Sensor

Abstract

The sensor comprises a substrate, a first supporting layer, a heating layer and a metal layer, the first supporting layer is at least partially connected with the substrate, the metal layer is arranged on the heating layer, and the first supporting layer is far away from the metal layer relative to the heating layer in the height direction of the sensor; the first supporting layer comprises a first sub-supporting layer and a second sub-supporting layer, and a gap is formed between the first sub-supporting layer and the second sub-supporting layer; the heating layer is arranged on the first sub-supporting layer, and a gap is formed between the second sub-supporting layer and the heating layer. A gap is formed between the first sub-supporting layer and the second sub-supporting layer, and at least part of the first sub-supporting layer is connected with the heating layer, so that heat transferred from the heating layer to the second sub-supporting layer is reduced, heat transfer between the heating layer and the first supporting layer is reduced, and then heat loss of the heating layer is reduced.

Description

Technical Field

[0001] This application relates to the technical field of sensors, and particularly to a sensor. Background Art

[0002] In the related art, a sensor includes a substrate, a support layer, a heating layer, and a metal layer. Along the height direction of the sensor, the substrate is connected to the support layer, the support layer is connected to the heating layer, and the heating layer is connected to the metal layer. When the metal layer is heated to a certain temperature by the heating layer, it will react with the gas to detect the corresponding gas and its concentration and convert it into an electrical signal. Of course, when the heating layer is heated, the heat will be transferred to the support layer, resulting in heat loss. Summary of the Invention

[0003] To this end, this application provides a sensor, which includes a substrate, a first support layer, a heating layer, and a metal layer; at least part of the first support layer is connected to the substrate, the metal layer is disposed on the heating layer, and along the height direction of the sensor, the first support layer is farther from the metal layer than the heating layer; the first support layer includes a first sub-support layer and a second sub-support layer, and there is a gap between the first sub-support layer and the second sub-support layer; the heating layer is disposed on the first sub-support layer, and there is a gap between the second sub-support layer and the heating layer.

[0004] In the sensor of this application, there is a gap between the first sub-support layer and the second sub-support layer, and at least part of the first sub-support layer is connected to the heating layer, reducing the heat transfer from the heating layer to the second sub-support layer. Therefore, the heat transfer between the heating layer and the first support layer is reduced, and further the heat loss of the heating layer is reduced. Brief Description of the Drawings

[0005] Figure 1 It is a top view of an embodiment of the sensor in this application;

[0006] Figure 2 For Figure 1 a top view of a sensing unit in

[0007] Figure 2-1 For Figure 2 a cross-sectional view of the sensing unit A-A in

[0008] Figure 2-2 For Figure 2 a cross-sectional view of the sensing unit B-B in

[0009] Figure 3 It is a cross-sectional view of the first sensing unit in this application;

[0010] Figure 4 It is a cross-sectional view of the second sensing unit in this application;

[0011] Figure 5 A cross-sectional view of the control unit in this application;

[0012] Figure 6 A cross-sectional view of the third sensing unit in this application. Detailed implementation manners

[0013] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with this application.

[0014] Next, with reference to the drawings, the sensors of the exemplary embodiments of this application will be described in detail.

[0015] In the related art, a sensor includes a substrate 1, a support layer, a heating layer 4, and a metal layer 9. Along the height direction H of the sensor, the substrate 1 is connected to the support layer, the support layer is connected to the heating layer 4, and the heating layer 4 is connected to the metal layer 9. When the metal layer 9 is heated to a certain temperature by the heating layer 4, it will react with the gas, and then detect the corresponding gas and concentration and convert them into electrical signals. Of course, when the heating layer 4 is heated, the heat will be transferred to the support layer, resulting in heat loss. To reduce heat loss, the sensors of this application include a substrate 1, a first support layer 31, a heating layer 4, and a metal layer 9; at least part of the first support layer 3 is connected to the substrate 1, the metal layer 9 is disposed on the heating layer 4, and along the height direction H of the sensor, the first support layer 3 is farther from the metal layer 9 than the heating layer 4; the first support layer 31 includes a first sub-support layer 31 and a second sub-support layer 32, and there is a gap between the first sub-support layer 31 and the second sub-support layer 32; the heating layer 4 is disposed on the first sub-support layer 31, and there is a gap between the second sub-support layer 32 and the heating layer 4. There is a gap between the first sub-support layer 31 and the second sub-support layer 32, and at least part of the first sub-support layer 31 is connected to the heating layer 4, reducing the heat transfer of the heating layer 4 to the second sub-support layer 32. Therefore, the heat transfer between the heating layer 4 and the first support layer 31 is reduced, and further the heat loss of the heating layer 4 is reduced. In other words, it is equivalent to dividing the first support layer 31 into two parts. The heat was originally transferred to the entire first support layer 31, but now it only transfers to part of the first support layer 31, that is, the first sub-support layer 31, reducing the heat transfer and minimizing the heat loss.

[0016] Furthermore, in one implementation manner, as Figure 1 shown, the first support layer 3 has an opening 321, the opening 321 penetrates through the second sub-support layer 32, and at least part of the first sub-support layer 31 is located in the opening 321. In one implementation manner, the first support layer 31 can be silicon dioxide.

[0017] In order to enable the sensor to detect multiple gases simultaneously, in one embodiment, as Figure 1 and Figure 3 shown, the sensor includes a first sensing unit 21 and a second sensing unit 22. The first sub-support layer 31 includes a third sub-support layer 311 and a fourth sub-support layer 312. The heating layer 4 includes a first heating layer 41 and a second heating layer 42. The metal layer 9 includes a first metal layer 91 and a second metal layer 92. The composition of the first metal layer 91 is different from that of the second metal layer 92. In this way, the metal layers 9 with different compositions can correspondingly detect different gases.

[0018] Further, in one embodiment, as Figure 2-1 、 Figure 3 and Figure 4 shown, the first sensing unit 21 includes the third sub-support layer 311, the first heating layer 41 and the first metal layer 91. The second sensing unit 22 includes the fourth sub-support layer 312, the second heating layer 42 and the second metal layer 92. The opening 321 includes a first opening 3211 and a second opening 3212. The first sensing unit 21 is at least partially located in the first opening 3211, and the second sensing unit 22 is at least partially located in the second opening 3212. The first sensing unit 21 and the second sensing unit 22 are separately arranged, which can reduce the mutual interference during the reaction of different gases during detection.

[0019] In one embodiment, as Figure 5 shown, the sensor includes a reference unit 20. The first sub-support layer 31 includes a fifth sub-support layer 313. The heating layer 4 includes a third heating layer 43. The reference unit 20 includes the fifth sub-support layer 313 and the third heating layer 43. The opening 321 includes a third opening 3213. The reference unit 20 is at least partially located in the third opening 3213. The reference unit 20 is used to measure the real-time temperature and can perform temperature compensation.

[0020] In one embodiment, as Figure 1 and Figure 6 shown, in order to enable the sensor to detect three gases, the sensor further includes a third sensing unit 23. The first sub-support layer 31 includes a sixth sub-support layer 314. The heating layer 4 includes a fourth heating layer 44. The metal layer 9 includes a third metal layer 93. The third sensing unit 23 includes the sixth sub-support layer 314, the third metal layer 93 and the fourth heating layer 44. The opening 321 includes a fourth opening 3214. The third sensing unit 23 is at least partially located in the fourth opening 3214. In another embodiment, the first sensing unit 21, the second sensing unit 22, the third sensing unit 23 and the reference unit 20 are arranged in an array. The first sensing unit 21, the second sensing unit 22, the third sensing unit 23 and the reference unit 20 are arranged in a cross shape. Here, the arrangement order of each unit is not required.

[0021] In one embodiment, the metal layer 9 includes at least one of zinc oxide, tin oxide, or tungsten oxide. Correspondingly, the heating temperature of the heating layer 4 is less than or equal to 400°C. Specifically, for example, the first metal layer 91 is zinc oxide. When the first heating layer 41 is heated to a certain temperature, zinc oxide can react with ethanol to detect ethanol; the second metal layer 92 is tin oxide. When the second heating layer 42 is heated to a certain temperature, tin oxide can react with carbon monoxide to detect carbon monoxide; the metal layer in the third sensing unit 23 is tungsten oxide. When the heating layer 4 is heated to a certain temperature, tungsten oxide can react with hydrogen to detect hydrogen.

[0022] Among them, in one embodiment, as Figure 2-1 shown, the sensor further includes interdigital electrodes 8. The interdigital electrodes 8 are connected to the metal layer 9. After the metal layer 9 reacts with the gas, the resistance value changes, and the signal is transmitted through the interdigital electrodes 8. In one embodiment, as Figure 2-2 shown, the sensor further includes a heating electrode 45. Along the height direction H of the sensor, the heating electrode 45 is connected to the first support layer 3. Among them, the heating electrode 45 is connected to the heating layer 4 to transmit the heating signal.

[0023] The temperature range heated by the heating layer 4 is from room temperature to 400°C. In order to improve the flexibility of the heating temperature range, in other words, relative to resistance heating where the resistance value is fixed and the heating temperature is also fixed, the resistance in this application is variable and the heating temperature can also be regulated. In one embodiment, the voltage of the heating layer 4 is a constant voltage, and the resistance is changed by adding different powers, thereby changing the heating temperature. In one embodiment, the heating layer 4 can be tungsten metal or platinum metal.

[0024] In one embodiment, as Figure 2-1 shown, the substrate 1 includes a through hole 11. Along the height direction H of the sensor, the through hole 11 penetrates the substrate 1, and the through hole 11 is at least partially aligned with the heating layer 4. When the heat is too high, the through hole 11 is conducive to the discharge of heat, preventing a short circuit phenomenon caused by the inability to dissipate heat when the sensor is working. Further, along the height direction H of the sensor, the projection of the heating layer 4 is located within the projection of the hole wall of the through hole 11. In one embodiment, the substrate 1 can be silicon. In one embodiment, the through hole 11 is formed by wet etching the substrate 1 with potassium hydroxide solution.

[0025] In order to improve the stress matching of the sensor, make it have better temperature attack resistance, and improve the reliability of the sensor, in one embodiment, as Figure 2-1As shown, the sensor includes a second support layer 6. The second support layer 6 is connected to the substrate 1 and the second support layer 6 is connected to the first support layer 3. Along the height direction H of the sensor, the first support layer 31 and the substrate 1 are located on both sides of the second support layer 6. In one embodiment, the first support layer 31 can be silicon dioxide; in another embodiment, the second support layer 6 can be silicon nitride.

[0026] In one embodiment, as Figure 2-1 shown, the sensor includes a protective layer 7. The protective layer 7 is at least partially connected to the heating layer 4 and the protective layer 7 is at least partially connected to the first support layer 31. Along the height direction H of the sensor, the protective layer 7 is at least partially located between the heating layer 4 and the metal layer. The protective layer 7 plays a role in protecting the heating layer 4. On the one hand, it can prevent the influence of the external environment on the heating layer 4, such as collision, dust accumulation, etc.; on the other hand, the protective layer 7 can prevent some harmful gases from contacting the heating layer when detecting gases. The protective layer 7 can reduce the direct contact between the heating layer 4 and the gas and reduce the adverse effects on the heating layer 4. In one embodiment, the material of the protective layer 4 can be silicon nitride.

[0027] Furthermore, in one embodiment, as Figure 2-1 shown, the protective layer 7 has a groove 71. Along the height direction H of the sensor, the groove 71 is recessed away from the first support layer 3; at least part of the heating layer 4 and at least part of the first sub-support layer 31 are both located in the groove 71. This further protects the heating layer 4 and also protects the first sub-support layer 3.

[0028] The manufacturing method of the sensor in this application is as follows: Provide the substrate 1, deposit the second support layer 6 on the substrate 1 through a plasma deposition process, and then deposit the first support layer 3 on the second support layer 6 through a chemical vapor deposition process. Deposit the metal layer 9 through an atomic layer deposition process and form a pattern through microelectromechanical lithography and dry etching techniques; in another embodiment, deposit the metal layer 9 through a screen printing process and form a pattern through microelectromechanical lithography and dry etching techniques. Deposit the interdigital electrode 8 by physical vapor deposition and form a pattern through microelectromechanical lithography and dry etching techniques. In one embodiment, the through hole 11 is formed by wet etching the substrate 1 with potassium hydroxide liquid, which is used to dissipate the heat provided by the heating layer 4 when the sensor is working.

[0029] The above are only the preferred embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application has been disclosed above with the preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to equivalent embodiments with equivalent changes within the scope of the technical solution of the present application by using the above-disclosed technical content. However, as long as it does not depart from the content of the technical solution of the present application, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A sensor, characterized in that: The sensor includes a substrate, a first support layer, a heating layer, and a metal layer; The first support layer is at least partially connected to the substrate, the metal layer is disposed on the heating layer, and along the height direction of the sensor, the first support layer is farther from the metal layer than the heating layer; The first support layer includes a first sub-support layer and a second sub-support layer, and there is a gap between the first sub-support layer and the second sub-support layer; The heating layer is disposed on the first sub-support layer, and there is a gap between the second sub-support layer and the heating layer.

2. The sensor according to claim 1, wherein: The first support layer has an opening that penetrates the second sub-support layer, and at least a part of the first sub-support layer is located in the opening.

3. The sensor according to claim 2, characterized in that: The sensor includes a first sensing unit and a second sensing unit, The first sub-support layer includes a third sub-support layer and a fourth sub-support layer, the heating layer includes a first heating layer and a second heating layer, The metal layer includes a first metal layer and a second metal layer, and the composition of the first metal layer is different from that of the second metal layer; The first sensing unit includes the third sub-support layer, the first heating layer, and the first metal layer, and the second sensing unit includes the fourth sub-support layer, the second heating layer, and the second metal layer; The opening includes a first opening and a second opening, At least a part of the first sensing unit is located in the first opening, and at least a part of the second sensing unit is located in the second opening.

4. The sensor according to claim 3, characterized in that: The sensor includes a reference unit, the first sub-support layer includes a fifth sub-support layer, the heating layer includes a third heating layer, and the reference unit includes the fifth sub-support layer and the third heating layer, The opening includes a third opening, and at least a part of the reference unit is located in the third opening.

5. The sensor according to claim 4, characterized in that: The sensor includes a third sensing unit, the first sub-support layer includes a sixth sub-support layer, the heating layer includes a fourth heating layer; the metal layer includes a third metal layer; The third sensing unit includes the sixth sub-support layer, the third metal layer, and the fourth heating layer; The opening includes a fourth opening, and at least a part of the third sensing unit is located in the fourth opening; The first sensing unit, the second sensing unit, the third sensing unit, and the reference unit are arranged in an array.

6. The sensor according to any one of claims 1 to 5, characterized in that: The metal layer includes at least one of zinc oxide, tin oxide, or tungsten oxide.

7. The sensor according to any one of claims 1 to 5, characterized in that: The heating temperature of the heating layer is less than or equal to 400 °C; the voltage of the heating layer is a constant voltage.

8. The sensor according to any one of claims 1 to 5, characterized in that: The sensor includes a second support layer, the second support layer is connected to the substrate, and the second support layer is connected to the first support layer; along the height direction of the sensor, the first support layer and the substrate are located on both sides of the second support layer.

9. The sensor according to any one of claims 1 to 5, characterized in that: The sensor includes a protective layer, the protective layer is at least partially connected to the heating layer, the protective layer is at least partially connected to the first support layer, and along the height direction of the sensor, the protective layer is at least partially located between the heating layer and the metal layer.

10. The sensor according to claim 9, characterized in that: The protective layer has a groove, which is recessed away from the first support layer along the height direction of the sensor; at least part of the heating layer and at least part of the first sub-support layer are both located in the groove.

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