CN211954507U - Beam island membrane piezoresistive pressure sensor - Google Patents
Beam island membrane piezoresistive pressure sensor Download PDFInfo
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- CN211954507U CN211954507U CN202021168291.2U CN202021168291U CN211954507U CN 211954507 U CN211954507 U CN 211954507U CN 202021168291 U CN202021168291 U CN 202021168291U CN 211954507 U CN211954507 U CN 211954507U
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Abstract
The utility model discloses a roof beam island membrane piezoresistive pressure sensor, including metal lead wire and silicon substrate, piezo-resistor is installed to metal lead wire's below, the below of first silicon dioxide layer is provided with single crystal silicon layer, the silicon substrate is located the below on second silica layer, be provided with the vacuum cavity between glass substrate and the silicon substrate, and the inside of vacuum cavity is provided with the island, piezo-resistor's top is provided with the roof beam, and the inboard of roof beam installs the center film, the top of center film is provided with flat membrane, metal lead wire's turn department is connected with the pad. This beam island membrane piezoresistive pressure sensor compares with current ordinary pressure sensor, and this equipment can reduce the amount of deflection of center membrane, reduces the bending of neutral surface, satisfies the little amount of deflection hypothesis, reduces the influence that nonlinear error brought, and this equipment piezo-resistor bends a width very big and doping concentration is very high, can make the resistance of bending a department very little like this, makes the better phase-match of piezo-resistor.
Description
Technical Field
The utility model relates to a MEMS piezoresistive pressure sensor technical field specifically is a beam island membrane piezoresistive pressure sensor.
Background
With the continuous development of Integrated Circuit (IC) silicon micromachining technology, MEMS pressure sensors are widely used, and can be classified into piezoresistive type, capacitive type, and resonant type according to the principle of the sensor. Among them, piezoresistive pressure sensors have been extensively studied and manufactured because of their simple structure and manufacturing process.
Common piezoresistive pressure sensor silicon cup structure adopts C type and E type, C type structure has the nonlinear rapid deterioration problem that large deflection brought, and improve its sensitivity and can only attenuate silicon film thickness, this has the degree of difficulty in the technology, E type structure can bear bigger deflection, overload protection ability has, nevertheless piezo-resistor places and can receive the restriction, can not effectively utilize the maximum stress, so in the place that the precision demand is high, traditional C type and E type structure use can receive the restriction, can not be fine satisfy people's user demand, to the above-mentioned condition, carry out technical innovation on current pressure sensor basis.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a beam island membrane piezoresistive pressure sensor to solve the problems that the general piezoresistive pressure sensor silicon cup structure in the background technology adopts C type and E type, the C type structure has nonlinear rapid deterioration caused by large deflection, and the sensitivity is improved, and only the thickness of a silicon membrane can be reduced, which has difficulty in the process; the E type structure can bear bigger amount of deflection, has overload protection ability, but piezo-resistor is placed and can be received the restriction, fails to effectively utilize the maximum stress, so in the place that the precision demand is high, traditional C type and E type structure use can receive the restriction, can not be fine satisfy people's user demand problem.
In order to achieve the above object, the utility model provides a following technical scheme: the utility model provides a roof beam island membrane piezoresistive pressure sensor, includes metal lead and silicon substrate, piezo-resistor is installed to metal lead's below, and is provided with first silicon dioxide layer around the metal lead, the below of first silicon dioxide layer is provided with single crystal silicon layer, and the below of single crystal silicon layer is provided with second silica layer, the silicon substrate is located the below on second silica layer, and the below of silicon substrate is fixed with the glass substrate, be provided with the vacuum cavity between glass substrate and the silicon substrate, and the inside of vacuum cavity is provided with the island, piezo-resistor's top is provided with the roof beam, and the inboard of roof beam installs the center film, the top of center film is provided with flat membrane, the turn department of metal lead is connected with the pad.
Preferably, the piezoresistor comprises a first resistor, a second resistor, a third resistor and a fourth resistor, wherein the first resistor and the third resistor are arranged perpendicular to the edge of the flat film, and the second resistor and the fourth resistor are arranged parallel to the edge of the flat film.
Preferably, the first resistor, the second resistor, the third resistor and the fourth resistor form a wheatstone bridge, and the first resistor, the second resistor, the third resistor and the fourth resistor are connected by metal leads.
Preferably, the glass substrate and the silicon substrate are bonded by an anode, and the silicon substrate is made of an SOI material.
Preferably, the ends of the beams are joined to the central membrane edge midportion.
Preferably, the piezoresistor is positioned on the top of the sensitive membrane, and the piezoresistor strip is made into a novel broken line shape.
Compared with the prior art, the beneficial effects of the utility model are as follows:
1. the utility model discloses an island, roof beam and center film, the end of the roof beam of this equipment is connected with center film edge middle part, can improve the effect of stress concentration, improves the sensitivity of sensor, and the island structure is located center film center department, can reduce the amount of deflection of center film, reduces the crooked of neutral plane, satisfies the small amount of deflection hypothesis, reduces the influence that nonlinear error brought;
2. the utility model discloses a piezo-resistor and roof beam, the resistance of this equipment adopts a broken line shape, and the border of roof beam is strideed across to some, has fully utilized stress area, and piezo-resistor uses different number of folds, makes the shape of resistance strip accord with the distribution of high stress more, and secondly, piezo-resistor is the doping area, and piezo-resistor bends the width very big and doping concentration very high, can make the resistance of bending very little like this, makes better phase-match of piezo-resistor;
3. the utility model discloses a piezo-resistor, the sensor piezo-resistor of this equipment use is the P type doping, and P type silicon piezoresistive coefficient is along with doping concentration and temperature variation and change, and surface doping concentration is higher, and piezoresistive coefficient is less, and along with doping concentration's rising, piezoresistive coefficient also can reduce along with temperature variation's degree, consequently synthesizes the influence of considering the sensitivity of sensor and temperature when designing the sensor to obtain the best effect.
Drawings
FIG. 1 is a schematic front view of the present invention;
FIG. 2 is a schematic view of the island structure of the present invention;
fig. 3 is the schematic diagram of the strip shape and the position distribution structure of the varistor of the present invention.
In the figure: 1. a metal lead; 2. a voltage dependent resistor; 201. a first resistor; 202. a second resistor; 203. a third resistor; 204. a fourth resistor; 3. a first silicon dioxide layer; 4. a single crystal silicon layer; 5. a second silicon dioxide layer; 6. an island; 7. a vacuum chamber; 8. a glass substrate; 9. flattening the film; 10. a beam; 11. a central membrane; 12. a silicon substrate; 13. and a bonding pad.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1-3, the present invention provides a technical solution: a beam island film piezoresistive pressure sensor comprises a metal lead 1 and a silicon substrate 12, wherein a piezoresistor 2 is arranged below the metal lead 1, a first silicon dioxide layer 3 is arranged around the metal lead 1, the piezoresistor 2 comprises a first resistor 201, a second resistor 202, a third resistor 203 and a fourth resistor 204, the first resistor 201 and the third resistor 203 are vertically arranged with the edge of a flat film 9, the second resistor 202 and the fourth resistor 204 are arranged in parallel with the edge of the flat film 9, the first resistor 201, the second resistor 202, the third resistor 203 and the fourth resistor 204 form a Wheatstone bridge, the first resistor 201, the second resistor 202, the third resistor 203 and the fourth resistor 204 are connected with each other through the metal lead 1, the piezoresistor 2 of the sensor of the device adopts P-type doping, and the piezoresistive coefficient of the P-type silicon is changed along with the change of doping concentration and temperature, the higher the surface doping concentration is, the smaller the piezoresistive coefficient is, and the degree of piezoresistive coefficient change along with the temperature is reduced along with the increase of the doping concentration, so that the sensitivity and the temperature influence of the sensor are comprehensively considered when the sensor is designed to obtain the best effect;
the piezoresistor 2 is positioned at the top of the sensitive diaphragm, the piezoresistor strip is made into a novel broken line shape, the piezoresistor 2 and the beam 10 are used, the resistor of the equipment adopts a broken line shape, one part of the resistor spans the boundary of the beam 10, the stress area is fully utilized, the piezoresistor 2 uses different broken numbers, the shape of the resistor strip is more in line with the distribution of high stress, and secondly, the piezoresistor 2 is a doped area, the bending part of the piezoresistor 2 has very large width and very high doping concentration, so that the resistor at the bending part is very small, and the piezoresistor 2 is better matched;
a monocrystalline silicon layer 4 is arranged below the first silicon dioxide layer 3, a second silicon dioxide layer 5 is arranged below the monocrystalline silicon layer 4, a silicon substrate 12 is arranged below the second silicon dioxide layer 5, a glass substrate 8 is fixed below the silicon substrate 12, the glass substrate 8 is in anodic bonding with the silicon substrate 12, the silicon substrate 12 is made of SOI material, a vacuum cavity 7 is arranged between the glass substrate 8 and the silicon substrate 12, an island 6 is arranged inside the vacuum cavity 7, a beam 10 is arranged above the piezoresistor 2, a central membrane 11 is arranged on the inner side of the beam 10, the tail end of the beam 10 is connected with the middle part of the edge of the central membrane 11, the tail end of the beam 10 of the device is connected with the middle part of the edge of the central membrane 11 through the island 6, the beam 10 and the central membrane 11, the effect of stress concentration can be improved, the sensitivity of the sensor can be improved, the island 6 structure is arranged at the center of the central membrane 11, and, the bending of a neutral surface is reduced, the assumption of small deflection is met, the influence caused by nonlinear errors is reduced, a flat film 9 is arranged above a central film 11, and a bonding pad 13 is connected to the turning part of the metal lead 1.
The working principle is as follows: when the beam island membrane piezoresistive pressure sensor is used, firstly, an SOI silicon wafer with N-type & lt 100 & gt crystal orientation double-side polishing is selected, wherein the upper layer of the SOI wafer is a single crystal silicon layer 4, the middle layer is a second silicon dioxide layer 5 buried layer, the lower layer is a silicon substrate 12, then the SOI wafer is cleaned and subjected to high-temperature oxidation to form a first silicon dioxide layer 3, then the front side thermal oxidation first silicon dioxide layer 3 is used for patterning, the ion etching process is used for removing the thermal oxidation first silicon dioxide layer 3 in a front side lightly doped region, the rest regions are used as masks, boron ions are lightly doped to form a piezoresistor 2, then a plasma enhanced chemical vapor deposition process is used for forming a second silicon dioxide layer 5 on the front side, the piezoresistor 2 is protected from being influenced in a heavily doped step, and a heavily doped plate is used for carrying out photoetching and reactive ion etching processes to realize the patterning of the second silicon dioxide layer 5 and remove the thermal oxidation first silicon dioxide layer 3 in the front side heavily doped region And a PE second silicon dioxide layer 5, the first silicon dioxide layer 3 in the rest areas is used as a mask, then boron ion heavy doping is carried out to form an ohmic contact area with low resistance, a redistribution diffusion annealing process is carried out, then a redistribution well push diffusion annealing process is carried out to ensure that the impurity concentration of a sensitive resistor and the ohmic contact area is uniformly distributed to ensure that a lead wire and a sensitive beam form stable contact, then the shape of the metal lead wire 1 is photoetched by using a metal lead wire 1 plate in the ohmic contact area, a metal layer is sputtered to form a metal lead wire 1 and a bonding pad 13 of a sensor chip, then a front etching plate is used to carry out photoetching on the top layer single crystal silicon layer 4 to form a flat film 9 and a beam 10, then a back etching plate is used to carry out etching on the lower silicon substrate 12 by adopting a deep silicon etching method, the required thickness is obtained by controlling the etching time, and then secondary etching is, and forming an island structure 6, so that a beam island film structure is obtained on the bottom surface of the lower monocrystalline silicon layer 4, and finally, carrying out anodic bonding on a silicon substrate 12 and a glass substrate 8, sealing a groove formed on the back surface, and forming a vacuum cavity 7.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. The utility model provides a beam island membrane piezoresistive pressure sensor, includes metal lead (1) and silicon substrate (12), its characterized in that: a piezoresistor (2) is arranged below the metal lead (1), a first silicon dioxide layer (3) is arranged around the metal lead (1), a monocrystalline silicon layer (4) is arranged below the first silicon dioxide layer (3), and a second silicon dioxide layer (5) is arranged below the monocrystalline silicon layer (4), the silicon substrate (12) is positioned below the second silicon dioxide layer (5), a glass substrate (8) is fixed below the silicon substrate (12), a vacuum cavity (7) is arranged between the glass substrate (8) and the silicon substrate (12), an island (6) is arranged in the vacuum cavity (7), a beam (10) is arranged above the piezoresistor (2), and the inboard of roof beam (10) is installed central membrane (11), be provided with flat membrane (9) above central membrane (11), the turning department of metal lead (1) is connected with pad (13).
2. The beam island membrane piezoresistive pressure sensor according to claim 1, wherein: the piezoresistor (2) comprises a first resistor (201), a second resistor (202), a third resistor (203) and a fourth resistor (204), the first resistor (201) and the third resistor (203) are vertically arranged with the edge of the flat film (9), and the second resistor (202) and the fourth resistor (204) are parallel arranged with the edge of the flat film (9).
3. The beam island membrane piezoresistive pressure sensor according to claim 2, wherein: the first resistor (201), the second resistor (202), the third resistor (203) and the fourth resistor (204) form a Wheatstone bridge, and the first resistor (201), the second resistor (202), the third resistor (203) and the fourth resistor (204) are connected through a metal lead (1).
4. The beam island membrane piezoresistive pressure sensor according to claim 1, wherein: the glass substrate (8) and the silicon substrate (12) are bonded through an anode, and the silicon substrate (12) is made of an SOI material.
5. The beam island membrane piezoresistive pressure sensor according to claim 1, wherein: the tail end of the beam (10) is connected with the middle part of the edge of the central membrane (11).
6. The beam island membrane piezoresistive pressure sensor according to claim 1, wherein: the piezoresistor (2) is positioned at the top of the sensitive membrane, and the piezoresistor strip is made into a novel broken line shape.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202021168291.2U CN211954507U (en) | 2020-06-22 | 2020-06-22 | Beam island membrane piezoresistive pressure sensor |
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| CN202021168291.2U CN211954507U (en) | 2020-06-22 | 2020-06-22 | Beam island membrane piezoresistive pressure sensor |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113465792A (en) * | 2021-06-17 | 2021-10-01 | 西安交通大学 | Silicon carbide pressure sensor chip with multilayer embossment and island film structure and preparation method thereof |
| CN113483926A (en) * | 2021-07-15 | 2021-10-08 | 西安近代化学研究所 | Explosion field MEMS piezoresistive pressure sensor |
| CN114235233A (en) * | 2021-12-16 | 2022-03-25 | 东南大学 | MEMS pressure sensor and preparation method thereof |
| CN114295262A (en) * | 2021-12-07 | 2022-04-08 | 华东光电集成器件研究所 | Island membrane structure silicon piezoresistive sensor device |
| CN114427930A (en) * | 2022-01-27 | 2022-05-03 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and preparation method thereof |
| CN114705332A (en) * | 2022-05-06 | 2022-07-05 | 西安思微传感科技有限公司 | High-sensitivity low-nonlinearity pressure sensor and preparation method thereof |
-
2020
- 2020-06-22 CN CN202021168291.2U patent/CN211954507U/en active Active
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113465792A (en) * | 2021-06-17 | 2021-10-01 | 西安交通大学 | Silicon carbide pressure sensor chip with multilayer embossment and island film structure and preparation method thereof |
| CN113483926A (en) * | 2021-07-15 | 2021-10-08 | 西安近代化学研究所 | Explosion field MEMS piezoresistive pressure sensor |
| CN113483926B (en) * | 2021-07-15 | 2022-09-23 | 西安近代化学研究所 | Explosion field MEMS piezoresistive pressure sensor |
| CN114295262A (en) * | 2021-12-07 | 2022-04-08 | 华东光电集成器件研究所 | Island membrane structure silicon piezoresistive sensor device |
| CN114235233A (en) * | 2021-12-16 | 2022-03-25 | 东南大学 | MEMS pressure sensor and preparation method thereof |
| CN114235233B (en) * | 2021-12-16 | 2024-01-05 | 东南大学 | MEMS pressure sensor and preparation method thereof |
| CN114427930A (en) * | 2022-01-27 | 2022-05-03 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and preparation method thereof |
| CN114427930B (en) * | 2022-01-27 | 2023-11-17 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and method for producing the same |
| CN114705332A (en) * | 2022-05-06 | 2022-07-05 | 西安思微传感科技有限公司 | High-sensitivity low-nonlinearity pressure sensor and preparation method thereof |
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