CN114544046A - Pressure sensor and preparation method thereof - Google Patents
Pressure sensor and preparation method thereof Download PDFInfo
- Publication number
- CN114544046A CN114544046A CN202111581041.0A CN202111581041A CN114544046A CN 114544046 A CN114544046 A CN 114544046A CN 202111581041 A CN202111581041 A CN 202111581041A CN 114544046 A CN114544046 A CN 114544046A
- Authority
- CN
- China
- Prior art keywords
- force
- silicon wafer
- silicon
- sensitive resistor
- pressure sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000002360 preparation method Methods 0.000 title abstract description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 187
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 187
- 239000010703 silicon Substances 0.000 claims abstract description 187
- 238000000034 method Methods 0.000 claims description 24
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 21
- YOCUPQPZWBBYIX-UHFFFAOYSA-N copper nickel Chemical compound [Ni].[Cu] YOCUPQPZWBBYIX-UHFFFAOYSA-N 0.000 claims description 21
- 239000000843 powder Substances 0.000 claims description 18
- 239000011248 coating agent Substances 0.000 claims description 17
- 238000000576 coating method Methods 0.000 claims description 17
- 239000000758 substrate Substances 0.000 claims description 15
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 238000004528 spin coating Methods 0.000 claims description 10
- 238000005530 etching Methods 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 238000002844 melting Methods 0.000 claims description 4
- 230000008018 melting Effects 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 239000002861 polymer material Substances 0.000 claims description 4
- 239000002243 precursor Substances 0.000 claims description 4
- 239000012528 membrane Substances 0.000 claims 1
- 238000012544 monitoring process Methods 0.000 abstract description 18
- 239000010408 film Substances 0.000 description 61
- 239000004205 dimethyl polysiloxane Substances 0.000 description 18
- 235000013870 dimethyl polysiloxane Nutrition 0.000 description 18
- CXQXSVUQTKDNFP-UHFFFAOYSA-N octamethyltrisiloxane Chemical compound C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C CXQXSVUQTKDNFP-UHFFFAOYSA-N 0.000 description 18
- 238000004987 plasma desorption mass spectroscopy Methods 0.000 description 18
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 description 18
- 238000005516 engineering process Methods 0.000 description 17
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 11
- 238000009826 distribution Methods 0.000 description 11
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- 239000010949 copper Substances 0.000 description 9
- 239000011521 glass Substances 0.000 description 7
- 238000002156 mixing Methods 0.000 description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 6
- 239000010931 gold Substances 0.000 description 5
- 238000001259 photo etching Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 238000007872 degassing Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 238000007790 scraping Methods 0.000 description 4
- 238000010023 transfer printing Methods 0.000 description 4
- 230000007774 longterm Effects 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 229910002065 alloy metal Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- FFBHFFJDDLITSX-UHFFFAOYSA-N benzyl N-[2-hydroxy-4-(3-oxomorpholin-4-yl)phenyl]carbamate Chemical compound OC1=C(NC(=O)OCC2=CC=CC=C2)C=CC(=C1)N1CCOCC1=O FFBHFFJDDLITSX-UHFFFAOYSA-N 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000007888 film coating Substances 0.000 description 1
- 238000009501 film coating Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/18—Measuring force or stress, in general using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Pressure Sensors (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The application relates to a pressure sensor, which comprises a silicon chip and a flexible film, wherein one side of the silicon chip is provided with at least one force sensitive resistor, the flexible film covers the silicon chip, and the thickness of the flexible film is greater than or equal to that of the silicon chip. The application also relates to a preparation method of the pressure sensor, which comprises the steps of providing a silicon wafer, wherein one side of the silicon wafer is provided with at least one force-sensitive resistor; and forming a flexible film coated with the silicon wafer to obtain the pressure sensor. The force-sensitive element that this application was made the silicon chip is embedded in flexible film, can improve the flexibility of device, reduces the device itself to the pressure interference of monitoring environment, can realize the accurate monitoring to contact interface pressure.
Description
Technical Field
The application relates to the technical field of pressure sensors, in particular to a pressure sensor and a preparation method thereof.
Background
The basic principle of measuring the contact pressure between the contact surfaces of two objects is to string a force-sensitive element into the force system structure, and the intervention of the force-sensitive element will cause a change in the environment of the system under test. However, in the prior art, the pressure sensor made based on the silicon wafer is generally made of the silicon wafer on the surface of the substrate, so that the whole thickness of the device is large, the flexibility is poor, the pressure sensor has strong pressure interference on the monitoring environment, and accurate monitoring of the pressure of the contact interface is difficult to realize.
Disclosure of Invention
In order to solve the technical problems, the application provides a pressure sensor and a preparation method thereof, wherein a force-sensitive element made of a silicon wafer is embedded in a flexible film, so that the flexibility of a device can be improved, the pressure interference of the device to a monitoring environment is reduced, and the accurate monitoring of the pressure of a contact interface can be realized.
In order to solve the technical problem, the application provides a pressure sensor, including silicon chip and flexible film, one side of silicon chip sets up an at least force sensing resistor, the cladding of flexible film the silicon chip, the thickness of flexible film is more than or equal to the thickness of silicon chip.
Optionally, a cavity is disposed on the other side of the silicon wafer, and the force-sensitive resistor is located in a projection area of the cavity along the thickness direction of the silicon wafer.
Optionally, the depth of the cavity is 2 μm to 5 μm, the thickness of the flexible thin film is 5 μm to 10 μm, and the thickness of the silicon wafer is less than 10 μm.
Optionally, a circuit is disposed on a side surface of the flexible film corresponding to the force-sensitive resistor, and one end of the circuit is connected to the force-sensitive resistor.
The application also provides a preparation method of the pressure sensor, which comprises the following steps:
a. providing a silicon wafer, wherein one side of the silicon wafer is provided with at least one force-sensitive resistor;
b. and forming a flexible film for coating the silicon wafer to obtain the pressure sensor.
Optionally, the step a includes:
a1. providing an SOI silicon chip, wherein a buried oxide layer of the SOI silicon chip separates the SOI silicon chip into upper silicon and lower silicon;
a2. forming at least one force sensitive resistor on one side surface of the upper silicon layer;
a3. and etching to remove the oxygen burying layer to obtain the upper silicon containing the force sensitive resistor as the silicon wafer.
Optionally, the a2 step, including:
a21. uniformly blade-coating nickel-copper alloy powder on the upper surface of the SOI silicon wafer;
a22. and melting the nickel-copper alloy powder positioned in the designated area through laser direct writing to form a uniform conductive layer, thereby obtaining the force-sensitive resistor.
Optionally, the step b includes:
b1. transferring the silicon wafer separated from the underlying silicon by a substrate having a flexible coating such that a side of the silicon wafer having the force-sensitive resistor is in contact with the flexible coating;
b2. and spin-coating a precursor solution of a high polymer material on the surface of one side of the substrate with the silicon wafer, and then curing to form the flexible film.
Optionally, after the step b2, the method further includes:
b3. and forming a cavity on one side of the silicon chip far away from the force-sensitive resistor, so that the force-sensitive resistor is positioned in a projection area of the cavity along the thickness direction of the silicon chip.
Optionally, the step b further includes:
b4. peeling the flexible film and the silicon wafer from the substrate;
b5. and manufacturing a circuit on one side of the flexible film corresponding to the force sensitive resistor, and connecting one end of the circuit with the force sensitive resistor.
The pressure sensor comprises a silicon wafer and a flexible film, wherein at least one force sensitive resistor is arranged on one side of the silicon wafer, the flexible film covers the silicon wafer, and the thickness of the flexible film is larger than or equal to that of the silicon wafer. The application also relates to a preparation method of the pressure sensor, which comprises the steps of providing a silicon wafer, wherein one side of the silicon wafer is provided with at least one force-sensitive resistor; and forming a flexible film coated with the silicon wafer to obtain the pressure sensor. The force-sensitive element made of the silicon chip is embedded in the flexible film, so that the flexibility of the device can be improved, the pressure interference of the device to the monitoring environment is reduced, and the accurate monitoring of the pressure of the contact interface can be realized.
Drawings
Fig. 1 is a schematic structural view of a pressure sensor shown according to a first embodiment;
fig. 2 is a schematic flow chart showing a method of manufacturing a pressure sensor according to a second embodiment;
fig. 3 is a process diagram illustrating a method of manufacturing a pressure sensor according to a second embodiment.
Detailed Description
The following description of the embodiments of the present application is provided for illustrative purposes, and other advantages and capabilities of the present application will become apparent to those skilled in the art from the present disclosure.
In the following description, reference is made to the accompanying drawings that describe several embodiments of the application. It is to be understood that other embodiments may be utilized and that mechanical, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present application. The following detailed description is not to be taken in a limiting sense, and the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
Although the terms first, second, etc. may be used herein to describe various elements in some instances, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.
Also, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used in this specification, specify the presence of stated features, steps, operations, elements, components, items, species, and/or groups, but do not preclude the presence, or addition of one or more other features, steps, operations, elements, components, species, and/or groups thereof. The terms "or" and/or "as used herein are to be construed as inclusive or meaning any one or any combination. Thus, "A, B or C" or "A, B and/or C" means "any of the following: a; b; c; a and B; a and C; b and C; A. b and C ". An exception to this definition will occur only when a combination of elements, functions, steps or operations are inherently mutually exclusive in some way.
First embodiment
Fig. 1 is a schematic structural view of a pressure sensor shown according to a first embodiment. As shown in fig. 1, the pressure sensor of the present embodiment includes a silicon chip 10 and a flexible film 11, and at least one force-sensitive resistor 12 is disposed on one side of the silicon chip 10. The flexible film 11 covers the silicon wafer 10, and the thickness of the flexible film 11 is larger than or equal to that of the silicon wafer 10.
This application passes through the embedding technique, with the embedding of force sensing element inside flexible film, the pressure sensor who so forms has good flexibility, has reduced the device itself to the pressure interference of monitoring environment, can realize the accurate monitoring to contact interface pressure.
In the present embodiment, the Silicon wafer 10 is made of an SOI (Silicon-On-Insulator) Silicon wafer. The buried oxide layer of the SOI silicon wafer divides the SOI silicon wafer into upper silicon and lower silicon, and the thickness of the upper silicon in the SOI silicon wafer is smaller than that of the lower silicon. In this example, after removing the buried oxide layer by etching, an ultra-thin upper layer silicon was obtained as the silicon wafer 10. Preferably, the thickness of the silicon wafer 10 is less than 10 μm. Therefore, the silicon wafer is embedded in the flexible film, so that the ultra-thin flexible pressure sensor is realized, the device has good flexibility, the pressure monitoring of the environments such as a curved surface and a narrow gap can be realized, and the gap contact is hardly influenced.
The distribution positions of the force-sensitive resistors 12 are determined according to the stress-strain distribution state of the surface of the silicon wafer 10, and the stress-strain distribution state of the surface of the silicon wafer 10 can be obtained through mechanical model simulation analysis. Alternatively, a laser direct writing technique may be used to fabricate a metal electrode on one side surface of the silicon wafer 10 as the force-sensitive resistor 12. Specifically, the force-sensitive resistor 12 may be obtained by uniformly coating a metal powder or an alloy powder on the upper surface of the silicon wafer 10 by a doctor blade method, and then melting the metal powder or the alloy powder located in a designated area for forming the force-sensitive resistor 12 by a laser direct writing technique to form a uniform conductive layer. The material of the force-sensitive resistor 12 can be copper, silver, nickel, or other metal or alloy metal. The nickel-copper alloy is sensitive to stress change and insensitive to temperature change, and is preferably selected from the nickel-copper alloy, wherein the mass fraction of nickel is 20-55%, and the mass fraction of copper is 45-80%.
Optionally, a cavity 101 may be further disposed on a side of the silicon wafer 10 away from the force-sensitive resistor 12, and the force-sensitive resistor 12 is located in a projection area of the cavity 101 along the thickness direction of the silicon wafer 10. The shape of the cavity 101 may match the shape of the silicon wafer 10, such as a circle or a rectangle. Preferably, the position of the flexible film 11 corresponding to the cavity 101 is hollowed out, that is, the area where the flexible film 11 does not cover the cavity 101.
According to the method, the thickness of the silicon chip 10 in the area corresponding to the force sensitive resistor 12 in the silicon chip 10 is further reduced by utilizing the cavity 13, so that the deformation degree of the pressure sensor is increased when the pressure sensor is stressed, and the pressure measuring sensitivity of a device is improved.
Alternatively, the depth of the cavity 101 is 2 μm to 5 μm, the thickness of the flexible film 11 is 5 μm to 10 μm, and the thickness of the silicon wafer 10 is less than or equal to 10 μm, so that the overall thickness of the device is less than or equal to 10 μm, and better flexibility can be obtained.
Optionally, a circuit 13 is disposed on a side surface of the flexible film 11 corresponding to the force-sensitive resistor 12, and one end of the circuit 13 is connected to the force-sensitive resistor 12. Since the side of the silicon chip 10 having the force-sensitive resistor 12 is connected to the flexible film 11 to form a continuous plane, the circuit 13 can be prepared by photolithography to output the signal of the force-sensitive resistor 12. The material of the circuit 13 may be gold, copper, aluminum, or other metals.
The pressure sensor comprises a silicon wafer and a flexible film, wherein at least one force sensitive resistor is arranged on one side of the silicon wafer, the flexible film covers the silicon wafer, and the thickness of the flexible film is larger than or equal to that of the silicon wafer. The force-sensitive element made of the silicon chip is embedded in the flexible film, so that the flexibility of the device can be improved, the pressure interference of the device to the monitoring environment is reduced, and the accurate monitoring of the pressure of the contact interface can be realized.
Second embodiment
Fig. 2 is a schematic flow chart showing a method of manufacturing the pressure sensor according to the second embodiment. As shown in fig. 2, the method for manufacturing a pressure sensor of the present embodiment includes the following steps:
step a, providing a silicon chip, wherein one side of the silicon chip is provided with at least one force-sensitive resistor.
Optionally, step a includes:
step a1. as shown in fig. 3 (a), an SOI silicon wafer is provided, comprising an upper layer of silicon 21, a buried oxide layer 22 and a lower layer of silicon 23. The buried oxide layer 22 separates the SOI silicon wafer into upper layer silicon 21 and lower layer silicon 23, the thickness of the upper layer silicon 21 in the SOI silicon wafer is smaller than that of the lower layer silicon 23, and the thickness of the upper layer silicon 21 is smaller than or equal to 10 μm.
Step a2. as shown in fig. 3 (b), at least one force-sensitive resistor 31 is formed on one side surface of the upper silicon 21.
Optionally, step a2 further includes:
and step a21, uniformly scraping the nickel-copper alloy powder on the upper surface of the SOI silicon chip.
And a step a22, melting the nickel-copper alloy powder in the designated area through laser direct writing to form a uniform conductive layer, so as to obtain the force-sensitive resistor 31.
Step a3. etches away the buried oxide layer 22 to obtain the upper silicon 21 containing the force sensitive resistor 31 as a silicon wafer.
In this embodiment, the distribution state of the surface stress strain of the upper silicon 21 in the SOI silicon wafer is analyzed by a mechanical model to determine the distribution position of the force-sensitive resistor 31 on the surface of the upper silicon 21, and then the laser direct writing technique is used to directly write a metal electrode on the surface of the upper silicon 21 to form the force-sensitive resistor 31. The material of the force-sensitive resistor 31 may be metal or metal alloy such as silver, copper, nickel, etc. Since the nickel-copper alloy is sensitive to stress variation and insensitive to temperature variation, the present embodiment preferably uses the nickel-copper alloy for manufacturing the force-sensitive resistor 31, wherein the mass fraction of nickel is 20% to 55%, and the mass fraction of copper is 45% to 80%. Specifically, nickel-copper alloy powder is uniformly coated on the surface of the upper silicon 21, then the force-sensitive resistor 31 is prepared by adopting a laser direct writing technology, and the nickel-copper alloy powder is melted under the action of laser heat to form a uniform conductive layer to serve as the force-sensitive resistor 31. The laser wavelength is 355-1064 nm, the power range is 1-20W, the scanning speed is 50-2000 mm/s, the scanning frequency is 1-20, and a laser with the wavelength of 1064nm is preferred, so that the metal powder can be melted and clad on the surface of a silicon wafer by utilizing the photo-thermal effect of the laser, and the conductivity of the metal powder and the bonding force between the metal powder and the silicon wafer are improved.
The SOI silicon wafer is etched with a BOE solution, and the buried oxide layer 22 of the SOI silicon wafer is etched away to obtain the upper silicon layer 21 including the force sensitive resistor 31 as a silicon wafer (i.e., the silicon wafer 30 shown in FIG. 3 (e)).
And b, forming a flexible film coating the silicon wafer to obtain the pressure sensor.
Alternatively, as shown in fig. 3 (e), step b includes:
b1, transferring the silicon wafer 30 separated from the lower silicon layer through the substrate 40 with the flexible coating 41, so that the side of the silicon wafer 30 with the force-sensitive resistor 31 is in contact with the flexible coating 41.
In this embodiment, as shown in fig. 3 (c), a substrate 40 is provided, and the substrate 40 may be a clean glass sheet. As shown in fig. 3 (d), the flexible coating 41 on the substrate 40 may be a PDMS film, specifically, a PDMS monomer and a curing agent are mixed in a ratio of 10: 1, uniformly mixing, degassing, spin-coating on the surface of the substrate 40, and curing at the temperature of 80-200 ℃ for 0.5-6 h to form a PDMS film, namely the flexible coating 41. As shown in fig. 3 (e), the silicon wafer 30 is transferred to the surface of the flexible coating 41, and the side of the silicon wafer 30 having the force-sensitive resistors 31 is in contact with the flexible coating 41.
Step b2. as shown in fig. 3 (f), spin coating a precursor solution of a polymer material on the surface of the substrate 40 having the silicon wafer 30, and then curing to form the flexible film 32.
In this embodiment, a PI solution is selected as a precursor solution of the polymer material. The PI solution is coated on the surface of the substrate 40 with the silicon wafer 30 in a spinning mode at the speed of 2000-4000 rmp, and the PI solution is solidified for 0.5-3 hours at the temperature of 80-250 ℃ to form the flexible film 32, so that the silicon wafer is embedded in the flexible film 32, and the overall flexibility of the device is improved.
Optionally, as shown in (g) in fig. 3, after step b2, the method further includes:
step b3. forms a cavity 301 on the side of the silicon die 30 remote from the force-sensitive resistor 31 such that the force-sensitive resistor 31 is located within the projected area of the cavity 301 in the thickness direction of the silicon die 30.
In this embodiment, a laser scanning technique is used to etch a cavity 301 on the upper surface of the flexible film 32, and the cavity 301 may be circular. Wherein, the thickness of the flexible film 32 is 5 μm to 10 μm, the depth of the cavity is 2 μm to 5 μm, and the laser parameters are as follows: the wavelength is 355-1064 nm, the power range is 1-20W, and the scanning speed is 50-2000 mm/s.
According to the silicon chip thickness measuring device, the thickness of the silicon chip 30 in the area corresponding to the force sensitive resistor 31 in the silicon chip 30 is further reduced by utilizing the cavity 301, so that the deformation degree of the pressure sensor is increased when the pressure sensor is stressed, and the pressure measuring sensitivity of the device is improved.
Optionally, as shown in (g) and (h) of fig. 3, step b, further includes:
step b4. peels the flexible film 32 and silicon wafer 30 from the substrate 40.
Step b5. is to form a circuit 33 on the side of the flexible film 32 corresponding to the force sensitive resistor 31 and to connect one end of the circuit 33 to the force sensitive resistor 31.
In this embodiment, the flexible film 32 with the silicon wafer 30 is peeled off from the surface of the flexible coating 41. Then, the circuit 33 can be prepared by photolithography technique, and the signal generated by the force-sensitive resistor 31 is outputted. The material of the circuit 13 may be gold, copper, aluminum, or other metals.
The pressure sensor is prepared by adopting a method of combining the laser direct writing technology and the transfer printing technology, the force sensitive resistor is prepared by utilizing the characteristics of high efficiency, high selectivity and high precision of the laser direct writing technology, the defects of complex process, high cost, environmental pollution and the like in the traditional photoetching technology (steps of ion implantation, photoetching and the like) are overcome, and the rapid and low-cost preparation of the force sensitive resistor is realized.
The following describes a method for manufacturing the pressure sensor of the present application by specifically describing three processes.
The process 1 comprises the following steps:
(1) preparing a force sensitive resistor: analyzing the stress-strain distribution state of the surface of the silicon wafer through a mechanical model, determining that the force-sensitive resistors are in a cross distribution state on the surface of the silicon wafer, directly writing nickel-copper alloy on the surface of the SOI silicon wafer by adopting a laser direct writing technology to serve as the force-sensitive resistors, uniformly scraping nickel-copper alloy powder (mass fraction: 45% of Ni and 55% of Cu) on the surface of the SOI silicon wafer, and then preparing the force-sensitive resistors by adopting the laser direct writing technology, wherein the laser wavelength is 1064nm, the power range is 10W, the scanning speed is 50mm/s, and the scanning frequency is 1, so that a nickel-copper alloy resistor strip graph is formed.
(2) Force sensitive resistance transfer printing: mixing PDMS monomer and curing agent according to the proportion of 10: 1, uniformly mixing, degassing, spin-coating on the surface of a clean glass sheet, curing at 80 ℃ for 6 hours to form a PDMS film, then adopting a BOE solution to corrode the SOI silicon sheet with the force-sensitive resistor in the step (1), after a buried oxide layer in the middle of the SOI silicon sheet is corroded and removed, transferring upper silicon (10 mu m) to the surface of the PDMS film, and contacting the side of the force-sensitive resistor in the silicon sheet with the PDMS film.
(3) Preparing a cavity: and spin-coating a PI solution on the surface of a glass sheet with a silicon sheet side at the speed of 2000rmp, curing for 0.5h at the temperature of 250 ℃ to form a flexible film, and embedding the silicon sheet in the flexible film. And then, etching a circular cavity structure on the upper surface of the silicon chip by adopting a laser scanning technology, wherein the thickness of the silicon chip is 10 microns, the depth of the cavity is 5 microns, and the laser parameters are as follows: the wavelength was 355nm, the power range was 2W, and the scanning speed was 500 mm/s.
(4) Preparing a circuit: the flexible film is peeled off from the surface of the PDMS film, an Au conducting circuit is prepared by adopting a photoetching technology, signals generated by the force sensitive resistor are output, and the thickness of the finally prepared flexible pressure sensor is about 10 mu m, so that the flexible pressure sensor is suitable for long-term real-time monitoring of narrow-gap pressure.
And (2) a process:
(1) preparing a force sensitive resistor: analyzing the stress-strain distribution state of the silicon wafer surface through a mechanical model, determining that the force-sensitive resistors are in a cross distribution state on the silicon wafer surface, directly writing nickel-copper alloy on the SOI silicon wafer surface by adopting a laser direct writing technology to serve as the force-sensitive resistors, uniformly coating nickel-copper alloy powder (mass fraction: 20% of Ni and 80% of Cu) on the SOI silicon wafer surface by scraping, and then preparing the force-sensitive resistors by adopting the laser direct writing technology, wherein the laser wavelength is 532nm, the power range is 15W, the scanning speed is 100mm/s, and the scanning times are 3, so that a nickel-copper alloy resistor strip graph is formed.
(2) Force sensitive resistance transfer printing: mixing PDMS monomer and curing agent according to the weight ratio of 10: 1, uniformly mixing, degassing, spin-coating on the surface of a clean glass sheet, curing at 80 ℃ for 6 hours to form a PDMS film, then adopting a BOE solution to corrode the SOI silicon wafer prepared in the step (1), after corroding and removing an oxygen buried layer in the middle of the SOI silicon wafer, transferring upper silicon onto the surface of the PDMS film, and enabling the side of the force sensitive resistor in the silicon wafer to be in contact with the PDMS film.
(3) Preparing a cavity: and spin-coating a PI solution on the surface of a glass sheet with a silicon sheet side at the speed of 2000rmp, curing for 0.5h at the temperature of 250 ℃ to form a flexible film, and embedding the silicon sheet in the flexible film. And then, etching a circular cavity structure on the upper surface of the silicon chip by adopting a laser scanning technology, wherein the thickness of the silicon chip is 5 microns, the depth of the cavity is 2 microns, and the laser parameters are as follows: the wavelength was 355nm, the power range was 2W, and the scanning speed was 500 mm/s.
(4) Preparing a circuit: the flexible film I is stripped from the surface of the PDMS film, an Au conducting circuit is prepared by adopting a photoetching technology, signals generated by the force sensitive resistor are output, and the thickness of the finally prepared flexible pressure sensor is about 5 mu m, so that the flexible pressure sensor is suitable for long-term real-time monitoring of narrow-gap pressure.
And (3) a process:
(1) preparing a force sensitive resistor: analyzing the stress-strain distribution state of the surface of the silicon wafer through a mechanical model, determining that the force-sensitive resistors are in a cross distribution state on the surface of the silicon wafer, adopting a laser direct writing technology to directly write nickel-copper alloy on the surface as the force-sensitive resistors, uniformly scraping nickel-copper alloy powder (mass fraction: 50% of Ni and 50% of Cu) on the surface of the SOI silicon wafer, then adopting the laser direct writing technology to prepare the force-sensitive resistors, wherein the laser wavelength is 355nm, the power range is 20W, the scanning speed is 200mm/s, and the scanning frequency is 10, so that a nickel-copper alloy resistor strip graph is formed.
(2) Force sensitive resistance transfer printing: mixing PDMS monomer and curing agent according to the weight ratio of 10: 1, uniformly mixing, degassing, spin-coating on the surface of a clean glass sheet, curing at 150 ℃ for 2h to form a PDMS film, then adopting a BOE solution to corrode the SOI silicon wafer prepared in the step (1), after corroding and removing an oxygen buried layer in the middle of the SOI silicon wafer, transferring upper silicon onto the surface of the PDMS film, and contacting the force sensitive resistor side of the silicon wafer with the PDMS film.
(3) Preparing a cavity: and spin-coating a PI solution on the surface of a glass sheet with a silicon sheet side at the speed of 2000rmp, curing for 0.5h at the temperature of 250 ℃ to form a flexible film, and embedding the silicon sheet in the flexible film. And then, etching a circular cavity structure on the upper surface of the silicon chip by adopting a laser scanning technology, wherein the thickness of the silicon chip is 8 mu m, the depth of the cavity is 4 mu m, and the laser parameters are as follows: the wavelength was 355nm, the power range was 2W, and the scanning speed was 500 mm/s.
(4) Preparing a circuit: the flexible film is peeled off from the surface of the PDMS film, an Au conducting circuit is prepared by adopting a photoetching technology, signals generated by the force sensitive resistor are output, and the thickness of the finally prepared flexible pressure sensor is about 8 mu m, so that the flexible pressure sensor is suitable for long-term real-time monitoring of narrow-gap pressure.
The preparation method of the pressure sensor comprises the following steps: providing a silicon chip, wherein one side of the silicon chip is provided with at least one force-sensitive resistor; and forming a flexible film coated with the silicon wafer to obtain the pressure sensor. The force-sensitive element made of the silicon wafer is embedded in the flexible film, so that the flexibility of the device can be improved, the pressure interference of the device to the monitoring environment is reduced, and the accurate monitoring of the pressure of the contact interface can be realized.
The above embodiments are merely illustrative of the principles and utilities of the present application and are not intended to limit the application. Any person skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present application. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical concepts disclosed in the present application shall be covered by the claims of the present application.
Claims (10)
1. The pressure sensor is characterized by comprising a silicon chip and a flexible film, wherein at least one force sensitive resistor is arranged on one side of the silicon chip, the flexible film coats the silicon chip, and the thickness of the flexible film is greater than or equal to that of the silicon chip.
2. The pressure sensor of claim 1, wherein a cavity is provided on the other side of the silicon wafer, and the force sensitive resistor is located in a projected area of the cavity in a thickness direction of the silicon wafer.
3. The pressure sensor of claim 2, wherein the cavity has a depth of 2 μm to 5 μm, the flexible membrane has a thickness of 5 μm to 10 μm, and the silicon wafer has a thickness of less than 10 μm.
4. The pressure sensor of claim 1, wherein a side surface of the flexible film corresponding to the force sensitive resistor is provided with an electric circuit, and one end of the electric circuit is connected to the force sensitive resistor.
5. A method for manufacturing a pressure sensor is characterized by comprising the following steps:
a. providing a silicon wafer, wherein one side of the silicon wafer is provided with at least one force-sensitive resistor;
b. and forming a flexible film for coating the silicon wafer to obtain the pressure sensor.
6. The method for manufacturing a pressure sensor according to claim 5, wherein the step a comprises:
a1. providing an SOI silicon chip, wherein a buried oxide layer of the SOI silicon chip separates the SOI silicon chip into upper silicon and lower silicon;
a2. forming at least one force sensitive resistor on one side surface of the upper silicon layer;
a3. and etching to remove the oxygen burying layer to obtain the upper silicon containing the force sensitive resistor as the silicon wafer.
7. The method for preparing a pressure sensor according to claim 6, wherein the step a2 includes:
a21. uniformly blade-coating nickel-copper alloy powder on the upper surface of the SOI silicon wafer;
a22. and melting the nickel-copper alloy powder positioned in the designated area through laser direct writing to form a uniform conductive layer, thereby obtaining the force-sensitive resistor.
8. The method for manufacturing a pressure sensor according to claim 6, wherein the step b includes:
b1. transferring the silicon wafer separated from the underlying silicon by a substrate having a flexible coating such that a side of the silicon wafer having the force-sensitive resistor is in contact with the flexible coating;
b2. and spin-coating a precursor solution of a high polymer material on the surface of one side of the substrate with the silicon wafer, and then curing to form the flexible film.
9. The method for preparing a pressure sensor according to claim 8, wherein after the step b2, the method further comprises:
b3. and forming a cavity on one side of the silicon chip far away from the force-sensitive resistor, so that the force-sensitive resistor is positioned in a projection area of the cavity along the thickness direction of the silicon chip.
10. The method for manufacturing a pressure sensor according to claim 8 or 9, wherein the step b further comprises:
b4. peeling the flexible film and the silicon wafer from the substrate;
b5. and manufacturing a circuit on one side of the flexible film corresponding to the force-sensitive resistor, and connecting one end of the circuit with the force-sensitive resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111581041.0A CN114544046B (en) | 2021-12-22 | 2021-12-22 | Method for manufacturing pressure sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111581041.0A CN114544046B (en) | 2021-12-22 | 2021-12-22 | Method for manufacturing pressure sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114544046A true CN114544046A (en) | 2022-05-27 |
| CN114544046B CN114544046B (en) | 2023-12-19 |
Family
ID=81669604
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111581041.0A Active CN114544046B (en) | 2021-12-22 | 2021-12-22 | Method for manufacturing pressure sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114544046B (en) |
Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0719975A (en) * | 1993-06-30 | 1995-01-20 | Mitsui Eng & Shipbuild Co Ltd | Pressure sensor chip, tactile sensor and manufacture of tactile sensor |
| JPH09307119A (en) * | 1996-05-17 | 1997-11-28 | Denso Corp | Manufacture of semiconductor mechanical quantity sensor |
| EP0895276A1 (en) * | 1997-07-31 | 1999-02-03 | STMicroelectronics S.r.l. | Process for manufacturing integrated microstructures of single-crystal semiconductor material |
| JP2002071475A (en) * | 2000-08-30 | 2002-03-08 | Olympus Optical Co Ltd | Pressure-sensitive sensor and manufacturing method thereof |
| WO2003065926A2 (en) * | 2001-07-16 | 2003-08-14 | Irvine Sensors Corporation | Wearable biomonitor with flexible thinned integrated circuit |
| JP2005201860A (en) * | 2004-01-19 | 2005-07-28 | Komyo Rikagaku Kogyo Kk | Gas sensor, and exhaust gas analyzer |
| CN101271028A (en) * | 2008-04-18 | 2008-09-24 | 中国科学院上海微系统与信息技术研究所 | Silicon pressure transducer chip and method based on silicon-silicon linking and silicon-on-insulating layer |
| US7998777B1 (en) * | 2010-12-15 | 2011-08-16 | General Electric Company | Method for fabricating a sensor |
| CN102419226A (en) * | 2011-09-07 | 2012-04-18 | 东北大学 | Thin flexible pressure sensor sensitive unit based on flatfish type electrode structure |
| CN107063520A (en) * | 2017-01-05 | 2017-08-18 | 中南大学 | Flexible piezoresistance sensor and its method of production based on built-in electrode |
| CN107673306A (en) * | 2017-08-12 | 2018-02-09 | 北方电子研究院安徽有限公司 | A kind of preparation method of MEMS pressure sensor |
| CN109238519A (en) * | 2018-10-22 | 2019-01-18 | 河北工业大学 | A kind of hybrid flexible touch sensation sensor |
| WO2019218552A1 (en) * | 2018-05-17 | 2019-11-21 | 浙江欧仁新材料有限公司 | Flexible pressure sensor and preparation method therefor |
| EP3581903A1 (en) * | 2018-06-14 | 2019-12-18 | Melexis Technologies NV | N-implant electrical shield for piezo-resistor sensor |
| CN112146796A (en) * | 2020-09-17 | 2020-12-29 | 有研工程技术研究院有限公司 | Flexible stress sensor and preparation method thereof |
-
2021
- 2021-12-22 CN CN202111581041.0A patent/CN114544046B/en active Active
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0719975A (en) * | 1993-06-30 | 1995-01-20 | Mitsui Eng & Shipbuild Co Ltd | Pressure sensor chip, tactile sensor and manufacture of tactile sensor |
| JPH09307119A (en) * | 1996-05-17 | 1997-11-28 | Denso Corp | Manufacture of semiconductor mechanical quantity sensor |
| EP0895276A1 (en) * | 1997-07-31 | 1999-02-03 | STMicroelectronics S.r.l. | Process for manufacturing integrated microstructures of single-crystal semiconductor material |
| JP2002071475A (en) * | 2000-08-30 | 2002-03-08 | Olympus Optical Co Ltd | Pressure-sensitive sensor and manufacturing method thereof |
| WO2003065926A2 (en) * | 2001-07-16 | 2003-08-14 | Irvine Sensors Corporation | Wearable biomonitor with flexible thinned integrated circuit |
| JP2005201860A (en) * | 2004-01-19 | 2005-07-28 | Komyo Rikagaku Kogyo Kk | Gas sensor, and exhaust gas analyzer |
| CN101271028A (en) * | 2008-04-18 | 2008-09-24 | 中国科学院上海微系统与信息技术研究所 | Silicon pressure transducer chip and method based on silicon-silicon linking and silicon-on-insulating layer |
| US7998777B1 (en) * | 2010-12-15 | 2011-08-16 | General Electric Company | Method for fabricating a sensor |
| CN102419226A (en) * | 2011-09-07 | 2012-04-18 | 东北大学 | Thin flexible pressure sensor sensitive unit based on flatfish type electrode structure |
| CN107063520A (en) * | 2017-01-05 | 2017-08-18 | 中南大学 | Flexible piezoresistance sensor and its method of production based on built-in electrode |
| CN107673306A (en) * | 2017-08-12 | 2018-02-09 | 北方电子研究院安徽有限公司 | A kind of preparation method of MEMS pressure sensor |
| WO2019218552A1 (en) * | 2018-05-17 | 2019-11-21 | 浙江欧仁新材料有限公司 | Flexible pressure sensor and preparation method therefor |
| EP3581903A1 (en) * | 2018-06-14 | 2019-12-18 | Melexis Technologies NV | N-implant electrical shield for piezo-resistor sensor |
| CN109238519A (en) * | 2018-10-22 | 2019-01-18 | 河北工业大学 | A kind of hybrid flexible touch sensation sensor |
| CN112146796A (en) * | 2020-09-17 | 2020-12-29 | 有研工程技术研究院有限公司 | Flexible stress sensor and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| KIRAN KUMAR SAPPATI 等: "0-3 Polymer/Barium Titanate Nano Structures Based Flexible Piezoelectric Film", 《2018 INTERNATIONAL FLEXIBLE ELECTRONICS TECHNOLOGY CONFERENCE (IFETC)》, pages 1 - 2 * |
| 杜琦峰: "激光表面改性聚酰亚胺关键技术与机理研究", 《中国博士学位论文全文数据库基础科学辑》, no. 05, pages 005 - 47 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114544046B (en) | 2023-12-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7357035B2 (en) | Sensor chip and apparatus for tactile and/or flow sensing | |
| KR100556265B1 (en) | A tactile sensor for measurement force and temperature and its manufacturing method | |
| JPH03502966A (en) | Silicon-based mass airflow sensor and its manufacturing method | |
| CN101950644A (en) | Manufacturing method of flexible heat-sensitive thin film resistor array | |
| CN1193218C (en) | NEMS piezoresistive pressure sensor chip and its making process | |
| CN107167630A (en) | A kind of design of MEMS acceleration transducers based on flexible material and preparation method thereof | |
| TW408417B (en) | Planar-shape thin probe having electrostatic actuator manufactured by using sacrificed layer technology and its manufacturing method | |
| CN114544046B (en) | Method for manufacturing pressure sensor | |
| CN112097946B (en) | Integrated flexible temperature and pressure sensor, method for making same, and system for non-planar temperature measurement | |
| CN108120858B (en) | Self-excitation self-detection probe and manufacturing method thereof | |
| KR100421177B1 (en) | Micro heat flux sensor by using electroplating, and method of making the same | |
| CN102730632A (en) | Method for processing metal film strainometer based on MEMS (Micro-electromechanical Systems) | |
| WO2023151234A1 (en) | Preparation method for flexible electronic device | |
| CN111351607B (en) | Manufacturing method of temperature and pressure composite sensor | |
| CN111397776B (en) | Temperature and pressure composite sensor | |
| JP2011089859A (en) | Temperature sensor | |
| CN111722707B (en) | Manufacturing method of back contact touch sensor and back contact touch sensor | |
| CN118125373B (en) | Preparation method of hydrogen sensor and hydrogen sensor | |
| CN212779270U (en) | Chip packaging structure | |
| Cheng et al. | Design and fabrication of an artificial skin using PI-copper films | |
| CN113790834B (en) | Manufacturing method of silicon pressure sensor chip with beam film structure | |
| CN104655688A (en) | Mini-sized resistive-type humidity sensor chip and sensor preparation method | |
| JP3441928B2 (en) | Probe for detecting minute force or minute current and method of manufacturing the same | |
| JPH0786619A (en) | Strain gauge and manufacture thereof | |
| CN112284424A (en) | Chip packaging structure and packaging method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |