Manufacturing process of active constant-temperature absolute pressure sensor and pressure sensor

Abstract

The invention relates to the technical field of sensors, and discloses a manufacturing process of an active constant-temperature absolute pressure sensor and a pressure sensor, and the manufacturing process comprises the following steps: carrying out the spin coating of photoresist on a POI silicon substrate; determining doping concentration and depth parameters; injecting monocrystalline silicon ions to form n-type and p-type thermocouples; removing the dielectric layer in the connection region by using an etching process, and exposing the thermocouple pair; forming a thermocouple interconnection line; depositing a metal layer on the surface of the piezoelectric layer, and depositing a dielectric layer to protect the piezoelectric electrode to obtain an upper substrate; manufacturing a dielectric layer, and manufacturing a cavity region to obtain a lower substrate; bonding the upper substrate and the lower substrate, and manufacturing a through hole to expose the thermocouple region; and forming a through hole seed layer, exposing an electrode interconnection pad region, and removing the photoresist. According to the invention, the magnitude / direction of the voltage at the two ends of the thermocouple pair can be controlled through the control circuit, the resonator is heated / cooled, the temperature of the resonator is kept constant, the temperature drift of the resonator is avoided, and the accuracy of air pressure detection is improved.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a manufacturing process of an active constant temperature absolute pressure sensor and a pressure sensor. Background Art

[0002] In the design of air pressure sensors, the piezoelectric material of the resonator is very sensitive to changes in external air pressure. When the external air pressure changes, the piezoelectric material will change its resonant frequency due to the stress. This resonant frequency drift can be accurately detected, and then the rate of change of the frequency drift (usually in ppm) can be calculated through the detection circuit, thereby realizing the detection of external air pressure changes. This mechanism makes the piezoelectric resonator one of the core components of a highly sensitive air pressure sensor.

[0003] However, despite the high sensitivity of this air pressure detection method, in actual applications, the temperature characteristics of the piezoelectric material itself seriously interfere with the detection accuracy. Piezoelectric materials have an inherent temperature drift effect (that is, the resonant frequency of the material will drift with temperature changes). Therefore, when the external temperature changes, even if the air pressure remains unchanged, the resonant frequency of the resonator will drift due to temperature changes. This effect of temperature on frequency will be superimposed on the resonant frequency change caused by air pressure, making it difficult to distinguish whether the frequency drift is caused by air pressure changes or temperature changes.

[0004] This temperature drift effect has a significant impact on the detection accuracy of the sensor, especially in application scenarios that require high-precision detection, such as aerospace, meteorological monitoring, or environmental control of precision equipment. In order to ensure that the pressure sensor can accurately detect the air pressure without being disturbed by temperature changes, measures must be taken to eliminate or compensate for the temperature drift effect of the piezoelectric material.

[0005] At present, commonly used compensation methods include auxiliary detection of external temperature sensors, or using complex electronic circuits and algorithms to compensate for the impact of temperature. However, these methods usually require additional hardware design, and the compensation effect is limited, and it is impossible to completely eliminate the interference of temperature changes. For this reason, it is particularly important to develop a pressure sensor that can actively control and stabilize temperature. Summary of the invention

[0006] In view of the problems in the related art, the present invention proposes a manufacturing process of an active constant temperature absolute pressure sensor and a pressure sensor to overcome the above technical problems existing in the existing related art.

[0007] To this end, the specific technical solution adopted by the present invention is as follows:

[0008] According to one aspect of the present invention, a manufacturing process of an active constant temperature absolute pressure sensor is provided, comprising the following steps:

[0009] S1. Select a POI silicon substrate according to the manufacturing requirements of the pressure sensor, and spin-coat photoresist on the POI silicon substrate; determine the doping concentration and depth parameters during the single crystal silicon ion implantation process based on the particle swarm optimization algorithm;

[0010] S2, using photolithography technology to pattern the photoresist, exposing the n-type and p-type ion implantation areas on the substrate, and based on doping concentration and depth parameters, implanting single crystal silicon ions on the POI silicon substrate to form n-type and p-type thermocouples;

[0011] S3, making a dielectric layer, spin-coating a photoresist and patterning it, exposing the connection area of ​​the np thermocouple pair, and removing the dielectric layer in the connection area by an etching process to expose the thermocouple pair;

[0012] S4, depositing a metal layer in the connection area by sputtering or evaporation process, spin-coating photoresist and patterning; removing the metal layer based on an etching process, and forming a thermocouple interconnection line by removing the photoresist;

[0013] S5, depositing a metal layer on the surface of the piezoelectric layer based on a sputtering or evaporation process, patterning and protecting the metal layer through a photolithography and etching process, depositing a dielectric layer to protect the piezoelectric electrode, and obtaining an upper substrate;

[0014] S6, forming a dielectric layer on both sides of a single-sided polished silicon substrate, spin-coating a photoresist and patterning and exposing the dielectric layer; removing the dielectric layer based on an etching process to expose the cavity area, removing the photoresist, and forming the cavity area using an etching process to obtain a lower substrate;

[0015] S7, bonding the upper substrate to the lower substrate, spin coating thick photoresist and patterning to form a through hole opening, making a through hole based on an etching process, and exposing a thermocouple area;

[0016] S8. Form a through-hole seed layer by photolithography, etching and electroplating processes, expose the electrode interconnection pad area based on the photolithography and etching processes, and remove the photoresist to obtain the active constant temperature absolute pressure sensor.

[0017] Furthermore, the material of the POI silicon substrate is LiNbO3 or AlN, and the thickness of the substrate is 130-300 μm.

[0018] Furthermore, the determination of doping concentration and depth parameters in the process of single crystal silicon ion implantation based on the particle swarm optimization algorithm includes the following steps:

[0019] Construct an objective function to quantify the deviation between actual parameters and expected values, determine the parameter range of doping concentration and depth during single crystal silicon ion implantation; define the number of particles, and randomly generate the initial position and velocity of each particle;

[0020] The fitness value of each particle is calculated through the objective function. If the current fitness value is better than the particle's historical best fitness value, the individual optimal position is updated to the current position, and the position of the particle with the smallest fitness value among all particles is selected as the global optimal position;

[0021] According to the speed update formula and the position update formula, the speed and position of each particle are updated; whether the convergence condition is met is determined, if not, the fitness value calculation step is returned to continue iteration, if so, the optimal doping concentration and optimal doping depth parameters are output.

[0022] Furthermore, the objective function is expressed as:

[0023]

[0024] In the formula, F(C,D) represents the objective function value, C represents the doping concentration, D represents the doping depth, and C target represents the desired doping concentration, D target represents the desired doping depth, w1 and w2 represent the weight coefficients of doping concentration and doping depth, respectively.

[0025] Furthermore, the speed update formula is:

[0026]

[0027] The position update formula is:

[0028]

[0029] In the formula, They represent the velocity components of the i-th particle at iteration time t in the direction of doping concentration and doping depth, respectively. α represents the inertia weight. c1 and c2 represent the learning factors that control the degree of convergence of particles to the individual optimal solution and the group optimal solution, respectively. r1 and r2 represent two random numbers between 0 and 1, respectively. represent the individual optimal position of the i-th particle in the direction of doping concentration and doping depth, respectively, and g C , g D They represent the global optimal positions of all particles at the current iteration time corresponding to the doping concentration and doping depth, respectively. i (t), D i (t) represents the current position of particle i at iteration time t, corresponding to the doping concentration and doping depth, respectively. i (t+1), Di (t+1) represent the doping concentration and depth position of particle i at iteration time t+1 respectively.

[0030] Furthermore, the method of patterning the photoresist using photolithography technology to expose the n-type and p-type ion implantation areas on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form n-type and p-type thermocouples includes the following steps:

[0031] S21, patterning the photoresist using photolithography technology to expose the n-type ion implantation area on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form an n-type thermocouple;

[0032] S22, removing the photoresist and re-spinning the photoresist, patterning the photoresist using photolithography technology, exposing the p-type ion implantation area on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form a p-type thermocouple.

[0033] Furthermore, the dielectric layer is SiO2 produced by thermal oxidation, LPCVD, or PECVD, and the etching process includes reactive ion etching and wet etching.

[0034] Furthermore, the metal layer in step S4 is a metal stack or a single metal layer of Ti / Pt / Au or Ti / Al; and the metal layer in step S5 is a metal stack of Ti / Al or Ti / AlCu.

[0035] Furthermore, the forming of the through-hole seed layer by photolithography, etching and electroplating processes, exposing the electrode interconnection pad area based on the photolithography and etching processes, and removing the photoresist to obtain the active constant temperature absolute pressure sensor includes the following steps:

[0036] S81, removing the photoresist, making an interconnection through-hole seed layer, spin-coating the photoresist and patterning it, and protecting the through-hole seed layer area;

[0037] S82, patterning the through hole seed layer based on ion beam etching or reactive ion etching, and completing the production of the through hole seed layer using an electroplating process;

[0038] S83, spin-coating photoresist and patterning to expose the dielectric layer above the electrode interconnection pad, etching the dielectric layer to expose the electrode interconnection pad, and removing the photoresist to obtain the active constant temperature absolute pressure sensor.

[0039] According to another aspect of the present invention, an active constant temperature absolute pressure sensor is provided, comprising a lower substrate, a matching upper substrate is arranged on the top of the lower substrate, and a dielectric layer is arranged at the bottom of the upper substrate and the top of the lower substrate; a p-type thermocouple and an n-type thermocouple are arranged on both sides of the bottom of the upper substrate, respectively, and the bottoms of the p-type thermocouple and the n-type thermocouple are connected through a thermocouple interconnection layer; a metal piezoelectric layer is arranged on the top of the upper substrate, a resonant electrode is arranged on the top of the metal piezoelectric layer, and electrode metal connection areas are arranged at both ends of the resonant electrode; through holes are opened on both sides of the upper substrate, and the bottoms of the through holes are connected to the tops of the p-type thermocouple and the n-type thermocouple, the tops of the through holes penetrate the metal piezoelectric layer and extend to the top of the metal piezoelectric layer, and through-hole metal is arranged inside the through holes.

[0040] The beneficial effects of the present invention are:

[0041] 1) The present invention manufactures a semiconductor thermocouple pair based on the Peltier effect and the Seebeck effect under the resonator. When the ambient temperature changes, the voltage magnitude / direction at both ends of the thermocouple pair is controlled by a control circuit to heat / cool the resonator and maintain a constant temperature of the resonator, thereby eliminating the temperature drift of the resonator and improving the accuracy of air pressure detection.

[0042] 2) The present invention uses the particle swarm optimization algorithm to control the doping concentration and depth during the single crystal silicon ion implantation process, thereby effectively improving the uniformity of doping and the accuracy of depth, and reducing a large number of trial and error steps in the experimental process. This algorithm is particularly suitable for solving multi-variable and multi-objective optimization problems, and is suitable for optimizing the doping process in sensor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 is a flow chart of a manufacturing process of an active constant temperature absolute pressure sensor according to an embodiment of the present invention;

[0045] Figure 2 Schematic diagram of the structure of an active constant temperature absolute pressure sensor according to an embodiment of the present invention.

[0046] In the figure:

[0047] 1. Upper substrate; 2. Dielectric layer; 3. Metal piezoelectric layer; 4. P-type thermocouple; 5. N-type thermocouple; 6. Thermocouple interconnect layer; 7. Resonant electrode; 8. Through hole; 9. Through hole metal; 10. Electrode metal connection area; 11. Lower substrate. DETAILED DESCRIPTION

[0048] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0049] According to an embodiment of the present invention, a manufacturing process of an active constant temperature absolute pressure sensor and a pressure sensor are provided.

[0050] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, the manufacturing process of the active constant temperature absolute pressure sensor and the pressure sensor according to the embodiment of the present invention include the following steps:

[0051] S1. Select a POI silicon substrate according to the manufacturing requirements of the pressure sensor, and spin-coat photoresist on the POI silicon substrate; determine the doping concentration and depth parameters during the single crystal silicon ion implantation process based on the particle swarm optimization algorithm;

[0052] The material of the POI silicon substrate is piezoelectric material such as LiNbO3 or AlN, and the thickness of the substrate is 130-300 μm.

[0053] Specifically, the method of determining the doping concentration and depth parameters in the process of single crystal silicon ion implantation based on the particle swarm optimization algorithm includes the following steps:

[0054] Construct an objective function to quantify the deviation between actual parameters and expected values, determine the parameter range of doping concentration and depth during single crystal silicon ion implantation; define the number of particles, and randomly generate the initial position and velocity of each particle;

[0055] The expression of the objective function is:

[0056]

[0057] In the formula, F(C,D) represents the objective function value, C represents the doping concentration, D represents the doping depth, and C target represents the desired doping concentration, D target represents the desired doping depth, w1 and w2 represent the weight coefficients of doping concentration and doping depth, respectively.

[0058] The fitness value of each particle is calculated through the objective function. If the current fitness value is better than the particle's historical best fitness value, the individual optimal position is updated to the current position, and the position of the particle with the smallest fitness value among all particles is selected as the global optimal position;

[0059] According to the speed update formula and the position update formula, the speed and position of each particle are updated; whether the convergence condition is met is determined, if not, the fitness value calculation step is returned to continue iteration, if so, the optimal doping concentration and optimal doping depth parameters are output.

[0060] The speed update formula is:

[0061]

[0062] The position update formula is:

[0063]

[0064] In the formula, They represent the velocity components of the i-th particle at iteration time t in the direction of doping concentration and doping depth, respectively. α represents the inertia weight. c1 and c2 represent the learning factors that control the degree of convergence of particles to the individual optimal solution and the group optimal solution, respectively. r1 and r2 represent two random numbers between 0 and 1, respectively. represent the individual optimal position of the i-th particle in the direction of doping concentration and doping depth, respectively, and g C , g D They represent the global optimal positions of all particles at the current iteration time corresponding to the doping concentration and doping depth, respectively. i (t), D i (t) represents the current position of particle i at iteration time t, corresponding to the doping concentration and doping depth, respectively. i (t+1), D i (t+1) represent the doping concentration and depth position of particle i at iteration time t+1 respectively.

[0065] S2, using photolithography technology to pattern the photoresist, exposing the n-type and p-type ion implantation areas on the substrate, and based on doping concentration and depth parameters, implanting single crystal silicon ions on the POI silicon substrate to form n-type and p-type thermocouples;

[0066] The method of patterning the photoresist using photolithography technology to expose the n-type and p-type ion implantation areas on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form n-type and p-type thermocouples includes the following steps:

[0067] S21, patterning the photoresist using photolithography technology to expose the n-type ion implantation area on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form an n-type thermocouple;

[0068] S22, removing the photoresist and re-spinning the photoresist, patterning the photoresist using photolithography technology, exposing the p-type ion implantation area on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form a p-type thermocouple.

[0069] S3, making a dielectric layer, spin-coating a photoresist and patterning it, exposing the connection area of ​​the np thermocouple pair, and removing the dielectric layer in the connection area by an etching process to expose the thermocouple pair;

[0070] S4, depositing a metal layer in the connection area by sputtering or evaporation process, spin-coating photoresist and patterning; removing the metal layer based on an etching process, and forming a thermocouple interconnection line by removing the photoresist;

[0071] Specifically, the dielectric layer is SiO2 by thermal oxidation, LPCVD, or PECVD, and the etching process includes reactive ion etching and wet etching. The metal layer in step S4 is a metal stack or single metal layer of Ti / Pt / Au or Ti / Al; the metal layer in step S5 is a metal stack of Ti / Al or Ti / AlCu.

[0072] S5, depositing a metal layer on the surface of the piezoelectric layer based on a sputtering or evaporation process, patterning and protecting the metal layer through a photolithography and etching process, depositing a dielectric layer to protect the piezoelectric electrode, and obtaining an upper substrate;

[0073] S6, forming a dielectric layer on both sides of a single-sided polished silicon substrate, spin-coating a photoresist and patterning and exposing the dielectric layer; removing the dielectric layer based on an etching process to expose the cavity area, removing the photoresist, and forming the cavity area using an etching process to obtain a lower substrate;

[0074] S7, bonding the upper substrate to the lower substrate, spin coating thick photoresist and patterning to form a through hole opening, making a through hole based on an etching process, and exposing a thermocouple area;

[0075] S8. Form a through-hole seed layer by photolithography, etching and electroplating processes, expose the electrode interconnection pad area based on the photolithography and etching processes, and remove the photoresist to obtain the active constant temperature absolute pressure sensor.

[0076] Specifically, the forming of the through-hole seed layer by photolithography, etching and electroplating processes, exposing the electrode interconnection pad area based on the photolithography and etching processes, and removing the photoresist to obtain the active constant temperature absolute pressure sensor includes the following steps:

[0077] S81, removing the photoresist, making an interconnection through-hole seed layer, spin-coating the photoresist and patterning it, and protecting the through-hole seed layer area;

[0078] S82, patterning the through hole seed layer based on ion beam etching or reactive ion etching, and completing the production of the through hole seed layer using an electroplating process;

[0079] S83, spin-coating photoresist and patterning to expose the dielectric layer above the electrode interconnection pad, etching the dielectric layer to expose the electrode interconnection pad, and removing the photoresist to obtain the active constant temperature absolute pressure sensor.

[0080] According to another aspect of the present invention, Figure 2 As shown, an active constant temperature absolute pressure sensor is provided, including a lower substrate 11, and an upper substrate 1 matched therewith is arranged on the top of the lower substrate 11. In specific applications, the substrate material is silicon, and a dielectric layer 2 is arranged at the bottom of the upper substrate 1 and the top of the lower substrate 11; a p-type thermocouple 4 and an n-type thermocouple 5 are arranged on both sides of the bottom of the upper substrate 1, and the bottoms of the p-type thermocouple 4 and the n-type thermocouple 5 are connected through a thermocouple interconnection layer 6 (the thermocouple interconnection layer is a metal stack or a single layer of metal such as Ti / Pt / Au or Ti / Al); a metal piezoelectric layer 3 is arranged on the top of the upper substrate 1, and the metal piezoelectric layer 3 A resonant electrode 7 (i.e., the electrode region of the surface acoustic wave resonator, which may be Ti / Al or Ti / AlCu) is arranged at the top, and electrode metal connection regions 10 are arranged at both ends of the resonant electrode 7; through holes 8 (TSV through hole seed layer, which may be a metal stack such as Ti / Pt / Au) are penetrated through both sides of the upper substrate 1, and the bottom end of the through hole 8 is connected to the top of the p-type thermocouple 4 and the n-type thermocouple 5, the top end of the through hole 8 penetrates the metal piezoelectric layer 3 and extends to the top of the metal piezoelectric layer 3, and through hole metal 9 (TSV through hole metal, which may be a metal such as Cu or a metal alloy) is arranged inside the through hole 8.

[0081] In summary, with the aid of the above technical solution of the present invention, the present invention makes a semiconductor thermocouple pair based on the Peltier effect and the Seebeck effect under the resonator. When the ambient temperature changes, the voltage magnitude / direction at both ends of the thermocouple pair is controlled by the control circuit to heat / cool the resonator, maintain the constant temperature of the resonator, eliminate the temperature drift of the resonator, and improve the accuracy of air pressure detection. In addition, the present invention can effectively improve the uniformity of doping and the accuracy of depth by controlling the doping concentration and depth in the process of single crystal silicon ion implantation using a particle swarm optimization algorithm, thereby reducing a large number of trial and error steps in the experimental process. This algorithm is particularly suitable for solving multi-variable and multi-objective optimization problems, and is suitable for optimizing doping processes in sensor manufacturing.

[0082] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "screw-on" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A manufacturing process of an active constant temperature absolute pressure sensor, characterized in that: The following steps are involved: S1. Select a POI silicon substrate according to the manufacturing requirements of the pressure sensor, and spin-coat photoresist on the POI silicon substrate; determine the doping concentration and depth parameters during the single crystal silicon ion implantation process based on the particle swarm optimization algorithm; S2, using photolithography technology to pattern the photoresist, exposing the n-type and p-type ion implantation areas on the substrate, and based on doping concentration and depth parameters, implanting single crystal silicon ions on the POI silicon substrate to form n-type and p-type thermocouples; S3, making a dielectric layer, spin-coating a photoresist and patterning it, exposing the connection area of ​​the np thermocouple pair, and removing the dielectric layer in the connection area by an etching process to expose the thermocouple pair; S4, depositing a metal layer on the connection area by sputtering or evaporation process, spin coating photoresist and patterning; removing the metal layer based on an etching process and forming a thermocouple interconnection line by removing the photoresist; S5, depositing a metal layer on the surface of the piezoelectric layer based on a sputtering or evaporation process, patterning and protecting the metal layer through a photolithography and etching process, depositing a dielectric layer to protect the piezoelectric electrode, and obtaining an upper substrate; S6, forming a dielectric layer on both sides of the single-side polished silicon substrate, spin-coating a photoresist and patterning and exposing the dielectric layer; The dielectric layer is removed based on an etching process to expose the cavity area, and the photoresist is removed, and the cavity area is manufactured using an etching process to obtain a lower substrate; S7, bonding the upper substrate to the lower substrate, spin coating thick photoresist and patterning to form a through hole opening, making a through hole based on an etching process, and exposing a thermocouple area; S8. Form a through-hole seed layer by photolithography, etching and electroplating processes, expose the electrode interconnection pad area based on the photolithography and etching processes, and remove the photoresist to obtain the active constant temperature absolute pressure sensor.

2. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 1, characterized in that: The material of the POI silicon substrate is LiNbO3 or AlN, and the thickness of the substrate is 130-300 μm.

3. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 1, characterized in that: The method of determining the doping concentration and depth parameters in the process of single crystal silicon ion implantation based on the particle swarm optimization algorithm includes the following steps: Construct an objective function to quantify the deviation between actual parameters and expected values, determine the parameter range of doping concentration and depth during single crystal silicon ion implantation; define the number of particles, and randomly generate the initial position and velocity of each particle; The fitness value of each particle is calculated through the objective function. If the current fitness value is better than the particle's historical best fitness value, the individual optimal position is updated to the current position, and the position of the particle with the smallest fitness value among all particles is selected as the global optimal position; According to the speed update formula and the position update formula, the speed and position of each particle are updated; whether the convergence condition is met is determined, if not, the fitness value calculation step is returned to continue iteration, if so, the optimal doping concentration and optimal doping depth parameters are output.

4. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 3, characterized in that: The expression of the objective function is: In the formula, F(C,D) represents the objective function value, C represents the doping concentration, D represents the doping depth, and C target represents the desired doping concentration, D target represents the desired doping depth, w1 and w2 represent the weight coefficients of doping concentration and doping depth, respectively.

5. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 3, characterized in that: The speed update formula is: The position update formula is: In the formula, They represent the velocity components of the i-th particle at iteration time t in the direction of doping concentration and doping depth, respectively. α represents the inertia weight. c1 and c2 represent the learning factors that control the degree of convergence of particles to the individual optimal solution and the group optimal solution, respectively. r1 and r2 represent two random numbers between 0 and 1, respectively. represent the individual optimal position of the i-th particle in the direction of doping concentration and doping depth, respectively, and g C , g D They represent the global optimal positions of all particles at the current iteration time corresponding to the doping concentration and doping depth, respectively. i (t), D i (t) represents the current position of particle i at iteration time t, corresponding to the doping concentration and doping depth, respectively. i (t+1), D i (t+1) represent the doping concentration and depth position of particle i at iteration time t+1 respectively.

6. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 1, characterized in that: The method of patterning the photoresist by photolithography technology, exposing the n-type and p-type ion implantation regions on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form n-type and p-type thermocouples includes the following steps: S21, patterning the photoresist using photolithography technology to expose the n-type ion implantation area on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form an n-type thermocouple; S22, removing the photoresist and re-spinning the photoresist, patterning the photoresist using photolithography technology, exposing the p-type ion implantation area on the substrate, and implanting single crystal silicon ions on the POI silicon substrate based on doping concentration and depth parameters to form a p-type thermocouple.

7. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 1, characterized in that: The dielectric layer is SiO2 by thermal oxidation, LPCVD, or PECVD, and the etching process includes reactive ion etching and wet etching.

8. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 1, characterized in that: The metal layer in step S4 is a metal stack or a single metal layer of Ti / Pt / Au or Ti / Al; the metal layer in step S5 is a metal stack of Ti / Al or Ti / AlCu.

9. The manufacturing process of an active constant temperature absolute pressure sensor according to claim 1, characterized in that: The step of forming a through-hole seed layer by photolithography, etching and electroplating, exposing the electrode interconnection pad area based on the photolithography and etching process, and removing the photoresist to obtain the active constant temperature absolute pressure sensor comprises the following steps: S81, removing the photoresist, making an interconnection through-hole seed layer, spin-coating the photoresist and patterning it, and protecting the through-hole seed layer area; S82, patterning the through hole seed layer based on ion beam etching or reactive ion etching, and completing the production of the through hole seed layer using an electroplating process; S83, spin-coating photoresist and patterning to expose the dielectric layer above the electrode interconnection pad, etching the dielectric layer to expose the electrode interconnection pad, and removing the photoresist to obtain the active constant temperature absolute pressure sensor.

10. An active constant temperature absolute pressure sensor, manufactured based on the manufacturing process of an active constant temperature absolute pressure sensor according to any one of claims 1 to 9, characterized in that: The active constant temperature absolute pressure sensor comprises a lower substrate (11), the top of the lower substrate (11) is provided with an upper substrate (1) matched therewith, and the bottom end of the upper substrate (1) and the top end of the lower substrate (11) are both provided with a dielectric layer (2); A p-type thermocouple (4) and an n-type thermocouple (5) are respectively arranged on both sides of the bottom of the upper substrate (1), and the bottoms of the p-type thermocouple (4) and the n-type thermocouple (5) are connected via a thermocouple interconnection layer (6); A metal piezoelectric layer (3) is arranged on the top of the upper substrate (1), a resonant electrode (7) is arranged on the top of the metal piezoelectric layer (3), and electrode metal connection areas (10) are arranged at both ends of the resonant electrode (7); Through holes (8) are provided on both sides of the upper substrate (1), and the bottom ends of the through holes (8) are connected to the top ends of the p-type thermocouple (4) and the n-type thermocouple (5), the top ends of the through holes (8) penetrate the metal piezoelectric layer (3) and extend to the top of the metal piezoelectric layer (3), and through-hole metal (9) is provided inside the through holes (8).

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