CN114812853A - Double-cavity cascade acceleration-temperature sensor and preparation method thereof - Google Patents

Abstract

The application relates to a double-cavity cascade acceleration-temperature sensor which comprises an acceleration sensor structure and a temperature sensor structure which are arranged up and down, wherein the acceleration sensor structure is an inertial motion structure formed by combining a cantilever beam and a mass block. When the sensor is subjected to acceleration parallel to the direction of the air cavity, the mass is displaced due to the influence of inertia, which in turn causes a change in the length of the air cavity, causing a shift in the wavelength of the interference spectrum. The temperature sensor structure is composed of a silicon cavity formed by monocrystalline silicon and optical films on the upper side and the lower side. The volume of silicon changes when the temperature changes, resulting in a change in the cavity length of the silicon, causing a wavelength shift in the interference spectrum. The difference between the air cavity and the silicon cavity is more than 1 magnitude, light beams vertically enter from the upper part of the sensor mass block and are emitted out after passing through the air cavity and the silicon cavity, emergent light carries wavelength shift information caused by the change of the cavity length of the air cavity and the silicon cavity, and acceleration and temperature can be measured simultaneously by demodulating the emergent light.

Description

Double-cavity cascade acceleration-temperature sensor and preparation method thereof

technical field

The application belongs to the technical field of optical sensing, and in particular relates to a dual-cavity cascaded F-P acceleration-temperature sensor and a preparation method thereof.

Background technique

Fabry-Perot Interferometer (F-P), a rectangular f-p cavity formed by the combination of a cover plate and a substrate, the incident light emitted by the light source is coupled into the sensor through an optical fiber, and is on the upper and lower surfaces of the F-P cavity of the sensor. Back and forth reflections form multi-beam interference, and some of the reflected beams return along the original path and meet to produce interference. The interference signal is related to the cavity length L. When the cavity length L changes due to the displacement or deformation of one side of the cavity caused by the change to be measured, the interference signal changes. By measuring the change of the interference signal, the change of the cavity length L can be derived to obtain The change to be measured.

Chinese patent document CN113029381A discloses a high-precision temperature sensor based on a quartz tube encapsulating a PDMS cavity and an air cavity, wherein the air cavity and the PDMS cavity are both Fabry-Perot interferometers, and the Fabry-Perot interferometer is a pair of The sensing interferometer is sensitive to the measured parameter, and the two interferometers have opposite temperature responses to temperature, thereby improving the sensitivity of temperature measurement. It can be seen that the existing dual-cavity cascaded optical sensors measure a single physical quantity, and since the Fabry-Perot interferometer is also affected by temperature, when measuring physical quantities such as acceleration, it is necessary to measure the temperature at the same time for compensation, Therefore, there is a need for a sensor that can measure acceleration and temperature simultaneously.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: in order to solve the deficiencies in the prior art, there is provided a dual-cavity cascade F-P acceleration-temperature sensor and a preparation method thereof for simultaneously measuring acceleration and temperature.

The technical scheme adopted by the present invention to solve its technical problems is:

A dual-cavity cascaded acceleration-temperature sensor, comprising an acceleration sensor structure and a temperature sensor structure arranged up and down;

The acceleration sensor structure includes:

side wall, a cavity is formed in the middle;

a mass block, located in the middle of the side wall, the top and bottom sides of the mass block are respectively coated with a first optical film;

a cantilever beam, connecting the mass block and the side wall to provide support for the mass block;

The temperature sensor structure includes:

The silicon-based material is arranged below the sidewall, and the top and bottom of the silicon-based material are respectively coated with a second optical film;

The transmittance of the first optical film and the second optical film is equal to the refractive index, and the distance between the first optical film under the proof block and the second optical film on top of the silicon-based material is h1, and the refractive index of the proof block is n1 , the distance between the top and bottom second optical films of the silicon-based material is h2, the refractive index of the silicon-based material is n2, lg[h1*n1/(h2*n2)] is less than 1, and lg is a common logarithm.

Preferably, in the dual-cavity cascaded acceleration-temperature sensor of the present invention, the silicon-based material has a concave-shaped structure, the upper hollow portion and the cavity form an air cavity, and the top of the silicon-based material is located on the top of the hollow portion.

Preferably, in the dual-cavity cascaded acceleration-temperature sensor of the present invention, the cantilever beam is a cantilever beam.

Preferably, in the dual-cavity cascaded acceleration-temperature sensor of the present invention, the acceleration sensor structure and the temperature sensor structure are bonded by BCB glue.

Preferably, in the dual-cavity cascaded acceleration-temperature sensor of the present invention, the acceleration sensor structure is prepared from an SOI sheet.

Preferably, in the dual-cavity cascaded acceleration-temperature sensor of the present invention, the SOI sheet has a five-layer structure, which are a first silicon layer, a first silicon oxide layer, a second silicon layer, a second silicon dioxide layer, and a third silicon dioxide layer. silicon layer.

The present invention also provides a method for preparing a dual-cavity cascaded acceleration-temperature sensor, and preparing the above-mentioned dual-cavity cascaded acceleration-temperature sensor, comprising:

Preparation steps of acceleration sensor structure:

S11: take an SOI sheet, the SOI sheet shown has a layer structure, which are a first silicon layer, a first silicon oxide layer, a second silicon layer, a second silicon dioxide layer and a third silicon layer;

S12: Coating photoresist on the top of the first silicon layer, leaving the area corresponding to the mass block to be processed empty, then plating a metal layer and cleaning the photoresist to form the first optical film on the top of the mass block;

S13: Coating photoresist on the bottom of the third silicon layer, leaving the area between the mass and the sidewall empty, and etching the area between the mass and the sidewall;

S14: remove the photoresist corresponding to the bottom of the third silicon layer of the mass block, and start etching from the bottom of the third silicon layer to form a mass block of the required thickness;

S15: from the bottom, the surface of the SOI sheet processed in step S except the mass block area is coated with photoresist, and the bottom surface of the mass block is plated with a metal layer, and then the photoresist is cleaned to form the first optical film at the bottom of the mass block;

S16: Coat photoresist on the surface of the SOI sheet processed in step S on the surface of the corresponding area of the cantilever beam and the sidewall, etch the SOI sheet from the top to form a cantilever beam, clean off the photoresist, and complete the acceleration sensor structure preparation;

Temperature sensor structure preparation steps:

S21 : take a silicon wafer, coat photoresist on the top surface of the silicon wafer except for the hollow part, etch the silicon wafer to form a concave structure on the whole silicon wafer, and clean the photoresist;

S22: On the top surface of the silicon wafer, coat photoresist except the area corresponding to the second optical film on the top of the silicon-based material, and then coat a metal layer on the top surface of the silicon wafer and clean the photoresist to form a second optical film on the top of the silicon-based material. optical film;

S23: On the bottom surface of the silicon wafer, coat photoresist except for the area corresponding to the second optical film at the bottom of the silicon-based material, and then coat a metal layer on the bottom surface of the silicon wafer and clean the photoresist to form the second optical film at the bottom of the silicon-based material , to complete the preparation of the temperature sensor structure;

Combine steps:

Bond the bottom of the accelerometer structure to the top of the temperature sensor structure.

Preferably, in the preparation method of the dual-cavity cascaded acceleration-temperature sensor of the present invention, before the bonding step, bumps are bonded on the top of the acceleration sensor structure.

Preferably, in the preparation method of the double-cavity cascaded acceleration-temperature sensor of the present invention, the acceleration sensor structure and the temperature sensor structure are bonded by BCB glue.

Preferably, in the preparation method of the dual-chamber cascaded acceleration-temperature sensor of the present invention, the bonding process is performed in a vacuum environment.

The beneficial effects of the present invention are:

The dual-cavity cascaded acceleration-temperature sensor of the present invention includes an acceleration sensor structure and a temperature sensor structure arranged up and down, and the acceleration sensor structure is an inertial motion structure composed of a cantilever beam-mass block combination. When the sensor is subjected to acceleration parallel to the direction of the air cavity, the mass is displaced due to the influence of inertia, which in turn causes the cavity length of the air cavity to change, thereby causing the wavelength shift of the interference spectrum. The temperature sensor structure is composed of a silicon cavity formed by single crystal silicon and an optical film on the upper and lower sides. When the external temperature changes, the volume of silicon changes accordingly, which leads to the change of the cavity length of the silicon cavity, thereby causing the wavelength shift of the interference spectrum. The difference between the air cavity and the silicon cavity is more than one order of magnitude. The light beam is vertically incident from the top of the sensor mass, and exits after passing through the air cavity and the silicon cavity. The outgoing light carries the wavelength shift information caused by the change of the cavity length of the air cavity and the silicon cavity. Acceleration and temperature can be measured simultaneously by demodulating the outgoing light.

Description of drawings

The technical solutions of the present application will be further described below with reference to the accompanying drawings and embodiments.

1 is a cross-sectional view of a dual-cavity cascaded acceleration-temperature sensor according to Embodiment 1 of the present application;

Fig. 2 is the schematic diagram of identifying the cavity length in Fig. 1;

3 is a schematic structural diagram of a cantilever beam in the dual-cavity cascaded acceleration-temperature sensor according to Embodiment 1 of the present application;

FIG. 4 is a flow chart of the preparation steps of the acceleration sensor structure according to Embodiment 2 of the present application;

FIG. 5 is a flow chart of the preparation steps of the acceleration sensor structure according to Embodiment 2 of the present application;

6 is a simulation diagram of the transmission spectrum of the sensor when the product of the refractive index and the cavity length of the air cavity and the silicon cavity is close to the effect embodiment;

7 is a simulation diagram of the transmission spectrum of the sensor when the product of the refractive index and the cavity length of the air cavity and the silicon cavity differs by one order of magnitude in the effect embodiment;

Fig. 8 is the cascaded spectrum simulation diagram under the influence of acceleration of the sensor in the effect embodiment;

Fig. 9 is the cascaded spectrum simulation diagram under the influence of temperature of the sensor in the effect embodiment;

The reference numbers in the figure are:

11 side walls;

12 cantilever beam;

13 mass blocks;

14 cavities;

15 the first optical film;

22 Silicon-based materials;

23 the second optical film;

24 the second optical film;

71 the first silicon layer;

72 the first silicon oxide layer;

73 the second silicon layer;

74 silicon dioxide layer;

75 The third silicon layer;

76 bumps;

8 silicon wafers;

9 Photoresist.

Detailed ways

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict.

In the description of this application, it should be understood that the terms "center", "portrait", "horizontal", "top", "bottom", "front", "rear", "left", "right", " The orientations or positional relationships indicated by vertical, horizontal, top, bottom, inner, and outer are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and The description is simplified rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", etc., may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood through specific situations.

The technical solutions of the present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

Example 1

This embodiment provides a dual-cavity cascaded acceleration-temperature sensor, as shown in FIG. 1 , including an acceleration sensor structure and a temperature sensor structure arranged up and down;

The acceleration sensor structure includes:

side wall 11, a cavity 14 is formed in the middle;

The mass block 13 is located in the middle of the side wall 11, and the top and bottom surfaces of the mass block 13 are respectively coated with the first optical film 15;

The cantilever beam 12 connects the mass block 13 and the side wall 11 to provide support for the mass block 13;

The temperature sensor structure includes:

The silicon-based material 22 is disposed under the sidewall 11, and the top and bottom of the silicon-based material 22 are respectively coated with second optical films 23 and 24;

The transmittance of the first optical film 15 and the second optical films 23 and 24 is equal to the refractive index.

The distance between the first optical film 15 under the mass block 13 and the second optical film on the top of the silicon-based material 22 is h1, the refractive index of the mass-block 13 is n1, and the distance between the top and bottom second optical films of the silicon-based material 22 is h1. The distance is h2, the refractive index of the silicon-based material 22 is n2, lg[h1*n1/(h2*n2)] is less than 1, and lg is a common logarithm.

The silicon-based material 22 has a concave-shaped structure, the upper hollow portion and the cavity 14 form an air cavity, and the top of the silicon-based material 22 is located on the top of the hollow portion;

The quality block 13 and the first optical film 15 on the top and bottom sides form the first-level F-P cavity optical structure, the silicon-based material 22 and the second optical films 23 and 24 on the top and bottom sides thereof form the second-level F-P cavity optical structure, Since the light of the second-level F-P cavity optical structure comes from the light emitted from the first-level F-P cavity optical structure, the wavelength ranges occupied by the two F-P cavities coincide.

The upper side of the air cavity formed by the cavity 14 is an inertial motion structure formed by the combination of the cantilever beam 12 and the mass 13 . When the sensor is subjected to acceleration parallel to the direction of the air cavity, the mass 13 is displaced due to the influence of inertia (the displacement in the up and down direction in Fig. 1 ), which in turn causes the cavity length of the air cavity to change, thereby causing the wavelength shift of the interference spectrum. The silicon cavity formed by the silicon-based material 22 is made of single crystal silicon, and the upper and lower surfaces thereof are provided with optical films. When the external temperature changes, the volume of silicon changes accordingly (the air cavity is not sensitive to the change of temperature), which leads to the change of the cavity length of the silicon cavity, thereby causing the wavelength shift of the interference spectrum. The nh (the product of the refractive index n and the cavity length h) of the air cavity and the silicon cavity differ by more than one order of magnitude. As shown in Figure 2, the cavity length of the air cavity is h1, and the cavity length of the silicon cavity is h2. The light beam is vertically incident from the top of the sensor mass 13 and exits after passing through the air cavity and the silicon cavity. The outgoing light carries the wavelength shift information caused by the change of the cavity length of the air cavity and the silicon cavity. , the acceleration and temperature can be measured simultaneously by demodulating the outgoing light.

Further, the cantilever beam 12 is a cantilever beam, as shown in FIG. 3 .

Further, the acceleration sensor structure and the temperature sensor structure are bonded by BCB glue, that is, the top of the silicon-based material 22 and the side wall 11 are bonded by BCB glue.

The acceleration sensor structure is prepared from SOI sheet. The SOI sheet has a five-layer structure, which are a first silicon layer, a first silicon oxide layer, a second silicon layer, a second silicon dioxide layer and a third silicon layer, and the multi-layer structure is convenient for controlling the thickness of photolithography.

Example 2

This embodiment provides a preparation method of a dual-cavity cascaded acceleration-temperature sensor, and the preparation of the dual-cavity cascaded acceleration-temperature sensor of Embodiment 1 includes:

The preparation steps of the acceleration sensor structure are shown in Figure 4:

S11: Take an SOI sheet 7, the SOI sheet 7 shown has a five-layer structure, which are a first silicon layer 71, a first silicon oxide layer 72, a second silicon layer 73, a second silicon dioxide layer 74 and a third silicon layer 75;

S12 : Coating photoresist 9 on top of the first silicon layer 71 , leaving the area corresponding to the proof block 13 to be processed empty, then plating a metal layer and cleaning the photoresist to form the first optical film 15 on the top of the proof block 13 ;

S13: Coat the photoresist 9 at the bottom of the third silicon layer 75, and leave the area between the mass 13 and the sidewall 11 empty, and etch the area between the mass 13 and the sidewall 11;

S14: remove the photoresist 9 corresponding to the bottom of the third silicon layer 75 from the mass block 13, and start etching from the bottom of the third silicon layer 75 to form the mass block 13 of the required thickness;

S15: Apply photoresist from the bottom to the surface of the SOI sheet 7 processed in step S14 except for the area of the mass block 13, plate the bottom surface of the mass block 13 with a metal layer, and then clean the photoresist to form the first optical layer at the bottom of the mass block 13. membrane 15;

S16: Apply photoresist 9 to the surface of the corresponding area of the cantilever beam 12 and the side wall 11 in the SOI sheet 7 processed in the step S15 from the top, and etch the SOI sheet 7 from the top to form the cantilever beam 12 (etch away the cantilever beam 12, the material between the mass block 13 and the side wall 11, so that the cantilever beam 12 can be suspended), the photoresist is cleaned off, and the preparation of the acceleration sensor structure is completed;

The preparation steps of the temperature sensor structure are shown in Figure 5:

S21: take a silicon wafer 8, coat photoresist on the top surface of the silicon wafer 8 except for the hollow part, and etch the silicon wafer 8 to form a concave structure on the entire silicon wafer, and clean the photoresist;

S22 : on the top surface of the silicon wafer 8 , coat photoresist except for the area corresponding to the second optical film on the top of the silicon wafer 8 , and then clean the photoresist after plating a metal layer on the top surface of the silicon wafer 8 to form the silicon base material 22 the second optical film on top;

S23: Coat the photoresist on the bottom surface of the silicon wafer 8 except for the area corresponding to the second optical film at the bottom of the silicon-based material 22, and then coat a metal layer on the bottom surface of the silicon wafer 8 and clean the photoresist to form the bottom surface of the silicon-based material 22. The second optical film, completes the preparation of the temperature sensor structure;

Combine steps:

Bond the bottom of the acceleration sensor structure to the top of the side wall 11 of the temperature sensor structure.

Further, before the bonding step, bumps 76 are bonded on the top of the acceleration sensor structure to prevent damage to the mass during the bonding step by the bumps 76 . After the bonding step is completed, the bumps 76 can be removed by etching, or they can be retained.

Further, the acceleration sensor structure and the temperature sensor structure are bonded by BCB glue, that is, the top of the silicon-based material 22 and the side wall 11 are bonded by BCB glue. The bonding is carried out in a vacuum environment.

Effect Example

This example uses the dual-cavity cascaded acceleration-temperature sensor of Example 1 for simulation testing. According to the free spectral domain (FSR) and full width at half maximum (FWHM) formulas, when the nh (refractive index and cavity) of the air cavity and the silicon cavity are long product), its transmission spectrum is shown in Figure 6.

At this time, it is difficult to separate the air cavity spectrum and the silicon cavity spectrum from the cascaded spectrum superimposed by the two cavities, so the acceleration and temperature information cannot be directly obtained by demodulating the outgoing light spectrum.

When the nh difference between the air cavity and the glass cavity exceeds 1 order of magnitude (10^1), the cascaded spectra of the outgoing light produce a phenomenon similar to an "envelope", as shown in Figure 7.

When the sensor is affected by the external acceleration and causes the inertial displacement of the mass on the upper side of the air cavity, the wavelength of the air cavity spectrum shifts, and the phenomenon reflected in the cascade spectrum is the shift of the "envelope", as shown in Figure 8.

The variation of the cavity length of the air cavity caused by the acceleration only causes the wavelength shift of the envelope, and the spectral lines inside the envelope do not shift. Therefore, acceleration information can be obtained by demodulating the wavelength shift of the envelope.

When the sensor is affected by the external temperature, the expansion/contraction of the silicon cavity causes the cavity length to change, the wavelength of the silicon cavity spectrum shifts, and the phenomenon reflected in the cascade spectrum is the shift of the spectral lines in the envelope, as shown in Figure 9.

The temperature-induced change in the cavity length of the air cavity only causes the wavelength shift of the spectral lines inside the envelope, and the envelope does not shift. Therefore, temperature information can be obtained by demodulating the wavelength shift of the envelope.

Taking the above ideal embodiments according to the present application as inspiration, and through the above descriptions, relevant personnel can make various changes and modifications without departing from the technical idea of the present application. The technical scope of the present application is not limited to the content in the description, and the technical scope must be determined according to the scope of the claims.

Claims (10)

1. a double cavity cascade acceleration-temperature sensor, is characterized in that, comprises the acceleration sensor structure and the temperature sensor structure that are arranged up and down; The acceleration sensor structure includes: a side wall (11), a cavity (14) is formed in the middle; a mass block (13), located in the middle of the side wall (11), the top and bottom surfaces of the mass block (13) are respectively coated with a first optical film (15); a cantilever beam (12), connecting the mass (13) and the side wall (11) to provide support for the mass (13); The temperature sensor structure includes: a silicon-based material (22), disposed below the sidewall (11), the top and bottom of the silicon-based material (22) are respectively coated with second optical films (23, 24); The transmittance of the first optical film (15) and the second optical film (23, 24) are equal to the refractive index, and the first optical film (15) under the mass (13) to the top of the silicon-based material (22) The distance between the two optical films is h1, the refractive index of the mass block (13) is n1, the distance between the top and bottom second optical films of the silicon-based material (22) is h2, and the refractive index of the silicon-based material (22) is h2 is n2, lg[h1*n1/(h2*n2)] is less than 1, and lg is the common logarithm. 2. The dual-cavity cascaded acceleration-temperature sensor according to claim 1, wherein the silicon-based material (22) is a concave-shaped structure, the upper hollow part and the cavity (14) form an air cavity, and the silicon-based material (22) is a concave-shaped structure. The top of the material (22) is the top of the hollow part. 3. The dual-cavity cascaded acceleration-temperature sensor according to claim 1, wherein the cantilever beam (12) is a cantilever beam. 4 . The dual-cavity cascaded acceleration-temperature sensor according to claim 1 , wherein the acceleration sensor structure and the temperature sensor structure are bonded by BCB glue. 5 . 5 . The dual-cavity cascaded acceleration-temperature sensor according to claim 1 , wherein the acceleration sensor structure is prepared from an SOI sheet. 6 . 6 . The dual-cavity cascaded acceleration-temperature sensor according to claim 5 , wherein the SOI sheet has a five-layer structure, which are a first silicon layer, a first silicon oxide layer, a second silicon layer, and a first silicon layer. A silicon dioxide layer and a third silicon layer. 7. A preparation method of a double-cavity cascaded acceleration-temperature sensor, preparing the double-cavity cascaded acceleration-temperature sensor of claim 1, comprising: Preparation steps of acceleration sensor structure: S11: take an SOI sheet, the SOI sheet shown has a layer structure, which are a first silicon layer, a first silicon oxide layer, a second silicon layer, a second silicon dioxide layer and a third silicon layer; S12: Coating photoresist on the top of the first silicon layer, leaving the corresponding area of the mass block to be processed empty, then plating a metal layer and cleaning the photoresist to form the first optical film on the top of the mass block; S13: Coating photoresist on the bottom of the third silicon layer, leaving the area between the proof block and the sidewall empty, and etching the area between the proof block and the sidewall; S14: remove the photoresist corresponding to the bottom of the third silicon layer of the mass block, and start etching from the bottom of the third silicon layer to form a mass block of the required thickness; S15: from the bottom, the surface of the SOI sheet processed in step S except the mass block area is coated with photoresist, and the bottom surface of the mass block is plated with a metal layer and then the photoresist is cleaned to form the first optical film at the bottom of the mass block; S16: Coat photoresist on the surface of the SOI sheet processed in step S on the surface of the corresponding area of the cantilever beam and the sidewall, etch the SOI sheet from the top to form a cantilever beam, wash off the photoresist, and complete the acceleration sensor structure preparation; Temperature sensor structure preparation steps: S21: take a silicon wafer, coat photoresist on the top surface of the silicon wafer except for the hollow part, etch the silicon wafer to form a concave structure on the whole silicon wafer, and clean the photoresist; S22: On the top surface of the silicon wafer, coat photoresist except for the area corresponding to the second optical film on the top of the silicon-based material, and then coat a metal layer on the top surface of the silicon wafer and clean the photoresist to form a second optical film on the top of the silicon-based material. optical film; S23: On the bottom surface of the silicon wafer, coat photoresist except for the area corresponding to the second optical film at the bottom of the silicon-based material, and then coat a metal layer on the bottom surface of the silicon wafer and clean the photoresist to form the second optical film at the bottom of the silicon-based material , to complete the preparation of the temperature sensor structure; Combine steps: Bond the bottom of the accelerometer structure to the top of the temperature sensor structure. 8. The method for preparing a dual-cavity cascaded acceleration-temperature sensor according to claim 7, characterized in that, before the bonding step, a bump (76) is bonded on the top of the acceleration sensor structure. 9 . The method for preparing a dual-cavity cascaded acceleration-temperature sensor according to claim 7 , wherein the acceleration sensor structure and the temperature sensor structure are bonded by BCB glue. 10 . 10 . The method for preparing a dual-chamber cascaded acceleration-temperature sensor according to claim 9 , wherein the bonding process is performed in a vacuum environment. 11 .

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