Four-partition flow sensor chip convenient to package

Abstract

The utility model relates to a four-partition flow sensor chip convenient to package. Comprising a central heat source structure of a cross structure and four groups of thermopile temperature measuring elements arranged around the central heat source structure; a first upstream thermopile temperature measurement positive electrode and a first upstream thermopile temperature measurement negative electrode which are arranged in parallel with the 45-degree shaft are led out from the first upstream thermopile temperature measurement element; a second upstream thermopile temperature measurement positive electrode and a second upstream thermopile temperature measurement negative electrode which are arranged in parallel with the 135-degree shaft are led out from the second upstream thermopile temperature measurement element; the first downstream thermopile temperature measuring element leads out a first downstream thermopile temperature measuring positive electrode and a first downstream thermopile temperature measuring negative electrode which are arranged parallel to the 45-degree shaft; the second downstream thermopile temperature measuring element leads out a second downstream thermopile temperature measuring positive electrode and a second downstream thermopile temperature measuring negative electrode which are arranged in parallel with the 135-degree shaft; and first central heat source heating positive and negative electrodes are symmetrically led out from the upper and lower ends of the central heat source structure in the cross direction, and second central heat source heating positive and negative electrodes are symmetrically led out from the left and right ends. According to the flow sensor, the problems that the packaging difficulty of the flow sensor is large, and gas in multiple inflow directions cannot be detected are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of flow sensors, in particular to a four-zone flow sensor chip which is easy to package. Background Art

[0002] Thermal flow sensors supply constant voltage to the heating resistor and measure the flow rate based on the temperature difference between the upstream and downstream temperature measuring elements at different flow rates. Depending on the temperature measuring resistor, thermal flow sensors can be divided into two types: thermistor type and thermopile type. Temperature measuring elements include thermistors and thermopiles. The thermopile is made up of multiple thermocouples connected in series. Thermocouples form a closed loop by connecting the two ends of two conductors of different materials. When there is a temperature difference between the two ends, an electric potential difference will be generated in the loop. This phenomenon is called the Seebeck effect.

[0003] However, existing flow sensor chips have some limitations in packaging and multi-directional detection capabilities. Traditional flow sensor chip designs usually consider flow detection in a single direction, which leads to reduced accuracy when performing multi-directional flow detection. In addition, traditional designs also have inconveniences in packaging processes. The complex electrode arrangement increases the difficulty of packaging, reduces packaging reliability and production efficiency. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the flow sensor in the prior art is difficult to package and cannot detect gases flowing in multiple directions.

[0005] In order to solve the above technical problems, the utility model provides a four-zone flow sensor chip that is easy to package, including:

[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 arranged around the central heat source structure; wherein the first upstream thermopile temperature measuring element and the second upstream thermopile temperature measuring element both include multiple rows of upstream temperature measuring element thermopiles arranged in parallel, and the first downstream thermopile temperature measuring element and the second downstream thermopile temperature measuring element both include multiple rows of downstream temperature measuring element thermopiles arranged in parallel;

[0008] 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] Multiple rows of the upstream temperature measuring element thermopiles in the first upstream thermopile temperature measuring element are connected by wires to lead out first upstream thermopile temperature measuring positive electrodes and first upstream thermopile temperature measuring negative electrodes arranged parallel to the 45° axis;

[0010] Multiple rows of the upstream temperature measuring element thermopiles in the second upstream thermopile temperature measuring element are connected by wires to lead out second upstream thermopile temperature measuring positive electrodes and second upstream thermopile temperature measuring negative electrodes arranged in parallel with the 135° axis;

[0011] Multiple rows of the downstream temperature measuring element thermopiles in the first downstream thermopile temperature measuring element are connected by wires to lead out first downstream thermopile temperature measuring positive electrodes and first downstream thermopile temperature measuring negative electrodes arranged parallel to the 45° axis;

[0012] Multiple rows of the downstream temperature measuring element thermopiles in the second downstream thermopile temperature measuring element are connected by wires to lead out second downstream thermopile temperature measuring positive electrodes and second downstream thermopile temperature measuring negative electrodes arranged in parallel with the 135° axis;

[0013] The upper and lower ends of the central heat source structure in the cross direction symmetrically lead out a first central heat source to heat the positive electrode and a first central heat source to heat the negative electrode, and the left and right ends symmetrically lead out a second central heat source to heat the positive electrode and a second central heat source to heat the negative electrode.

[0014] 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.

[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, the upstream temperature measuring element thermopile and the downstream temperature measuring element thermopile both include a cold junction area through hole and a hot junction area through hole; 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;

[0017] 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;

[0018] The upstream thermopile structure hot junction area is connected between the upstream thermopile lower layer thermocouple and the upstream thermopile upper layer thermocouple;

[0019] The cold junction area of ​​the first upstream thermopile structure is connected to the lower thermocouple of the upstream thermopile;

[0020] The second upstream thermopile structure cold junction area is connected to the upper thermocouple of the upstream thermopile;

[0021] The downstream thermopile structure hot junction area is connected between the downstream thermopile lower layer thermocouple and the downstream thermopile upper layer thermocouple;

[0022] The cold junction area of ​​the first downstream thermopile structure is connected to the lower thermocouple of the downstream thermopile;

[0023] The second downstream thermopile structure cold junction area is connected to the upper thermocouple of the downstream thermopile.

[0024] In one embodiment of the utility model, all the cold 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 flush; all the hot junction area through holes of each are arranged at right angles to the X-axis and the Y-axis, respectively, and are respectively close to the two arms perpendicular to the central heat source structure.

[0025] 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.

[0026] The above technical solution of the utility model has the following advantages compared with the prior art:

[0027] The utility model discloses a four-zone flow sensor chip that is easy to package, and the electrodes of each thermopile temperature measuring element are arranged around the central heat source structure, which is easy to package. The temperature of the central heat source is detected by designing four sets of diagonally symmetrical thermopile temperature measuring element structures. The diagonal design increases the length of the thermocouple in a limited area, improves the sensitivity of chip temperature detection, and can stably detect the flow flowing in from six directions such as the X-axis, Y-axis, 45° axis, 135° axis, or any direction. By decomposing the flow in any direction into three directions of the XY axis and the 45° axis, and using four sets of diagonally symmetrical thermopile temperature measurement data to calibrate the big data algorithm, the flow size can be determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 It is a top view structural diagram of the chip of the utility model.

[0030] Figure 2 It is a structural cross-sectional view of the chip 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; 41a. The first central heat source heats the positive electrode; 41b. The first central heat source heats the negative electrode; 42a. The second central heat source heats the positive electrode; 42b. The second central heat source heats the negative electrode;

[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] 9. Passivation layer;

[0041] 13a, upstream temperature measuring element thermopile; 13b, downstream temperature measuring element thermopile;

[0042] 14. First upstream thermopile temperature measuring element; 14a. First upstream thermopile temperature measuring positive electrode; 14b. First upstream thermopile temperature measuring negative electrode;

[0043] 15. Second upstream thermopile temperature measurement element; 15a. Second upstream thermopile temperature measurement positive electrode; 15b. Second upstream thermopile temperature measurement negative electrode;

[0044] 16. First downstream thermopile temperature measurement element; 16a. First downstream thermopile temperature measurement positive electrode; 16b. First downstream thermopile temperature measurement negative electrode;

[0045] 17. Second downstream thermopile temperature measurement element; 17a. Second downstream thermopile temperature measurement positive electrode; 17b. Second downstream thermopile temperature measurement negative electrode;

[0046] 18a, through hole in cold junction area; 18b, through hole in hot junction area. DETAILED DESCRIPTION

[0047] 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.

[0048] 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.

[0049] Reference Figure 1 , Figure 2 As shown, a four-zone flow sensor chip that is easy to package includes:

[0050] The central heat source structure 4 is a cross structure;

[0051] Four groups of thermopile temperature measuring elements, including a first upstream thermopile temperature measuring element 14, a first downstream thermopile temperature measuring element 16, a second upstream thermopile temperature measuring element 15 and a second downstream thermopile temperature measuring element 17 arranged around the central heat source structure 4; wherein the first upstream thermopile temperature measuring element 14 and the second upstream thermopile temperature measuring element 15 both include multiple rows of upstream temperature measuring element thermopiles 13a arranged in parallel, and the first downstream thermopile temperature measuring element 16 and the second downstream thermopile temperature measuring element 17 both include multiple rows of downstream temperature measuring element thermopiles 13b arranged in parallel;

[0052] The first upstream thermopile temperature measuring element 14 and the first downstream thermopile temperature measuring element 16 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 15 and the second downstream thermopile temperature measuring element 17 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 14 is respectively arranged symmetrically with the second upstream thermopile temperature measuring element 15 along the X axis and symmetrically with the second downstream thermopile temperature measuring element 17 along the Y axis;

[0053] The multiple rows of the upstream thermopile temperature measuring element thermopiles 13a in the first upstream thermopile temperature measuring element 14 are connected by wires to lead out the first upstream thermopile temperature measuring positive electrode 14a and the first upstream thermopile temperature measuring negative electrode 14b arranged parallel to the 45° axis;

[0054] The multiple rows of the upstream thermopile temperature measuring element thermopiles 13a in the second upstream thermopile temperature measuring element 15 are connected by wires to lead out the second upstream thermopile temperature measuring positive electrodes 15a and the second upstream thermopile temperature measuring negative electrodes 15b arranged parallel to the 135° axis;

[0055] Multiple rows of the downstream thermopile temperature measuring element thermopiles 13b in the first downstream thermopile temperature measuring element 16 are connected by wires to lead out first downstream thermopile temperature measuring positive electrodes 16a and first downstream thermopile temperature measuring negative electrodes 16b arranged parallel to the 45° axis;

[0056] Multiple rows of the downstream thermopile temperature measuring element thermopiles 13b in the second downstream thermopile temperature measuring element 17 are connected by wires to lead out second downstream thermopile temperature measuring positive electrodes 17a and second downstream thermopile temperature measuring negative electrodes 17b arranged parallel to the 135° axis;

[0057] The upper and lower ends of the central heat source structure 4 in the cross direction symmetrically lead out the first central heat source heating positive electrode 41a and the first central heat source heating negative electrode 41b, and the left and right ends symmetrically lead out the second central heat source heating positive electrode 42a and the second central heat source heating negative electrode 42b; the heating negative electrodes at the upper and lower ends and the left and right ends are used in one group, and the other group is used as a spare electrode.

[0058] Specifically, it also includes a substrate 1 supported below the central heat source structure 4 and the four groups of thermopile temperature measuring elements, and 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.

[0059] Specifically, the upstream temperature measuring element thermopile 13a includes an upstream thermopile lower layer thermocouple 5a and an upstream thermopile upper layer thermocouple 7a, and the downstream temperature measuring element thermopile 13b includes a downstream thermopile lower layer thermocouple 5b and the downstream thermopile upper layer thermocouple 7b.

[0060] Specifically, the upstream temperature measuring element thermopile 13a and the downstream temperature measuring element thermopile 13b both include a cold junction area through hole 18a and a hot junction area through hole 18b; an upstream thermopile structure hot junction area 81 is arranged in the hot junction area through hole 18b in the upstream temperature measuring element thermopile 13a, and a first upstream thermopile structure cold junction area 82 and a second upstream thermopile structure cold junction area 83 are arranged in the cold junction area through hole 18a in the upstream temperature measuring element thermopile 13a;

[0061] A downstream thermopile structure hot junction area 84 is arranged in the hot junction area through hole 18b in the downstream temperature measuring element thermopile 13b, 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 18a in the downstream temperature measuring element thermopile 13b;

[0062] 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;

[0063] The first upstream thermopile structure cold junction area 82 is connected to the upstream thermopile lower layer thermocouple 5a;

[0064] The second upstream thermopile structure cold junction area 83 is connected to the upstream thermopile upper layer thermocouple 7a;

[0065] 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;

[0066] The first downstream thermopile structure cold junction area 85 is connected to the downstream thermopile lower layer thermocouple 5b;

[0067] The second downstream thermopile structure cold junction area 86 is connected to the downstream thermopile upper layer thermocouple 7b.

[0068] Specifically, all the cold junction area through holes 18a of the first upstream thermopile temperature measuring element 14, the first downstream thermopile temperature measuring element 16, the second upstream thermopile temperature measuring element 15 and the second downstream thermopile temperature measuring element 17 are flush (i.e., parallel to the 45° axis or the 135° axis); all the hot junction area through holes 18b of each are arranged at right angles to the X-axis and the Y-axis, respectively, and are respectively close to the two arms perpendicular to the central heat source structure 4.

[0069] 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.

[0070] Furthermore, the outer contours of all electrodes are regular octagonal structures. The above arrangement makes the overall electrode pads compactly distributed and convenient for packaging.

[0071] Furthermore, a passivation layer 9 is provided on the top surface of the chip.

[0072] Through the above settings, the electrodes in each thermopile temperature measuring element are symmetrically arranged around the central heat source structure 4, which is convenient for packaging. Whether the flow is from the six directions of X-axis, Y-axis, 45° axis, 135° axis or any direction, it can be stably detected. By decomposing the flow in any direction into three axes of XY and 45° axis, the flow size can be determined by calibrating the big data algorithm through four sets of diagonally symmetrical thermopile temperature measurement data. Similarly, the flow direction can be determined by calculating the flow size based on the data of four sets of thermopile.

[0073] 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 four-zone flow sensor chip that is easy to package, characterized in that: include: The central heat source structure (4) is a cross structure; Four groups of thermopile temperature measuring elements, comprising a first upstream thermopile temperature measuring element (14), a first downstream thermopile temperature measuring element (16), a second upstream thermopile temperature measuring element (15) and a second downstream thermopile temperature measuring element (17) arranged around the central heat source structure (4); wherein the first upstream thermopile temperature measuring element (14) and the second upstream thermopile temperature measuring element (15) both comprise a plurality of rows of upstream temperature measuring element thermopiles (13a) arranged in parallel, and the first downstream thermopile temperature measuring element (16) and the second downstream thermopile temperature measuring element (17) both comprise a plurality of rows of downstream temperature measuring element thermopiles (13b) arranged in parallel; The first upstream thermopile temperature measuring element (14) and the first downstream thermopile temperature measuring element (16) 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 (15) and the second downstream thermopile temperature measuring element (17) 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 (14) is respectively arranged symmetrically with the second upstream thermopile temperature measuring element (15) along the X axis and symmetrically with the second downstream thermopile temperature measuring element (17) along the Y axis; A plurality of rows of the upstream temperature measuring element thermopiles (13a) in the first upstream thermopile temperature measuring element (14) are connected by wires to lead out a first upstream thermopile temperature measuring positive electrode (14a) and a first upstream thermopile temperature measuring negative electrode (14b) arranged parallel to the 45° axis; A plurality of rows of the upstream temperature measuring element thermopiles (13a) in the second upstream thermopile temperature measuring element (15) are connected by wires to lead out a second upstream thermopile temperature measuring positive electrode (15a) and a second upstream thermopile temperature measuring negative electrode (15b) arranged parallel to the 135° axis; A plurality of rows of the downstream temperature measuring element thermopiles (13b) in the first downstream thermopile temperature measuring element (16) are connected by wires to lead out a first downstream thermopile temperature measuring positive electrode (16a) and a first downstream thermopile temperature measuring negative electrode (16b) arranged parallel to the 45° axis; A plurality of rows of the downstream thermopile temperature measuring element thermopiles (13b) in the second downstream thermopile temperature measuring element (17) are connected by wires to lead out a second downstream thermopile temperature measuring positive electrode (17a) and a second downstream thermopile temperature measuring negative electrode (17b) arranged parallel to the 135° axis; The central heat source structure (4) has a first central heat source heating positive electrode (41a) and a first central heat source heating negative electrode (41b) symmetrically led out at the upper and lower ends in the cross direction, and a second central heat source heating positive electrode (42a) and a second central heat source heating negative electrode (42b) symmetrically led out at the left and right ends.

2. A four-zone flow sensor chip that is easy to package 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.

3. The four-zone flow sensor chip that is easy to package according to claim 1 is characterized in that: The upstream temperature measuring element thermopile (13a) comprises an upstream thermopile lower layer thermocouple (5a) and an upstream thermopile upper layer thermocouple (7a), and the downstream temperature measuring element thermopile (13b) comprises a downstream thermopile lower layer thermocouple (5b) and a downstream thermopile upper layer thermocouple (7b).

4. A four-zone flow sensor chip that is easy to package according to claim 3, characterized in that: The upstream temperature measuring element thermopile (13a) and the downstream temperature measuring element thermopile (13b) both comprise a cold junction region through hole (18a) and a hot junction region through hole (18b); An upstream thermopile structure hot junction region (81) is arranged in the hot junction region through hole (18b) in the upstream temperature measuring element thermopile (13a), 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 (18a) in the upstream temperature measuring element thermopile (13a); A downstream thermopile structure hot junction region (84) is arranged in the hot junction region through hole (18b) in the downstream temperature measuring element thermopile (13b), 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 (18a) in the downstream temperature measuring element thermopile (13b); 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).

5. The four-zone flow sensor chip that is easy to package according to claim 4 is characterized in that: All the cold junction area through holes (18a) of the first upstream thermopile temperature measuring element (14), the first downstream thermopile temperature measuring element (16), the second upstream thermopile temperature measuring element (15) and the second downstream thermopile temperature measuring element (17) are flush with each other, and all the hot junction area through holes (18b) of each are arranged at right angles to the X-axis and the Y-axis, respectively, and are close to the two arms perpendicular to the central heat source structure (4).

6. The four-zone flow sensor chip that is easy to package according to claim 5, 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).

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