Manufacturing Method of Sensor Chip and Suspension Bridge-Type Sensor Structure

Abstract

The present invention provides a sensor chip and a manufacturing method of a suspension bridge type sensor structure. The sensor chip is a single chip integrating a thermal acceleration sensor and an infrared sensor, and it includes a first wafer part. The first wafer part includes: a first substrate; a first cavity, which is arranged in the first substrate, and a filling gas is sealed in the first cavity, and the filling gas is a gas that does not absorb or absorbs less of a specific infrared spectrum; a suspension bridge type sensor structure, which is arranged on the front surface of the first substrate and opposite to the first cavity, and can be switched to an acceleration detection mode or an infrared detection mode; a signal processing circuit, which is arranged on the front surface of the first substrate and is used for processing the sensing signals generated by the suspension bridge type sensor structure. Compared with the prior art, the present invention shares the same sensor structure, can be switched between acceleration measurement and infrared temperature detection, and respectively realizes the measurement of acceleration and temperature, thereby improving the integration degree, reducing the chip occupation area and the usage cost.

Description

Technical Field

[0001] The present invention relates to the field of MEMS (Micro-Electro-Mechanical System) devices, and particularly to a single chip (or sensor chip) integrating a thermal acceleration and an infrared sensor and a manufacturing method of a suspension bridge type sensor structure.

Background Art

[0002] In recent years, acceleration sensors and infrared sensors based on MEMS technology have been widely used in people's daily lives, such as sports, health monitoring, epidemic prevention monitoring, etc. The acceleration sensor can be used to monitor the state of the device, playing roles such as posture detection and motion perception. The infrared sensor can play roles such as temperature detection, infrared imaging, and human body induction monitoring.

[0003] In the current technology, usually two independent devices, an acceleration sensor and an infrared detector, are required to complete acceleration measurement and infrared temperature measurement. Since the manufacturing processes of the acceleration sensor and the infrared thermopile sensor are different, usually separate wafer runs are required, and after packaging, they are assembled on the same substrate. This requires more substrate area and more cost.

[0004] Therefore, it is necessary to propose a technical solution to overcome the above problems.

Summary of the Invention

[0005] One object of the present invention is to provide a single chip integrating a thermal acceleration and an infrared sensor and a manufacturing method of a suspension bridge type sensor structure, which can improve the integration degree, reduce the chip occupied area and the usage cost.

[0006] According to one aspect of the present invention, the present invention provides a single chip integrating a thermal acceleration and an infrared sensor, which includes a first wafer part, and the first wafer part includes: a first substrate; a first cavity, which is arranged in the first substrate, and a filling gas is sealed in the first cavity, and the filling gas is a gas that does not absorb or absorbs less for a specific infrared spectrum; a suspension bridge type sensor structure, which is arranged on the front side of the first substrate and opposite to the first cavity, and can be switched to an acceleration detection mode or an infrared detection mode; a signal processing circuit, which is arranged on the front side of the first substrate and is used for processing the sensing signal generated by the suspension bridge type sensor structure.

[0007] Furthermore, the suspension bridge type sensor structure includes: a support layer located on the front side of the first substrate and above the first cavity; a thermopile including a first thermopile unit, a second thermopile unit, a third thermopile unit, and a fourth thermopile unit. The first thermopile unit and the second thermopile unit are arranged in the x-axis direction and are respectively located on the opposite first side and second side of the first cavity. The third thermopile unit and the fourth thermopile unit are arranged in the y-axis direction and are respectively located on the opposite third side and fourth side of the first cavity, where the x-axis and the y-axis form a rectangular coordinate system; a heater arranged in the middle of the suspension bridge type sensor structure.

[0008] Furthermore, the heater includes four groups of heating units, where two groups of heating units are arranged in parallel in the x-axis direction, and the other two groups of heating units are arranged in parallel in the y-axis direction.

[0009] Furthermore, the single chip of the integrated thermal acceleration and infrared sensor further includes a second wafer part. The front side of the second wafer part is bonded to the front side of the first wafer part. The second wafer part includes: a second substrate; a second cavity provided in the second substrate and opposite to the suspension bridge type sensor structure, and the filling gas is sealed in the second cavity.

[0010] Furthermore, when in the acceleration detection mode, a current is applied to the heater to heat the filling gas, and the signal processing circuit obtains the acceleration in the x-axis direction based on the difference between the voltage signals output by the first thermopile unit and the second thermopile unit; the signal processing circuit obtains the acceleration in the y-axis direction based on the difference between the voltage signals output by the third thermopile unit and the fourth thermopile unit. When in the infrared temperature detection mode, the heater is turned off, and the voltage signals output by the first thermopile unit, the second thermopile unit, the third thermopile unit, and the fourth thermopile unit are connected in series through a switch to make the thermopile output a total voltage signal, and the signal processing circuit obtains the infrared temperature based on the total voltage signal output by the thermopile.

[0011] Furthermore, the thermopile is composed of N-doped or P-doped polysilicon and metal; the thermopile is composed of N-doped and P-doped polysilicon; the thermopile is composed of other materials with the Seebeck effect; or the heater is made of metallized polysilicon or metal.

[0012] Furthermore, when in the acceleration detection mode, the filling gas serves as a medium for detecting acceleration; when in the infrared detection mode, the filling gas plays an adiabatic role to enhance the infrared detection efficiency.

[0013] Further, the filling gas is nitrogen, xenon or krypton; the signal processing circuit has the same layer as the suspension bridge type sensor structure and is fabricated simultaneously.

[0014] According to another aspect of the present invention, the present invention provides a manufacturing method of a suspension bridge type sensor structure, which includes: providing a first substrate; forming a support layer on the first substrate; depositing polysilicon on the support layer, doping the deposited polysilicon with P type and / or N type and patterning; metallizing the deposited polysilicon to form a heater; depositing a first dielectric layer on the doped and metallized polysilicon layer; forming a through hole penetrating the first dielectric layer and interconnected with the polysilicon on the first dielectric layer; depositing and patterning a first metal layer on the first dielectric layer with the through hole formed therein, wherein the thermopile is composed of N-doped or P-doped polysilicon and the patterned first metal; or the thermopile is composed of N-doped and P-doped polysilicon.

[0015] Further, the thermopile includes a first thermopile unit, a second thermopile unit, a third thermopile unit and a fourth thermopile unit. The first thermopile unit and the second thermopile unit are arranged in the x-axis direction and are respectively located on the opposite first side and second side of the first cavity. The third thermopile unit and the fourth thermopile unit are arranged in the y-axis direction and are respectively located on the opposite third side and fourth side of the first cavity, wherein the x-axis and the y-axis form a rectangular coordinate system; a heater, which is arranged in the middle of the suspension bridge type sensor structure.

[0016] Further, the heater includes four groups of heating units, wherein two groups of heating units are arranged in parallel in the x-axis direction, and the other two groups of heating units are arranged in parallel in the y-axis direction.

[0017] Further, the manufacturing method of the suspension bridge type sensor structure further includes: etching layer by layer from top to bottom to form an etching hole to expose the first substrate; etching the first substrate through the etching hole to fabricate the first cavity; filling the first cavity with a filling gas, and the filling gas is a gas that does not absorb or absorbs less of a specific infrared spectrum.

[0018] Further, between the step of "depositing and patterning a first metal layer on the first dielectric layer with the through hole formed therein" and the step of "etching layer by layer from top to bottom to form an etching hole to expose the first substrate", the method further includes: depositing a second dielectric layer on the patterned first metal layer; depositing and patterning a second metal layer on the second dielectric layer; depositing a third dielectric layer on the patterned second metal layer; depositing a passivation layer on the third dielectric layer; fabricating an etching protection layer on the passivation layer, wherein based on the etching protection layer, an etching hole is etched layer by layer from top to bottom to expose the first substrate.

[0019] Compared with the prior art, the present invention uses CMOS-MEMS processing technology to integrate a thermal acceleration sensor and a thermopile infrared sensor on the same chip, sharing the same sensor structure. It can switch between acceleration measurement and infrared temperature detection according to requirements, and respectively achieve the measurement of acceleration and temperature, thereby improving the integration degree, reducing the chip occupation area and the usage cost.

Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0021] Figure 1 It is a longitudinal cross-sectional schematic diagram of a single chip integrating a thermal acceleration and an infrared sensor in an embodiment of the present invention;

[0022] Figure 2 In an embodiment of the present invention, as Figure 1 shown, it is a top view of a suspension bridge type sensor structure;

[0023] Figure 3 In an embodiment of the present invention, as Figure 2 shown, it is a flowchart of a manufacturing method of a suspension bridge type sensor structure.

Detailed Embodiments

[0024] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0025] As used herein, the term "one embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments. Unless otherwise specified, the terms indicating electrical connection such as "connected", "coupled", and "joined" herein all mean directly or indirectly electrically connected.

[0026] Please refer to Figure 1 shown, which is a longitudinal cross-sectional schematic diagram of a single chip integrating a thermal acceleration and an infrared sensor in an embodiment of the present invention. Figure 1The single chip integrating a thermal acceleration and infrared sensor as shown includes a first wafer portion 110, a second wafer portion 120, and a filling gas (not labeled). After wafer-level packaging, a wafer dicing step is performed to form a plurality of independent packaging structures, i.e., independent chips. From the perspective before wafer dicing, i.e., from the wafer-level perspective, the first wafer portion 110 and the second wafer portion 120 belong to two independent wafers respectively. From the perspective after wafer dicing, i.e., from the chip-level perspective, the first wafer portion 110 and the second wafer portion 120 can be understood as wafers cut from the corresponding wafers.

[0027] The first wafer portion 110 includes a first substrate 112, a MEMS suspension bridge sensor structure (or suspension bridge detection structure) 114, a signal processing circuit (not shown), and a first cavity 116. The first cavity 116 extends from the front surface of the first substrate 112 into the first substrate 112; the MEMS suspension bridge sensor structure 114 is disposed on the front surface of the first substrate 112 and is opposite to the first cavity 116 (or the first cavity 116 is located below the MEMS suspension bridge sensor structure 114), and the MEMS suspension bridge sensor structure 114 is used for acceleration measurement and infrared temperature measurement; the signal processing circuit is disposed on the front surface of the first substrate 112 and is used for processing the sensing signals (e.g., voltage signals) generated by the MEMS suspension bridge sensor structure 114. In Figure 1 In the specific embodiment shown, the first substrate 112 is a silicon substrate, and the first cavity 116 located below the MEMS suspension bridge sensor structure 114 can be obtained by etching the silicon substrate.

[0028] The second wafer portion 120 includes a second substrate 122 and a second cavity 124. The second cavity 124 extends from the front surface of the second substrate 122 into the second substrate 122. The front surface of the second wafer portion 120 (or the front surface of the second substrate 122) is bonded to the front surface of the first wafer portion 110, and the second cavity 124 is opposite to the MEMS suspension bridge sensor structure 114. In Figure 1 In the specific embodiment shown, the second substrate 122 is a capping wafer, and the second cavity 124 located above the MEMS suspension bridge sensor structure 114 can be obtained by etching or processing the capping wafer; an infrared filter coating 130 is disposed (or covered) on the back surface of the second wafer portion 120 (or the side of the second wafer portion 120 away from the first wafer portion 110).

[0029] The first cavity 116 and the second cavity 124 need to be hermetically filled with a gas. The filling gas is a gas that does not absorb or absorbs less of a specific infrared spectrum, which can be nitrogen, xenon, krypton, etc. When the single chip (or the MEMS suspension bridge sensor structure 114) is in the acceleration detection mode, the filling gas serves as a medium for detecting acceleration; when the single chip (or the MEMS suspension bridge sensor structure 114) is in the infrared detection mode, the filling gas can play a good heat insulation role and enhance the infrared detection efficiency.

[0030] Please refer to Figure 2 as shown, which is a top view of the suspension bridge sensor structure in an embodiment of the present invention as Figure 1 shown. Figure 2 The MEMS suspension bridge sensor structure shown includes a support layer 210, a thermopile 220, and a heater 230. For the convenience of subsequent description, a rectangular coordinate system is defined in Figure 2 where the x-axis extends from left to right, the y-axis extends from bottom to top, and the plane where the x-axis and the y-axis are located is parallel to Figure 1 the surface of the first wafer portion 110 shown.

[0031] The support layer 210 is located on the front side of the first substrate 112 and above the first cavity 116. The support layer material can be silicon dioxide, silicon nitride, polysilicon, metal, or organic material, and the support layer material itself can be used to absorb infrared rays.

[0032] The thermopile 220 includes four groups of thermopile units, namely the first thermopile unit TP1, the second thermopile unit TP2, the third thermopile unit TP3, and the fourth thermopile unit TP4, which are respectively arranged in the four directions of up, down, left, and right of the first cavity 116 (i.e., the surface direction of the first wafer portion 110). Among them, the first thermopile unit TP1 and the second thermopile unit TP2 are arranged in the x-axis direction and are respectively located on the opposite first side and second side of the first cavity 116, and the third thermopile unit TP3 and the fourth thermopile unit TP4 are arranged in the y-axis direction and are respectively located on the opposite third side and fourth side of the first cavity 116. The thermopile 220 can be composed of N-doped or P-doped polysilicon and metal (for example, aluminum), or can be composed of N-doped and P-doped polysilicon, or can be composed of other materials with the Seebeck effect.

[0033] The heater 230 is arranged in the middle of the MEMS suspension bridge sensor structure 114, such as the center position, and includes four groups of heating units (not labeled). Among them, two groups of heating units are arranged in parallel in the x-axis direction, and the other two groups of heating units are arranged in parallel in the y-axis direction. The heater 230 can be made of metallized polysilicon or metal.

[0034] In one embodiment, the signal processing circuit is at the same level as the MEMS suspension bridge sensor structure 114 and is fabricated simultaneously. The signal processing circuit includes signal processing units such as operational amplifiers and analog-to-digital converters.

[0035] The following Figure 2 specifically introduces Figure 1 the working process of the single chip of the integrated thermal acceleration and infrared sensor shown.

[0036] When Figure 1 the single chip shown is in the acceleration detection mode, by applying a current to the heater 230, the heater 230 heats the filling gas in the closed cavity (for example, the first cavity 116 and the second cavity 124). After being heated, the filling gas flows along the direction and magnitude of the acceleration. By detecting the direction and speed of the flow of the heated filling gas in the closed cavity, the direction and magnitude of the acceleration can be obtained.

[0037] The temperatures of the thermopile units TP1, TP2, TP3, and TP4 in the four directions are T1, T2, T3, and T4 respectively; the voltage signals output by the thermopile units TP1, TP2, TP3, and TP4 in the four directions are V1, V2, V3, and V4 respectively.

[0038] When there is no acceleration, the temperature is symmetrically distributed, so the temperatures of the thermopile units TP1, TP2, TP3, and TP4 in the four directions are the same.

[0039] T1 = T2

[0040] T3 = T4

[0041] Therefore, the voltage signals output by the thermopile units TP1, TP2, TP3, and TP4 in the four directions are also the same:

[0042] V1 = V2

[0043] V3 = V4

[0044] If there is an acceleration in the x-axis direction and the direction is positive (or negative), the temperatures of the thermopile units TP1 and TP2 corresponding to the x-axis direction change and are proportional to the acceleration in the x-axis direction. The voltage signals of the two groups of thermopile units TP1 and TP2 also change with the acceleration in the x-axis direction:

[0045] T1 - T2 = ΔT x

[0046] ΔT x ∝ a x

[0047] V1 - V2 = ΔV x∝a x

[0048] where ΔT x is the temperature difference between the thermopile units TP1 and TP2 corresponding to the x-axis direction, a x is the acceleration in the x-axis direction, and ΔV x is the voltage signal difference between the thermopile units TP1 and TP2 corresponding to the x-axis direction. The signal processing circuit obtains (or acquires) the acceleration a x in the x-axis direction based on the difference ΔV x .

[0049] Similarly, if there is an acceleration in the y-axis direction and the direction is positive (or negative), the temperatures of the thermopile units TP3 and TP4 corresponding to the y-axis direction change and are proportional to the acceleration in the y-axis direction. The voltage signals of the two groups of thermopile units TP3 and TP4 also change with the acceleration in the y-axis direction:

[0050] T3 - T4 = ΔT y

[0051] ΔT y ∝a y

[0052] V3 - V4 = ΔV y ∝a y

[0053] where ΔT y is the temperature difference between the thermopile units TP3 and TP4 corresponding to the y-axis direction, a y is the acceleration in the y-axis direction, and ΔV y is the voltage signal difference between the thermopile units TP3 and TP4 corresponding to the y-axis direction. The signal processing circuit obtains (or acquires) the acceleration a y in the y-axis direction based on the difference ΔVy = V3 - V4

[0054] When Figure 1When the single chip shown is in the infrared temperature detection mode, the heater 230 is turned off. The entire MEMS suspension bridge sensor structure 114 can absorb infrared rays and its temperature increases. The heat mainly flows out through the MEMS suspension bridge sensor structure 114 in contact with the first substrate 112. Therefore, a temperature distribution is formed where the temperature in the middle of the MEMS suspension bridge sensor structure 114 is high and the temperature around it is low. Due to the Seebeck effect, the temperature difference causes a voltage difference to be generated in the four thermopile units TP1, TP2, TP3, and TP4. The voltage signals output by the first thermopile unit TP1, the second thermopile unit TP2, the third thermopile unit TP3, and the fourth thermopile unit TP4 are connected in series through a switch (not shown). The total voltage signal output by the thermopile 220 is:

[0055] V total = V1 + V2 + V3 + V4

[0056] The total voltage signal V total is proportional to the intensity of the infrared rays. The signal processing circuit obtains (or acquires) the corresponding infrared temperature based on the total voltage signal output by the thermopile 220.

[0057] That is to say, when Figure 1 the single chip shown is in the acceleration detection mode, a current is applied to the heater 230 to heat the filling gas in the closed cavity. The signal processing circuit obtains the acceleration in the y-axis direction based on the difference between the voltage signals output by the first thermopile unit TP1 and the second thermopile unit TP2; the signal processing circuit obtains the acceleration in the y-axis direction based on the difference between the voltage signals output by the third thermopile unit TP3 and the fourth thermopile unit TP4. When Figure 1 the single chip shown is in the infrared temperature detection mode, the heater 230 is turned off. The voltage signals output by the first thermopile unit TP1, the second thermopile unit TP2, the third thermopile unit TP3, and the fourth thermopile unit TP4 are connected in series through a switch. The thermopile 220 outputs a total voltage signal. The signal processing circuit obtains the infrared temperature based on the total voltage signal output by the thermopile 220.

[0058] Please refer to Figure 3 shown, which is a schematic flow chart of the manufacturing method of the suspension bridge sensor structure as shown in an embodiment of the present invention. It manufactures the suspension bridge sensor structure on the first substrate 112 using standard CMOS circuit processes. Figure 2 The manufacturing method of the suspension bridge sensor structure as shown includes the following steps. Figure 3 The manufacturing method of the suspension bridge sensor structure as shown includes the following steps.

[0059] Step 301: Provide the first substrate 112. In one embodiment, the first substrate 112 is a silicon substrate.

[0060] Step 302: Form a support layer 210 on the first substrate 112. In one embodiment, grow a silicon oxide thin film on the first substrate 112 to act as the support layer 210.

[0061] Step 303: Deposit polysilicon on the support layer 210, and perform P-type and / or N-type doping and patterning on the deposited polysilicon. This depends on the composition of the thermopile 220: If the thermopile 220 is composed of N-type doped and P-type doped polysilicon, then perform P-type and N-type doping and patterning on the polysilicon; if the thermopile 220 is composed of N-type doped polysilicon and metal, then perform N-type doping and patterning on the polysilicon; if the thermopile 220 is composed of P-type doped polysilicon and metal, then perform P-type doping and patterning on the polysilicon.

[0062] Step 304: Metalize the deposited polysilicon to form the heater 230. The metalization material can be titanium silicide or tungsten silicide.

[0063] Step 305: Deposit a first dielectric layer on the doped and metalized polysilicon layer.

[0064] Step 306: Form a through hole in the first dielectric layer that penetrates the first dielectric layer and is interconnected with the polysilicon.

[0065] Step 307: Deposit a first metal layer on the first dielectric layer with the through hole formed and pattern it. If the thermopile 220 is composed of N-type doped and P-type doped polysilicon, the patterned first metal layer mainly serves as a wire; if the thermopile 220 is composed of metal and N-type doped or P-type doped polysilicon, the patterned first metal layer serves as the positive or negative electrode of the thermopile 220. In one embodiment, the material of the first metal layer is aluminum.

[0066] Step 308: Deposit a second dielectric layer on the patterned first metal layer.

[0067] Step 309: Deposit a second metal layer on the second dielectric layer and pattern it. The patterned second metal layer can be used to improve the infrared absorption efficiency. In one embodiment, the material of the second metal layer is aluminum.

[0068] Step 310: Deposit a third dielectric layer on the patterned second metal layer.

[0069] Step 311: Deposit a passivation layer on the third dielectric layer. The passivation layer can be a material such as silicon nitride.

[0070] Step 312: Fabricate an etching protection layer on the passivation layer. The etching protection layer can be photoresist or a passivation material such as polyimide.

[0071] Step 313: Etch downward layer by layer based on the etching protection layer to form an etching hole 240 to expose the first substrate 112.

[0072] Step 314: Perform deep silicon etching (DRIE) and dry etching on the first substrate 112 through the etching hole 240 to fabricate a cavity, remove the first substrate 112 under the thin film, and form an adiabatic cavity, i.e., the first cavity 116. The longitudinal etching depth of the first cavity 116 is about 50 - 400 microns; the lateral etching depth is about 40 - 100 microns.

[0073] Step 315: Fill the first cavity 116 with a filling gas with controllable purity, such as nitrogen, xenon, krypton, etc. When Figure 1 the single chip shown is in the acceleration detection mode, the filling gas serves as a medium for detecting acceleration; when Figure 1 the single chip shown is in the infrared detection mode, the filling gas can play a good adiabatic role and enhance the infrared detection efficiency.

[0074] In summary, the present invention uses CMOS - MEMS processing technology to integrate a thermal acceleration sensor and a thermopile infrared sensor on the same chip, sharing the same sensor structure, and can switch between acceleration measurement and infrared temperature detection according to requirements, respectively realizing the measurement of acceleration and temperature, thereby improving the integration degree, reducing the chip occupied area and usage cost.

[0075] In the present invention, words indicating electrical connection such as "connected", "linked", "joined", "connected" etc., unless otherwise specified, represent direct or indirect electrical connection.

[0076] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above - mentioned embodiment. Any equivalent modification or change made by those of ordinary skill in the art according to the disclosure of the present invention should be included in the protection scope recorded in the claims.

Claims

1. A single chip integrating a thermal accelerometer and an infrared sensor, characterized in that, It includes a first wafer part, and the first wafer part includes: A first substrate; A first cavity, which is arranged in the first substrate. The first cavity is sealed with a filling gas, and the filling gas is a gas that does not absorb or absorbs less of a specific infrared spectrum; A suspension bridge type sensor structure, which is arranged on the front side of the first substrate and opposite to the first cavity. It can be switched to an acceleration detection mode or an infrared detection mode. The suspension bridge type sensor structure includes: a support layer, which is located on the front side of the first substrate and above the first cavity; a thermopile, which includes a first thermopile unit, a second thermopile unit, a third thermopile unit, and a fourth thermopile unit. The first thermopile unit and the second thermopile unit are arranged in the x-axis direction and are respectively located on the opposite first side and second side of the first cavity. The third thermopile unit and the fourth thermopile unit are arranged in the y-axis direction and are respectively located on the opposite third side and fourth side of the first cavity. Among them, the x-axis and the y-axis form a rectangular coordinate system; a heater, which is arranged in the middle of the suspension bridge type sensor structure; A signal processing circuit, which is arranged on the front side of the first substrate and is used to process the sensing signals generated by the suspension bridge type sensor structure; When in the acceleration detection mode, a current is applied to the heater to heat the filling gas. The signal processing circuit obtains the acceleration in the x-axis direction based on the difference between the voltage signals output by the first thermopile unit and the second thermopile unit; the signal processing circuit obtains the acceleration in the y-axis direction based on the difference between the voltage signals output by the third thermopile unit and the fourth thermopile unit, When in the infrared temperature detection mode, the heater is turned off, and the voltage signals output by the first thermopile unit, the second thermopile unit, the third thermopile unit, and the fourth thermopile unit are connected in series through a switch, so that the thermopile outputs a total voltage signal. The signal processing circuit obtains the infrared temperature based on the total voltage signal output by the thermopile.

2. The single chip integrating a thermal accelerometer and an infrared sensor according to claim 1, characterized in that, The heater includes four groups of heating units. Among them, two groups of heating units are arranged in parallel in the x-axis direction, and the other two groups of heating units are arranged in parallel in the y-axis direction.

3. The single chip integrating a thermal accelerometer and an infrared sensor according to claim 1, characterized in that, It further includes a second wafer part. The front side of the second wafer part is bonded to the front side of the first wafer part. The second wafer part includes: A second substrate; A second cavity, which is arranged in the second substrate and opposite to the suspension bridge type sensor structure. The second cavity is sealed with the filling gas.

4. The single chip integrating a thermal accelerometer and an infrared sensor according to claim 3, characterized in that, The thermopile is composed of N-doped or P-doped polysilicon and metal; or The thermopile is composed of N-doped and P-doped polysilicon; or The thermopile is composed of other materials with the Seebeck effect; or The heater is made of metallized polysilicon or metal.

5. The single chip integrating a thermal accelerometer and an infrared sensor according to claim 3, characterized in that, When in the acceleration detection mode, the filling gas serves as a medium for detecting acceleration; When in the infrared detection mode, the filling gas plays an adiabatic role and enhances the infrared detection efficiency.

6. The single chip integrating a thermal accelerometer and an infrared sensor according to claim 3, characterized in that, The filling gas is nitrogen, xenon or krypton; The signal processing circuit and the suspension bridge type sensor structure have the same layer and are fabricated simultaneously.

7. A manufacturing method of the single chip integrating a thermal accelerometer and an infrared sensor according to any one of claims 1-6, characterized in that, It includes: Provide a first substrate; Form a support layer on the first substrate; Deposit polysilicon on the support layer, perform P-type and / or N-type doping on the deposited polysilicon, and pattern it; Metalize the deposited polysilicon to form a heater; Deposit a first dielectric layer on the doped and metalized polysilicon layer; Form a via hole through the first dielectric layer and interconnected with the polysilicon on the first dielectric layer; Deposit a first metal layer on the first dielectric layer with the via hole formed thereon and pattern it; Wherein, the thermopile is composed of N-doped or P-doped polysilicon and the patterned first metal; or the thermopile is composed of N-doped and P-doped polysilicon.

8. The manufacturing method of a single core of an integrated thermal acceleration and infrared sensor according to claim 7, characterized in that, The thermopile includes a first thermopile unit, a second thermopile unit, a third thermopile unit, and a fourth thermopile unit. The first thermopile unit and the second thermopile unit are arranged in the x-axis direction and are respectively located on the opposite first side and second side of the first cavity. The third thermopile unit and the fourth thermopile unit are arranged in the y-axis direction and are respectively located on the opposite third side and fourth side of the first cavity, wherein the x-axis and the y-axis form a rectangular coordinate system; A heater, which is arranged in the middle of the suspension bridge type sensor structure.

9. The manufacturing method of a single core of an integrated thermal acceleration and infrared sensor according to claim 8, characterized in that, The heater includes four groups of heating units, wherein two groups of heating units are arranged in parallel in the x-axis direction, and the other two groups of heating units are arranged in parallel in the y-axis direction.

10. The manufacturing method of a single core of an integrated thermal acceleration and infrared sensor according to claim 7, characterized in that, It further includes: Etch downward layer by layer to form an etch hole to expose the first substrate; Etch the first substrate through the etch hole to fabricate the first cavity; Fill the first cavity with a filling gas, and the filling gas is a gas that does not absorb or absorbs less of a specific infrared spectrum.

11. The manufacturing method of a single core of an integrated thermal acceleration and infrared sensor according to claim 10, characterized in that, Between the step of "depositing a first metal layer on the first dielectric layer with the via hole formed thereon and patterning it" and the step of "etching downward layer by layer to form an etch hole to expose the first substrate", it further includes: Deposit a second dielectric layer on the patterned first metal layer; Deposit a second metal layer on the second dielectric layer and pattern it; Deposit a third dielectric layer on the patterned second metal layer; Deposit a passivation layer on the third dielectric layer; Fabricate an etch protection layer on the passivation layer; Wherein, based on the etch protection layer, etch downward layer by layer to form an etch hole to expose the first substrate.

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