High-sensitivity wide-range MEMS pressure sensor and preparation method thereof

Abstract

This invention discloses a highly sensitive, wide-range MEMS pressure sensor and its fabrication method, belonging to the field of pressure sensors. The sensor comprises two stacked force-receiving components: the first-stage component includes a first silicon substrate, a first force-sensitive diaphragm, a first force-receiving bump, and four first piezoresistors; the second-stage component includes a second silicon substrate, a second force-sensitive diaphragm, a second force-receiving bump, and four second piezoresistors. The second force-receiving bump is located directly below the first force-receiving bump with a gap. The thickness of the second force-sensitive diaphragm is greater than that of the first force-sensitive diaphragm, and the size of the first force-sensitive diaphragm is larger than that of the second force-sensitive diaphragm. The piezoresistors and leads are placed in a sealed cavity bonded between the two silicon substrates and led out to the bottom electrode through silicon vias. This invention employs a stacked two-stage force-receiving structure, combining high sensitivity and a wide range, with a small size, reliable structure, over-range self-protection, and easy integration and installation of the bottom leads, making it suitable for mass production.

Description

Technical Field

[0001] This invention relates to a sensor and its fabrication method, and more particularly to a high-sensitivity, wide-range MEMS pressure sensor and its fabrication method. Background Technology

[0002] In fields such as healthcare, smart wearables, industrial monitoring, and robotic sensing, force sensors, as devices that sense external forces, are one of the fundamental components for achieving human signal acquisition, intelligent equipment control, safe and precise human-machine collaboration. The diversity of application scenarios places higher demands on the performance of force sensors. For example, in the healthcare field, it is necessary to accurately capture a wide range of pressures, from carotid artery pulsation, jugular vein pulsation, and laryngeal vibration to plantar pressure and related intracranial pressure. This requires not only high sensitivity to capture minute force changes but also a wide measurement range and long-term stability.

[0003] MEMS pressure sensors are thin-film elements manufactured using microelectromechanical systems technology. They sense pressure by measuring changes in electrical properties caused by the deformation of the thin film. More specifically, the force-sensitive diaphragm experiences strain under stress, leading to changes in the resistance of an embedded piezoresistor. The thinner the force-sensitive diaphragm, the higher its force sensitivity, but the shorter its measurement range. Therefore, existing pressure sensors cannot simultaneously meet the requirements of high sensitivity and wide measurement range. Summary of the Invention

[0004] The purpose of this invention is to overcome the existing defects and provide a high-sensitivity, wide-range MEMS pressure sensor and its fabrication method, solving the problem that current pressure sensors cannot simultaneously meet the requirements of high sensitivity and wide range.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A highly sensitive, wide-range MEMS pressure sensor includes a primary force-receiving component and a secondary force-receiving component stacked vertically. The primary force-receiving component includes a first force-sensitive diaphragm with a first force-receiving protrusion at its center. The secondary force-receiving component includes a second force-sensitive diaphragm with a second force-receiving protrusion at its center. The second force-receiving protrusion is located directly below the first force-receiving protrusion with a gap between them. The size of the first force-sensitive diaphragm is larger than that of the second force-sensitive diaphragm, and the thickness of the second force-sensitive diaphragm is greater than that of the first force-sensitive diaphragm.

[0006] Furthermore, both the first force-sensitive diaphragm and the second force-sensitive diaphragm are square.

[0007] Furthermore, the primary force-bearing component includes a first silicon substrate, a first force-sensitive diaphragm disposed in the middle of the first silicon substrate, a first force-bearing bump disposed in the center of the upper surface of the first force-sensitive diaphragm, and a top protrusion formed on the upper surface of the first silicon substrate around the first force-sensitive diaphragm; a first varistor is disposed on the lower surface of the first force-sensitive diaphragm near the midpoint of each of the four sides, each first varistor being connected to a first electrical lead; a first insulating layer is disposed on the lower surface of the first silicon substrate, the first insulating layer covering the first varistor and the first electrical lead.

[0008] Furthermore, the two first varistors on opposite sides form a group. One group of first varistors is arranged symmetrically parallel to the edge of the first force-sensitive diaphragm, and the other group of first varistors is arranged symmetrically perpendicular to the edge of the first force-sensitive diaphragm. The initial resistance values ​​of the four first varistors are equal.

[0009] Furthermore, the upper surface of the first force-sensitive diaphragm is lower than the upper surface of the top boss, and the upper end of the first force-receiving protrusion is higher than the upper surface of the top boss.

[0010] Furthermore, the secondary force-receiving component includes a second silicon substrate, a second force-sensitive diaphragm disposed in the center of the second silicon substrate, a second force-receiving bump disposed in the center of the upper surface of the second force-sensitive diaphragm, and a connecting boss formed on the portion of the upper surface of the second silicon substrate surrounding the second force-sensitive diaphragm. The upper surfaces of the second force-sensitive diaphragm and the upper ends of the second force-receiving bump are both lower than the upper surfaces of the connecting bosses. A second varistor is disposed on the upper surface of the four sides of the second force-sensitive diaphragm near the midpoints, and each second varistor is connected to a second electrical lead. A second insulating layer is disposed on the upper surfaces of the second force-sensitive diaphragm and the second bump, and the second insulating layer covers the second varistor and the second electrical lead.

[0011] Furthermore, the two second varistors on opposite sides form a group. One group of second varistors is arranged symmetrically parallel to the edge of the second force-sensitive diaphragm, and the other group of second varistors is arranged symmetrically perpendicular to the edge of the second force-sensitive diaphragm. The initial resistance values ​​of the four second varistors are equal.

[0012] Furthermore, four first through-silicon vias are vertically disposed on the second silicon substrate. Each first through-silicon via is connected to an intermediate electrode and a first lead electrode at its upper and lower ends, respectively. The intermediate electrode penetrates the first insulating layer and is connected to the first electrical lead. Four second through-silicon vias are vertically disposed on the second silicon substrate. The upper end of each second through-silicon via is connected to the second electrical lead, and the lower end of each second through-silicon via is connected to a second lead electrode.

[0013] A method for fabricating a highly sensitive, wide-range MEMS pressure sensor includes the following steps: S1. A silicon dioxide insulating layer is prepared on the outer surface of the first silicon substrate using a thermal oxidation process. On the front side of the first silicon substrate, a portion of the silicon dioxide is removed to form a window using a photolithography process. Boron ions are implanted through this window using an ion implantation process to form a first varistor. Contact holes are etched on the doped substrate using a RIE etching process. Then, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the first electrical lead. S2. A layer of photoresist is coated on the back side of the first silicon substrate and patterned as a mask. After etching away the silicon dioxide insulating layer, anisotropic wet etching is performed using TMAH or KOH solution to form an annular cavity with a trapezoidal cross-section, releasing the first force-sensitive film. The first force-receiving bump is formed in the center of the cavity. S3. Photolithography is performed on the back side of the first silicon substrate, and deep silicon etching is used to etch and thin the part outside the cavity to form a top protrusion. S4. A silicon oxide layer is formed on the front side of the first silicon substrate using PECVD process. A contact hole is etched on the first insulating layer using RIE etching process to expose the first electrical lead. Then, metal deposition is performed to form the upper intermediate electrode. S5. Photoresist is used on the front side of the second silicon substrate and patterned as a mask, and then a first groove is formed using a silicon etching process. S6. Photoresist is used and patterned on the front side of the second silicon substrate as a mask. A second groove with a depth greater than the first groove is etched around the first groove using a silicon etching process. The central part of the annular second groove forms a second force-bump. S7. Two sets of TSV vias are etched on the second silicon substrate using photolithography and deep silicon etching. One set is inside the second groove, and the other set is outside the second groove. Then, a silicon dioxide insulating layer is prepared on the outer surface of the second silicon substrate and inside the TSV vias using thermal oxidation. Next, Ti and Cu are deposited in the TSV vias using magnetron sputtering and TSV via electroplating is completed, thus completing the preparation of the first and second silicon vias. S8. A window is formed by removing part of the silicon dioxide on both sides of the second force bump on the front side of the second silicon substrate through photolithography. Boron ions are implanted through this window to form a second varistor using ion implantation. Contact holes are etched on the doped substrate through RIE etching. Then, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the second electrical lead and the lower intermediate electrode. Silicon oxide is formed on the silicon surface of the front side of the second silicon substrate corresponding to the second groove and the second force bump as a second insulating layer using PECVD. S9. Photoresist is used on the back side of the second silicon substrate and patterned as a mask. After etching away the silicon dioxide insulating layer, TMAH or KOH solution is used for anisotropic wet etching to form a cavity and release the second force-sensitive film. S10. On the back side of the second silicon substrate, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the first and second lead electrodes. S11. Using a flip-chip bonding machine, the front side of the first silicon substrate is bonded to the front side of the second silicon substrate, and the upper intermediate electrode and the lower intermediate electrode are combined to form an intermediate electrode.

[0014] The beneficial effects of this invention are as follows: 1. By using two force-sensitive diaphragms of different thicknesses and sensitivities, the upper force-sensitive diaphragm is thinner and more sensitive to force, giving the pressure sensor higher sensitivity, while the lower force-sensitive diaphragm is thicker and can withstand greater force, increasing the pressure sensor's range. 2. The first force-sensitive diaphragm is larger in size, with greater deformation and strain, resulting in a more significant change in resistance of the first piezoresistor and higher pressure sensing sensitivity. The larger deformation of the upper first force-sensitive diaphragm allows it to contact the second force-receiving protrusion without failure, thereby transmitting the force to the lower second force-sensitive diaphragm. The lower second force-sensitive diaphragm provides support for the upper first force-sensitive diaphragm, protecting it when measuring larger forces. When the pressure sensor is subjected to excessive force, the first force-receiving protrusion will align with the upper surface of the top protrusion, which will bear the pressure, thus protecting both force-sensitive diaphragms and providing over-range self-protection, thereby improving the reliability of the pressure sensor. 3. The first and second varistors are located in a sealed cavity, which can isolate them from air and harsh environments, reduce temperature interference, and extend their service life; 4. The first and second varistors are both set up with one set symmetrically and parallelly distributed on the edge of the force-sensitive diaphragm, and the other set symmetrically and perpendicularly distributed on the edge of the sensitive diaphragm. The two sets of varistors (a total of four resistors) form a full-bridge Wheatstone bridge test, which superimposes the longitudinal and transverse piezoresistive effects, improves the sensitivity, and can effectively suppress zero-point temperature drift and reduce the influence of temperature. 5. The electrical leads of the first and second varistors are led out to the bottom of the sensor through TSV silicon through-silicon vias. They can be directly fixed to the substrate by flip-chip bonding without the need for external wire bonding. This makes it easier to reduce the size of the sensor package and integrate the pressure sensor. The bottom leads also enhance the anti-interference capability and effectively isolate the leads from the corrosion and interference of the external environment.

[0015] This invention discloses a high-sensitivity, wide-range MEMS pressure sensor and its fabrication method. It adopts a stacked two-stage force-bearing structure, which can simultaneously meet the requirements of high sensitivity and wide range. It is small in size, reliable in structure, realizes over-range self-protection, and the bottom lead is easy to integrate and install, making it suitable for mass production. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the pressure sensor in this invention; Figure 2 This is a schematic diagram of the structure of the preparation result in step S1 of the preparation method in this invention; Figure 3 This is a schematic diagram of the structure of the preparation result in step S2 of the preparation method in this invention; Figure 4 This is a schematic diagram of the structure of the preparation result in step S3 of the preparation method in this invention; Figure 5 This is a schematic diagram of the structure of the preparation result in step S4 of the preparation method in this invention; Figure 6 This is a schematic diagram of the structure of the preparation result in step S5 of the preparation method in this invention; Figure 7 This is a schematic diagram of the structure of the preparation result in step S6 of the preparation method in this invention; Figure 8 This is a schematic diagram of the structure of the preparation result in step S7 of the preparation method in this invention; Figure 9 This is a schematic diagram of the structure of the preparation result in step S8 of the preparation method in this invention; Figure 10 This is a schematic diagram of the structure of the preparation result in step S9 of the preparation method in this invention; Figure 11 This is a schematic diagram of the structure of the preparation result in step S10 of the preparation method in this invention; Figure 12 This is a schematic diagram of the structure of the preparation result in step S11 of the preparation method in this invention. Detailed Implementation

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] like Figure 1As shown, a highly sensitive, wide-range MEMS pressure sensor includes a primary force-receiving component and a secondary force-receiving component stacked on top of each other. The primary force-receiving component includes a first force-sensitive diaphragm 1, with a first force-receiving protrusion 2 disposed in the center of the first force-sensitive diaphragm 1. The secondary force-receiving component includes a second force-sensitive diaphragm 3, with a second force-receiving protrusion 4 disposed in the center of the second force-sensitive diaphragm 3. The second force-receiving protrusion 4 is located directly below the first force-receiving protrusion 2 with a gap between them. The size of the first force-sensitive diaphragm 1 is larger than the size of the second force-sensitive diaphragm 3, and the thickness of the second force-sensitive diaphragm 3 is greater than the thickness of the first force-sensitive diaphragm 1.

[0019] Both the first force-sensitive membrane 1 and the second force-sensitive membrane 3 are square.

[0020] The primary force-bearing component includes a first silicon substrate 5, a first force-sensitive diaphragm 1 disposed in the middle of the first silicon substrate 5, a first force-bearing bump 2 disposed in the center of the upper surface of the first force-sensitive diaphragm 1, and a top bump 6 formed on the upper surface of the first silicon substrate 5 around the first force-sensitive diaphragm 1; a first varistor 7 is disposed on the lower surface of the four sides of the first force-sensitive diaphragm 1 near the midpoint of each side, and each first varistor 7 is connected to a first electrical lead 8; a first insulating layer 9 is disposed on the lower surface of the first silicon substrate 5, and the first insulating layer 9 covers the first varistor 7 and the first electrical lead 8.

[0021] Two first varistors 7 on opposite sides form a group. One group of first varistors 7 is arranged symmetrically parallel to the side of the first force-sensitive diaphragm 1, and the other group of first varistors 7 is arranged symmetrically perpendicular to the side of the first force-sensitive diaphragm 1. The initial resistance values ​​of the four first varistors 7 are equal.

[0022] The upper surface of the first force-sensitive diaphragm 1 is lower than the upper surface of the top protrusion 6, and the upper end of the first force-receiving protrusion 2 is higher than the upper surface of the top protrusion 6.

[0023] The secondary force-receiving component includes a second silicon substrate 10, a second force-sensitive diaphragm 3 disposed in the middle of the second silicon substrate 10, a second force-receiving bump 4 disposed in the center of the upper surface of the second force-sensitive diaphragm 3, and a connecting bump 11 formed on the upper surface of the second silicon substrate 10 around the second force-sensitive diaphragm 3. The upper surface of the second force-sensitive diaphragm 3 and the upper end of the second force-receiving bump 4 are both lower than the upper surface of the connecting bump 11. A second varistor 12 is disposed on the upper surface of the four sides of the second force-sensitive diaphragm 3 near the midpoint of each side. Each second varistor 12 is connected to a second electrical lead 13. A second insulating layer 14 is disposed on the upper surface of the second force-sensitive diaphragm 3 and the second bump, and the second insulating layer 14 covers the second varistor 12 and the second electrical lead 13.

[0024] Two second varistors 12 on opposite sides form a group. One group of second varistors 12 is arranged symmetrically parallel to the edge of the second force-sensitive diaphragm, and the other group of second varistors 12 is arranged symmetrically perpendicular to the edge of the second force-sensitive diaphragm. The initial resistance values ​​of the four second varistors 12 are equal.

[0025] Four first silicon vias 15 are vertically disposed on the second silicon substrate 10. Each first silicon via 15 is connected to an intermediate electrode 16 and a first lead electrode 17 at its upper and lower ends, respectively. The intermediate electrode 16 penetrates the first insulating layer 9 and is connected to the first electrical lead 8. Four second silicon vias 18 are vertically disposed on the second silicon substrate 10. The upper end of each second silicon via 18 is connected to the second electrical lead 13, and the lower end of each second silicon via 18 is connected to the second lead electrode 19.

[0026] Working principle: When a small force is applied, the higher first force-receiving bump 2 bears the applied force, and the thinner and larger first force-sensitive diaphragm 1 undergoes a small deformation. The bottom of the first force-receiving bump 2 does not contact the second force-receiving bump 4, the resistance of the first varistor 7 changes, and the resistance of the second varistor 12 remains unchanged. At this time, the resistance of one set of first varistor 7 located at the edge of the first force-sensitive diaphragm 1 increases, and the resistance of another set of first varistor 7 decreases. The Wheatstone bridge composed of these four first varistor 7s becomes unbalanced, and the output voltage changes. The full-bridge structure maximizes sensitivity while suppressing temperature drift.

[0027] When a large force is applied, the first force-sensitive diaphragm 1 will undergo a large deformation. The bottom of the first force-receiving bump 2 will contact the second force-receiving bump 4 and apply a force. The thicker second force-sensitive diaphragm 3 will deform, and the resistance of the second varistor 12 will also change. The Wheatstone bridge composed of the four second varistors 12 will also become unbalanced, and the output voltage will change.

[0028] If the force is too great, the first force-sensitive diaphragm 1 undergoes significant deformation. The upper surfaces of the first force-bearing protrusion 2 and the top protrusion 6 become flush, and the top protrusion 6 bears the pressure, thus protecting the force-sensitive diaphragm. It should be noted that the relatively thin and large first force-sensitive diaphragm 1 possesses a large deformation capacity and did not fail during the deformation under force or the process of being protected by the top protrusion 6, further improving the reliability of the pressure sensor. The first piezoresistive resistor 7 and the second piezoresistive resistor 12 are located in a sealed cavity and are electrically connected to the first lead-out electrode 17 and the second lead-out electrode 19 at the bottom of the sensor through through-silicon vias, thereby connecting to the measurement circuit.

[0029] like Figure 2-12 As shown, a method for fabricating a highly sensitive, wide-range MEMS pressure sensor includes the following steps: S1. A silicon dioxide insulating layer is prepared on the outer surface of the first silicon substrate 5 using a thermal oxidation process. On the front side of the first silicon substrate 5, part of the silicon dioxide is removed to form a window using a photolithography process. Boron ions are implanted through this window using an ion implantation process (instead of a diffusion process, the ion implantation process is mainly used to improve the consistency of the varistor and thus improve the measurement accuracy) to form the first varistor 7. Contact holes are etched on the doped substrate using a RIE etching process. Then, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the first electrical lead 8. S2. A layer of photoresist is coated on the back side of the first silicon substrate 5 and patterned as a mask. After etching away the silicon dioxide insulating layer, anisotropic wet etching is performed using TMAH or KOH solution to form an annular cavity with a trapezoidal cross section, releasing the first force-sensitive film 1. The first force-receiving bump 2 is formed in the center of the cavity. S3. Photolithography is performed on the back side of the first silicon substrate 5, and a top protrusion 6 is formed by etching and thinning the part outside the cavity using a deep silicon etching process. S4. A silicon oxide layer 9 is formed on the front side of the first silicon substrate 5 using PECVD process. Contact holes are etched on the first insulating layer 9 using RIE etching process to expose the first electrical lead 8. Then, metal deposition is performed to form the upper intermediate electrode. S5. Photoresist is used and patterned on the front side of the second silicon substrate 10 as a mask, and then a first groove is formed using a silicon etching process. S6. Photoresist is used and patterned on the front side of the second silicon substrate 10 as a mask. A second groove with a depth greater than the first groove is etched around the first groove using a silicon etching process. The central part of the annular second groove forms a second force-bump 4. S7. Two sets of TSV vias are etched on the second silicon substrate 10 using photolithography and deep silicon etching. One set is inside the second groove, and the other set is outside the second groove. Then, a silicon dioxide insulating layer is prepared on the outer surface of the second silicon substrate 10 and inside the TSV vias using thermal oxidation. Next, Ti and Cu are deposited in the TSV vias using magnetron sputtering and TSV via electroplating is completed, thus completing the preparation of the first silicon via 15 and the second silicon via 18. S8. A window is formed by removing part of the silicon dioxide on both sides of the second force-bump 4 on the front side of the second silicon substrate 10 through photolithography. Boron ions are implanted through this window to form the second varistor 12 using ion implantation. Contact holes are etched on the doped substrate through RIE etching. Then, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the second electrical lead 13 and the lower intermediate electrode. Silicon oxide is formed on the silicon surface of the second silicon substrate 10 corresponding to the second groove and the second force-bump 4 as the second insulating layer 14 using PECVD. S9. Photoresist is used on the back side of the second silicon substrate 10 and patterned as a mask. After etching away the silicon dioxide insulating layer, TMAH or KOH solution is used for anisotropic wet etching to form a cavity and release the second force-sensitive film 3. S10. On the back side of the second silicon substrate 10, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the first lead-out electrode 17 and the second lead-out electrode 19. S11. Using a flip-chip bonding machine, the front side of the first silicon substrate 5 is bonded to the front side of the second silicon substrate 10, and the upper intermediate electrode and the lower intermediate electrode are combined to form the intermediate electrode 16.

[0030] This invention discloses a high-sensitivity, wide-range MEMS pressure sensor and its fabrication method. It adopts a stacked two-stage force-bearing structure, which can simultaneously meet the requirements of high sensitivity and wide range. It is small in size, reliable in structure, realizes over-range self-protection, and the bottom lead is easy to integrate and install, making it suitable for mass production.

[0031] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly sensitive, wide-range MEMS pressure sensor, characterized in that: This includes primary and secondary load-bearing components stacked on top of each other; The primary force-bearing component includes a first force-sensitive diaphragm, and a first force-bearing protrusion is provided in the center of the first force-sensitive diaphragm; The secondary force-receiving component includes a second force-sensitive diaphragm, and a second force-receiving protrusion is provided in the center of the second force-sensitive diaphragm; The second force-receiving protrusion is located directly below the first force-receiving protrusion with a gap between them. The size of the first force-sensitive diaphragm is larger than that of the second force-sensitive diaphragm, and the thickness of the second force-sensitive diaphragm is greater than that of the first force-sensitive diaphragm.

2. The high-sensitivity, wide-range MEMS pressure sensor according to claim 1, characterized in that: Both the first force-sensitive diaphragm and the second force-sensitive diaphragm are square.

3. The high-sensitivity, wide-range MEMS pressure sensor according to claim 2, characterized in that: The primary force-bearing component includes a first silicon substrate, a first force-sensitive diaphragm is disposed in the middle of the first silicon substrate, a first force-bearing bump is disposed in the center of the upper surface of the first force-sensitive diaphragm, and a top protrusion is formed on the portion of the upper surface of the first silicon substrate surrounding the first force-sensitive diaphragm. A first varistor is disposed on the lower surface of the four sides of the first force-sensitive diaphragm, with the midpoint of the midpoint of each side being a first varistor. Each first varistor is connected to a first electrical lead. A first insulating layer is disposed on the lower surface of the first silicon substrate, covering the first varistor and the first electrical lead.

4. A high-sensitivity, wide-range MEMS pressure sensor according to claim 3, characterized in that: The two first varistors on opposite sides form a group. One group of first varistors is arranged symmetrically parallel to the edge of the first force-sensitive diaphragm, and the other group of first varistors is arranged symmetrically perpendicular to the edge of the first force-sensitive diaphragm. The initial resistance values ​​of the four first varistors are equal.

5. A high-sensitivity, wide-range MEMS pressure sensor according to claim 3, characterized in that: The upper surface of the first force-sensitive diaphragm is lower than the upper surface of the top protrusion, and the upper end of the first force-receiving protrusion is higher than the upper surface of the top protrusion.

6. A high-sensitivity, wide-range MEMS pressure sensor according to claim 3, characterized in that: The secondary force-bearing component includes a second silicon substrate, a second force-sensitive diaphragm is disposed in the middle of the second silicon substrate, a second force-bearing bump is disposed in the center of the upper surface of the second force-sensitive diaphragm, and a connecting boss is formed on the upper surface of the second silicon substrate around the second force-sensitive diaphragm. The upper surface of the second force-sensitive diaphragm and the upper end of the second force-bearing bump are both lower than the upper surface of the connecting boss. A second varistor is respectively disposed on the upper surface of the four sides of the second force-sensitive diaphragm near the midpoint. Each second varistor is connected to a second electrical lead. A second insulating layer is disposed on the upper surface of the second force-sensitive diaphragm and the second protrusion. The second insulating layer covers the second varistor and the second electrical lead.

7. A high-sensitivity, wide-range MEMS pressure sensor according to claim 6, characterized in that: The two second varistors on opposite sides form a group. One group of second varistors is arranged symmetrically parallel to the edge of the second force-sensitive diaphragm, and the other group of second varistors is arranged symmetrically perpendicular to the edge of the second force-sensitive diaphragm. The initial resistance values ​​of the four second varistors are equal.

8. A high-sensitivity, wide-range MEMS pressure sensor according to claim 6, characterized in that: The second silicon substrate has four vertically penetrating first silicon vias. Each first silicon via is connected to an intermediate electrode and a first lead electrode at its upper and lower ends, respectively. The intermediate electrode penetrates the first insulating layer and is connected to the first electrical lead. Four second silicon vias are vertically disposed on the second silicon substrate. The upper end of each second silicon via is connected to the second electrical lead, and the lower end of each second silicon via is connected to a second lead electrode.

9. A method for fabricating a high-sensitivity, wide-range MEMS pressure sensor, characterized in that... Includes the following steps: S1. A silicon dioxide insulating layer is prepared on the outer surface of the first silicon substrate using a thermal oxidation process. On the front side of the first silicon substrate, a portion of the silicon dioxide is removed to form a window using a photolithography process. Boron ions are implanted through this window using an ion implantation process to form a first varistor. Contact holes are etched on the doped substrate using a RIE etching process. Then, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the first electrical lead. S2. A layer of photoresist is coated on the back side of the first silicon substrate and patterned as a mask. After etching away the silicon dioxide insulating layer, anisotropic wet etching is performed using TMAH or KOH solution to form an annular cavity with a trapezoidal cross-section, releasing the first force-sensitive film. The first force-receiving bump is formed in the center of the cavity. S3. Photolithography is performed on the back side of the first silicon substrate, and deep silicon etching is used to etch and thin the part outside the cavity to form a top protrusion. S4. A silicon oxide layer is formed on the front side of the first silicon substrate using PECVD process. A contact hole is etched on the first insulating layer using RIE etching process to expose the first electrical lead. Then, metal deposition is performed to form the upper intermediate electrode. S5. Photoresist is used on the front side of the second silicon substrate and patterned as a mask, and then a first groove is formed using a silicon etching process. S6. Photoresist is used and patterned on the front side of the second silicon substrate as a mask. A second groove with a depth greater than the first groove is etched around the first groove using a silicon etching process. The central part of the annular second groove forms a second force-bump. S7. Two sets of TSV vias are etched on the second silicon substrate using photolithography and deep silicon etching. One set is inside the second groove, and the other set is outside the second groove. Then, a silicon dioxide insulating layer is prepared on the outer surface of the second silicon substrate and inside the TSV vias using thermal oxidation. Next, Ti and Cu are deposited in the TSV vias using magnetron sputtering and TSV via electroplating is completed, thus completing the preparation of the first and second silicon vias. S8. A window is formed by removing part of the silicon dioxide on both sides of the second force bump on the front side of the second silicon substrate through photolithography. Boron ions are implanted through this window to form a second varistor using ion implantation. Contact holes are etched on the doped substrate through RIE etching. Then, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the second electrical lead and the lower intermediate electrode. Silicon oxide is formed on the silicon surface of the front side of the second silicon substrate corresponding to the second groove and the second force bump as a second insulating layer using PECVD. S9. Photoresist is used on the back side of the second silicon substrate and patterned as a mask. After etching away the silicon dioxide insulating layer, TMAH or KOH solution is used for anisotropic wet etching to form a cavity and release the second force-sensitive film. S10. On the back side of the second silicon substrate, aluminum or Ti / Au is deposited by magnetron sputtering and etched to form the first and second lead electrodes; S11. Using a flip-chip bonding machine, the front side of the first silicon substrate is bonded to the front side of the second silicon substrate, and the upper intermediate electrode and the lower intermediate electrode are combined to form an intermediate electrode.

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