Note that the processing procedure described below is merely an example, and each processing may be changed as much as possible. Further, in the processing procedure described below, steps can be omitted, replaced, and added as appropriate according to the embodiment.
　（ステップＳ１０１）
　図４は、ステップＳ１０１における工程の概要の一例を模式的に例示する。ただし、図４は、検出装置１の片側を示す断面図の一例である。ステップＳ１０１では、基板１０を用意する。この基板１０は例えば、単結晶シリコンにより形成される。そして、シリコン酸化膜１３を基板１０の全面に成膜する。その後、シリコン酸化膜１３の所定の部分をフォトリソグラフィ、エッチングなどにより、除去する。ここで、シリコン酸化膜１３は、本発明の「素子薄膜層」の一例であり、本発明の「絶縁膜」の一例である。また、シリコン酸化膜１３が基板１０の全面に成膜されることは、本発明の「基板の表面に絶縁膜が形成される工程」の一例である。また、シリコン酸化膜１３の所定の部分を除去することは、本発明の「素子薄膜層を部分的に腐食除去」すること、及び本発明の「絶縁膜の一部が除去される工程」の一例である。 (Step S101)
FIG. 4 schematically illustrates an example of the outline of the process in step S101. However, FIG. 4 is an example of a cross-sectional view showing one side of the detection device 1. In step S101, the substrate 10 is prepared. The substrate 10 is made of, for example, single crystal silicon. Then, the silicon oxide film 13 is formed on the entire surface of the substrate 10. After that, a predetermined portion of the silicon oxide film 13 is removed by photolithography, etching or the like. Here, the silicon oxide film 13 is an example of the “element thin film layer” of the present invention and an example of the “insulating film” of the present invention. Forming the silicon oxide film 13 on the entire surface of the substrate 10 is an example of the “step of forming an insulating film on the surface of the substrate” in the present invention. Further, removing a predetermined portion of the silicon oxide film 13 means "partially corroding and removing the element thin film layer" of the present invention and "the step of removing a part of the insulating film" of the present invention. This is an example.
　（ステップＳ１０２）
　図５は、ステップＳ１０２における工程の概要の一例を模式的に例示する。ステップＳ１０２では、シリコン酸化膜１３を除去した部分に、ポリシリコン層１５（以降、犠牲層Ｐｏｌｙ－Ｓｉ層１５という）を形成する。犠牲層Ｐｏｌｙ－Ｓｉ層１５は、シリコンの多結晶体を含む。犠牲層Ｐｏｌｙ－Ｓｉ層１５は、シリコン酸化膜１３を除去した部分を囲むシリコン酸化膜１３の表面部分１６まで延長して形成される。ここで、犠牲層Ｐｏｌｙ－Ｓｉ層１５は、本発明の「犠牲層膜」の一例である。また、表面部分１６は、本発明の「露出部分を囲む絶縁膜の縁の表面」の一例である。また、ステップＳ１０２は、本発明の「単結晶半導体からなる基板の表面に、多結晶半導体からなる薄膜である犠牲層膜を形成する工程」の一例である。また、ステップＳ１０２は、本発明の「絶縁膜が除去され基板が露出した露出部分の表面と、露出部分を囲む絶縁膜の縁の表面に犠牲層膜が形成される工程」の一例である。 (Step S102)
FIG. 5 schematically illustrates an example of the outline of the process in step S102. In step S102, a polysilicon layer 15 (hereinafter referred to as a sacrifice layer Poly-Si layer 15) is formed in the portion where the silicon oxide film 13 is removed. The sacrificial layer Poly-Si layer 15 includes a polycrystal of silicon. The sacrificial layer Poly-Si layer 15 is formed so as to extend to the surface portion 16 of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 is removed. Here, the sacrificial layer Poly-Si layer 15 is an example of the “sacrificial layer film” in the present invention. The surface portion 16 is an example of the “surface of the edge of the insulating film surrounding the exposed portion” in the present invention. Step S102 is an example of the "step of forming a sacrificial layer film, which is a thin film made of a polycrystalline semiconductor, on the surface of the substrate made of a single crystal semiconductor" of the present invention. Step S102 is an example of the "step of forming the sacrificial layer film on the surface of the exposed portion where the insulating film is removed and the substrate is exposed and on the surface of the edge of the insulating film surrounding the exposed portion" of the present invention.
　（ステップＳ１０３）
　図６は、ステップＳ１０３における工程の概要の一例を模式的に例示する。ステップＳ１０３では、シリコン酸化膜８が基板１０を系外と絶縁させるために基板１０の上に形成される。また、シリコン酸化膜８の上には、ポリシリコン層７が形成される。そして、ヒータ２がポリシリコン層７の上に形成される。また、ポリシリコン層７の上にサーモパイル３Ａ、３Ｂが形成される。ここで、シリコン酸化膜８は、本発明の「素子薄膜層」を形成する膜の一例である。 (Step S103)
FIG. 6 schematically illustrates an example of the outline of the process in step S103. In step S103, the silicon oxide film 8 is formed on the substrate 10 to insulate the substrate 10 from the outside of the system. Further, a polysilicon layer 7 is formed on the silicon oxide film 8. Then, the heater 2 is formed on the polysilicon layer 7. Further, the thermopiles 3A and 3B are formed on the polysilicon layer 7. Here, the silicon oxide film 8 is an example of a film forming the "element thin film layer" of the present invention.
　（ステップＳ１０４）
　図７は、ステップＳ１０４における工程の概要の一例を模式的に例示する。ステップＳ１０４では、ポリシリコン層７やその上に形成されるヒータ２及びサーモパイル３Ａ、３Ｂをシリコン酸化膜８、及びシリコン窒化膜９によって被覆する。また、シリコン酸化膜８、及びシリコン窒化膜９を貫通し、系外と犠牲層Ｐｏｌｙ－Ｓｉ層１５とを連通させるエッチングホール１４を設ける。ここで、シリコン窒化膜９は、本発明の「素子薄膜層」を形成する膜の一例である。また、エッチングホール１４は、本発明の「孔」の一例である。また、ステップＳ１０３及びステップＳ１０４は、本発明の「犠牲層膜の上に、検出素子としての機能を含む素子薄膜層を形成する工程」の一例である。また、エッチングホール１４を設けることは、本発明の「素子薄膜層を貫通し、系外と犠牲層膜の表面とを繋ぐ孔を形成する工程」の一例である。 (Step S104)
FIG. 7 schematically illustrates an example of the outline of the process in step S104. In step S104, the polysilicon layer 7 and the heater 2 and the thermopiles 3A and 3B formed thereon are covered with the silicon oxide film 8 and the silicon nitride film 9. Further, an etching hole 14 is provided which penetrates the silicon oxide film 8 and the silicon nitride film 9 and connects the outside of the system to the sacrificial layer Poly-Si layer 15. Here, the silicon nitride film 9 is an example of a film forming the “element thin film layer” of the present invention. The etching hole 14 is an example of the "hole" in the present invention. Steps S103 and S104 are an example of the "step of forming an element thin film layer having a function as a detection element on the sacrificial layer film" of the present invention. Providing the etching hole 14 is an example of the "step of forming a hole that penetrates the element thin film layer and connects the outside of the system to the surface of the sacrificial layer film" of the present invention.
　（ステップＳ１０５）
　図８は、ステップＳ１０５における工程の概要の一例を模式的に例示する。ステップＳ１０５では、エッチングホール１４から犠牲層Ｐｏｌｙ－Ｓｉ層１５及び基板１０を腐食させる腐食液を供給する。腐食液は、例えばＴＭＡＨ(Ｔｅｔｒａｍｅｔｈｙｌａｍｍｏｎｉｕｍ　ｈｙｄｒｏｘｉｄｅ)液である。ここで、ＴＭＡＨ液は、本発明の「所定の腐食液」の一例である。 (Step S105)
FIG. 8 schematically illustrates an example of the outline of the process in step S105. In step S105, a corrosive liquid that corrodes the sacrificial layer Poly-Si layer 15 and the substrate 10 is supplied from the etching hole 14. The corrosive liquid is, for example, TMAH (Tetramethylammonium hydroxide) liquid. Here, the TMAH liquid is an example of the "predetermined corrosive liquid" of the present invention.
　犠牲層Ｐｏｌｙ－Ｓｉ層１５は、シリコンの多結晶体を含むため、ＴＭＡＨ液によって腐食が等方的に進行する性質を有する。すなわち、犠牲層Ｐｏｌｙ－Ｓｉ層１５は、基板１０の実装面方向に腐食が等方的に進行していく。また、ＴＭＡＨ液は、犠牲層Ｐｏｌｙ－Ｓｉ層１５を介し、基板１０へも浸透する。そして、基板１０も腐食が進行する。 Since the sacrificial layer Poly-Si layer 15 contains a polycrystal of silicon, it has a property that corrosion proceeds isotropically by the TMAH solution. That is, the sacrificial layer Poly-Si layer 15 isotropically corrodes in the mounting surface direction of the substrate 10. Further, the TMAH liquid also penetrates into the substrate 10 via the sacrificial layer Poly-Si layer 15. Then, the substrate 10 is also corroded.
　（ステップＳ１０６）
　図９は、ステップＳ１０６における工程の概要の一例を模式的に例示する。ステップＳ１０６では、ＴＭＡＨ液の腐食は、ステップＳ１０２において、シリコン酸化膜１３を除去した部分を囲むシリコン酸化膜１３の表面部分１６の上に存在する犠牲層Ｐｏｌｙ－Ｓｉ層１５が腐食され、隙間１７が形成されるまで行われる。そして、基板１０が所望の深さまで腐食が進行し、基板１０に空洞１１が形成される。そして、ＴＭＡＨ液のエッチングホール１４からの供給は停止される。ここで、ステップＳ１０６及びステップＳ１０７は、本発明の「孔から腐食液を供給することで、犠牲層膜を等方的に腐食させて除去する工程」の一例である。また、ステップＳ１０６及びステップＳ１０７は、本発明の「前記犠牲層膜が除去された空間を介して腐食液を供給して前記基板を腐食させることで、前記基板に、前記素子薄膜層に対して開口する空洞を形成する工程」の一例である。 (Step S106)
FIG. 9 schematically illustrates an example of the outline of the process in step S106. In the step S106, the TMAH solution is corroded by corroding the sacrificial layer Poly-Si layer 15 existing on the surface portion 16 of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 is removed in the step S102, and the gap 17 is formed. Until the formation of. Then, the substrate 10 is corroded to a desired depth, and the cavity 11 is formed in the substrate 10. Then, the supply of the TMAH liquid from the etching hole 14 is stopped. Here, step S106 and step S107 are an example of the "step of removing the sacrificial layer film by isotropically corroding and removing the sacrificial layer film by supplying the corrosive liquid from the hole" of the present invention. In addition, steps S106 and S107 are performed by supplying the corrosive liquid through the space from which the sacrificial layer film is removed to corrode the substrate, so that the substrate is provided with respect to the element thin film layer. It is an example of a "process of forming a cavity that opens."
　図１０は、従来の検出装置３０の形成工程によって形成された従来の検出装置３０の上面図の概要の一例を示している。従来の検出装置３０の形成工程では、基板１０Ａの上に犠牲層Ｐｏｌｙ－Ｓｉ層１５を設けない。また、従来の検出装置３０の形成工程では、エッチングホール３４は、シリコン酸化膜８、及びシリコン窒化膜９を貫通するように設けない。従来の検出装置３０では、エッチングホール３４を基板１０Ａに設ける。また、従来の検出装置３０では、基板１０Ａの中央部分にエッチングホール３４を複数備える。 FIG. 10 shows an example of an outline of a top view of the conventional detection device 30 formed by the forming process of the conventional detection device 30. In the conventional process of forming the detection device 30, the sacrificial layer Poly-Si layer 15 is not provided on the substrate 10A. Further, in the conventional process of forming the detection device 30, the etching hole 34 is not provided so as to penetrate the silicon oxide film 8 and the silicon nitride film 9. In the conventional detection device 30, the etching hole 34 is provided in the substrate 10A. Further, the conventional detection device 30 includes a plurality of etching holes 34 in the central portion of the substrate 10A.
　図１１Ａ、図１１Ｂ、及び図１１Ｃは、基板にエッチングホールを設け、エッチングホールからＴＭＡＨ液が入れられた場合に、形成される空洞の一例を示している。図１１Ａは、エッチングホール１４Ｆが矩形である場合、図１１Ｂはエッチングホール１４Ｆが楕円形である場合、図１１Ｃは、エッチングホール１４Ｆがスリット状である場合を示している。図１１Ａ、図１１Ｂ、及び図１１Ｃに示されるように、基板１０Ａが標準的なシリコン基板（（１００）基板、ＸＹ軸が＜１１０＞方向）である場合、エッチングホールのＸ軸方向の最大横幅とＹ軸方向の最大縦幅からなる矩形の空洞１１Ｇが形成される。 11A, 11B, and 11C show an example of a cavity formed when an etching hole is provided in the substrate and the TMAH liquid is introduced from the etching hole. 11A shows the case where the etching hole 14F is rectangular, FIG. 11B shows the case where the etching hole 14F is elliptical, and FIG. 11C shows the case where the etching hole 14F is slit-shaped. As shown in FIGS. 11A, 11B, and 11C, when the substrate 10A is a standard silicon substrate ((100) substrate, XY axes are in the <110> direction), the maximum lateral width of the etching hole in the X axis direction. And a rectangular cavity 11G having the maximum vertical width in the Y-axis direction is formed.
　図１２は、基板１０Ａに複数のエッチングホール１４Ｇが設けられる場合に、形成される空洞１１Ｇの一例を示している。図１２に示されるように、複数のエッチングホール１４Ｇが設けられ、それぞれのエッチングホール１４ＧからＴＭＡＨ液が入れられた場合、エッチングホール１４Ｇ以上の大きさの空洞１１Ｇが作製可能となる。 FIG. 12 shows an example of a cavity 11G formed when a plurality of etching holes 14G are provided in the substrate 10A. As shown in FIG. 12, when a plurality of etching holes 14G are provided and the TMAH liquid is introduced from each etching hole 14G, a cavity 11G having a size larger than the etching hole 14G can be produced.
　つまり、図１１Ａ、図１１Ｂ、図１１Ｃ、及び図１２のように複数のエッチングホール３４から基板１０Ａを腐食させるための腐食液が入れられることにより、基板１０Ａの腐食が進行する。そして、基板１０Ａの中央部分に空洞４１が形成される。そして、基板表面上にヒータ２及びサーモパイル３Ａ、３Ｂが形成される。このような形成工程により従来の検出装置３０は形成される。 That is, as shown in FIGS. 11A, 11B, 11C, and 12, the corrosive liquid for corroding the substrate 10A is introduced from the plurality of etching holes 34, so that the substrate 10A is corroded. Then, the cavity 41 is formed in the central portion of the substrate 10A. Then, the heater 2 and the thermopiles 3A and 3B are formed on the surface of the substrate. The conventional detection device 30 is formed by such a forming process.
　しかしながら、従来の腐食方法の場合、基板１０Ａは、腐食液によって腐食される場合に、犠牲層Ｐｏｌｙ－Ｓｉ層１５よりも異方的に腐食される。よって、従来の腐食方法の場合、空洞４１及び開口４２の寸法にはばらつきが生じる。また、エッチングホールの位置、個数が適切に設定されない場合には、空洞４１及び開口４２を所望の形状・寸法とすることができなくなる。 However, in the case of the conventional corrosion method, the substrate 10A is anisotropically corroded than the sacrificial layer Poly-Si layer 15 when corroded by the corrosive liquid. Therefore, in the case of the conventional corrosion method, the dimensions of the cavity 41 and the opening 42 vary. Further, if the positions and the number of the etching holes are not properly set, the cavities 41 and the openings 42 cannot be formed into desired shapes and sizes.
　［作用・効果］
　上記の検出装置１の形成方法によれば、ＴＭＡＨ液がエッチングホール１４へ入れられる場合、ＴＭＡＨ液による犠牲層Ｐｏｌｙ－Ｓｉ層１５の腐食が進行する。また、犠牲層Ｐｏｌｙ－Ｓｉ層１５に浸透したＴＭＡＨ液が基板１０へも浸透し、基板１０の腐食が進行する。よって、犠牲層Ｐｏｌｙ－Ｓｉ層１５が設けられた部分が開口１２となる空洞１１が基板１０に形成される。そして、開口１２の部分にサーモパイル３Ａ、３Ｂが存在する検出装置１が形成される。 [Action/effect]
According to the method of forming the detection device 1 described above, when the TMAH liquid is introduced into the etching hole 14, the sacrifice layer Poly-Si layer 15 is corroded by the TMAH liquid. Further, the TMAH liquid that has penetrated into the sacrificial layer Poly-Si layer 15 also penetrates into the substrate 10, and the substrate 10 is corroded. Therefore, the cavity 11 having the opening 12 at the portion where the sacrificial layer Poly-Si layer 15 is provided is formed in the substrate 10. Then, the detection device 1 in which the thermopiles 3A and 3B exist in the opening 12 is formed.
　また、上記の検出装置１の形成方法によれば、犠牲層Ｐｏｌｙ－Ｓｉ層１５はシリコンの多結晶体を含む。よって、犠牲層Ｐｏｌｙ－Ｓｉ層１５の腐食は、等方的に進行する。換言すれば、ＴＭＡＨ液を供給するエッチングホール１４の位置が何れの位置であっても、エッチングホール１４から供給されたＴＭＡＨ液は犠牲層Ｐｏｌｙ－Ｓｉ層１５を腐食除去し、このように腐食除去された領域に基づいて、さらに基板１０を腐食除去することが可能となる。すなわち、上記の検出装置１の形成方法によれば、エッチングホールの設置場所の自由度は向上する。よって、サーモパイル３Ａ、３Ｂの設置場所の自由度も向上する。すなわち、当該方法によれば、検出装置１の性能を向上させるためにサーモパイル３Ａ、３Ｂ及びエッチングホール１４の設置場所を柔軟に変更することができる。 Further, according to the method of forming the detection device 1 described above, the sacrificial layer Poly-Si layer 15 includes a polycrystalline silicon body. Therefore, the corrosion of the sacrificial layer Poly-Si layer 15 proceeds isotropically. In other words, regardless of the position of the etching hole 14 for supplying the TMAH solution, the TMAH solution supplied from the etching hole 14 corrodes and removes the sacrificial layer Poly-Si layer 15. It is possible to further corrode and remove the substrate 10 based on the formed area. That is, according to the method for forming the detection device 1 described above, the degree of freedom of the installation location of the etching hole is improved. Therefore, the degree of freedom of the installation location of the thermopiles 3A and 3B is also improved. That is, according to the method, it is possible to flexibly change the installation locations of the thermopiles 3A and 3B and the etching hole 14 in order to improve the performance of the detection device 1.
　また、上記の検出装置１の形成方法によれば、ＴＭＡＨ液を入れる量に応じて基板１０の腐食が進行する。よって、所定の膜厚以上の深さの空洞１１を形成することができる。よって、空洞１１の底を介して熱が基板１０へ移動することは抑制される。よって、熱の変化に対するサーモパイル３Ａ、３Ｂの検出感度が低下することは抑制される。 Further, according to the method for forming the detection device 1 described above, the corrosion of the substrate 10 progresses according to the amount of the TMAH liquid added. Therefore, the cavity 11 having a depth equal to or larger than a predetermined film thickness can be formed. Therefore, heat transfer to the substrate 10 via the bottom of the cavity 11 is suppressed. Therefore, it is possible to prevent the detection sensitivity of the thermopiles 3A and 3B from decreasing due to heat change.
　また、上記の検出装置１の形成方法によれば、基板１０の裏面側に開口１２が形成される場合と比較し、空洞１１の寸法のばらつきを抑制することができる。よって、熱の分布のばらつきは抑制され、サーモパイル３Ａ、３Ｂの出力がばらつくことは抑制される。 Further, according to the method of forming the detection device 1 described above, it is possible to suppress variation in the dimensions of the cavity 11 as compared with the case where the opening 12 is formed on the back surface side of the substrate 10. Therefore, variations in heat distribution are suppressed, and variations in the outputs of the thermopiles 3A and 3B are suppressed.
　また、上記の検出装置１の形成方法によれば、基板１０の表側に空洞１１の開口１２を形成することができる。よって、基板の表側と裏側とが開口している空洞を有する基板よりも、剛性の高い基板１０を生成することができる。 Further, according to the method for forming the detection device 1 described above, the opening 12 of the cavity 11 can be formed on the front side of the substrate 10. Therefore, it is possible to generate the substrate 10 having higher rigidity than that of the substrate having the cavities whose front and back sides are open.
　また、上記の検出装置１の形成方法によれば、シリコン酸化膜１３が除去された部分に設けられる犠牲層Ｐｏｌｙ－Ｓｉ層１５が腐食される。また、当該犠牲層Ｐｏｌｙ－Ｓｉ層１５の下方に位置する基板１０も腐食される。ここで、基板１０の腐食にばらつきが生じることが考えられる。しかしながら、このような場合であっても、シリコン酸化膜１３が除去された部分を囲むシリコン酸化膜１３の縁の表面に設けられた犠牲層Ｐｏｌｙ－Ｓｉ層１５の腐食は等方的に進行する。そして、所定の隙間１７が形成される。すなわち、基板１０の腐食がばらつくことにより空洞１１の寸法にばらつきが生じる場合であっても、隙間１７の寸法のばらつきは抑制される。よって、空洞１１に露出するシリコン酸化膜８の面積のばらつきは抑制される。よって、空洞１１内に分布する熱がシリコン酸化膜８を介してサーモパイル３Ａ、３Ｂへ伝わる度合いのばらつきは抑制される。よって、サーモパイル３Ａ、３Ｂの感度のばらつきは抑制される。 Further, according to the method of forming the detection device 1 described above, the sacrificial layer Poly-Si layer 15 provided in the portion where the silicon oxide film 13 is removed is corroded. Further, the substrate 10 located below the sacrifice layer Poly-Si layer 15 is also corroded. Here, it is considered that the corrosion of the substrate 10 varies. However, even in such a case, the sacrificial layer Poly-Si layer 15 provided on the surface of the edge of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 has been removed corrodes isotropically. .. Then, a predetermined gap 17 is formed. That is, even when the dimensions of the cavity 11 vary due to the variation in the corrosion of the substrate 10, the variation in the dimension of the gap 17 is suppressed. Therefore, the variation in the area of the silicon oxide film 8 exposed in the cavity 11 is suppressed. Therefore, the variation in the degree of transfer of heat distributed in the cavity 11 to the thermopiles 3A and 3B through the silicon oxide film 8 is suppressed. Therefore, variations in the sensitivity of the thermopiles 3A and 3B are suppressed.
　また、上記の検出装置１によれば、ヒータ２による加熱により、ヒータ２を中心として対称に熱の分布が生じる。そして、例えばシリコン窒化膜９の表面近傍にサーモパイル３Ａからサーモパイル３Ｂへ向かって流体が流れる場合、当該熱の分布に変化が生じる。よって、流体が流れる場合と流れない場合とによってサーモパイル３Ａの出力とサーモパイル３Ｂの出力とに差が生じる。そして、上記の数１に基づき、流体の流量は算出可能となる。 Further, according to the detection device 1 described above, heating by the heater 2 causes a symmetrical heat distribution about the heater 2. Then, for example, when the fluid flows from the thermopile 3A to the thermopile 3B in the vicinity of the surface of the silicon nitride film 9, the heat distribution changes. Therefore, a difference occurs between the output of the thermopile 3A and the output of the thermopile 3B depending on whether the fluid flows or not. Then, the flow rate of the fluid can be calculated based on the above equation 1.
　また、上記の検出装置１によれば、エッチングホール１４の存在により、シリコン酸化膜８又はシリコン窒化膜９に含まれる熱が基板１０へ移動することは抑制される。よって、シリコン酸化膜８又はシリコン窒化膜９の周辺に分布する熱量の低下は抑制される。よって、シリコン酸化膜８又はシリコン窒化膜９の表面の近傍においてサーモパイル３Ａからサーモパイル３Ｂへ向かって流体が流れる場合、流体の流速の変化に対する熱の分布の変化の感度は高まる。よって、サーモパイル３Ａ、３Ｂの感度は向上する。また、流体の流速が速く、熱が流体によって奪われやすい状態であっても、流体の流量は検出可能となる。 Further, according to the detection device 1 described above, the heat contained in the silicon oxide film 8 or the silicon nitride film 9 is suppressed from moving to the substrate 10 due to the existence of the etching hole 14. Therefore, a decrease in the amount of heat distributed around the silicon oxide film 8 or the silicon nitride film 9 is suppressed. Therefore, when the fluid flows from the thermopile 3A to the thermopile 3B in the vicinity of the surface of the silicon oxide film 8 or the silicon nitride film 9, the sensitivity of the change in the heat distribution to the change in the flow velocity of the fluid increases. Therefore, the sensitivity of the thermopiles 3A and 3B is improved. In addition, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
　また、上記の検出装置１によれば、サーモパイル３Ａ、３Ｂを覆うシリコン酸化膜８又はシリコン窒化膜９が基板１０の表側に露出するだけではなく、空洞１１へも露出する。よって、外部環境の変化がシリコン酸化膜８又はシリコン窒化膜９に伝わりやすくなる。また、シリコン酸化膜８又はシリコン窒化膜９に伝わった熱が基板１０へ逃げづらくなる。よって、サーモパイル３Ａ、３Ｂの感度が向上する。 Further, according to the detection device 1 described above, not only the silicon oxide film 8 or the silicon nitride film 9 covering the thermopiles 3A and 3B is exposed on the front side of the substrate 10, but also on the cavity 11. Therefore, changes in the external environment are easily transmitted to the silicon oxide film 8 or the silicon nitride film 9. Further, the heat transferred to the silicon oxide film 8 or the silicon nitride film 9 becomes difficult to escape to the substrate 10. Therefore, the sensitivity of the thermopiles 3A and 3B is improved.
　また、上記の検出装置１によれば、エッチングホール１４を介して空洞１１の外側を流れる流体が空洞１１の内部へ流入する。よって、サーモパイル３Ａ、３Ｂの周辺の熱の移動が促進される。また、エッチングホール１４は、サーモパイル３Ａ及び３Ｂの側方であって、開口１２の縁に設けられている。すなわち、エッチングホール１４が設けられる場所は、ヒータ２やその他の部品などが存在しない場所であり、エッチングホール１４を１つの開口として大きく設けることが可能となる。よって、空洞１１の内部への流体の流入量を増大させることが容易となる。よって、空洞１１の内部に流体が流入しない場合と比較して、熱の分布の変化を検出するサーモパイル３Ａ、３Ｂの感度は向上する。また、エッチングホール１４の大きさが大きく設けられることにより、ＴＭＡＨ液を多く入れることは容易となる。よって、腐食の進行は促進される。 Further, according to the detection device 1 described above, the fluid flowing outside the cavity 11 flows into the cavity 11 through the etching hole 14. Therefore, the movement of heat around the thermopiles 3A and 3B is promoted. Further, the etching hole 14 is provided on the side of the thermopiles 3A and 3B and at the edge of the opening 12. That is, the place where the etching hole 14 is provided is a place where the heater 2 and other parts do not exist, and the etching hole 14 can be provided as a large opening. Therefore, it becomes easy to increase the amount of fluid flowing into the inside of the cavity 11. Therefore, the sensitivities of the thermopiles 3A and 3B for detecting changes in heat distribution are improved as compared with the case where the fluid does not flow into the cavity 11. Further, since the etching hole 14 is provided with a large size, it becomes easy to add a large amount of TMAH liquid. Therefore, the progress of corrosion is accelerated.
　また、上記の検出装置１によれば、エッチングホール１４の存在により系外と空洞１１とは通じている。よって、空洞１１の内部に流体が存在する場合、空洞１１の内部が昇温されつつ密閉されることにより、流体の圧力などの特性が変化することは抑制される。よって、流体の特性が変化することにより、サーモパイル３Ａ、３Ｂへの熱の伝わりの度合いが変化することは抑制される。すなわち、サーモパイル３Ａ、３Ｂの検出結果が変化し、検出の正確性が低下することは抑制される。 Further, according to the above-mentioned detection device 1, the existence of the etching hole 14 allows the outside of the system to communicate with the cavity 11. Therefore, when the fluid is present inside the cavity 11, the inside of the cavity 11 is sealed while being heated, so that the characteristics such as the pressure of the fluid are prevented from changing. Therefore, changes in the degree of heat transfer to the thermopiles 3A and 3B due to changes in the characteristics of the fluid are suppressed. That is, it is possible to prevent the detection results of the thermopiles 3A and 3B from changing and the detection accuracy from decreasing.
　また、上記の検出装置１によれば、エッチングホール１４がサーモパイル３Ａ、３Ｂの側方に設けられており、ヒータ２とサーモパイル３Ａ又は３Ｂとの間に設けられていない。よって、ヒータ２によって生成された熱が、シリコン酸化膜８又はシリコン窒化膜９を介してサーモパイル３Ａ、３Ｂへ伝わる。よって、熱が空気を介してサーモパイル３Ａ、３Ｂへ伝わる場合よりも分布する熱の変化に対するサーモパイル３Ａ、３Ｂの応答速度は向上する。 According to the detection device 1 described above, the etching hole 14 is provided on the side of the thermopile 3A, 3B, and is not provided between the heater 2 and the thermopile 3A or 3B. Therefore, the heat generated by the heater 2 is transmitted to the thermopiles 3A and 3B through the silicon oxide film 8 or the silicon nitride film 9. Therefore, the response speed of the thermopile 3A, 3B to the change of the distributed heat is improved as compared with the case where the heat is transferred to the thermopile 3A, 3B via air.
　また、上記の検出装置１によれば、ヒータ２によって生成された熱がシリコン酸化膜８又はシリコン窒化膜９を介してサーモパイル３Ａ、３Ｂへ伝わる。よって、空気を介してサーモパイル３Ａ、３Ｂへ伝わる場合よりもサーモパイル３Ａ、３Ｂへ伝わる熱量は多くなる。よって、サーモパイル３Ａ、３Ｂの出力は大きくなり、サーモパイル３Ａ、３Ｂの出力に含まれるノイズの影響は相対的に低減される。また、流体の流速が速く、熱が流体によって奪われやすい状態である場合であっても、流体の流量は検出可能となる。 Further, according to the detection device 1 described above, the heat generated by the heater 2 is transmitted to the thermopiles 3A and 3B via the silicon oxide film 8 or the silicon nitride film 9. Therefore, the amount of heat transferred to the thermopiles 3A and 3B is larger than that when transferred to the thermopiles 3A and 3B via air. Therefore, the outputs of the thermopiles 3A and 3B are increased, and the influence of noise contained in the outputs of the thermopiles 3A and 3B is relatively reduced. Further, the flow rate of the fluid can be detected even when the flow velocity of the fluid is high and heat is easily taken away by the fluid.
　§４　変形例
　以上、本発明の実施の形態を詳細に説明してきたが、前述までの説明はあらゆる点において本発明の例示に過ぎない。本発明の範囲を逸脱することなく種々の改良や変形を行うことができることは言うまでもない。例えば、以下のような変更が可能である。なお、以下では、上記実施形態と同様の構成要素に関しては同様の符号を用い、上記実施形態と同様の点については、適宜説明を省略した。以下の変形例は適宜組み合わせ可能である。 §4 Modifications The embodiments of the present invention have been described in detail above, but the above description is merely an example of the present invention in all respects. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. For example, the following changes are possible. In addition, below, the same code|symbol is used about the same component as the said embodiment, and about the same point as the said embodiment, description was abbreviate|omitted suitably. The following modifications can be combined as appropriate.
　＜４．１＞
　図１３Ａ、図１３Ｂ、及び図１３Ｃは、本実施形態の変形例に係る検出装置の概要の一例を示している。図１３Ａは、エッチングホール１４Ａが、複数の小さな孔から形成される検出装置１Ａの概要の一例を示している。そして、それら複数の小さな孔は、夫々略等しい間隔で設けられる。このような検出装置１Ａによれば、複数の孔の開孔面積の総和と同じある面積を有する１つのエッチングホールが開けられる場合と比較し、シリコン酸化膜８及びシリコン窒化膜９の剛性は高められる。 <4.1>
FIG. 13A, FIG. 13B, and FIG. 13C show an example of an outline of a detection device according to a modified example of this embodiment. FIG. 13A shows an example of the outline of the detection device 1A in which the etching hole 14A is formed by a plurality of small holes. The plurality of small holes are provided at substantially equal intervals. According to such a detection apparatus 1A, the rigidity of the silicon oxide film 8 and the silicon nitride film 9 is increased as compared with the case where one etching hole having the same area as the sum of the opening areas of the plurality of holes is opened. To be
　図１３Ｂは、エッチングホール１４Ｂが、複数の小さな孔から形成され、さらにそれらの孔の一部がヒータ２とサーモパイル３Ａ、３Ｂとの間に設けられる検出装置１Ｂの概要の一例を示している。 FIG. 13B shows an example of the outline of the detection device 1B in which the etching hole 14B is formed by a plurality of small holes, and a part of these holes is provided between the heater 2 and the thermopiles 3A, 3B.
　このような検出装置１Ｂによれば、ヒータ２により生じた熱の空気を介して移動する量が大きくなる。よって、シリコン酸化膜８又はシリコン窒化膜９の表面近傍を流れる流体の流速に対するサーモパイル３Ａ、３Ｂの感度が高まる。 According to such a detection device 1B, the amount of heat generated by the heater 2 moving through air increases. Therefore, the sensitivity of the thermopiles 3A and 3B to the flow velocity of the fluid flowing near the surface of the silicon oxide film 8 or the silicon nitride film 9 is increased.
　また、このような検出装置１Ｂによれば、シリコン酸化膜８又はシリコン窒化膜９の表面近傍を流体が流れる場合、シリコン酸化膜８又はシリコン窒化膜９の表面近傍を流れる流体がエッチングホール１４Ｂを介して空洞１１の内部へ流入する量は増大する。よって、流体の流量が変化した場合のサーモパイル３Ａ、３Ｂの周囲の熱の移動が促進される。すなわち、サーモパイル３Ａ、３Ｂの感度の低下は抑制される。 Further, according to such a detection apparatus 1B, when the fluid flows near the surface of the silicon oxide film 8 or the silicon nitride film 9, the fluid flowing near the surface of the silicon oxide film 8 or the silicon nitride film 9 causes the etching hole 14B to flow. The amount flowing into the inside of the cavity 11 through the inside increases. Therefore, the movement of heat around the thermopiles 3A and 3B when the flow rate of the fluid changes is promoted. That is, the decrease in sensitivity of the thermopiles 3A and 3B is suppressed.
　図１３Ｃは、ヒータ２とサーモパイル３Ａ、３Ｂとの間に設けられるエッチングホール１４Ｃが、複数の小さな孔から形成される検出装置１Ｃの概要の一例を示している。また、検出装置１Ｃは、エッチングホール１４Ｄが、サーモパイル３Ａ、３Ｂの側方に設けられ、開口１２の縁と連通し、１つの大きな孔から形成される部分を有する。 FIG. 13C shows an example of an outline of a detection device 1C in which an etching hole 14C provided between the heater 2 and the thermopiles 3A and 3B is formed by a plurality of small holes. Further, the detection device 1C has a portion in which the etching hole 14D is provided on the side of the thermopile 3A, 3B, communicates with the edge of the opening 12, and is formed by one large hole.
　このような検出装置１Ｃは、検出装置１Ｂの構成に加え、サーモパイル３Ａ、３Ｂの側方に設けられるエッチングホールを大きな開口とした構成である。よって、基板１０に空洞１１を形成するために、エッチングホール１４Ｄから基板１０を腐食させるＴＭＡＨ液を入れる場合、ＴＭＡＨ液を多く入れることができ、腐食の進行は促進される。 Such a detection device 1C has a configuration in which, in addition to the configuration of the detection device 1B, etching holes provided on the sides of the thermopiles 3A and 3B are large openings. Therefore, when the TMAH liquid that corrodes the substrate 10 is added from the etching hole 14D to form the cavity 11 in the substrate 10, a large amount of the TMAH liquid can be added, and the progress of the corrosion is accelerated.
　また、このような検出装置１Ｃによれば、エッチングホール１４Ｄの存在により、シリコン酸化膜８又はシリコン窒化膜９に含まれる熱が基板１０へ移動することは抑制される。よって、シリコン酸化膜８又はシリコン窒化膜９の周辺に分布する熱量の低下は抑制される。よって、シリコン酸化膜８又はシリコン窒化膜９の表面の近傍においてサーモパイル３Ａからサーモパイル３Ｂへ向かって流体が流れる場合であって、流体の流速が速く、熱が流体によって奪われやすい状態であっても、流体の流量は検出可能となる。 Further, according to such a detection device 1C, the heat contained in the silicon oxide film 8 or the silicon nitride film 9 is suppressed from moving to the substrate 10 due to the presence of the etching hole 14D. Therefore, a decrease in the amount of heat distributed around the silicon oxide film 8 or the silicon nitride film 9 is suppressed. Therefore, even when the fluid flows from the thermopile 3A to the thermopile 3B in the vicinity of the surface of the silicon oxide film 8 or the silicon nitride film 9, even if the flow velocity of the fluid is high and heat is easily removed by the fluid. , The flow rate of the fluid can be detected.
　また、このような検出装置１Ｃによれば、シリコン酸化膜８又はシリコン窒化膜９の表面近傍を流体が流れる場合、エッチングホール１４Ｄを介して空洞１１の外側を流れる流体が空洞１１の内部へ流入する。よって、サーモパイル３Ａ、３Ｂの周辺の熱の移動が促進される。また、エッチングホール１４Ｄの大きさは拡大しやすく、空洞１１の内部への流体の流入量を増大させることが容易となる。よって、空洞１１の内部に流体が流入しない場合と比較して、熱の変化を検出するサーモパイル３Ａ、３Ｂの感度は向上する。 Further, according to such a detection device 1C, when the fluid flows near the surface of the silicon oxide film 8 or the silicon nitride film 9, the fluid flowing outside the cavity 11 flows into the cavity 11 through the etching hole 14D. To do. Therefore, the movement of heat around the thermopiles 3A and 3B is promoted. Further, the size of the etching hole 14D is easily expanded, and it is easy to increase the amount of fluid flowing into the inside of the cavity 11. Therefore, the sensitivity of the thermopiles 3A and 3B for detecting a change in heat is improved as compared with the case where the fluid does not flow into the cavity 11.
　＜４．２＞
　図１４Ａ及び図１４Ｂは、本実施形態の変形例に係る検出装置の概要の一例を示している。図１４Ａは、検出装置１Ｄの上面図の概要の一例を示している。そして、図１４Ｂは、図１４ＡにおけるＡ―Ａ矢印断面図を示している。検出装置１Ｄは、ヒータ２を備えていない。そして、検出装置１Ｄのエッチングホール１４Ｅは、サーモパイル３Ａ、３Ｂの側方に位置する部分であって、系外と開口１２の縁とが連通するように設けられる。また、エッチングホール１４Ｅは、スリット状に設けられる。 <4.2>
14A and 14B show an example of an outline of a detection device according to a modified example of this embodiment. FIG. 14A shows an example of an outline of a top view of the detection device 1D. And FIG. 14B has shown the AA arrow sectional view in FIG. 14A. The detection device 1D does not include the heater 2. Then, the etching hole 14E of the detection device 1D is a portion located laterally of the thermopiles 3A and 3B, and is provided so that the outside of the system and the edge of the opening 12 communicate with each other. Further, the etching hole 14E is provided in a slit shape.
　［作用・効果］
　このような検出装置１Ｄによれば、系外からシリコン酸化膜８又はシリコン窒化膜９へ向けて赤外線が照射された場合、シリコン酸化膜８又はシリコン窒化膜９が赤外線のエネルギーを吸収することにより加熱され、温接点５Ａ又は温接点５Ｂの温度が上昇する。すなわち、このような検出装置１Ｄによれば、赤外線を検出することができる。また、エッチングホール１４Ｅがスリット状に設けられることにより、赤外線のエネルギーを吸収する部分が狭まることは抑制される。よって、感度の高い赤外線検出装置を形成することができる。 [Action/effect]
According to such a detection device 1D, when infrared rays are radiated from outside the system toward the silicon oxide film 8 or the silicon nitride film 9, the silicon oxide film 8 or the silicon nitride film 9 absorbs the infrared energy. When heated, the temperature of the hot junction 5A or the hot junction 5B rises. That is, according to such a detection device 1D, infrared rays can be detected. Further, since the etching hole 14E is provided in a slit shape, it is possible to suppress the narrowing of the portion that absorbs the infrared energy. Therefore, an infrared detection device with high sensitivity can be formed.
　また、上記のような検出装置１Ｄによれば、シリコン窒化膜９の表面に、赤外線を吸収する膜がコーティングされてもよい。赤外線を吸収する膜は、例えば、窒化チタンや金によって形成される。このような検出装置１Ｄによれば、赤外線の吸収効率は向上する。 Further, according to the detection device 1D as described above, the surface of the silicon nitride film 9 may be coated with a film that absorbs infrared rays. The film that absorbs infrared rays is formed of, for example, titanium nitride or gold. According to such a detection device 1D, the infrared absorption efficiency is improved.
　＜その他変形例＞
　また、上記の実施形態や変形例における検出装置の形成工程において、空洞１１が完成した（ステップＳ１０６）後に、ステップＳ１０７として、エッチングホール１４からフッ酸水溶液が入れられることにより、空洞１１の上部に位置するシリコン酸化膜８が腐食されてもよい。図１５は、空洞１１の上部に位置するシリコン酸化膜８がフッ酸水溶液の腐食により除去された場合の検出装置の概要の一例を示している。このような工程を含む検出装置の形成工程によれば、空洞１１の上部に位置するシリコン酸化膜８が無くなる。よって、サーモパイル３Ａ、３Ｂを覆う膜が薄くなり、空洞１１中の熱がサーモパイル３Ａ、３Ｂを覆う膜を介してサーモパイル３Ａ、３Ｂへ移動する速さは増大する。よって、流体の流量の変化に対するサーモパイル３Ａ、３Ｂの出力の感度は向上する。 <Other modifications>
In addition, in the step of forming the detection device in the above-described embodiment or modification, after the cavity 11 is completed (step S106), in step S107, the hydrofluoric acid aqueous solution is introduced from the etching hole 14, so that the cavity 11 is formed above the cavity 11. The silicon oxide film 8 located may be corroded. FIG. 15 shows an example of the outline of the detection device when the silicon oxide film 8 located above the cavity 11 is removed by the corrosion of the hydrofluoric acid aqueous solution. According to the forming process of the detecting device including such steps, the silicon oxide film 8 located above the cavity 11 is eliminated. Therefore, the film covering the thermopile 3A, 3B becomes thin, and the speed at which the heat in the cavity 11 moves to the thermopile 3A, 3B via the film covering the thermopile 3A, 3B increases. Therefore, the sensitivity of the outputs of the thermopiles 3A and 3B to changes in the flow rate of the fluid is improved.
　また、サーモパイル３Ａ、３Ｂが並べられる向きは、流体の流れる方向に限定されず、例えば流体の流れる方向を遮る方向に並べられてもよい。 The direction in which the thermopiles 3A and 3B are arranged is not limited to the direction in which the fluid flows, and may be arranged, for example, in a direction that blocks the direction in which the fluid flows.
　また、検出装置１の形成工程のステップＳ１０２において、犠牲層Ｐｏｌｙ－Ｓｉ層１５は、シリコン酸化膜１３を除去した部分を囲むシリコン酸化膜１３の表面部分１６まで延長して形成されなくともよい。すなわち、隙間１７が形成されなくともよい。 Further, in step S102 of the process of forming the detection device 1, the sacrificial layer Poly-Si layer 15 may not be formed to extend to the surface portion 16 of the silicon oxide film 13 surrounding the portion where the silicon oxide film 13 is removed. That is, the gap 17 may not be formed.
　また、エッチングホール１４の位置は、上記で例示した場所に限定されず、犠牲層Ｐｏｌｙ－Ｓｉ層１５及び基板１０を腐食可能な場所であればよい。 The position of the etching hole 14 is not limited to the position illustrated above, and may be any position where the sacrificial layer Poly-Si layer 15 and the substrate 10 can be corroded.
　また、検出装置１Ｄのエッチングホール１４Ｄは、スリット状でなくともよく、夫々略等しい間隔で設けられる複数の小さな孔から形成されてもよく、赤外線のエネルギーを吸収するシリコン窒化膜９の表面の面積が狭まることが抑制される形状であればよい。 In addition, the etching hole 14D of the detection device 1D does not have to be slit-shaped, and may be formed of a plurality of small holes provided at substantially equal intervals, and the surface area of the silicon nitride film 9 that absorbs infrared energy. It suffices that the shape is such that the narrowing is suppressed.
　また、エッチングホール１４Ａ等を形成する複数の小さな孔は、シリコン酸化膜８及びシリコン窒化膜９の剛性が高められるように形成されていればよい。よって、当該複数の小さな孔は、等しい間隔で設けられていなくともよい。また、当該複数の小さな孔の径は同一でも異なっていてもよい。 Also, the plurality of small holes forming the etching holes 14A and the like may be formed so as to increase the rigidity of the silicon oxide film 8 and the silicon nitride film 9. Therefore, the plurality of small holes may not be provided at equal intervals. The diameters of the plurality of small holes may be the same or different.
　以上で開示した実施形態や変形例はそれぞれ組み合わせる事ができる。 The embodiments and modifications disclosed above can be combined.
　なお、以下には本発明の構成要件と実施例の構成とを対比可能とするために、本発明の構成要件を図面の符号付きで記載しておく。
＜付記１＞
　単結晶半導体からなる基板（１０）の表面に、多結晶半導体からなる薄膜である犠牲層膜（１５）を形成する工程と、
　前記犠牲層膜（１５）の上に、検出素子としての機能を含む素子薄膜層（８、９、１３）を形成する工程と、
　前記素子薄膜層（８、９、１３）を部分的に腐食除去することで、該素子薄膜層（８、９、１３）を貫通し、系外と前記犠牲層膜（１５）の表面とを繋ぐ孔（１４、１４Ａ、１４Ｂ、１４Ｃ、１４Ｄ、１４Ｅ）を形成する工程と、
　前記孔（１４、１４Ａ、１４Ｂ、１４Ｃ、１４Ｄ、１４Ｅ）から腐食液を供給することで、前記犠牲層膜（１５）を等方的に腐食させて除去する工程と、
　さらに、前記犠牲層膜（１５）が除去された空間を介して腐食液を供給して前記基板（１０）を腐食させることで、前記基板（１０）に、前記素子薄膜層（８、９、１３）に対して開口（１２）する空洞（１１）を形成する工程と、
　を有する、検出素子の形成方法。
＜付記２＞
　前記犠牲層膜（１５）が形成される工程は、
　　前記基板（１０）の表面に絶縁膜（１３）が形成される工程と、
　　前記絶縁膜（１３）の一部が除去される工程と、
　　前記絶縁膜（１３）が除去され前記基板（１０）が露出した露出部分の表面と、前記露出部分を囲む前記絶縁膜（１３）の縁の表面（１６）に前記犠牲層膜（１５）が形成される工程を含む、
　付記１に記載の検出素子の形成方法。
＜付記３＞
　前記検出素子は、
　　第一の温接点（５Ａ）、及び第一の冷接点（５Ｂ）を有する第一の熱電対を直列に繋げて長手方向と垂直な方向に並べた第一熱電対列（３Ａ）と、
　　第二の温接点（６Ａ）、及び第二の冷接点（６Ｂ）を有する第二の熱電対を直列に繋げて長手方向と垂直な方向に並べた第二熱電対列（３Ｂ）と、を有し、
　前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）とを、前記第一の温接点（５Ａ）の列と前記第二の温接点（６Ａ）の列とが直線状の電熱ヒータ（２）を挟んで対向するように配置することで形成された検出素子であり、
　前記孔（１４、１４Ａ、１４Ｂ、１４Ｄ）は、前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側に設けられることを特徴とする、付記１または２に記載の検出素子の形成方法。
＜付記４＞
　前記孔（１４、１４Ａ、１４Ｂ、１４Ｄ）は、前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側において、其々前記電熱ヒータ（２）を挟んで二箇所ずつ設けられることを特徴とする、付記３に記載の検出素子の形成方法。
＜付記５＞
　前記孔（１４Ｂ、１４Ｃ）は、さらに、前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の少なくとも一部において、前記電熱ヒータ（２）を挟んで設けられることを特徴とする、付記４に記載の検出素子の形成方法。
＜付記６＞
　前記孔（１４Ａ、１４Ｂ、１４Ｃ）の少なくとも一部は、微小な点状の微小孔の集合として形成されることを特徴とする、付記３から５のいずれか一項に記載の検出素子の形成方法。
＜付記７＞
　付記１または２に記載の方法によって形成された検出素子を有する検出装置（１、１Ａ、１Ｂ、１Ｃ、１Ｄ）であって、
　前記検出素子は、
　　第一の温接点（５Ａ）、及び第一の冷接点（５Ｂ）を有する第一の熱電対を直列に繋げて長手方向と垂直な方向に並べた第一熱電対列（３Ａ）と、
　　第二の温接点（６Ａ）、及び第二の冷接点（６Ｂ）を有する第二の熱電対を直列に繋げて長手方向と垂直な方向に並べた第二熱電対列（３Ｂ）と、を有し、
　前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）とを、前記第一の温接点（５Ａ）の列と前記第二の温接点（６Ａ）の列とが直線状の電熱ヒータ（２）を挟んで対向するように配置することで形成された検出素子であり、
　前記孔（１４、１４Ａ、１４Ｂ、１４Ｄ）は、前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側に設けられることを特徴とする、検出装置（１、１Ａ、１Ｂ、１Ｃ）。
＜付記８＞
　前記孔（１４、１４Ａ、１４Ｂ、１４Ｄ）は、前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側において、其々前記電熱ヒータ（２）を挟んで二箇所ずつ設けられることを特徴とする、付記７に記載の検出装置（１、１Ａ、１Ｂ、１Ｄ）。
＜付記９＞
　前記孔（１４Ｂ、１４Ｃ）は、さらに、前記第一熱電対列（３Ａ）と前記第二熱電対列（３Ｂ）が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の少なくとも一部において、前記電熱ヒータ（２）を挟んで設けられることを特徴とする、付記８に記載の検出装置（１Ｂ、１Ｃ）。
＜付記１０＞
　前記孔（１４Ａ、１４Ｂ、１４Ｃ）の少なくとも一部は、微小な点状の微小孔の集合として形成されることを特徴とする、付記７から９のいずれか一項に記載の検出装置（１Ａ、１Ｂ、１Ｃ）。 In addition, in order to make it possible to compare the constitutional requirements of the present invention with the constitutions of the embodiments, the constitutional requirements of the present invention are described with reference numerals in the drawings.
<Appendix 1>
A step of forming a sacrificial layer film (15), which is a thin film made of a polycrystalline semiconductor, on the surface of a substrate (10) made of a single crystal semiconductor;
A step of forming an element thin film layer (8, 9, 13) having a function as a detection element on the sacrificial layer film (15);
By partially corroding and removing the element thin film layer (8, 9, 13), the element thin film layer (8, 9, 13) is penetrated and the outside of the system and the surface of the sacrificial layer film (15) are separated. A step of forming connecting holes (14, 14A, 14B, 14C, 14D, 14E),
Supplying a corrosive liquid through the holes (14, 14A, 14B, 14C, 14D, 14E) to isotropically corrode and remove the sacrificial layer film (15);
Further, a corrosive liquid is supplied through the space where the sacrificial layer film (15) is removed to corrode the substrate (10), so that the element thin film layers (8, 9, Forming a cavity (11) that opens (12) to 13);
A method of forming a detection element, comprising:
<Appendix 2>
The step of forming the sacrificial layer film (15) includes
A step of forming an insulating film (13) on the surface of the substrate (10),
A step of removing a part of the insulating film (13),
The sacrificial layer film (15) is formed on the surface of the exposed portion where the insulating film (13) is removed and the substrate (10) is exposed, and on the edge surface (16) of the insulating film (13) surrounding the exposed portion. Including the steps formed,
The method for forming a detection element according to attachment 1.
<Appendix 3>
The detection element is
A first thermocouple row (3A) in which a first thermocouple having a first hot junction (5A) and a first cold junction (5B) is connected in series and arranged in a direction perpendicular to the longitudinal direction;
A second thermocouple row (3B) in which a second thermocouple having a second hot junction (6A) and a second cold junction (6B) is connected in series and arranged in a direction perpendicular to the longitudinal direction, Have,
The first thermocouple row (3A) and the second thermocouple row (3B) have a linear shape between the first hot junction (5A) row and the second hot junction (6A) row. A detection element formed by arranging so as to face each other with the electric heater (2) interposed therebetween,
The holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple. The method for forming a detection element according to appendix 1 or 2, wherein the detection element is provided on both sides in the direction of arrangement of the thermocouples.
<Appendix 4>
The holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple. 4. The method for forming a detection element according to appendix 3, characterized in that the detection element is provided in two places on both sides in the direction of arrangement of the thermocouples with the electrothermal heater (2) interposed therebetween.
<Appendix 5>
The holes (14B, 14C) further include the first thermocouple and the second thermocouple in a region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged. 5. The method for forming a detection element according to appendix 4, characterized in that the detection element is provided so as to sandwich the electrothermal heater (2) in at least a part of the arrangement direction.
<Appendix 6>
At least a part of the holes (14A, 14B, 14C) is formed as an assembly of minute dot-shaped minute holes, wherein the detection element according to any one of appendices 3 to 5 is formed. Method.
<Appendix 7>
A detection device (1, 1A, 1B, 1C, 1D) having a detection element formed by the method according to Appendix 1 or 2,
The detection element is
A first thermocouple row (3A) in which a first thermocouple having a first hot junction (5A) and a first cold junction (5B) is connected in series and arranged in a direction perpendicular to the longitudinal direction;
A second thermocouple row (3B) in which a second thermocouple having a second hot junction (6A) and a second cold junction (6B) is connected in series and arranged in a direction perpendicular to the longitudinal direction, Have,
The first thermocouple row (3A) and the second thermocouple row (3B) have a linear shape between the first hot junction (5A) row and the second hot junction (6A) row. A detection element formed by arranging so as to face each other with the electric heater (2) interposed therebetween,
The holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple. A detection device (1, 1A, 1B, 1C), which is provided on both sides in the direction of arrangement of thermocouples.
<Appendix 8>
The holes (14, 14A, 14B, 14D) are provided in the region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged, the first thermocouple and the second thermocouple. The detection device (1, 1A, 1B, 1D) according to appendix 7, characterized in that the detection device (1, 1A, 1B, 1D) is provided in two places on both sides in the direction of arrangement of the thermocouples with the electrothermal heater (2) interposed therebetween.
<Appendix 9>
The holes (14B, 14C) further include the first thermocouple and the second thermocouple in a region where the first thermocouple string (3A) and the second thermocouple string (3B) are arranged. The detection device (1B, 1C) according to appendix 8, wherein the detection device (1B, 1C) is provided so as to sandwich the electrothermal heater (2) in at least a part of the arranging direction.
<Appendix 10>
At least a part of the holes (14A, 14B, 14C) is formed as an assembly of minute dot-shaped minute holes, The detection device (1A according to any one of appendices 7 to 9, characterized in that 1B, 1C).
１　　　　：検出装置
１Ａ　　　：検出装置
１Ｂ　　　：検出装置
１Ｃ　　　：検出装置
１Ｄ　　　：検出装置
２　　　　：ヒータ
３Ａ　　　：サーモパイル
３Ｂ　　　：サーモパイル
５Ａ　　　：温接点
５Ｂ　　　：温接点
６Ａ　　　：冷接点
６Ｂ　　　：冷接点
７　　　　：ポリシリコン層
８　　　　：シリコン酸化膜
９　　　　：シリコン窒化膜
１０　　　：基板
１０Ａ　　：基板
１１　　　：空洞
１１Ｇ　　：空洞
１２　　　：開口
１３　　　：シリコン酸化膜
１４　　　：エッチングホール
１４Ａ　　：エッチングホール
１４Ｂ　　：エッチングホール
１４Ｃ　　：エッチングホール
１４Ｄ　　：エッチングホール
１４Ｅ　　：エッチングホール
１４Ｆ　　：エッチングホール
１４Ｇ　　：エッチングホール
１５　　　：犠牲層Ｐｏｌｙ－Ｓｉ層
１６　　　：表面部分
１７　　　：隙間
３０　　　：検出装置
３４　　　：エッチングホール
４１　　　：空洞
４２　　　：開口 1: Detection device 1A: Detection device 1B: Detection device 1C: Detection device 1D: Detection device 2: Heater 3A: Thermopile 3B: Thermopile 5A: Hot junction 5B: Hot junction 6A: Cold junction 6B: Cold junction 7: Polysilicon layer 8: Silicon oxide film 9: Silicon nitride film 10: Substrate 10A: Substrate 11: Cavity 11G: Cavity 12: Opening 13: Silicon oxide film 14: Etching hole 14A: Etching hole 14B: Etching hole 14C: Etching hole 14D: Etching hole 14D 14E: Etching hole 14F: Etching hole 14G: Etching hole 15: Sacrificial layer Poly-Si layer 16: Surface portion 17: Gap 30: Detector 34: Etching hole 41: Cavity 42: Opening

Claims (10)

  1. 　単結晶半導体からなる基板の表面に、多結晶半導体からなる薄膜である犠牲層膜を形成する工程と、
    　前記犠牲層膜の上に、検出素子としての機能を含む素子薄膜層を形成する工程と、
    　前記素子薄膜層を部分的に腐食除去することで、該素子薄膜層を貫通し、系外と前記犠牲層膜の表面とを繋ぐ孔を形成する工程と、
    　前記孔から腐食液を供給することで、前記犠牲層膜を等方的に腐食させて除去する工程と、
    　さらに、前記犠牲層膜が除去された空間を介して腐食液を供給して前記基板を腐食させることで、前記基板に、前記素子薄膜層に対して開口する空洞を形成する工程と、
    　を有する、検出素子の形成方法。     A step of forming a sacrificial layer film, which is a thin film made of a polycrystalline semiconductor, on the surface of a substrate made of a single crystal semiconductor;
    A step of forming an element thin film layer having a function as a detection element on the sacrificial layer film;
    By partially removing the element thin film layer by corrosion, a step of penetrating the element thin film layer and forming a hole connecting the outside of the system and the surface of the sacrificial layer film,
    Supplying a corrosive liquid from the holes, isotropically corroding and removing the sacrificial layer film,
    Further, by supplying a corrosive liquid through the space from which the sacrificial layer film has been removed to corrode the substrate, forming a cavity in the substrate that opens to the element thin film layer,
    A method of forming a detection element, comprising:
  2. 　前記犠牲層膜が形成される工程は、
    　　前記基板の表面に絶縁膜が形成される工程と、
    　　前記絶縁膜の一部が除去される工程と、
    　　前記絶縁膜が除去され前記基板が露出した露出部分の表面と、前記露出部分を囲む前記絶縁膜の縁の表面に前記犠牲層膜が形成される工程を含む、
    　請求項１に記載の検出素子の形成方法。     The step of forming the sacrificial layer film includes
    A step of forming an insulating film on the surface of the substrate,
    A step of removing a part of the insulating film,
    And a step of forming the sacrificial layer film on a surface of an exposed portion where the insulating film is removed and the substrate is exposed, and a surface of an edge of the insulating film that surrounds the exposed portion.
    The method for forming a detection element according to claim 1.
  3. 　前記検出素子は、
    　　第一の温接点、及び第一の冷接点を有する第一の熱電対を直列に繋げて長手方向と垂直な方向に並べた第一熱電対列と、
    　　第二の温接点、及び第二の冷接点を有する第二の熱電対を直列に繋げて長手方向と垂直な方向に並べた第二熱電対列と、を有し、
    　前記第一熱電対列と前記第二熱電対列とを、前記第一の温接点の列と前記第二の温接点の列とが直線状の電熱ヒータを挟んで対向するように配置することで形成された検出素子であり、
    　前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側に設けられることを特徴とする、請求項１または２に記載の検出素子の形成方法。     The detection element is
    A first thermocouple row in which a first thermocouple having a first hot junction and a first cold junction is connected in series and arranged in a direction perpendicular to the longitudinal direction,
    A second thermocouple row in which a second thermocouple having a second hot junction and a second cold junction is connected in series and arranged in a direction perpendicular to the longitudinal direction,
    Arranging the first thermocouple row and the second thermocouple row such that the first hot junction row and the second hot junction row face each other with a linear electric heater interposed therebetween. Is a detection element formed by
    The holes are provided on both sides in a direction in which the first thermocouple and the second thermocouple are arranged in a region where the first thermocouple row and the second thermocouple row are arranged. The method for forming a detection element according to claim 1 or 2.
  4. 　前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側において、其々前記電熱ヒータを挟んで二箇所ずつ設けられることを特徴とする、請求項３に記載の検出素子の形成方法。 The hole, in the region where the first thermocouple row and the second thermocouple row are arranged, on both sides in the direction of arrangement of the first thermocouple and the second thermocouple, the electrothermal heater, respectively. The method for forming a detection element according to claim 3, wherein the detection element is provided in two places so as to be sandwiched therebetween.
  5. 　前記孔は、さらに、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の少なくとも一部において、前記電熱ヒータを挟んで設けられることを特徴とする、請求項４に記載の検出素子の形成方法。 The hole is further provided in the region where the first thermocouple row and the second thermocouple row are arranged, in at least a part of a direction in which the first thermocouple and the second thermocouple are arranged, The method for forming a detection element according to claim 4, wherein the detection element is provided with a heater interposed therebetween.
  6. 　前記孔の少なくとも一部は、微小な点状の微小孔の集合として形成されることを特徴とする、請求項３から５のいずれか一項に記載の検出素子の形成方法。 The method for forming a detection element according to any one of claims 3 to 5, wherein at least a part of the holes is formed as a set of minute dot-shaped minute holes.
  7. 　請求項１または２に記載の方法によって形成された検出素子を有する検出装置であって、
    　前記検出素子は、
    　　第一の温接点、及び第一の冷接点を有する第一の熱電対を直列に繋げて長手方向と垂直な方向に並べた第一熱電対列と、
    　　第二の温接点、及び第二の冷接点を有する第二の熱電対を直列に繋げて長手方向と垂直な方向に並べた第二熱電対列と、を有し、
    　前記第一熱電対列と前記第二熱電対列とを、前記第一の温接点の列と前記第二の温接点の列とが直線状の電熱ヒータを挟んで対向するように配置することで形成された検出素子であり、
    　前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側に設けられることを特徴とする、検出装置。     A detection device having a detection element formed by the method according to claim 1 or 2.
    The detection element is
    A first thermocouple row in which a first thermocouple having a first hot junction and a first cold junction is connected in series and arranged in a direction perpendicular to the longitudinal direction,
    A second thermocouple row in which a second thermocouple having a second hot junction and a second cold junction is connected in series and arranged in a direction perpendicular to the longitudinal direction,
    Arranging the first thermocouple row and the second thermocouple row such that the first hot junction row and the second hot junction row face each other with a linear electric heater interposed therebetween. Is a detection element formed by
    The holes are provided on both sides in a direction in which the first thermocouple and the second thermocouple are arranged in a region where the first thermocouple row and the second thermocouple row are arranged. , Detection device.
  8. 　前記孔は、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の両側において、其々前記電熱ヒータを挟んで二箇所ずつ設けられることを特徴とする、請求項７に記載の検出装置。 The hole, in the region where the first thermocouple row and the second thermocouple row are arranged, on both sides in the direction of arrangement of the first thermocouple and the second thermocouple, the electrothermal heater, respectively. The detection device according to claim 7, wherein the detection device is provided at two places sandwiching it.
  9. 　前記孔は、さらに、前記第一熱電対列と前記第二熱電対列が配置された領域の、前記第一の熱電対と前記第二の熱電対の並び方向の少なくとも一部において、前記電熱ヒータを挟んで設けられることを特徴とする、請求項８に記載の検出装置。 The hole is further provided in the region where the first thermocouple row and the second thermocouple row are arranged, in at least a part of a direction in which the first thermocouple and the second thermocouple are arranged, The detection device according to claim 8, wherein the detection device is provided with a heater interposed therebetween.
  10. 　前記孔の少なくとも一部は、微小な点状の微小孔の集合として形成されることを特徴とする、請求項７から９のいずれか一項に記載の検出装置。
          The detection device according to claim 7, wherein at least a part of the holes is formed as an assembly of minute dot-shaped minute holes.
PCT/JP2019/046785 2019-01-31 2019-11-29 Method for forming detection element and detection device WO2020158156A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63250865A (en) * 1987-04-08 1988-10-18 Nippon Denso Co Ltd Pressure detecting element and manufacture thereof
JP2001116617A (en) * 1999-10-14 2001-04-27 Korai Kagi Kofun Yugenkoshi Thin-film type device and manufacturing method therefor
JP2008224354A (en) * 2007-03-12 2008-09-25 Omron Corp Thermal sensor
JP2012127965A (en) * 2010-12-15 2012-07-05 Honeywell Internatl Inc Sensor bridge with opening to be thermally separated

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63250865A (en) * 1987-04-08 1988-10-18 Nippon Denso Co Ltd Pressure detecting element and manufacture thereof
JP2001116617A (en) * 1999-10-14 2001-04-27 Korai Kagi Kofun Yugenkoshi Thin-film type device and manufacturing method therefor
JP2008224354A (en) * 2007-03-12 2008-09-25 Omron Corp Thermal sensor
JP2012127965A (en) * 2010-12-15 2012-07-05 Honeywell Internatl Inc Sensor bridge with opening to be thermally separated

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