Heat-insulating and high-sensitivity flow sensor chip

Abstract

The utility model relates to a heat-insulating and high-sensitivity flow sensor chip. The light emitting diode comprises a substrate; the supporting structure layer is arranged on the surface of the substrate; the upstream temperature measuring element thermopile, the downstream temperature measuring element thermopile and the central heat source structure are respectively arranged on the surface of the supporting structure layer; the passivation layer covers the upstream temperature measuring element thermopile, the downstream temperature measuring element thermopile and the central heat source structure respectively; and the shading heat insulation layer is arranged on the surface of the passivation layer and only covers the central heat source structure, the hot end of the upstream temperature measurement element thermopile and the hot end of the downstream temperature measurement element thermopile. Heat inside the chip can be effectively prevented from diffusing outwards, so that the heat is uniformly distributed at the hot end part, and the sensitivity of the chip is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of flow sensors, in particular to a heat-insulating and highly sensitive flow sensor chip. Background Art

[0002] Thermal flow sensors are widely used in flow measurement, which determine the flow rate by measuring the temperature difference on both sides of the heating resistor. Such sensors usually use constant voltage power supply and rely on the change of fluid flow rate to measure the temperature difference between the upstream and downstream temperature sensing elements to calculate the flow rate.

[0003] The heat of existing thermal flow sensors is easily diffused outward during use, resulting in uneven temperature distribution at the hot end, thereby affecting the measurement sensitivity. Summary of the invention

[0004] To this end, the utility model provides a heat-insulating and highly sensitive flow sensor chip, which can effectively prevent the heat inside the chip from diffusing outward, so that the heat is evenly distributed in the hot end part, thereby improving the sensitivity of the chip.

[0005] In order to solve the above technical problems, the utility model provides a heat-insulating and highly sensitive flow sensor chip, comprising:

[0006] substrate;

[0007] A supporting structure layer is arranged on the surface of the substrate;

[0008] An upstream temperature measuring element thermopile, a downstream temperature measuring element thermopile and a central heat source structure are respectively arranged on the surface of the supporting structure layer;

[0009] A passivation layer covers the upstream temperature measuring element thermopile, the downstream temperature measuring element thermopile and the central heat source structure respectively;

[0010] The light-shielding and heat-insulating layer is arranged on the surface of the passivation layer and only covers the central heat source structure, the hot end of the upstream temperature measuring element thermopile and the hot end of the downstream temperature measuring element thermopile.

[0011] In one implementation of the utility model, the light-shielding and heat-insulating layer is black photoresist.

[0012] In one embodiment of the present utility model, the thickness of the light-shielding and heat-insulating layer is 0.05-1 μm.

[0013] In one embodiment of the present invention, the support structure layer includes a silicon oxide support layer and a silicon nitride support layer which are sequentially arranged on the surface of the substrate.

[0014] In one embodiment of the present invention, the thickness of the silicon oxide support layer is 0.1-5 μm; the thickness of the silicon nitride support layer is 0.01-0.5 μm.

[0015] In one embodiment of the utility model, the upstream temperature measuring element thermopile includes an upstream thermopile lower layer thermocouple and an upstream thermopile upper layer thermocouple, and the downstream temperature measuring element thermopile includes a downstream thermopile lower layer thermocouple and an upstream thermopile upper layer thermocouple.

[0016] In one embodiment of the utility model, it also includes a first insulating layer and a second insulating layer, the first insulating layer respectively covers the surfaces of the lower thermocouple of the upstream thermopile, the lower thermocouple of the downstream thermopile and the central heat source structure; the second insulating layer respectively covers the surfaces of the upper thermocouple of the upstream thermopile, the upper thermocouple of the downstream thermopile and a portion of the first insulating layer.

[0017] In one embodiment of the present invention, the first insulating layer and / or the second insulating layer is made of silicon oxide with a thickness of 0.05-0.5 μm.

[0018] In one embodiment of the utility model, it also includes an upstream thermopile structure hot junction area connected between the upstream thermopile lower layer thermocouple and the upstream thermopile upper layer thermocouple, a first upstream thermopile structure cold junction area connected to the upstream thermopile lower layer thermocouple, a second upstream thermopile structure cold junction area connected to the upstream thermopile upper layer thermocouple, a downstream thermopile structure hot junction area connected between the downstream thermopile lower layer thermocouple and the downstream thermopile upper layer thermocouple, a first downstream thermopile structure cold junction area connected to the downstream thermopile lower layer thermocouple, a second downstream thermopile structure cold junction area connected to the downstream thermopile upper layer thermocouple, and a heat source wire structure connected to the central heat source structure.

[0019] In one embodiment of the present invention, the passivation layer is made of silicon oxide with a thickness of 0.1 to 10 μm.

[0020] The above technical solution of the utility model has the following advantages compared with the prior art:

[0021] The utility model discloses a heat-insulating and highly sensitive flow sensor chip, which can prevent the internal heat of the chip from rapidly diffusing outward by arranging a light-shielding and heat-insulating layer on the surface of the passivation layer on the top surface of the chip, which only covers the central hot end position of the chip, so that the heat is concentrated and evenly distributed in the hot end part, thereby improving the sensitivity of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments of the utility model in combination with the accompanying drawings.

[0023] Figure 1 It is a schematic diagram of the overall structure of the heat-insulating and highly sensitive flow sensor chip of the utility model.

[0024] Description of the Figures in the Specification:

[0025] 1. Substrate;

[0026] 2. Silicon oxide support layer;

[0027] 3. Silicon nitride support layer;

[0028] 4. Central heat source structure;

[0029] 5a, thermocouple of the lower layer of the upstream thermopile; 5b, thermocouple of the lower layer of the downstream thermopile;

[0030] 6a, a first insulating layer; 6b, a second insulating layer;

[0031] 7a, upper thermocouple of upstream thermopile; 7b, upper thermocouple of downstream thermopile;

[0032] 81. hot junction area of ​​upstream thermopile structure; 82. cold junction area of ​​first upstream thermopile structure; 83. cold junction area of ​​second upstream thermopile structure; 84. hot junction area of ​​downstream thermopile structure; 85. cold junction area of ​​first downstream thermopile structure; 86. cold junction area of ​​second downstream thermopile structure; 87. heat source wire structure;

[0033] 9. Passivation layer;

[0034] 10. Shading and heat insulation layer;

[0035] 11. Back cavity. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0037] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0038] In the present utility model, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present utility model, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0039] Reference Figure 1 As shown, a heat-insulated and highly sensitive flow sensor chip of the utility model comprises:

[0040] Substrate 1;

[0041] A supporting structure layer, arranged on the surface of the substrate 1;

[0042] The upstream temperature measuring element thermopile, the downstream temperature measuring element thermopile and the central heat source structure 4 are respectively arranged on the surface of the supporting structure layer;

[0043] A passivation layer 9, covering the upstream temperature measuring element thermopile, the downstream temperature measuring element thermopile and the central heat source structure 4 respectively;

[0044] The light-shielding and heat-insulating layer 10 is disposed on the surface of the passivation layer 9 and only covers the central heat source structure 4, the hot end of the upstream temperature measuring element thermopile and the hot end of the downstream temperature measuring element thermopile.

[0045] In one embodiment, the light-shielding and heat-insulating layer 10 is black photoresist, and the thickness of the light-shielding and heat-insulating layer 10 is 0.05-1 μm.

[0046] In one embodiment, the support structure layer includes a silicon oxide support layer 2 and a silicon nitride support layer 3 sequentially disposed on the surface of the substrate 1. The double-layer support structure layer can improve the stress of the support film layer through the stress reverse action of silicon nitride and silicon oxide.

[0047] Specifically, the thickness of the silicon oxide support layer 2 is 0.1-5 μm; the thickness of the silicon nitride support layer 3 is 0.01-0.5 μm.

[0048] In one embodiment, the upstream temperature measuring element thermopile includes an upstream thermopile lower thermocouple 5a and an upstream thermopile upper thermocouple 7a, and the downstream temperature measuring element thermopile includes a downstream thermopile lower thermocouple 5b and a downstream thermopile upper thermocouple 7b.

[0049] Specifically, it also includes a first insulating layer 6a and a second insulating layer 6b, the first insulating layer 6a respectively covers the surfaces of the lower thermocouple 5a of the upstream thermopile, the lower thermocouple 5b of the downstream thermopile and the central heat source structure 4; the second insulating layer 6b respectively covers the surfaces of the upper thermocouple 7a of the upstream thermopile, the upper thermocouple 7b of the downstream thermopile and part of the first insulating layer 6a.

[0050] Specifically, the first insulating layer 6a and / or the second insulating layer 6b is made of silicon oxide with a thickness of 0.05-0.5 μm.

[0051] Specifically, it also includes an upstream thermopile structure hot junction area 81 connected between the upstream thermopile lower layer thermocouple 5a and the upstream thermopile upper layer thermocouple 7a, a first upstream thermopile structure cold junction area 82 connected to the upstream thermopile lower layer thermocouple 5a, a second upstream thermopile structure cold junction area 83 connected to the upstream thermopile upper layer thermocouple 7a, a downstream thermopile structure hot junction area 84 connected between the downstream thermopile lower layer thermocouple 5b and the downstream thermopile upper layer thermocouple 7b, a first downstream thermopile structure cold junction area 85 connected to the downstream thermopile lower layer thermocouple 5b, a second downstream thermopile structure cold junction area 86 connected to the downstream thermopile upper layer thermocouple 7b, and a heat source wire structure 87 connected to the central heat source structure 4.

[0052] In one embodiment, the passivation layer 9 is made of silicon oxide with a thickness of 0.1-10 μm.

[0053] In one embodiment, the substrate 1 is provided with a back release cavity 11 to release the hot end position of the upstream temperature measuring element thermopile, the hot end position of the downstream temperature measuring element thermopile and the position of the central heat source structure 4 .

[0054] By providing the light-shielding and heat-insulating layer 10, the heat inside the chip can be prevented from rapidly diffusing outward, so that the heat is evenly distributed at the hot end, thereby improving the chip sensitivity. The light-shielding and heat-insulating layer 10 can be formed by spin coating a black photoresist on the surface of the passivation layer 9 and etching the black photoresist by photolithography patterning.

[0055] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to examples, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A heat-insulating and highly sensitive flow sensor chip, characterized in that: include: Substrate (1); A supporting structure layer, arranged on the surface of the substrate (1); An upstream temperature measuring element thermopile, a downstream temperature measuring element thermopile and a central heat source structure (4) are respectively arranged on the surface of the support structure layer; A passivation layer (9) respectively covers the upstream temperature measuring element thermopile, the downstream temperature measuring element thermopile and the central heat source structure (4); A light-shielding and heat-insulating layer (10) is arranged on the surface of the passivation layer (9) and only covers the central heat source structure (4), the hot end of the upstream temperature measuring element thermopile, and the hot end of the downstream temperature measuring element thermopile.

2. A heat-insulated and highly sensitive flow sensor chip according to claim 1, characterized in that: The light-shielding and heat-insulating layer (10) is black photoresist.

3. A heat-insulated and highly sensitive flow sensor chip according to claim 2, characterized in that: The thickness of the light-shielding and heat-insulating layer (10) is 0.05-1 μm.

4. A heat-insulated and highly sensitive flow sensor chip according to claim 1, characterized in that: The support structure layer comprises a silicon oxide support layer (2) and a silicon nitride support layer (3) which are sequentially arranged on the surface of the substrate (1).

5. A heat-insulated and highly sensitive flow sensor chip according to claim 4, characterized in that: The thickness of the silicon oxide support layer (2) is between 0.1 and 5 μm; the thickness of the silicon nitride support layer (3) is between 0.01 and 0.5 μm.

6. A heat-insulated and highly sensitive flow sensor chip according to claim 1, characterized in that: The upstream temperature measuring element thermopile comprises an upstream thermopile lower layer thermocouple (5a) and an upstream thermopile upper layer thermocouple (7a), and the downstream temperature measuring element thermopile comprises a downstream thermopile lower layer thermocouple (5b) and a downstream thermopile upper layer thermocouple (7b).

7. A heat-insulated and highly sensitive flow sensor chip according to claim 6, characterized in that: It also includes a first insulating layer (6a) and a second insulating layer (6b), wherein the first insulating layer (6a) covers the surfaces of the lower thermocouple (5a) of the upstream thermopile, the lower thermocouple (5b) of the downstream thermopile and the central heat source structure (4); and the second insulating layer (6b) covers the surfaces of the upper thermocouple (7a) of the upstream thermopile, the upper thermocouple (7b) of the downstream thermopile and a portion of the first insulating layer (6a).

8. The heat-insulating and highly sensitive flow sensor chip according to claim 7, characterized in that: The first insulating layer (6a) and / or the second insulating layer (6b) are made of silicon oxide with a thickness of 0.05 to 0.5 μm.

9. The heat-insulated and highly sensitive flow sensor chip according to claim 6, characterized in that: The invention also comprises an upstream thermopile structure hot junction area (81) connected between the upstream thermopile lower layer thermocouple (5a) and the upstream thermopile upper layer thermocouple (7a), a first upstream thermopile structure cold junction area (82) connected to the upstream thermopile lower layer thermocouple (5a), a second upstream thermopile structure cold junction area (83) connected to the upstream thermopile upper layer thermocouple (7a), a downstream thermopile structure hot junction area (84) connected between the downstream thermopile lower layer thermocouple (5b) and the downstream thermopile upper layer thermocouple (7b), a first downstream thermopile structure cold junction area (85) connected to the downstream thermopile lower layer thermocouple (5b), a second downstream thermopile structure cold junction area (86) connected to the downstream thermopile upper layer thermocouple (7b), and a heat source wire structure (87) connected to the central heat source structure (4).

10. The heat-insulated and highly sensitive flow sensor chip according to claim 1, characterized in that: The passivation layer (9) is made of silicon oxide with a thickness of 0.1 to 10 μm.

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