CN117782223A - Temperature and pressure integrated sensor and manufacturing method thereof - Google Patents
Temperature and pressure integrated sensor and manufacturing method thereof Download PDFInfo
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- CN117782223A CN117782223A CN202311873840.4A CN202311873840A CN117782223A CN 117782223 A CN117782223 A CN 117782223A CN 202311873840 A CN202311873840 A CN 202311873840A CN 117782223 A CN117782223 A CN 117782223A
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 23
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 141
- 239000010703 silicon Substances 0.000 claims abstract description 141
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 140
- 239000000758 substrate Substances 0.000 claims abstract description 119
- 238000000034 method Methods 0.000 claims abstract description 106
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 94
- 230000008569 process Effects 0.000 claims abstract description 88
- 239000011521 glass Substances 0.000 claims abstract description 73
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 47
- 238000005530 etching Methods 0.000 claims abstract description 18
- 238000005468 ion implantation Methods 0.000 claims abstract description 12
- 238000005488 sandblasting Methods 0.000 claims abstract description 10
- 238000004080 punching Methods 0.000 claims abstract description 9
- 238000000605 extraction Methods 0.000 claims description 30
- 238000005269 aluminizing Methods 0.000 claims description 23
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 17
- 229910052782 aluminium Inorganic materials 0.000 claims description 17
- 238000005566 electron beam evaporation Methods 0.000 claims description 4
- 238000000227 grinding Methods 0.000 claims description 4
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 4
- 238000001039 wet etching Methods 0.000 claims description 4
- 238000001259 photo etching Methods 0.000 claims description 3
- 230000008859 change Effects 0.000 abstract description 21
- 239000013307 optical fiber Substances 0.000 abstract 1
- 239000000835 fiber Substances 0.000 description 12
- 230000006872 improvement Effects 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 238000012544 monitoring process Methods 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
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- 230000007774 longterm Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 239000005388 borosilicate glass Substances 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
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Abstract
The invention relates to a temperature and pressure integrated sensor and a manufacturing method thereof, belongs to the technical field of sensors, and solves the problem of how to monitor a pressure sensor for pressure change in an optical fiber gyroscope in real time. The method comprises the following steps: forming a plurality of piezoresistive strips in a first silicon wafer through an ion implantation process; etching the quadrangular frustum pyramid cavity in the second silicon wafer by using an etching process; bonding the first silicon wafer and the second silicon wafer through a first bonding process to form a silicon layer structure, wherein a plurality of piezoresistive strips face the quadrangular frustum-shaped cavity; forming a substrate through hole in the glass substrate by using a sand blasting punching process, and arranging a platinum resistor above the top surface of the glass substrate; and bonding the silicon layer structure with the glass substrate by using a second bonding process, wherein the platinum resistor faces the quadrangular frustum-shaped cavity. The pressure and the temperature come from the same area, and the rapid temperature change of the pressure sensor can be compensated with high precision.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a temperature and pressure integrated sensor and a manufacturing method thereof.
Background
The fiber optic gyroscope is an optical angular rate sensor manufactured by utilizing the SAGAC effect, has the characteristics of strong environment adaptability and high precision, and is widely applied to an inertial navigation system. The core component of the fiber optic gyroscope is a fiber optic ring, and the fiber optic ring can change under the influence of temperature, thereby affecting the precision of the fiber optic gyroscope. The inside of the fiber optic gyroscope is a closed environment, once leakage occurs in the use process, the precision of the fiber optic gyroscope can be rapidly reduced and even the fiber optic gyroscope is invalid, so that the real-time monitoring of the internal gas pressure of the fiber optic gyroscope is particularly necessary in the use process. In fact, when the temperature of the external environment changes rapidly, the temperature of the internal pressure also changes rapidly, and the monitoring accuracy is easily affected, so that a pressure sensor capable of monitoring the internal pressure change of the fiber-optic gyroscope in real time is needed, and the rapid temperature change characteristic of the pressure sensor can be met.
Disclosure of Invention
In view of the above analysis, the present invention is directed to providing a temperature and pressure integrated sensor and a manufacturing method thereof, which are used for solving the problem of how to monitor the pressure sensor in the fiber optic gyroscope in real time and can meet the rapid temperature change characteristic.
In one aspect, an embodiment of the present invention provides a method for manufacturing a temperature and pressure integrated sensor, including: forming a plurality of piezoresistive strips in a first silicon wafer through an ion implantation process; etching the quadrangular frustum pyramid cavity in the second silicon wafer by using an etching process; bonding the first silicon wafer and the second silicon wafer through a first bonding process to form a silicon layer structure, wherein the plurality of piezoresistive strips face the top surface of the quadrangular frustum-shaped cavity; forming a substrate through hole in a glass substrate by using a sand blasting punching process, and arranging a platinum resistor above the top surface of the glass substrate; and bonding the silicon layer structure to the glass substrate using a second bonding process, wherein the platinum resistor faces the bottom surface of the quadrangular frustum-shaped cavity.
The beneficial effects of the technical scheme are as follows: in the manufacturing method of the temperature-pressure integrated sensor, the pressure and the temperature can be sensed at the same position through the temperature-pressure integrated scheme built in the piezoresistive strip and the temperature sensor, if the fiber-optic gyroscope is in a rapid temperature change environment, the pressure and the temperature come from the same area, so that the pressure sensor can be subjected to high-precision temperature compensation of rapid temperature change, the air pressure change in the fiber-optic gyroscope can be accurately reflected, and the temperature-pressure integrated sensor manufactured by the method can be popularized to any occasion needing to accurately monitor the rapid temperature-pressure change.
Based on a further improvement of the above method, forming the plurality of piezoresistive strips in the first silicon die by an ion implantation process further comprises: thinning the first silicon wafer through a grinding process; forming a plurality of piezoresistive strips in the middle of the first silicon wafer through the ion implantation process; forming a plurality of first extraction electrodes above the top surface of the first silicon wafer by utilizing an aluminizing process, wherein the first extraction electrodes are electrically connected with corresponding piezoresistive strips, and the aluminizing process comprises an electron beam evaporation aluminizing process or a magnetron sputtering aluminizing process.
Based on further improvement of the method, etching the quadrangular frustum-shaped cavity in the second silicon wafer by using an etching process comprises: etching the quadrangular frustum-shaped cavity in the second silicon wafer by utilizing a wet etching process, wherein the quadrangular frustum-shaped cavity penetrates through the second silicon wafer, the top surface of the quadrangular frustum-shaped cavity is a first square, the bottom surface of the quadrangular frustum-shaped cavity is a second square, and the area of the first square is smaller than that of the second square; and forming an aluminum electrode on the side wall of the quadrangular frustum pyramid-shaped cavity part and the bottom surface of the second silicon wafer.
Based on a further improvement of the above method, bonding the first silicon wafer to the second silicon wafer by a first bonding process to form a silicon layer structure comprises: and bonding the top surface of the first silicon wafer and the top surface of the second silicon wafer through the first bonding process to form the first silicon wafer into the top surface of the quadrangular frustum-shaped cavity, and taking the bonded first silicon wafer and second silicon wafer as a silicon layer structure, wherein the piezoresistive strips are positioned right above the square top surface of the quadrangular frustum-shaped cavity and positioned at four sides of the square top surface, and the first bonding process is a silicon-silicon bonding process.
Based on a further improvement of the above method, forming a substrate via in the glass substrate using a sand blasting and perforating process, and disposing a platinum resistor above a top surface of the glass substrate comprises: forming a plurality of through holes in the glass substrate using the sand blasting and perforating process; forming a platinum resistor over a top surface of the glass substrate as a temperature sensor, wherein the plurality of piezoresistive strips are spaced apart from the platinum resistor in horizontal and vertical directions; and photoetching the glass substrate, aluminizing the top surface of the glass substrate to form a second extraction electrode, aluminizing the side walls of the substrate through holes to form a second substrate electrode for extracting the temperature electric signal of the platinum resistor, and simultaneously forming a first substrate electrode for extracting the pressure electric signal of the aluminum electrode.
Based on a further improvement of the above method, bonding the silicon layer structure to the glass substrate using a second bonding process comprises: and bonding the bottom surface of the silicon layer structure with the top surface of the glass substrate by using a second bonding process to form the bottom surface of the quadrangular frustum pyramid cavity, wherein the second bonding process is an anodic bonding process, and vacuumizing the quadrangular frustum pyramid cavity to enable the piezoresistive strips and the platinum resistor to be located in the same quadrangular frustum pyramid cavity.
Based on the further improvement of the method, the plurality of piezoresistive bars comprise four piezoresistive bars, wherein the piezoresistive bars are connected into a Wheatstone bridge through a plurality of first extraction electrodes, and the pressure electric signals of the first extraction electrodes are extracted to four first substrate through holes through four aluminum electrodes so that the singlechip collects the pressure electric signals through the four first substrate electrodes; and leading out the temperature electric signals to two second substrate electrodes through two second leading-out electrodes, so that the singlechip collects the temperature electric signals through the two second substrate electrodes.
In another aspect, an embodiment of the present invention provides a temperature and pressure integrated sensor, including: a glass substrate including a platinum resistor on a top surface of the glass substrate and a plurality of substrate through holes in the glass substrate; the silicon layer structure is positioned above the glass substrate and comprises a first silicon wafer and a second silicon wafer positioned below the first silicon wafer; a plurality of piezoresistive strips are arranged on the bottom surface of the first silicon wafer; and the second silicon wafer comprises a quadrangular frustum-shaped cavity, wherein the bottom surface of the first silicon wafer is used as the top surface of the quadrangular frustum-shaped cavity, and the top surface of the glass substrate is used as the bottom surface of the quadrangular frustum-shaped cavity, so that the piezoresistive strips and the platinum resistor are exposed in the quadrangular frustum-shaped cavity.
Further improvements based on the above device, the quadrangular frustum-shaped cavity comprises a square top surface and a square bottom surface; the plurality of piezoresistive bars are four piezoresistive bars, wherein the four piezoresistive bars are positioned at four edges of the square top surface and are connected into a Wheatstone bridge through a plurality of first extraction electrodes positioned on the square top surface.
Based on the further improvement of the device, the temperature and pressure integrated sensor further comprises: four aluminum electrodes positioned on the side wall of the quadrangular frustum pyramid cavity and the bottom surface of the second silicon wafer; four first substrate electrodes located right below corners of the square top surface and on side walls of four substrate through holes of the plurality of substrate through holes, connected with the four piezoresistive strips through the plurality of first extraction electrodes and the four aluminum electrodes; two second extraction electrodes positioned on both sides of the platinum resistor on the top surface of the glass substrate; and the two second substrate electrodes are positioned on the side walls of two substrate through holes in the plurality of substrate through holes and are connected with the platinum resistor through the two extraction electrodes.
Compared with the prior art, the invention has at least one of the following beneficial effects:
1. in the manufacturing method of the temperature-pressure integrated sensor, the pressure and the temperature can be sensed at the same position through the temperature-pressure integrated scheme built in the piezoresistive strip and the temperature sensor, if the fiber-optic gyroscope is in a rapid temperature change environment, the pressure and the temperature come from the same area, so that the pressure sensor can be subjected to high-precision temperature compensation of rapid temperature change, the air pressure change in the fiber-optic gyroscope can be accurately reflected, and the temperature-pressure integrated sensor manufactured by the method can be popularized to any occasion needing to accurately monitor the rapid temperature-pressure change;
2. according to the temperature and pressure integrated chip provided by the embodiment of the invention, the tightness of the fiber-optic gyroscope can be monitored in real time, and the temperature sensor and the pressure sensor are integrated on one silicon wafer, so that the temperature and pressure integrated chip has good heat conduction, can be used for measuring in real time, and is accurate in pressure when the temperature of the external environment changes rapidly;
3. the temperature pressure chip is different from the traditional chip in that the piezoresistive strip is arranged in the vacuum cavity, but not on the surface of the chip, and the traditional pressure chip is characterized in that a layer of silicon oxide and a layer of silicon nitride are added for protecting the piezoresistive strip, wherein one layer provides compressive stress to the silicon wafer, and the other layer provides tensile stress to the silicon wafer, so that the balance between the compressive stress and the tensile stress is achieved;
4. the electrode and the pressure acting surface of the traditional pressure sensor are on the same side, the pressure of the scheme acts on the upper end of the chip, and the electrode is led out from the thick glass at the lower end of the chip, and the thick glass can well isolate the bonding stress, so that the pressure sensor has smaller bonding stress, and the long-term stability and the precision of the pressure sensor are theoretically higher than those of the scheme of the traditional chip;
5. in addition, the temperature and pressure integrated sensor can be popularized to any monitoring scene requiring temperature and pressure integrated measurement.
In the invention, the technical schemes can be mutually combined to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, like reference numerals being used to refer to like parts throughout the several views.
FIG. 1 is a flow chart of a method for manufacturing an integrated temperature and pressure sensor according to an embodiment of the invention;
FIGS. 2A-2D are cross-sectional views of a first silicon wafer during the fabrication of the first silicon wafer in a temperature and pressure integrated sensor, respectively, according to an embodiment of the present invention;
FIGS. 3A to 3C are sectional views of an initial second silicon wafer during the fabrication of the second silicon wafer in the temperature and pressure integrated sensor, etching the initial second silicon wafer, and forming an aluminum electrode, respectively, according to an embodiment of the present invention;
FIG. 3D is a cross-sectional view of a silicon layer structure including a bonded first silicon wafer and second silicon wafer in accordance with an embodiment of the present invention;
fig. 4A to 4D are sectional views of a glass substrate, respectively, including an initial glass substrate, a through-substrate via, a platinum resistor, and an extraction electrode during the process of manufacturing the glass substrate according to an embodiment of the present invention;
FIG. 4E is a cross-sectional view of a temperature and pressure integrated sensor including a bonded silicon layer structure and a glass substrate according to an embodiment of the present invention;
FIG. 5 is a graph showing a substrate electrode profile of an integrated temperature and pressure sensor according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an application of a single-chip microcomputer and a temperature and pressure integrated sensor according to an embodiment of the invention;
fig. 7A and 7B are schematic diagrams of a wheatstone bridge and a pressure-acting deformation caused by pressure acting on a temperature-pressure integrated sensor, respectively.
Detailed Description
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and together with the description serve to explain the principles of the invention, and are not intended to limit the scope of the invention.
Referring to fig. 1, a method for manufacturing a temperature and pressure integrated sensor is disclosed, which comprises the following steps: in step S101, forming a plurality of piezoresistive strips in a first silicon wafer through an ion implantation process; in step S102, etching a quadrangular frustum pyramid-shaped cavity in a second silicon wafer by using an etching process; in step S103, bonding the first silicon wafer and the second silicon wafer through a first bonding process to form a silicon layer structure, wherein a plurality of piezoresistive strips face the top surface of the quadrangular frustum-shaped cavity; in step S104, forming a substrate through hole in the glass substrate by a sand blasting and punching process, and disposing a platinum resistor above the top surface of the glass substrate; and bonding the silicon layer structure to the glass substrate using a second bonding process in step S105, wherein the platinum resistor faces the bottom surface of the quadrangular frustum-shaped cavity.
Compared with the prior art, in the manufacturing method of the temperature and pressure integrated sensor, the pressure and the temperature can be sensed at the same position through the temperature and pressure integrated scheme built in the piezoresistive strip and the temperature sensor, if the fiber optic gyroscope is in a rapid temperature change environment, the pressure and the temperature come from the same area, so that the pressure sensor can be subjected to high-precision temperature compensation of rapid temperature change, the air pressure change in the fiber optic gyroscope can be accurately reflected, and the temperature and pressure integrated sensor manufactured through the method can be popularized to any occasion needing to accurately monitor the rapid temperature and pressure change.
Hereinafter, a method for manufacturing the temperature and pressure integrated sensor according to an embodiment of the present invention will be described in detail with reference to fig. 1 to 4E.
In step S101, a plurality of piezoresistive strips are formed in a first silicon wafer by an ion implantation process. Specifically, forming a plurality of piezoresistive strips in a first silicon die by an ion implantation process with reference to fig. 2A and 2B further comprises: thinning the first silicon wafer through a grinding process; referring to fig. 2C, a plurality of piezoresistive bars are formed in the middle of a first silicon wafer through an ion implantation process as piezoresistive pressure sensors, and referring to fig. 5, four piezoresistive bars are formed on four sides of a quadrilateral in the first silicon wafer, and the piezoresistive pressure sensors can convert external pressure values into electrical signals by using resistors; referring to fig. 2D, a plurality of first extraction electrodes are formed over the top surface of the first silicon wafer using an aluminizing process, wherein the first extraction electrodes are electrically connected with corresponding piezoresistive strips, the aluminizing process comprising an electron beam evaporation aluminizing process or a magnetron sputtering aluminizing process. The plurality of piezoresistive strips comprise four piezoresistive strips, the four piezoresistive strips are arranged on the edge of the central square of the first silicon wafer, and the four piezoresistive strips are connected together through extraction electrodes at two ends of each piezoresistive strip. Optionally, the first extraction electrode does not extend to an opposite end of the first silicon wafer.
In step S102, a quadrangular frustum-shaped cavity is etched in a second silicon wafer using an etching process. Specifically, etching the quadrangular frustum pyramid cavity in the second silicon wafer by using the etching process comprises: referring to fig. 3A and 3B, a rectangular frustum-shaped cavity is etched in a second silicon wafer by a wet etching process, the rectangular frustum-shaped cavity penetrates through the second silicon wafer, wherein the top surface of the rectangular frustum-shaped cavity is a first square, the bottom surface of the rectangular frustum-shaped cavity is a second square, and the area of the first square is smaller than that of the second square; referring to fig. 3C, aluminum electrodes are formed on the sidewalls of the quadrangular frustum-shaped cavity portion and the bottom surface of the second silicon wafer.
In step S103, the first silicon wafer and the second silicon wafer are bonded by a first bonding process to form a silicon layer structure, wherein the plurality of piezoresistive strips face the quadrangular frustum-shaped cavity. In particular, the piezoresistive strip faces the face of the quadrangular frustum-shaped cavity where the first square is located. The aluminum electrode is connected with the piezoresistive strip through the lead-out electrode. Referring to fig. 3D, bonding a first silicon wafer and a second silicon wafer through a first bonding process to form a silicon layer structure includes: bonding the top surface of the first silicon wafer and the top surface of the second silicon wafer through a first bonding process to form the first silicon wafer into the top surface of the quadrangular frustum-shaped cavity, and taking the bonded first silicon wafer and second silicon wafer as a silicon layer structure, wherein a plurality of piezoresistive strips are positioned right above the square top surface of the quadrangular frustum-shaped cavity and positioned at four sides of the square top surface, and the first bonding process is a silicon-silicon bonding process.
In step S104, a substrate through-hole is formed in the glass substrate using a sand blast punching process, and a platinum resistor is disposed above the top surface of the glass substrate. Specifically, forming a substrate through-hole in a glass substrate using a sand blast punching process, and disposing a platinum resistor above a top surface of the glass substrate includes: referring to fig. 4A and 4B, a plurality of through holes are formed in a glass substrate using a sand blasting and punching process, in particular, fig. 5 shows the relative positions of 6 through holes formed in the glass substrate, wherein through holes 1,2,3,4 are used to form a first substrate electrode, and through holes 5 and 6 are used to form a second substrate electrode; referring to fig. 4C, a platinum resistor is formed as a temperature sensor over the top surface of the glass substrate by a platinum evaporation process, wherein a plurality of piezoresistive strips are spaced apart from the platinum resistor in horizontal and vertical directions; referring to fig. 4D, the glass substrate is subjected to photolithography and aluminizing of the top surface of the glass substrate to form a second extraction electrode, the sidewalls of the plurality of substrate vias are aluminized to form a second substrate electrode that extracts a temperature electrical signal of platinum resistance, and simultaneously a first substrate electrode that extracts a pressure electrical signal of aluminum electrode is formed, so that the acquired temperature electrical signal and pressure electrical signal are independent of each other due to spatial misalignment of the first substrate electrode and the second substrate electrode.
Bonding the silicon layer structure to the glass substrate using a second bonding process in which the platinum resistor faces the quadrangular frustum-shaped cavity in step S105; in particular, the platinum resistor faces the face of the quadrangular frustum-shaped cavity where the second square is located. Referring to fig. 4E, bonding the silicon layer structure to the glass substrate using the second bonding process includes: and bonding the bottom surface of the silicon layer structure with the top surface of the glass substrate by utilizing a second bonding process to form the bottom surface of the quadrangular frustum-shaped cavity, wherein the second bonding process is an anode bonding process, and vacuumizing the quadrangular frustum-shaped cavity so that a plurality of piezoresistive strips and platinum resistors are positioned in the same quadrangular frustum-shaped cavity.
Referring to fig. 4E, the piezoresistive strips 201 are connected to form a wheatstone bridge through the first extraction electrodes 202, and the pressure electric signals of the first extraction electrodes 202 are extracted to the four first substrate through holes through the four aluminum electrodes 302, so that the singlechip collects the pressure electric signals through the four first substrate electrodes.
Referring to fig. 4E, the temperature electric signals are led out to the two second substrate electrodes 403 through the two second lead-out electrodes 402, so that the single chip microcomputer collects the temperature electric signals through the two second substrate electrodes.
Referring to fig. 4E, another embodiment of the present invention discloses a temperature and pressure integrated sensor, comprising: a glass substrate 400 including a platinum resistor 401 on a top surface of the glass substrate and a plurality of substrate through holes in the glass substrate; a silicon layer structure located above the glass substrate and comprising a first silicon wafer 200 and a second silicon wafer 300 located below the first silicon wafer 200 and above the glass substrate 400; a plurality of piezoresistive strips 201 are arranged on the bottom surface of the first silicon wafer 200; and second silicon wafer 300 includes a quadrangular frustum-shaped cavity 301, wherein a bottom surface of first silicon wafer 200 serves as a top surface of quadrangular frustum-shaped cavity 301 and a top surface of glass substrate 400 serves as a bottom surface of quadrangular frustum-shaped cavity 301, such that plurality of piezoresistive strips 201 and platinum resistor 401 are exposed in quadrangular frustum-shaped cavity 301.
The quadrangular frustum-shaped cavity 301 includes a square top surface and a square bottom surface; the plurality of piezoresistive strips 201 are four piezoresistive strips, wherein the four piezoresistive strips are located at four sides of the square top surface and are connected as a wheatstone bridge via a plurality of first extraction electrodes located on the square top surface.
Four aluminum electrodes 302 located on the side walls of the quadrangular frustum-shaped cavity and the bottom surface of the second silicon wafer; four first substrate electrodes located directly below corners of the square top surface and on sidewalls of four substrate through holes of the plurality of substrate through holes, connected with the four piezoresistive strips 201 via the plurality of first extraction electrodes 202 and the four aluminum electrodes 302; two second extraction electrodes 402 located on both sides of the platinum resistor 401 on the top surface of the glass substrate; two second base electrodes 403 are located on the sidewalls of two base vias among the plurality of base vias, and are connected to the platinum resistor 401 via two extraction electrodes.
The invention provides a temperature and pressure integrated chip scheme, namely, a pressure chip and a temperature chip are integrated on a silicon chip, so that the temperature fields of the pressure chip and the temperature chip are consistent, and when the external temperature changes rapidly, the temperature chip is used for carrying out temperature compensation on the output of the pressure chip, so that the rapid change of the external temperature can be responded.
The aim of the invention is mainly realized by the following technical scheme:
as shown in fig. 2A to 2D, the process for manufacturing the silicon layer of the temperature-pressure integrated chip is as follows:
(1) Preparing a silicon wafer 1, and grinding and thinning the silicon wafer 1;
(2) Ion implantation is carried out on a specific area of the piezoresistive strip to form the piezoresistive strip;
(3) Carrying out surface aluminizing, namely, carrying out electron beam evaporation aluminizing or magnetron sputtering aluminizing to lead out electrodes of the piezoresistive strip;
(4) Preparing a silicon wafer 2, and performing wet etching on the silicon wafer to form a structure shown in fig. 3A to 3C;
(5) Aluminizing the material, and aluminizing the slope subjected to wet corrosion;
(6) Silicon bonding is carried out on the silicon wafer 1 and the silicon wafer 2 to form a structure shown in figure 3D;
thus, a silicon layer structure has been formed, and the preparation of a glass layer structure will be performed.
As shown in fig. 4A to 4D, the glass layer manufacturing process of the temperature-pressure integrated chip is as follows:
(1) Preparing borosilicate glass sheets;
(2) Sand blasting and punching are carried out on the glass sheet, and the electrode part is released;
(3) Evaporating a platinum resistor on the upper surface of the glass sheet (namely forming the platinum resistor by a platinum evaporation process) to be used as a temperature sensor;
(4) Photoetching the glass sheet and aluminizing to lead out the electrical signals of the platinum resistor and the electrode hole;
after the silicon wafer and glass wafer are prepared, they are subjected to anodic bonding to form the structure shown in fig. 4E.
The electrode distribution diagram of the temperature and pressure integrated sensor is shown in fig. 5.
The temperature and pressure integrated sensor chip has 6 substrate electrodes, wherein 1,2,3 and 4 substrate electrodes are pressure sensor electrodes, and as shown in fig. 5, piezoresistive strips are arranged among the 4 electrodes to form a Wheatstone bridge, when pressure acts, the resistance in the Wheatstone bridge changes, and when a voltage is applied to the Wheatstone bridge, the pressure change is reflected on output, namely the output voltage linearly changes along with the input pressure. 5. And a platinum resistor is arranged between the substrate electrodes and is used for measuring temperature.
Referring to FIG. 7A, in an ideal case, when no pressure is applied, R is due to 1 、R 2 、R 3 And R is 4 The manufacturing process is the same, and the resistance values of the four piezoresistive strips are the same. Shadow of temperature on the four piezoresistive stripsIf the same occurs, the resistance is set to R, and the output of the Wheatstone bridge is zero.
Referring to fig. 7B, when external uniform pressure P acts on the temperature and pressure integrated sensor, the first silicon wafer is deformed, and each resistor has a variable resistance value Δr. Specifically, R 1 And R is 3 Reduction, R 2 And R is 4 Increasing. The changed resistance is set as R i ＇
R i ＇＝R i +(-1) i Δr, i=1, 2,3,4 equation 1
The wheatstone bridge equilibrium state at this point is destroyed and the sensor output is not zero. Let the voltage output value be V out ：
V out ＝V B -V D Equation 2
Because the bridge arm resistance is R, V under the ideal condition of no pressurization out =0; after the pressure P is applied, the output of the bridge changes to:
the normalized sensitivity of the pressure sensor can be obtained from equation 6 as:
as can be seen from equation 7, the output change of the pressure sensor is determined by the algebraic difference of the orthogonal stresses of the resistors under the unit pressure.
The temperature of the output of the pressure sensor is affected by temperature drift, so that the temperature of the output is required to be compensated, as shown in fig. 6, the temperature is typically compensated by a temperature compensation circuit of the pressure sensor, a platinum resistor is adopted for temperature acquisition, the pressure sensor and the platinum resistor are powered by a current source or a voltage source, the output of the pressure sensor enters a singlechip for voltage acquisition and processing, and the temperature information measured by the temperature sensor is used for compensating the output of the pressure sensor, so that the effect that the pressure sensor is insensitive to temperature is achieved. However, when the temperature of the external environment changes rapidly, the temperature sensed by the pressure sensor and the temperature sensor are inconsistent, so that a larger pressure measurement error can be introduced.
Compared with the prior art, the invention has at least one of the following beneficial effects:
1. the temperature and pressure integrated chip is designed, can be used for real-time monitoring of the tightness of the fiber-optic gyroscope, has good heat conduction due to the fact that the temperature sensor and the pressure sensor are integrated on the same silicon wafer, can measure in real time, and is accurate in pressure when the temperature of the external environment changes rapidly;
2. the temperature pressure chip is different from the traditional chip in that the piezoresistive strip is arranged in the vacuum cavity, but not on the surface of the chip, and the traditional pressure chip is characterized in that a layer of silicon oxide and a layer of silicon nitride are added for protecting the piezoresistive strip, wherein one layer provides compressive stress to the silicon wafer, and the other layer provides tensile stress to the silicon wafer, so that the balance between the compressive stress and the tensile stress is achieved;
3. the electrode and the pressure acting surface of the traditional pressure sensor are on the same side, the pressure of the scheme acts on the upper end of the chip, and the electrode is led out from the thick glass at the lower end of the chip, and the thick glass can well isolate the bonding stress, so that the pressure sensor has smaller bonding stress, and the long-term stability and the precision of the pressure sensor are theoretically higher than those of the scheme of the traditional chip;
4. the invention can be popularized to any monitoring scene needing to carry out temperature and pressure integrated measurement.
Those skilled in the art will appreciate that all or part of the flow of the methods of the embodiments described above may be accomplished by way of a computer program to instruct associated hardware, where the program may be stored on a computer readable storage medium. Wherein the computer readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (10)
1. The manufacturing method of the temperature and pressure integrated sensor is characterized by comprising the following steps of:
forming a plurality of piezoresistive strips in a first silicon wafer through an ion implantation process;
etching the quadrangular frustum pyramid cavity in the second silicon wafer by using an etching process;
bonding the first silicon wafer and the second silicon wafer through a first bonding process to form a silicon layer structure, wherein the plurality of piezoresistive strips face the top surface of the quadrangular frustum-shaped cavity;
forming a substrate through hole in a glass substrate by using a sand blasting punching process, and arranging a platinum resistor above the top surface of the glass substrate; and
and bonding the silicon layer structure with the glass substrate by using a second bonding process, wherein the platinum resistor faces the bottom surface of the quadrangular frustum-shaped cavity.
2. The method of fabricating a temperature and pressure integrated sensor of claim 1, wherein forming a plurality of piezoresistive strips in the first silicon die by an ion implantation process further comprises:
thinning the first silicon wafer through a grinding process;
forming a plurality of piezoresistive strips in the middle of the first silicon wafer through the ion implantation process;
forming a plurality of first extraction electrodes above the top surface of the first silicon wafer by utilizing an aluminizing process, wherein the first extraction electrodes are electrically connected with corresponding piezoresistive strips, and the aluminizing process comprises an electron beam evaporation aluminizing process or a magnetron sputtering aluminizing process.
3. The method for manufacturing a temperature and pressure integrated sensor according to claim 2, wherein etching the quadrangular frustum pyramid-shaped cavity in the second silicon wafer by using an etching process comprises:
etching the quadrangular frustum-shaped cavity in the second silicon wafer by utilizing a wet etching process, wherein the quadrangular frustum-shaped cavity penetrates through the second silicon wafer, the top surface of the quadrangular frustum-shaped cavity is a first square, the bottom surface of the quadrangular frustum-shaped cavity is a second square, and the area of the first square is smaller than that of the second square;
and forming an aluminum electrode on the side wall of the quadrangular frustum pyramid-shaped cavity part and the bottom surface of the second silicon wafer.
4. The method of manufacturing a temperature and pressure integrated sensor according to claim 3, wherein bonding the first silicon wafer and the second silicon wafer by a first bonding process to form a silicon layer structure comprises: and bonding the top surface of the first silicon wafer and the top surface of the second silicon wafer through the first bonding process to form the first silicon wafer into the top surface of the quadrangular frustum-shaped cavity, and taking the bonded first silicon wafer and second silicon wafer as a silicon layer structure, wherein the piezoresistive strips are positioned right above the square top surface of the quadrangular frustum-shaped cavity and positioned at four sides of the square top surface, and the first bonding process is a silicon-silicon bonding process.
5. The method of manufacturing a temperature and pressure integrated sensor according to claim 4, wherein forming a substrate through hole in a glass substrate using a sand blasting and punching process, and disposing a platinum resistor above a top surface of the glass substrate comprises:
forming a plurality of through holes in the glass substrate using the sand blasting and perforating process;
forming a platinum resistor over a top surface of the glass substrate as a temperature sensor, wherein the plurality of piezoresistive strips are spaced apart from the platinum resistor in horizontal and vertical directions;
and photoetching the glass substrate, aluminizing the top surface of the glass substrate to form a second extraction electrode, aluminizing the side walls of the substrate through holes to form a second substrate electrode for extracting the temperature electric signal of the platinum resistor, and simultaneously forming a first substrate electrode for extracting the pressure electric signal of the aluminum electrode.
6. The method of claim 5, wherein bonding the silicon layer structure to the glass substrate using a second bonding process comprises: and bonding the bottom surface of the silicon layer structure with the top surface of the glass substrate by using a second bonding process to form the bottom surface of the quadrangular frustum pyramid cavity, wherein the second bonding process is an anodic bonding process, and vacuumizing the quadrangular frustum pyramid cavity to enable the piezoresistive strips and the platinum resistor to be located in the same quadrangular frustum pyramid cavity.
7. The method of claim 5, wherein the plurality of piezoresistive strips comprises four piezoresistive strips, wherein,
the piezoresistance strips are connected into a Wheatstone bridge through the first extraction electrodes, and the pressure electric signals of the first extraction electrodes are extracted to the four first substrate through holes through the four aluminum electrodes, so that the singlechip collects the pressure electric signals through the four first substrate electrodes; and
and the temperature electric signals are led out to the two second substrate electrodes through the two second leading-out electrodes, so that the singlechip collects the temperature electric signals through the two second substrate electrodes.
8. A temperature and pressure integrated sensor, comprising:
a glass substrate including a platinum resistor on a top surface of the glass substrate and a plurality of substrate through holes in the glass substrate;
the silicon layer structure is positioned above the glass substrate and comprises a first silicon wafer and a second silicon wafer positioned below the first silicon wafer;
a plurality of piezoresistive strips are arranged on the bottom surface of the first silicon wafer; and
the second silicon wafer comprises a quadrangular frustum pyramid cavity, wherein the bottom surface of the first silicon wafer is used as the top surface of the quadrangular frustum pyramid cavity, and the top surface of the glass substrate is used as the bottom surface of the quadrangular frustum pyramid cavity, so that the plurality of piezoresistive strips and the platinum resistor are exposed in the quadrangular frustum pyramid cavity.
9. The temperature and pressure integrated sensor according to claim 8, wherein,
the quadrangular frustum pyramid cavity comprises a square top surface and a square bottom surface;
the plurality of piezoresistive strips are four piezoresistive strips, wherein,
the four piezoresistive strips are located at four sides of the square top surface and are connected into a wheatstone bridge through a plurality of first extraction electrodes located on the square top surface.
10. The temperature and pressure integrated sensor of claim 9, further comprising:
four aluminum electrodes positioned on the side wall of the quadrangular frustum pyramid cavity and the bottom surface of the second silicon wafer;
four first substrate electrodes located right below corners of the square top surface and on side walls of four substrate through holes of the plurality of substrate through holes, connected with the four piezoresistive strips through the plurality of first extraction electrodes and the four aluminum electrodes;
two second extraction electrodes positioned on both sides of the platinum resistor on the top surface of the glass substrate;
and the two second substrate electrodes are positioned on the side walls of two substrate through holes in the plurality of substrate through holes and are connected with the platinum resistor through the two extraction electrodes.
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| CN202311873840.4A CN117782223A (en) | 2023-12-29 | 2023-12-29 | Temperature and pressure integrated sensor and manufacturing method thereof |
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| CN202311873840.4A CN117782223A (en) | 2023-12-29 | 2023-12-29 | Temperature and pressure integrated sensor and manufacturing method thereof |
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