Flow sensor chip capable of self-checking and multi-directional measurement

Abstract

The utility model relates to a flow sensor chip capable of self-checking and multidirectional measurement. The heat exchanger comprises a central heat source structure which is of a cross-shaped structure; the four groups of thermopile temperature measuring elements comprise a first upstream thermopile temperature measuring element, a first downstream thermopile temperature measuring element, a second upstream thermopile temperature measuring element and a second downstream thermopile temperature measuring element; the first upstream thermopile temperature measurement element and the second upstream thermopile temperature measurement element both comprise a plurality of rows of upstream temperature measurement element thermopiles which are arranged in parallel; the first downstream thermopile temperature measurement element and the second downstream thermopile temperature measurement element both comprise multiple rows of downstream temperature measurement element thermopiles which are arranged in parallel; the upstream temperature measurement element thermopiles and the downstream temperature measurement element thermopiles both comprise cold junction region through holes and hot junction region through holes; and all cold junction region through holes and all corresponding hot junction region through holes of the four groups of thermopile temperature measurement elements are oppositely arranged and are respectively of a right-angle structure. The utility model has the multidirectional measurement capability and the self-detection function.

Description

Technical Field

[0001] The utility model relates to the technical field of flow sensors, in particular to a flow sensor chip capable of self-checking and multi-directional measurement. Background Art

[0002] Thermal flow sensors detect flow through temperature difference. The core principle is to use the heat conduction relationship between the heating resistor and the temperature measuring resistor. Thermistor sensors rely on their sensitivity to temperature. Temperature changes cause changes in resistance value. The temperature changes are reflected by resistance changes to measure flow. Thermopile sensors connect multiple thermocouples in series to superimpose the potential differences generated by each thermocouple, thereby amplifying the temperature difference signal and improving measurement accuracy.

[0003] However, the existing MEMS flow sensor with single flow direction or single-axis bidirectional design is prone to introduce measurement errors due to flow direction changes when gas flows in multiple directions. Summary of the invention

[0004] To this end, the utility model provides a flow sensor chip capable of self-detection and multi-directional measurement, which has multi-directional measurement capability and self-detection function, can effectively cope with complex fluid flow conditions, and is widely used in various flow measurement scenarios.

[0005] In order to solve the above technical problems, the utility model provides a flow sensor chip capable of self-checking and multi-directional measurement, comprising:

[0006] The central heat source structure is a cross structure;

[0007] Four groups of thermopile temperature measuring elements, including a first upstream thermopile temperature measuring element, a first downstream thermopile temperature measuring element, a second upstream thermopile temperature measuring element, and a second downstream thermopile temperature measuring element;

[0008] Wherein, the first upstream thermopile temperature measuring element and the first downstream thermopile temperature measuring element are respectively arranged symmetrically with the cross of the central heat source structure as the 45° axis of the XY axis coordinate system, and the length direction is parallel to the 135° axis; the second upstream thermopile temperature measuring element and the second downstream thermopile temperature measuring element are respectively arranged symmetrically with the 135° axis of the cross XY axis coordinate system of the central heat source structure, and the length direction is parallel to the 45° axis; the first upstream thermopile temperature measuring element is respectively arranged symmetrically with the second upstream thermopile temperature measuring element along the X axis and symmetrically with the second downstream thermopile temperature measuring element along the Y axis;

[0009] The first upstream thermopile temperature measuring element and the second upstream thermopile temperature measuring element both include multiple rows of upstream thermopile temperature measuring elements arranged in parallel; the first downstream thermopile temperature measuring element and the second downstream thermopile temperature measuring element both include multiple rows of downstream thermopile temperature measuring elements arranged in parallel, and the upstream thermopile temperature measuring element and the downstream thermopile temperature measuring element both include cold junction area through holes and hot junction area through holes;

[0010] All the cold junction area through holes and all the corresponding hot junction area through holes of each of the first upstream thermopile temperature measuring element, the first downstream thermopile temperature measuring element, the second upstream thermopile temperature measuring element and the second downstream thermopile temperature measuring element are arranged opposite to each other and respectively form a right angle structure, and two sides of the right angle structure are parallel to the X axis and the Y axis respectively.

[0011] 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.

[0012] In one embodiment of the utility model, the hot junction area through hole in the upstream temperature measuring element thermopile is provided with an upstream thermopile structure hot junction area, and the cold junction area through hole in the upstream temperature measuring element thermopile is provided with a first upstream thermopile structure cold junction area and a second upstream thermopile structure cold junction area;

[0013] A downstream thermopile structure hot junction region is arranged in the hot junction region through hole in the downstream temperature measuring element thermopile, and a first downstream thermopile structure cold junction region and a second downstream thermopile structure cold junction region are arranged in the cold junction region through hole in the downstream temperature measuring element thermopile;

[0014] The upstream thermopile structure hot junction area is connected between the upstream thermopile lower layer thermocouple and the upstream thermopile upper layer thermocouple;

[0015] The cold junction area of ​​the first upstream thermopile structure is connected to the lower thermocouple of the upstream thermopile;

[0016] The second upstream thermopile structure cold junction area is connected to the upper thermocouple of the upstream thermopile;

[0017] The downstream thermopile structure hot junction area is connected between the downstream thermopile lower layer thermocouple and the downstream thermopile upper layer thermocouple;

[0018] The cold junction area of ​​the first downstream thermopile structure is connected to the lower thermocouple of the downstream thermopile;

[0019] The second downstream thermopile structure cold junction area is connected to the upper thermocouple of the downstream thermopile.

[0020] In one embodiment of the present invention, a heat source wire structure connected to the central heat source structure is also included.

[0021] 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.

[0022] In one embodiment of the utility model, it also includes a substrate supported below the central heat source structure and the four groups of thermopile temperature measuring elements, and the substrate includes a silicon wafer and a silicon oxide support layer and a silicon nitride support layer respectively arranged along the surface of the silicon wafer.

[0023] In one embodiment of the present invention, all the hot junction area through holes of the first upstream thermopile temperature measuring element, the first downstream thermopile temperature measuring element, the second upstream thermopile temperature measuring element and the second downstream thermopile temperature measuring element are close to and distributed between two vertical arms of the central heat source structure.

[0024] The above technical solution of the utility model has the following advantages compared with the prior art:

[0025] The utility model discloses a flow sensor chip capable of self-checking and multi-directional measurement. The central heat source structure adopts a cross structure, which can ensure that the four groups of temperature measuring thermopile elements surrounding it can sense sufficient and symmetrical heat. The diagonal design of the temperature measuring thermopile element can make the thermocouple longer in a limited area, improve the sensitivity of chip temperature detection, and at the same time, whether the flow is flowing in from the six directions of X-axis, Y-axis, 45° axis, 135° axis or any direction, it can be stably detected.

[0026] The four-zone structure of the thermopile temperature measurement group design of the utility model has a certain self-detection function. For example, when the flow flows in from the 45° axial direction, there is still a group of thermopiles in the upstream and downstream; when the flow is 0SLM, zero-point detection can be performed, that is, self-detection of the preparation process of the current upstream and downstream thermopiles to determine whether the zero point of the chip is inaccurate due to process fluctuations. Then, through the flow in the 135° axial direction, it can be determined whether the preparation process of the other two groups of upstream and downstream thermopiles has zero-point deviations caused by process fluctuations, which in turn leads to inaccuracy in flow measurement. Therefore, the four-zone thermopile temperature measurement group design can realize the self-detection function of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 It is a schematic top view of the overall structure of the flow sensor chip capable of self-checking and multi-directional measurement of the utility model.

[0029] Figure 2 The utility model is a cross-sectional schematic diagram of a flow sensor chip capable of self-checking and multi-directional measurement.

[0030] Figure 3 It is a schematic diagram of the distribution of through holes in the hot junction area and the cold junction area of ​​the utility model.

[0031] Description of the Figures in the Specification:

[0032] 1. Substrate;

[0033] 2. Silicon oxide support layer;

[0034] 3. Silicon nitride support layer;

[0035] 4. Central heat source structure;

[0036] 5a, thermocouple of the lower layer of the upstream thermopile; 5b, thermocouple of the lower layer of the downstream thermopile;

[0037] 6a, a first insulating layer; 6b, a second insulating layer;

[0038] 7a, upper thermocouple of upstream thermopile; 7b, upper thermocouple of downstream thermopile;

[0039] 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;

[0040] 91. first upstream thermopile temperature measuring element; 92. first downstream thermopile temperature measuring element; 93. second upstream thermopile temperature measuring element; 94. second downstream thermopile temperature measuring element; 9a. upstream temperature measuring element thermopile; 9b. downstream temperature measuring element thermopile;

[0041] 10a, through hole in cold junction area; 10b, through hole in hot junction area;

[0042] 11. Passivation layer;

[0043] 12. Back release cavity. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] 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.

[0047] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0048] Reference Figures 1 to 3 As shown, the utility model is a flow sensor chip capable of self-checking and multi-directional measurement, comprising:

[0049] The central heat source structure 4 is a cross structure;

[0050] Four groups of thermopile temperature measuring elements, including a first upstream thermopile temperature measuring element 91, a first downstream thermopile temperature measuring element 92, a second upstream thermopile temperature measuring element 93, and a second downstream thermopile temperature measuring element 94;

[0051] Wherein, the first upstream thermopile temperature measuring element 91 and the first downstream thermopile temperature measuring element 92 are respectively arranged symmetrically with the cross of the central heat source structure 4 as the 45° axis of the XY axis coordinate system, and the length direction is parallel to the 135° axis; the second upstream thermopile temperature measuring element 93 and the second downstream thermopile temperature measuring element 94 are respectively arranged symmetrically with the 135° axis of the cross XY axis coordinate system of the central heat source structure 4, and the length direction is parallel to the 45° axis; the first upstream thermopile temperature measuring element 91 is respectively arranged symmetrically with the second upstream thermopile temperature measuring element along the X axis and symmetrically with the second downstream thermopile temperature measuring element 94 along the Y axis;

[0052] The first upstream thermopile temperature measuring element 91 and the second upstream thermopile temperature measuring element 93 both include multiple rows of upstream temperature measuring element thermopiles 9a arranged in parallel; the first downstream thermopile temperature measuring element 92 and the second downstream thermopile temperature measuring element 94 both include multiple rows of downstream temperature measuring element thermopiles 9b arranged in parallel, and the upstream temperature measuring element thermopiles 9a and the downstream temperature measuring element thermopiles 9b both include cold junction area through holes 10a and hot junction area through holes 10b;

[0053] All the cold junction area through holes 10a and the corresponding hot junction area through holes 10b of each of the first upstream thermopile temperature measuring element 91, the first downstream thermopile temperature measuring element 92, the second upstream thermopile temperature measuring element 93 and the second downstream thermopile temperature measuring element 94 are arranged opposite to each other and respectively form a right-angle structure, and the two sides of the right-angle structure are parallel to the X-axis and the Y-axis respectively.

[0054] In one embodiment, the upstream temperature measuring element thermopile 9a includes an upstream thermopile lower layer thermocouple 5a and an upstream thermopile upper layer thermocouple 7a, and the downstream temperature measuring element thermopile 9b includes a downstream thermopile lower layer thermocouple 5b and the downstream thermopile upper layer thermocouple 7b.

[0055] Specifically, the hot junction area through hole 10b in the upstream temperature measuring element thermopile 9a is provided with an upstream thermopile structure hot junction area 81, and the cold junction area through hole 10a in the upstream temperature measuring element thermopile 9a is provided with a first upstream thermopile structure cold junction area 82 and a second upstream thermopile structure cold junction area 83;

[0056] A downstream thermopile structure hot junction area 84 is arranged in the hot junction area through hole 10b in the downstream temperature measuring element thermopile 9b, and a first downstream thermopile structure cold junction area 85 and a second downstream thermopile structure cold junction area 86 are arranged in the cold junction area through hole 10a in the downstream temperature measuring element thermopile 9b;

[0057] The upstream thermopile structure hot junction area 81 is connected between the upstream thermopile lower layer thermocouple 5a and the upstream thermopile upper layer thermocouple 7a;

[0058] The first upstream thermopile structure cold junction area 82 is connected to the upstream thermopile lower layer thermocouple 5a;

[0059] The second upstream thermopile structure cold junction area 83 is connected to the upstream thermopile upper layer thermocouple 7a;

[0060] The downstream thermopile structure hot junction area 84 is connected between the downstream thermopile lower layer thermocouple 5b and the downstream thermopile upper layer thermocouple 7b;

[0061] The first downstream thermopile structure cold junction area 85 is connected to the downstream thermopile lower layer thermocouple 5b;

[0062] The second downstream thermopile structure cold junction area 86 is connected to the downstream thermopile upper layer thermocouple 7b.

[0063] Specifically, it also includes a heat source wire structure 87 connected to the central heat source structure 4.

[0064] It can be understood that the multiple rows of upstream temperature measuring element thermopiles 9a arranged in parallel and the multiple rows of downstream temperature measuring element thermopiles 9b arranged in parallel are connected by wires and then the electrodes are led out.

[0065] In one embodiment, it further includes a first insulating layer 6a and a second insulating layer 6b, wherein the first insulating layer 6a covers the surfaces of the upstream thermopile lower thermocouple 5a, the downstream thermopile lower thermocouple 5b and the central heat source structure 4, respectively; and the second insulating layer 6b covers the surfaces of the upstream thermopile upper thermocouple 7a, the downstream thermopile upper thermocouple 7b and part of the first insulating layer 6a. The first insulating layer 6a and the second insulating layer 6b may be made of silicon oxide.

[0066] In one embodiment, it also includes a substrate 1 supported under the central heat source structure 4 and the four groups of thermopile temperature measuring elements, the substrate 1 includes a silicon wafer and a silicon oxide support layer 2 and a silicon nitride support layer 3 respectively arranged along the surface of the silicon wafer. The front side of the chip is covered with a passivation layer 11 made of silicon oxide.

[0067] In one embodiment, the substrate 1 is provided with a back release cavity 12 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 .

[0068] In one embodiment, all the hot junction area through holes 10b of the first upstream thermopile temperature measuring element 91, the first downstream thermopile temperature measuring element 92, the second upstream thermopile temperature measuring element 93 and the second downstream thermopile temperature measuring element 94 are close to and distributed between the two vertical arms of the central heat source structure 4. Through the above arrangement, the central heat source structure 4 adopts a cross structure, which can ensure that the four groups of temperature measuring thermopile elements surrounding it feel sufficient and symmetrical heat generation. The four groups of thermopile temperature measuring elements are rectangular as a whole, compact in structure and easy to package.

[0069] The four-zone structure of the thermopile temperature measurement group design has a certain self-detection function. For example, when the flow flows in from the 45° axial direction, there is still a set of thermopiles upstream and downstream; when the flow is 0SLM (Standard Liters per Minute), zero-point detection can be performed, that is, self-detection of the current upstream and downstream thermopiles’ preparation process to determine whether the zero point of the chip is inaccurate due to process fluctuations. Then, through the flow in the 135° axial direction, it can be determined whether the preparation process of the other two sets of upstream and downstream thermopiles has zero-point deviations caused by process fluctuations, which in turn leads to inaccurate flow measurement. Therefore, the four-zone thermopile temperature measurement group design can realize the self-detection function of the chip.

[0070] In addition, the diagonal design allows the thermocouple to be designed longer in a limited area, improving the sensitivity of chip temperature detection. At the same time, stable detection can be achieved regardless of whether the flow is flowing in from the six directions of the X-axis, Y-axis, 45° axis, 135° axis, or any direction.

[0071] 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 flow sensor chip capable of self-checking and multi-directional measurement, characterized in that: include: The central heat source structure (4) is a cross structure; Four groups of thermopile temperature measuring elements, including a first upstream thermopile temperature measuring element (91), a first downstream thermopile temperature measuring element (92), a second upstream thermopile temperature measuring element (93) and a second downstream thermopile temperature measuring element (94); The first upstream thermopile temperature measuring element (91) and the first downstream thermopile temperature measuring element (92) are respectively arranged symmetrically with the cross of the central heat source structure (4) as the 45° axis of the XY axis coordinate system, and the length direction is parallel to the 135° axis; the second upstream thermopile temperature measuring element (93) and the second downstream thermopile temperature measuring element (94) are respectively arranged symmetrically with the 135° axis of the cross XY axis coordinate system of the central heat source structure (4), and the length direction is parallel to the 45° axis; the first upstream thermopile temperature measuring element (91) is respectively arranged symmetrically with the second upstream thermopile temperature measuring element along the X axis and symmetrically with the second downstream thermopile temperature measuring element (94) along the Y axis; The first upstream thermopile temperature measuring element (91) and the second upstream thermopile temperature measuring element (93) both comprise a plurality of rows of upstream temperature measuring element thermopiles (9a) arranged in parallel; the first downstream thermopile temperature measuring element (92) and the second downstream thermopile temperature measuring element (94) both comprise a plurality of rows of downstream temperature measuring element thermopiles (9b) arranged in parallel, and the upstream temperature measuring element thermopiles (9a) and the downstream temperature measuring element thermopiles (9b) both comprise cold junction area through holes (10a) and hot junction area through holes (10b); All the cold junction area through holes (10a) and all the corresponding hot junction area through holes (10b) of the first upstream thermopile temperature measuring element (91), the first downstream thermopile temperature measuring element (92), the second upstream thermopile temperature measuring element (93) and the second downstream thermopile temperature measuring element (94) are arranged opposite to each other and are respectively in a right-angle structure, and two sides of the right-angle structure are respectively parallel to the X-axis and the Y-axis.

2. A flow sensor chip capable of self-checking and multi-directional measurement according to claim 1, characterized in that: The upstream temperature measuring element thermopile (9a) comprises an upstream thermopile lower layer thermocouple (5a) and an upstream thermopile upper layer thermocouple (7a), and the downstream temperature measuring element thermopile (9b) comprises a downstream thermopile lower layer thermocouple (5b) and a downstream thermopile upper layer thermocouple (7b).

3. A flow sensor chip capable of self-checking and multi-directional measurement according to claim 2, characterized in that: An upstream thermopile structure hot junction region (81) is arranged in the hot junction region through hole (10b) in the upstream temperature measuring element thermopile (9a), and a first upstream thermopile structure cold junction region (82) and a second upstream thermopile structure cold junction region (83) are arranged in the cold junction region through hole (10a) in the upstream temperature measuring element thermopile (9a); A downstream thermopile structure hot junction region (84) is arranged in the hot junction region through hole (10b) in the downstream temperature measuring element thermopile (9b), and a first downstream thermopile structure cold junction region (85) and a second downstream thermopile structure cold junction region (86) are arranged in the cold junction region through hole (10a) in the downstream temperature measuring element thermopile (9b); The upstream thermopile structure hot junction area (81) is connected between the upstream thermopile lower layer thermocouple (5a) and the upstream thermopile upper layer thermocouple (7a); The first upstream thermopile structure cold junction area (82) is connected to the upstream thermopile lower layer thermocouple (5a); The second upstream thermopile structure cold junction area (83) is connected to the upper thermocouple (7a) of the upstream thermopile; The downstream thermopile structure hot junction area (84) is connected between the downstream thermopile lower layer thermocouple (5b) and the downstream thermopile upper layer thermocouple (7b); The first downstream thermopile structure cold junction area (85) is connected to the downstream thermopile lower layer thermocouple (5b); The second downstream thermopile structure cold junction area (86) is connected to the downstream thermopile upper layer thermocouple (7b).

4. A flow sensor chip capable of self-checking and multi-directional measurement according to claim 3, characterized in that: It also includes a heat source wire structure (87) connected to the central heat source structure (4).

5. The flow sensor chip capable of self-checking and multi-directional measurement according to claim 2, 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).

6. The flow sensor chip capable of self-checking and multi-directional measurement according to claim 1, characterized in that: It also includes a substrate (1) supported below the central heat source structure (4) and the four groups of thermopile temperature measuring elements, the substrate (1) including a silicon wafer and a silicon oxide support layer (2) and a silicon nitride support layer (3) respectively arranged along the surface of the silicon wafer.

7. The flow sensor chip capable of self-checking and multi-directional measurement according to claim 1, characterized in that: All of the hot junction area through holes (10b) of each of the first upstream thermopile temperature measuring element (91), the first downstream thermopile temperature measuring element (92), the second upstream thermopile temperature measuring element (93) and the second downstream thermopile temperature measuring element (94) are close to and distributed between two vertical arms of the central heat source structure (4).

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