JP5907688B2 - Flow sensor and method of manufacturing flow sensor - Google Patents

Description

  The present invention relates to a measurement technique, and more particularly to a flow sensor and a method for manufacturing the flow sensor.

  In industrial furnaces, boilers, air-conditioning heat source devices, and the like, it is required that a fluid having an appropriate flow rate be supplied. For this reason, various flow sensors used in flow meters for accurately measuring the flow rate have been developed (see, for example, Patent Documents 1 and 2).

JP 2010-133829 A JP 2009-92475 A

  In response to the recent increase in environmental awareness, it is desired that the power consumption of the flow sensor be reduced. Therefore, an object of the present invention is to provide a flow sensor with low power consumption and a method for manufacturing the flow sensor.

  According to an aspect of the present invention, (a) a substrate having a first recess provided on the back surface and a second recess provided on the upper surface of the first recess, and (b) covering the second recess. A film disposed on the front surface of the substrate, and (c) a first temperature measuring element, a heating element, and a second temperature measuring element disposed on the back surface of the film and stored in the second recess Are provided.

  According to the aspect of the present invention, (a) the first recess is formed on the back surface of the first substrate, and the second recess is formed on the surface above the first recess of the first substrate. And (b) forming a first temperature measuring element, a heating element, and a second temperature measuring element on the back surface of the second substrate, and (c) first covering the second recess. Disposing a second substrate on the surface of the substrate and storing the first temperature measuring element, the heating element, and the second temperature measuring element in the second recess; and (d) the surface of the second substrate. A method of manufacturing a flow sensor is provided that includes reducing the thickness to form a film.

  According to the present invention, it is possible to provide a flow sensor with low power consumption and a method for manufacturing the flow sensor.

It is a top view of the flow sensor which concerns on embodiment of this invention. It is sectional drawing seen from the II-II direction of the flow sensor shown in FIG. 1 which concerns on embodiment of this invention. It is sectional drawing seen from the III-III direction of the flow sensor shown in FIG. 1 which concerns on embodiment of this invention. It is a process top view of a flow sensor concerning an embodiment of the invention. It is process sectional drawing of the flow sensor seen from the VV direction of FIG. 4 which concerns on embodiment of this invention. It is a process top view of a flow sensor concerning an embodiment of the invention. It is process sectional drawing of the flow sensor seen from the VII-VII direction of FIG. 6 which concerns on embodiment of this invention. It is process sectional drawing of the flow sensor seen from the VII-VII direction of FIG. 6 which concerns on embodiment of this invention. It is process sectional drawing of the flow sensor seen from the IX-IX direction of FIG. 6 which concerns on embodiment of this invention. It is a process top view of a flow sensor concerning an embodiment of the invention. It is process sectional drawing of the flow sensor seen from the XI-XI direction of FIG. 10 which concerns on embodiment of this invention. It is process sectional drawing of the flow sensor seen from the XII-XII direction of FIG. 10 which concerns on embodiment of this invention. It is a process back view of a flow sensor concerning an embodiment of the invention. It is process sectional drawing of the flow sensor seen from the XIV-XIV direction of FIG. 13 which concerns on embodiment of this invention. It is a process back view of a flow sensor concerning an embodiment of the invention. It is process sectional drawing of the flow sensor seen from the XVI-XVI direction of FIG. 15 which concerns on embodiment of this invention. It is a process top view of a flow sensor concerning an embodiment of the invention. It is process sectional drawing of the flow sensor seen from the XVIII-XVIII direction of FIG. 17 which concerns on embodiment of this invention. It is process sectional drawing of the flow sensor seen from the XIX-XIX direction of FIG. 17 which concerns on embodiment of this invention. It is process sectional drawing of the flow sensor which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The flow sensor according to the embodiment shown in FIG. 1 to FIG. 3 includes a substrate 1 in which a first recess 11 is provided on the back surface and a second recess 12 is provided on the upper surface of the first recess 11. The film 2 disposed on the surface of the substrate 1 so as to cover the second recess 12, and the first temperature measuring element 32 and the heating element disposed on the back surface of the film 2 and stored in the second recess 12 31 and a second temperature measuring element 33. The flow sensor according to the embodiment is used to measure, for example, the flow velocity and flow rate of the fluid flowing through the flow path. The fluid may be a gas or a liquid.

The thickness of the substrate 1 shown in FIGS. 2 and 3 is, for example, about 0.5 mm. The vertical and horizontal dimensions of the substrate 1 are each about 2 mm, for example. As the material of the substrate 1, a corrosion-resistant material such as quartz (SiO ₂ ) or sapphire can be used. For example, the first recess 11 is deeper than the second recess 12. The depth of the second recess 12 is, for example, about 10 μm. Further, for example, a portion sandwiched between the bottom surface of the first recess 11 and the bottom surface of the second recess 12 of the substrate 1 forms a thin film having a thickness of about 10 μm.

  The thickness of the film 2 is, for example, about 10 μm. As the material of the film 2, a corrosion-resistant material such as quartz (SiO2) or sapphire can be used. The heating element 31 is, for example, a resistor and generates heat when supplied with electric power, and heats the fluid flowing on the surface of the film 2. The first temperature measuring element 32 and the second temperature measuring element 33 shown in FIG. 2 are electronic elements such as passive elements such as resistors, and output electrical signals depending on the temperature of the fluid flowing on the surface of the film 2. To do. The first temperature measuring element 32 is used, for example, to detect the temperature of the fluid upstream of the heating element 31, and the second temperature measuring element 33, for example, detects the temperature of the fluid downstream of the heating element 31. Used for. A conductive material such as platinum (Pt) can be used for each material of the heating element 31, the first temperature measuring element 32, and the second temperature measuring element 33.

  A space having a width of about 10 μm is provided between the first temperature measuring element 32, the heating element 31, the second temperature measuring element 33, and the bottom surface of the recess 12 of the substrate 1.

  When the fluid in contact with the surface of the membrane 2 shown in FIG. 2 is stationary, the heat applied to the fluid from the heating element 31 propagates symmetrically in the upstream direction and the downstream direction. Accordingly, the temperatures of the first temperature measuring element 32 and the second temperature measuring element 33 are equal, and the electric resistances of the first temperature measuring element 32 and the second temperature measuring element 33 made of platinum or the like are equal. On the other hand, when the fluid flows from the side where the first temperature measuring element 32 is arranged toward the side where the second temperature measuring element 33 is arranged, the heat applied to the fluid from the heating element 31 is The second temperature measuring element 33 is carried to the side where it is disposed. Therefore, the temperature of the second temperature measuring element 33 is higher than the temperature of the first temperature measuring element 32. Therefore, there is a difference between the electric resistance of the first temperature measuring element 32 and the electric resistance of the second temperature measuring element 33. The difference between the electric resistance of the second temperature measuring element 33 and the electric resistance of the first temperature measuring element 32 correlates with the velocity of the fluid in contact with the surface of the film 2. Therefore, the flow rate of the fluid in contact with the surface of the film 2 is obtained from the difference between the electric resistance of the second temperature measuring element 33 and the electric resistance of the first temperature measuring element 32.

  As shown in FIGS. 1 and 3, electrodes 41, 42, 43, 51, 52, 53 are further arranged on the back surface of the film 2. The electrode 41 is electrically connected to one end of the heating element 31, and the electrode 51 is electrically connected to the other end of the heating element 31. The electrode 42 is electrically connected to one end portion of the first temperature measuring element 32, and the electrode 52 is electrically connected to the other end portion of the first temperature measuring element 32. The electrode 43 is electrically connected to one end of the second temperature measuring element 33, and the electrode 53 is electrically connected to the other end of the second temperature measuring element 33. The substrate 1 is provided with a wiring through hole 13 for exposing the electrodes 41, 42, 43 and a wiring through hole 14 for exposing the electrodes 51, 52, 53.

  Further, as shown in FIGS. 1 and 2, the flow sensor has fluid communication holes 21 and 22 penetrating from the surface of the film 2 to the first recess 11 of the substrate 1 in the second recess 12 of the substrate 1. Adjacent to each other. Thereby, the pressure applied to the surface of the film 2 and the pressure applied to the bottom surface of the first recess 11 can be made substantially equal. Further, by appropriately setting the opening areas of the fluid communication holes 21 and 22, the velocity of the fluid flowing into the first recess 11 from the fluid communication hole 21 and flowing out of the fluid communication hole 22 is made substantially zero. It becomes possible.

In the flow sensor according to the embodiment described above, as shown in FIG. 2, the first temperature measuring element 32, the heating element 31, and the second temperature measuring element 33 are provided in the second recess 12 of the substrate 1. The space is provided between the first temperature measuring element 32, the heat generating element 31, the second temperature measuring element 33, and the bottom surface of the recess 12 of the substrate 1. Since the space has a heat insulating effect, the heat generated by the heat generating element 31 is efficiently propagated to the surface of the film 2 in contact with the fluid to be measured. For this reason, the power applied to the heat generating element 31 is efficiently consumed, so that useless power consumption can be reduced. In addition, since the fluid is efficiently heated by the heating element 31, it is possible to shorten the time for detecting the temperature change by the first temperature measuring element 32 and the second temperature measuring element 33. Further, by storing the first temperature measuring element 32, the heating element 31, and the second temperature measuring element 33 in the second recess 12, the first temperature measuring element 32, the heating element 31, and the second temperature measuring element 32 are stored. The temperature measuring element 33 is not exposed to the fluid. Therefore, the flow sensor according to the embodiment is also used for measuring a corrosive fluid such as a gas (gas) containing SOx, NOx, Cl ₂ , BCl ₃ , or a chemical solution (liquid) containing sulfuric acid or nitric acid. Adaptable.

Next, a method for manufacturing a flow sensor according to the embodiment will be described with reference to FIGS.
(A) First, as shown in FIGS. 4 and 5, a flat first substrate 1 is prepared. Next, as shown in FIGS. 6 and 7, the wiring through holes 13 and 14 are formed on the first substrate 1 by a sandblasting method, an ultrasonic processing method, a drilling method, a laser processing method, an etching method, or the like. Is provided. Thereafter, as shown in FIGS. 8 and 9, the first concave portion 11 is formed on the back surface of the first substrate 1 by a sandblasting method, an ultrasonic processing method, a drilling method, a laser processing method, an etching method, or the like. Provide. Further, as shown in FIGS. 10 to 12, a second recess 12 is provided on the surface of the first substrate 1 by etching or the like. The order in which the wiring through holes 13 and 14, the first concave portion 11, and the second concave portion 12 are provided is arbitrary.

  (B) Also, as shown in FIGS. 13 and 14, a flat second substrate 102 is prepared, and a metal such as platinum is deposited on the back surface of the second substrate by a method such as sputtering or vacuum evaporation. The first temperature measuring element 32, the heat generating element 31, and the second temperature measuring element 33 are formed (patterned) by attaching them. Next, as shown in FIGS. 15 and 16, electrodes 41, 42, 43, 51, 52, and 53 are formed (patterned) on the back surface of the second substrate by the same method. 14 and 16 depict the second substrate 102 with the back surface facing up.

  (C) The first substrate 1 provided with the wiring through holes 13, 14, the first recess 11, and the second recess 12 shown in FIGS. 10 to 12, and shown in FIGS. 15 and 16. The first temperature measuring element 32, the heating element 31, the second temperature measuring element 33, and the second substrate 102 provided with the electrodes 41, 42, 43, 51, 52, 53 are shown in FIGS. 19, the first temperature measuring element 32, the heat generating element 31, and the second temperature measuring element 33 are stored in the second recess 12, and the electrodes 41, 42, 43, 51, 52, 53 are wired. It joins by methods, such as normal temperature activation joining, so that it may expose from the through-holes 13 and 14 for an object.

  (D) The thickness of the second substrate 102 is reduced by a grinding method, a polishing method, an etching method, or the like to form a film 2 as shown in FIG. Thereafter, fluid communication holes 21 and 22 penetrating the substrate 1 and the film 2 shown in FIG. 2 are formed by a sandblasting method, an ultrasonic processing method, a drilling method, a laser processing method, an etching method, or the like. The manufacturing method of the flow sensor according to the above is terminated. Note that the film 2 may be formed by reducing the thickness of the second substrate 102 after forming the fluid communication holes 21 and 22 penetrating the second substrate 102 and the first substrate 1.

  With the manufacturing method described above, the flow sensor according to the embodiment shown in FIGS. 1 to 3 can be manufactured.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, embodiments, and operation techniques should be apparent to those skilled in the art. For example, the space between the first temperature measuring element 32, the heating element 31, the second temperature measuring element 33 and the bottom surface of the recess 12 of the substrate 1 shown in FIG. Thereby, it becomes possible to further improve the heat insulation effect of space. In the embodiment described above, one wiring through hole 13 is provided for the three electrodes 41, 42, 43, and one wiring through hole 14 is provided for the three electrodes 51, 52, 53. Although the example provided is shown, for example, six wiring through holes may be individually provided for each of the six electrodes 41, 42, 43, 51, 52, 53, and the through electrodes may be further formed. Further, the arrangement and connection method of the electrodes 41, 42, 43, 51, 52, 53 with respect to the heating element 31, the first temperature measuring element 32, and the second temperature measuring element 33 are not limited to the above-described embodiment. . For example, the electricity 42 and the electrode 43 may be electrically connected by wiring. Thus, it should be understood that the present invention includes various embodiments and the like not described herein.

1 substrate (first substrate)
2 Film 11 1st recessed part 12 2nd recessed part 13 and 14 Through-hole 21 and 22 for wiring Fluid communication hole 31 Heating element 32 1st temperature measuring element 33 2nd temperature measuring element 41, 42, 43, 51, 52, 53 Electrode 102 Second substrate

Claims (12)

A substrate having a first recess provided on the back surface and a second recess provided on the upper surface of the first recess;
A film disposed on the surface of the substrate so as to cover the second recess;
A first temperature measuring element, a heating element, and a second temperature measuring element disposed on the back surface of the film and stored in the second recess;
A flow sensor comprising :
A fluid communication hole penetrating from the surface of the membrane to the first recess of the substrate is provided next to the second recess.
Flow sensor .   The flow sensor according to claim 1, wherein a space is provided between a bottom surface of the second recess and the first temperature measuring element, the heating element, and the second temperature measuring element. It said first recess, deeper than the second recess, the flow sensor according to claim 1 or 2. A bottom surface of said first recess of said substrate, the flow sensor according to the bottom surface and, in part sandwiched by the second recess has been no thin film, in any one of claims 1 to 3 . The first temperature measuring element, the heating element, and the second, further comprising an electrode connected to each of the temperature measuring element of the flow sensor according to any one of claims 1 to 4. The flow sensor according to claim 5 , wherein a wiring through hole for exposing the electrode is provided in the substrate. Forming a first recess on a back surface of the first substrate, and forming a second recess on a surface above the first recess of the first substrate;
Forming a first temperature measuring element, a heating element, and a second temperature measuring element on the back surface of the second substrate;
The second substrate is disposed on the surface of the first substrate so as to cover the second recess, and the first temperature measuring element, the heating element, and the second temperature measuring element are arranged in the first Storing in the two recesses;
And to reduce the thickness, a film from the surface of the second substrate,
Forming a fluid communication hole penetrating from the surface of the film to the first recess of the first substrate next to the second recess;
The manufacturing method of the flow sensor containing this. The first temperature measuring element, the first temperature measuring element, and the second temperature measuring element so that a space is provided between the bottom surface of the second recess and the first temperature measuring element, the heating element, and the second temperature measuring element; The method for manufacturing a flow sensor according to claim 7 , wherein the heating element and the second temperature measuring element are stored in the second recess. The method for manufacturing a flow sensor according to claim 7 , wherein the first recess is deeper than the second recess. The first recess, the second recess, and the portion sandwiched between the bottom surface of the first recess and the bottom surface of the second recess of the first substrate form a thin film, forming a method of manufacturing a flow sensor according to any one of claims 7 to 9. The first temperature measuring element, the heating element, and the second further comprises a second forming a electrode connected to each of the temperature measuring element, the flow sensor according to any one of claims 7 to 10 Manufacturing method. The method for manufacturing a flow sensor according to claim 11 , further comprising forming a through-hole for wiring exposing the electrode in the first substrate.

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