CN109809355B - Pressure sensor and method for manufacturing the same - Google Patents
Pressure sensor and method for manufacturing the same Download PDFInfo
- Publication number
- CN109809355B CN109809355B CN201910166629.6A CN201910166629A CN109809355B CN 109809355 B CN109809355 B CN 109809355B CN 201910166629 A CN201910166629 A CN 201910166629A CN 109809355 B CN109809355 B CN 109809355B
- Authority
- CN
- China
- Prior art keywords
- grooves
- substrate
- heat treatment
- vacuum chamber
- 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.)
- Active
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
-
- 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
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
- G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Hardware Design (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Pressure Sensors (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention relates to a pressure sensor and a method of manufacturing the same, the method comprising providing a substrate; the method comprises the steps of forming a plurality of first holes on the surface of a substrate at intervals, carrying out first heat treatment to enable the plurality of first holes to be combined into a suspended first vacuum cavity, and forming a groove communicated with the first vacuum cavity and an induction body surrounded by the groove. The method simplifies the manufacturing process of the pressure sensor. Meanwhile, the pressure sensing film of the prepared pressure sensor is less influenced by external stress.
Description
Technical Field
The present invention relates to the field of microelectromechanical systems, and more particularly to a pressure sensor and method of manufacturing the same.
Background
With the continuous development of micro-electromechanical system technology, the cost of the pressure sensor is gradually reduced, and the application of the pressure sensor has also entered into a plurality of fields such as medical treatment, automobiles, weather detection, altitude measurement, consumer electronics and the like. The pressure sensor is commonly used in three types of capacitive pressure sensor, piezoelectric pressure sensor and piezoresistive pressure sensor, wherein the piezoresistive pressure sensor has simple process and is suitable for mass production, and is the main flow direction of pressure sensor development.
The pressure sensing film of the piezoresistive pressure sensor is the most critical structure, and the following methods are commonly used for preparing the piezoresistive pressure sensing film at present. A method for anisotropically corroding back surface of silicon wafer by alkaline solution features that the back cavity is controlled in time and a pressure-sensitive film with a certain thickness is obtained. The second is electrochemical corrosion, which requires expensive potentiostats and is costly to produce. The third method is that a C-SOI technology is adopted, grooves in the shape of a pressure cavity are etched on the front surface of one Si wafer (called wafer 1), then silicon oxide is deposited on the two sides of the other Si wafer (called wafer 2), si-SiO 2 bonding is carried out on the front surface of the wafer 1 and any side of the wafer 2, the wafer 2 is thinned to achieve a certain thickness, a suspended film is obtained, a closed pressure cavity is obtained at the same time, and if the pressure sensor is used for preparing a gauge pressure sensor, the back of the wafer 1 is etched in a deep reactive ion etching mode, so that the pressure cavity is communicated with the outside. The film obtained by the method has larger thickness and higher production cost for preparing the small-range pressure sensor.
For piezoresistive pressure sensors, the pressure sensing diaphragm is very sensitive to stresses introduced by external factors such as packaging, which can lead to insufficient stability of the pressure sensor output.
Therefore, how to obtain a pressure sensor with low manufacturing cost and good output stability is a technical problem to be solved in the art.
Disclosure of Invention
The invention aims to solve the technical problems of reducing the manufacturing cost of the pressure sensor, reducing the influence of external stress on the pressure sensing film of the pressure sensor and improving the output stability of the pressure sensor.
In order to solve the problems, the invention provides a manufacturing method of a pressure sensor, which comprises the steps of providing a substrate, forming a plurality of first holes which are arranged at intervals on the surface of the substrate, performing first heat treatment to enable the plurality of first holes to be combined into a suspended first vacuum cavity, and forming a groove communicated with the first vacuum cavity and an induction body surrounded by the groove.
Optionally, the first heat treatment is rapid thermal annealing.
Optionally, the temperature of the first heat treatment is not less than 1100 ℃.
Optionally, forming a device layer covering the substrate through an epitaxial process.
Optionally, the method further comprises the steps of forming a plurality of second holes which are arranged at intervals on the surface of the device layer, and performing second heat treatment to enable the plurality of second holes to be combined into a suspended second vacuum cavity, wherein the second vacuum cavity is located in the induction body.
Optionally, the second heat treatment is rapid thermal annealing.
Optionally, the temperature of the second heat treatment is not less than 1100 ℃.
Optionally, the diameter of the second hole is 0.5-1.5 microns, and the diameter of the first hole is 0.5-1.5 microns.
Optionally, the second vacuum chamber is located directly above the first vacuum chamber.
The number of the grooves is two, namely a first groove and a second groove, the first groove surrounds the outer side of the second groove, and the notches of the first groove and the second groove are arranged at 180-degree intervals.
In addition, the invention also provides a pressure sensor which comprises a semiconductor substrate, a first suspended vacuum cavity positioned in the semiconductor substrate, grooves positioned in the semiconductor substrate, penetrating through part of the semiconductor substrate and communicated with the first vacuum cavity, and an induction body formed by surrounding the grooves and the first vacuum cavity.
Optionally, the semiconductor substrate comprises a substrate and a device layer located on the substrate, wherein the device layer is an epitaxial layer.
Optionally, a second suspended vacuum cavity is arranged in the device layer, and the second vacuum cavity is positioned in the induction body and is formed by combining a plurality of second grooves which are arranged at intervals through second heat treatment.
Optionally, the second vacuum chamber is located directly above the first vacuum chamber.
Optionally, the second heat treatment is rapid thermal annealing.
The number of the grooves is two, namely a first groove and a second groove, the first groove surrounds the outer side of the second groove, and the notches of the first groove and the second groove are arranged at 180-degree intervals.
Optionally, the first heat treatment is rapid thermal annealing.
According to the invention, the first holes are formed on the surface of the substrate at intervals, and then the first heat treatment is carried out on the substrate, so that the first holes are combined into the suspended first vacuum cavity, and the parts between the first holes are combined together to form the pressure sensing film (also referred to as suspended film), so that the manufacturing process of the pressure sensing film is simplified. Meanwhile, the pressure sensing film formed by the heat treatment process has high flatness and thinner thickness, and can be as thin as 1 micrometer. Furthermore, the side wall of the first vacuum cavity formed by the heat treatment process is smoother, and corners are rounded, so that the pressure-sensitive film basically has no stress.
Further, after the first heat treatment is performed, a device layer may be formed on the substrate through an epitaxial process, and the material of the device layer is the same as that of the pressure sensitive film and may be a part of the pressure sensitive film. The thickness of the device layer is easy to control, so that the whole thickness of the pressure sensing film of the pressure sensor can be adjusted in a larger range.
Drawings
FIGS. 1-15 are cross-sectional views of a pressure sensor at various stages of manufacture in accordance with an embodiment of the present invention;
FIG. 16 is a plan view of a pressure sensor in an embodiment of the invention.
Detailed Description
The following describes in detail the specific embodiments of the method for manufacturing a pressure sensor according to the present invention with reference to the accompanying drawings.
As shown in fig. 1, a substrate 1 is provided, the substrate 1 comprising an upper surface 11 and a lower surface 12. In this embodiment, the substrate 1 is a single crystal silicon substrate. Of course, in other embodiments, other suitable semiconductor materials may be used for the substrate 1.
As shown in fig. 2, a protective layer 13 having a plurality of patterns 14 (i.e., windows) is formed on the upper surface of the substrate 1. The method of manufacturing the protective layer 13 includes forming a protective material layer (not shown) on the upper surface of the substrate 1 by low pressure chemical vapor deposition, plasma chemical vapor deposition, or thermal oxidation, and then removing a portion of the protective material layer by photolithography and wet etching processes, or photolithography and dry etching processes, to form the protective layer 13 having the pattern 14. In this embodiment, the material of the protective layer 13 is silicon oxide, and in other embodiments of the present invention, the material of the protective layer 13 may be a dielectric material such as silicon nitride, silicon carbide, silicon oxynitride, or the like, and may have a single-layer or multi-layer composite structure.
As shown in fig. 3, the substrate 1 is etched with the protective layer 13 as a mask, and a plurality of first holes 15 are formed in the substrate 1. Since the first holes 15 are located on the surface of the substrate 1, they may also be referred to as first grooves. In this embodiment, the substrate 1 is etched using an anisotropic etching process, such as a deep reactive ion silicon etching (DRIE) process, to obtain a plurality of first holes 15, and a portion between two adjacent first holes 15 is defined as a pattern 15a. In this embodiment, the plurality of first holes 15 are arranged in an array, the first holes 15 are circular holes, the depth of the circular holes is several micrometers, the diameter of the circular holes is about 0.5 micrometers to 1.5 micrometers, for example, the circular holes can be 1 micrometer, and the interval between the circular holes is about 0.5 micrometer. Of course, in other embodiments, the first holes 15 may be configured as holes having other shapes, which may be rectangular, circular, pentagonal, hexagonal, or other polygonal, and the size and spacing of the first holes may be adapted according to the lithographic capability of the lithographic apparatus.
As shown in fig. 4, the protective layer 13 is removed. In a specific embodiment, the protective layer 13 is removed using a dry etching or wet etching process, such as with buffered hydrofluoric acid (BOE).
As shown in fig. 5, the substrate 1 is subjected to a first heat treatment such that a plurality of first holes 15 (refer to fig. 4) are combined into a suspended first vacuum chamber 16, wherein suspended means that the first vacuum chamber 16 is located inside the substrate 1 and has a certain interval from the upper surface 11 of the substrate 1. The portion of the substrate 1 between the upper surface 11 and the first vacuum chamber 16 is defined as a first suspended membrane 17.
As shown in fig. 4 to 5, under the effect of the first heat treatment, the first holes 15 are enlarged in the horizontal direction, so that the first holes 15 are communicated with each other, and thus are combined into a complete large hole, i.e., the first vacuum chamber 16. At the same time, under the effect of the first heat treatment, the energy of the upper surface of the substrate 1 is reduced, so that the upper surface of the substrate 1 migrates, and the end portions of the patterns 15a are combined into a whole, thereby forming a first suspended film 17 above the first vacuum chamber 16. The first suspended film 17 formed by the first heat treatment process is flat and thin, which may be as thin as 1 μm. In a specific embodiment, the first vacuum chamber 16 is located in an off-centered position inside the substrate 1. Moreover, the side wall of the first vacuum chamber 16 formed by the first heat treatment process is smoother, and as shown in fig. 5, corners of the first vacuum chamber 16 are rounded, so that the first suspended film 17 basically has no stress. Because the vacuum cavity and the suspended film are formed by utilizing a heat treatment process, a series of adverse effects caused by traditional bulk silicon etching, sacrificial layer etching and wafer bonding are avoided.
Specifically, the first heat treatment is performed in an oxygen-free, low-pressure (sub-atmospheric pressure) environment to prevent the substrate 1 from being oxidized. In one embodiment, the oxygen-free environment is a pure hydrogen environment. Of course, in other embodiments, the oxygen-free environment may also be an inert gas environment. The ambient pressure of the first heat treatment may be less than 1 atmosphere, such that the pressure within the first vacuum chamber 16 formed is less than 1 atmosphere.
In this embodiment, the temperature of the first heat treatment is 1100 ℃. Of course, in other embodiments, the temperature of the first heat treatment may be higher than 1100 degrees celsius. Further, in this embodiment, the first heat treatment is rapid thermal annealing.
As shown in fig. 6, a device layer 18 covering the substrate 1 is formed by an epitaxial process. Since an epitaxial process is used, the material of the device layer 18 is the same as that of the substrate 1, and in this embodiment, the material of the device layer 18 is monocrystalline silicon.
As shown in fig. 7, a protective layer 19 having a number of patterns 20 (i.e., windows) is formed on the device layer 18. The method for manufacturing the protective layer 19 includes forming a protective material layer (not shown) on the upper surface of the device layer 18 by low pressure chemical vapor deposition, plasma chemical vapor deposition, thermal oxidation, or the like, and then removing a portion of the protective material layer by photolithography and wet etching processes, or photolithography and dry etching processes, to form the protective layer 19 having the pattern 20. In this embodiment, the material of the protective layer 19 is silicon oxide, and in other embodiments of the present invention, the material of the protective layer 19 may be a dielectric material such as silicon nitride, silicon carbide, silicon oxynitride, or the like, and may have a single-layer or multi-layer composite structure.
As shown in fig. 8, the substrate 1 having the device layer 18 is etched with the protective layer 19 as a mask, and a plurality of second holes 21 are formed in the substrate 1. Since the second hole 21 is located on the surface of the device layer 18, the second hole 21 may also be referred to as a second trench. In this embodiment, the substrate 1 is etched using an anisotropic etching process, such as a deep reactive ion silicon etching (DRIE) process, to obtain a plurality of second holes 21, and a portion between two adjacent second holes 21 is defined as a pattern 21a. In this embodiment, the plurality of second holes 21 are arranged in an array, the second holes 21 are circular holes, the depth of the circular holes is several micrometers, the diameter of the circular holes can be 0.5 micrometers to 1.5 micrometers, for example, 1 micrometer, and the interval between the circular holes is about 0.5 micrometer. Of course, in other embodiments, the second holes 21 may be provided as holes of other shapes, which may be rectangular, circular, pentagonal, hexagonal or other polygonal shapes. Further, in the present embodiment, the plurality of second holes 21 are located directly above the first vacuum chamber 16.
As shown in fig. 9, the protective layer 19 is removed. In a particular embodiment, the protective layer 19 is removed using a dry etching or wet etching process, such as with buffered hydrofluoric acid (BOE).
As shown in fig. 10, the substrate 1 is subjected to a first heat treatment so that a plurality of second holes 21 (refer to fig. 9) are combined into a suspended second vacuum chamber 7, wherein suspended means that the second vacuum chamber 7 is located inside the substrate 1 with the device layer 18 and has a certain interval from the upper surface of the device layer 18. The portion between the upper surface 11 of the device layer 18 and the second vacuum chamber 7 is defined as a second suspended membrane 8 (also referred to as a pressure sensitive membrane). In the present embodiment, the second vacuum chamber 7 is located directly above the first vacuum chamber 16, and the width (horizontal dimension) of the second vacuum chamber 7 is smaller than the width of the first vacuum chamber 16.
As shown in fig. 9 to 10, under the effect of the second heat treatment, the second holes 21 are enlarged in the horizontal direction, so that the second holes 21 are communicated with each other, and thus are combined into a complete large hole, i.e., the second vacuum chamber 7. At the same time, under the effect of the second heat treatment, the energy of the upper surface of the device layer 18 is reduced, so that the upper surface of the device layer 18 migrates, and the ends of the patterns 21a are combined together to form a whole, thereby forming the second suspended film 8 above the second vacuum chamber 7. The second suspended film 8 formed by the second heat treatment process is flat and thin, which can be as thin as 1 μm. Moreover, the side wall of the second vacuum chamber 7 formed by the first heat treatment process is smoother, and as shown in fig. 10, corners of the second vacuum chamber 7 are rounded corners, and the second suspended film 8 basically has no stress.
Specifically, the second heat treatment is performed in an oxygen-free, low-pressure (sub-atmospheric pressure) environment to prevent the substrate 1 from being oxidized. In one embodiment, the oxygen-free environment is a pure hydrogen environment. Of course, in other embodiments, the oxygen-free environment may also be an inert gas environment. The ambient pressure of the second heat treatment may be less than 1 atmosphere, such that the pressure in the formed second vacuum chamber 7 is less than 1 atmosphere.
In this embodiment, the second heat treatment is performed at a temperature of 1100 ℃. Of course, in other embodiments, the temperature of the second heat treatment may be higher than 1100 degrees celsius. Further, in this embodiment, the second heat treatment is rapid thermal annealing.
As shown in fig. 11, a first dielectric layer 23 is formed on the device layer 18, and may be formed of silicon oxide, silicon nitride, silicon oxynitride, or the like, as a barrier layer, and the forming process may be a low-pressure chemical vapor deposition, a plasma chemical vapor deposition, or a thermal oxidation process, or the like.
With continued reference to FIG. 11, a number of piezoresistors 10 are formed, with the piezoresistors 10 being located directly above the second vacuum chamber 7. In this embodiment, the piezoresistive 10 is formed by ion implantation, i.e., ion implantation is performed on specific areas of the surface layer of the device layer 18 to obtain the piezoresistive 10.
With continued reference to fig. 11, a second dielectric layer 22 is formed overlying the first dielectric layer 23. The material of the second dielectric layer 22 may be silicon oxide, silicon nitride, silicon oxynitride, etc., and the forming process may be low pressure chemical vapor deposition, plasma chemical vapor deposition, thermal oxidation, etc.
As shown in fig. 12, portions of the second dielectric layer 22 and the first dielectric layer 23 are removed to form a plurality of windows 24, each window 24 exposing a corresponding portion of the piezo-resistor 10. The window 24 is formed by photolithography followed by reactive ion etching.
As shown in fig. 13, a plurality of metal electrodes 9 are formed on the second dielectric layer 22, and a portion of the metal electrodes 9 fills the window 24 and makes ohmic contact with the piezoresistor 10. In this embodiment, the method for forming the metal electrode 9 includes forming a metal material layer covering the second dielectric layer 22, wherein a portion of the metal material layer is filled into the window 24 and forms ohmic contact with the underlying piezoresistor 10, the method for forming the metal material layer may be deposition or electroplating, forming a patterned mask layer above the metal material layer, and etching the metal material layer with the patterned mask layer as a mask to form the metal electrode 9, wherein the etching process may be dry etching or wet etching, and the patterned mask layer may be a photoresist layer.
As shown in fig. 14, a protective layer 26 with a pattern 27 is formed on the metal electrode 9, the protective layer 26 covers the second dielectric layer 22, and the pattern 27 is located at the periphery of the metal electrode 9.
The method for manufacturing the protective layer 26 includes forming a protective material layer (not shown) on the upper surfaces of the second dielectric layer 22 and the metal electrode 9 by low pressure chemical vapor deposition, plasma chemical vapor deposition, thermal oxidation, or the like, and then removing a portion of the protective material layer by photolithography and wet etching, or photolithography and dry etching, to form the protective layer 26 having the pattern 27. In this embodiment, the material of the protective layer 26 is silicon oxide, and in other embodiments of the present invention, the material of the protective layer 26 may be a dielectric material such as silicon nitride, silicon carbide, silicon oxynitride, or the like, and may have a single-layer or multi-layer composite structure.
As shown in fig. 15, the second dielectric layer 22 and the first dielectric layer 23 are etched to the substrate 1 by using the protection layer 26 as a mask, so as to form a trench 25 and a sensing body 6 surrounded by the trench 25, wherein the trench 25 is communicated with the first vacuum chamber 16 to form a containing chamber (not shown). In this embodiment, the etching process is a dry etching process, specifically a deep reactive ion silicon etching (DRIE) process.
Specifically, the second vacuum chamber 7 is located in the sensing body 6, and the piezoresistor 10 and the metal electrode 9 are both located in the sensing body 6. The sensing body 6 is surrounded by the groove 25 and the first vacuum chamber 16, and can move along the direction perpendicular to the substrate 1, so as to deform when being subjected to external force, thereby detecting pressure according to the resistance change of the piezoresistor 10.
As shown in fig. 15 and 16, in the present embodiment, the grooves 25 are annular with notches (not labeled), and the number of the grooves 25 is two, namely an outer groove and an inner groove, wherein the notches of the outer groove and the notches of the inner groove are arranged at 180-degree intervals. More specifically, the groove 25 is rectangular, one side of which is provided with a notch. The part of the substrate 1 between the outer side groove and the inner side groove forms a supporting beam 5, and the part of the substrate 1 at the notch of the groove 25 also forms another supporting beam, and the two supporting beams are connected with the sensing body 6, so that the sensing body 6 can be suspended.
It should be noted that, referring to fig. 15, in the embodiment of the present invention, the number of the grooves 25 is not limited to two, and may be arbitrarily set, for example, the number of the grooves 25 may be only one. The number of notches in each groove 25 may be arbitrarily set, and may be two, for example. The shape of the groove 25 is not limited to a rectangle, and may be a polygon such as a circle, a pentagon, or a hexagon.
In addition, the number of the first vacuum chambers 16 is not limited to one, and may be two, the two first vacuum chambers 16 are disposed at intervals in the horizontal direction, the second vacuum chamber 7 is located between the two first vacuum chambers 16, and each first vacuum chamber is in communication with a vertically extending groove, in which case all the first vacuum chambers and all the grooves enclose an induction body.
Furthermore, in the alternative embodiment of the present invention, after the first vacuum chamber 16 is formed, the steps of forming the device layer and the second vacuum chamber may be omitted, and the steps of forming the piezoresistor, the metal electrode, and the trench may be directly performed, so that the sensing body formed according to the alternative method does not have the second suspended film, and the first suspended film formed according to the first heat treatment step is the pressure sensing film.
The following describes in detail the embodiments of the pressure sensor provided by the present invention with reference to the accompanying drawings.
As shown in fig. 15, the pressure sensor includes a substrate 1. In this embodiment, the substrate 1 is a single crystal silicon substrate. Of course, in other embodiments, other suitable semiconductor materials may be used for the substrate 1.
A first vacuum chamber 16 is formed in the substrate 1 in a suspended manner, wherein the suspended manner means that the first vacuum chamber 16 is located inside the substrate 1 and has a certain distance from the upper surface (not shown) of the substrate 1. The first vacuum chamber 16 is formed by combining a plurality of first grooves arranged at intervals, which are located on the surface of the substrate 1, through a first heat treatment. In other words, by forming a plurality of first grooves arranged at intervals on the surface of the substrate 1 and then performing the first heat treatment, the first grooves can be combined into the suspended first vacuum chamber 16.
Under the effect of the first heat treatment, the first grooves are enlarged in the horizontal direction, so that the first grooves are communicated with each other, and are combined into a complete large hole, namely, the first vacuum chamber 16. At the same time, under the effect of the first heat treatment, the upper surface energy of the substrate 1 is reduced, so that the upper surface of the substrate 1 migrates, and the end portions of the portions between the first grooves are integrated with each other, thereby forming a first suspended film (not shown) above the first vacuum chamber 16. The first suspended film formed by the first heat treatment process is very flat and thin, and can be as thin as 1 micron. In a specific embodiment, the first vacuum chamber 16 is located in an off-centered position inside the substrate 1.
Specifically, the first heat treatment is performed in an oxygen-free, low-pressure (sub-atmospheric pressure) environment to prevent the substrate 1 from being oxidized. In one embodiment, the oxygen-free environment is a pure hydrogen environment. Of course, in other embodiments, the oxygen-free environment may also be an inert gas environment. The ambient pressure of the first heat treatment may be less than 1 atmosphere, such that the pressure within the first vacuum chamber 16 formed is less than 1 atmosphere.
In this embodiment, the temperature of the first heat treatment is 1100 ℃. Of course, in other embodiments, the temperature of the first heat treatment may be higher than 1100 degrees celsius. Further, in this embodiment, the first heat treatment is rapid thermal annealing.
In this embodiment, the device layer 18 is formed on the substrate 1, the device layer 18 is formed by epitaxial growth, that is, is an epitaxial layer, and has the same material as the substrate 1, and the substrate 1 and the device layer 18 form a semiconductor substrate (not shown).
The device layer 18 is formed with a first dielectric layer 23, which is used as a barrier layer, and may be made of silicon oxide, silicon nitride, silicon oxynitride, etc., and the forming process may be a low pressure chemical vapor deposition, a plasma chemical vapor deposition, a thermal oxidation, etc.
The first dielectric layer 23 has a second dielectric layer 22 formed thereon. The material of the second dielectric layer 22 may be silicon oxide, silicon nitride, silicon oxynitride, etc., and the forming process may be low pressure chemical vapor deposition, plasma chemical vapor deposition, thermal oxidation, etc.
The trench 25 passes through the semiconductor substrate, the first dielectric layer 23, and the second dielectric layer 22 above the first vacuum chamber 16, and communicates with the first vacuum chamber 16. The groove 25 encloses the sensing body 6 with the first vacuum chamber 16.
As shown in fig. 15 and 16, in the present embodiment, the grooves 25 are annular with notches (not labeled), and the number of the grooves 25 is two, namely an outer groove and an inner groove, wherein the notches of the outer groove and the notches of the inner groove are arranged at 180-degree intervals. More specifically, the groove 25 is rectangular, one side of which is provided with a notch. The part of the substrate 1 between the outer side groove and the inner side groove forms a supporting beam 5, and the part of the substrate 1 at the notch of the groove 25 also forms another supporting beam, and the two supporting beams are connected with the sensing body 6, so that the sensing body 6 can be suspended.
It should be noted that, referring to fig. 15, in the embodiment of the present invention, the number of the grooves 25 is not limited to two, and may be arbitrarily set, for example, the number of the grooves 25 may be only one. The number of notches in each groove 25 may be arbitrarily set, and may be two, for example. The shape of the groove 25 is not limited to a rectangle, and may be a polygon such as a circle, a pentagon, or a hexagon.
In this embodiment, the second vacuum chamber 7 is formed in the device layer 18 in a suspended manner, which means that the second vacuum chamber 7 is located inside the device layer 18 and has a certain distance from the upper surface (not labeled) of the device layer 18. The second vacuum chamber 7 is located within the sensing body 6 and directly above the first vacuum chamber 16.
The second vacuum chamber 7 is formed by combining a plurality of second grooves arranged at intervals through a second heat treatment, and the second grooves are positioned on the surface of the device layer 18. In other words, by forming a plurality of second grooves arranged at intervals on the surface of the device layer 18, and then performing the second heat treatment, the second grooves can be combined into the suspended second vacuum chamber 7.
Under the action of the second heat treatment, the second grooves are enlarged along the horizontal direction, so that the second grooves are communicated with each other, and are combined into a complete large hole, namely the second vacuum cavity 7. At the same time, under the effect of the second heat treatment, the energy of the upper surface of the device layer 18 is reduced, so that the upper surface of the device layer 18 migrates, and the end portions of the portions between the second grooves are combined together into a whole, thereby forming a second suspended film (not shown) above the second vacuum chamber 7. The second suspended film formed by the second heat treatment process is very flat and thin, and can be as thin as 1 micron. In a specific embodiment, the second vacuum chamber 7 is located in an off-centered position inside the device layer 18.
Specifically, the second heat treatment is performed in an oxygen-free, low-pressure (sub-atmospheric pressure) atmosphere to prevent the device layer 18 and the substrate 1 from being oxidized. In one embodiment, the oxygen-free environment is a pure hydrogen environment. Of course, in other embodiments, the oxygen-free environment may also be an inert gas environment. The ambient pressure of the second heat treatment may be less than 1 atmosphere, such that the pressure in the formed second vacuum chamber 7 is less than 1 atmosphere.
In this embodiment, the second heat treatment is performed at a temperature of 1100 ℃. Of course, in other embodiments, the temperature of the second heat treatment may be higher than 1100 degrees celsius. Further, in this embodiment, the second heat treatment is rapid thermal annealing.
It should be noted that the number of the first vacuum chambers 16 is not limited to one, but may be two, and the two first vacuum chambers 16 are disposed at intervals along the horizontal direction, the second vacuum chamber 7 is located between the two first vacuum chambers 16, and each first vacuum chamber is in communication with a vertically extending groove, in which case all the first vacuum chambers and all the grooves enclose an induction body.
In an alternative embodiment of the invention, there is no second vacuum chamber or device layer 18 within the pressure sensor (so that the semiconductor substrate is composed of a mere substrate), the first dielectric layer 23 directly covers the surface of the substrate 1, and the piezoresistors 10 are directly formed on the surface of the substrate 1.
The surface of the device layer 18 is formed with a number of piezo-resistances 10, the piezo-resistances 10 being located directly above the second vacuum chamber 7. In this embodiment, the piezoresistive 10 is formed by ion implantation, i.e., ion implantation is performed on specific areas of the surface layer of the device layer 18 to obtain the piezoresistive 10. The metal electrode 9 is located above the second dielectric layer 22 and has one end penetrating the second dielectric layer 22 and the first dielectric layer 23 to form an ohmic contact with the underlying piezo-resistor 10.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (15)
1. A method of manufacturing a pressure sensor, comprising:
Providing a substrate;
forming a plurality of first holes which are arranged at intervals on the surface of the substrate;
Performing first heat treatment to ensure that a plurality of first holes are combined into a suspended first vacuum cavity, wherein corners of the first vacuum cavity are rounded corners;
The induction body that forms with the slot of first vacuum chamber intercommunication and by the slot surrounds, the slot is the cyclic annular that has the breach, the quantity of slot is two, is first, two slots respectively, first slot surrounds the outside of second slot, just the breach of first slot is 180 degrees intervals setting with the breach of second slot, and the part that lies in between first slot and the second slot constitutes a supporting beam in the substrate, and the part that lies in the breach of this slot constitutes another supporting beam in the substrate, and two supporting beams all are connected with the induction body for the induction body is unsettled.
2. The method of manufacturing according to claim 1, wherein the first heat treatment is rapid thermal annealing.
3. The method of manufacturing according to claim 1, wherein the temperature of the first heat treatment is not less than 1100 degrees celsius.
4. The method of manufacturing according to claim 1, characterized by further comprising:
And forming a device layer covering the substrate through an epitaxial process.
5. The method of manufacturing according to claim 4, further comprising:
Forming a plurality of second holes which are arranged at intervals on the surface of the device layer;
And performing second heat treatment to enable the plurality of second holes to be combined into a suspended second vacuum cavity, wherein the second vacuum cavity is positioned in the induction body.
6. The method of manufacturing according to claim 5, wherein the second heat treatment is rapid thermal annealing.
7. The method of manufacturing according to claim 5, wherein the temperature of the second heat treatment is not less than 1100 ℃.
8. The method of manufacturing according to claim 5, wherein the diameter of the second hole is 0.5 to 1.5 microns, and the diameter of the first hole is 0.5 to 1.5 microns.
9. The method of manufacturing according to claim 5, wherein the second vacuum chamber is located directly above the first vacuum chamber.
10. A pressure sensor, comprising:
A semiconductor substrate;
the semiconductor device comprises a semiconductor substrate, a plurality of first grooves, a first heat treatment device and a second heat treatment device, wherein the first vacuum grooves are arranged in the semiconductor substrate at intervals and are formed by combining the first grooves through first heat treatment, and corners of the first vacuum grooves are rounded corners;
The semiconductor device comprises a semiconductor substrate, a plurality of grooves, a plurality of support beams, a plurality of induction bodies and a plurality of induction grooves, wherein the grooves are positioned in the semiconductor substrate, penetrate through part of the semiconductor substrate until being communicated with the first vacuum cavity, the grooves and the first vacuum cavity enclose an induction body, the grooves are annular with gaps, the number of the grooves is two, the grooves are respectively a first groove and a second groove, the first grooves encircle the outer side of the second grooves, the gaps of the first grooves and the gaps of the second grooves are arranged at intervals of 180 degrees, the part of the substrate, which is positioned between the first grooves and the second grooves, forms the support beam, the part of the substrate, which is positioned between the gaps of the grooves, forms the other support beam, and the two support beams are connected with the induction bodies, so that the induction bodies are suspended.
11. The pressure sensor of claim 10, wherein the semiconductor substrate comprises a substrate and a device layer on the substrate, the device layer being an epitaxial layer.
12. The pressure sensor of claim 11, wherein the device layer has a suspended second vacuum chamber, the second vacuum chamber being located within the sensing body and being formed by combining a plurality of spaced apart second grooves by a second heat treatment.
13. The pressure sensor of claim 12, wherein the second vacuum chamber is located directly above the first vacuum chamber.
14. The pressure sensor of claim 12, wherein the second thermal treatment is rapid thermal annealing.
15. The pressure sensor of any one of claims 10 to 14, wherein the first heat treatment is rapid thermal annealing.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910166629.6A CN109809355B (en) | 2019-03-06 | 2019-03-06 | Pressure sensor and method for manufacturing the same |
| PCT/CN2019/112938 WO2020177339A1 (en) | 2019-03-06 | 2019-10-24 | Pressure sensor and manufacturing method therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910166629.6A CN109809355B (en) | 2019-03-06 | 2019-03-06 | Pressure sensor and method for manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109809355A CN109809355A (en) | 2019-05-28 |
| CN109809355B true CN109809355B (en) | 2025-02-28 |
Family
ID=66608218
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910166629.6A Active CN109809355B (en) | 2019-03-06 | 2019-03-06 | Pressure sensor and method for manufacturing the same |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN109809355B (en) |
| WO (1) | WO2020177339A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109809355B (en) * | 2019-03-06 | 2025-02-28 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and method for manufacturing the same |
| CN112701128B (en) * | 2020-12-29 | 2022-04-19 | 上海烨映微电子科技股份有限公司 | SON structure and preparation method thereof |
| CN113008420A (en) * | 2021-03-01 | 2021-06-22 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and method for manufacturing the same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103991836A (en) * | 2013-02-19 | 2014-08-20 | 苏州敏芯微电子技术有限公司 | Micro electro mechanical system sensor and manufacturing method thereof |
| CN105890827A (en) * | 2016-01-18 | 2016-08-24 | 上海芯赫科技有限公司 | Capacitive pressure sensor and manufacturing method thereof |
| CN106744649A (en) * | 2015-11-19 | 2017-05-31 | 意法半导体股份有限公司 | Micro electro mechanical device and its manufacture method with two buried cavities |
| CN210559358U (en) * | 2019-03-06 | 2020-05-19 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7294536B2 (en) * | 2000-07-25 | 2007-11-13 | Stmicroelectronics S.R.L. | Process for manufacturing an SOI wafer by annealing and oxidation of buried channels |
| DE602004010117D1 (en) * | 2004-09-16 | 2007-12-27 | St Microelectronics Srl | Process for the production of compacted semiconductor wafers by means of layer transfer |
| CN105036059B (en) * | 2015-06-24 | 2017-01-25 | 上海芯赫科技有限公司 | Processing method of capacitive MEMS sensor and sensor structure |
| ITUA20162174A1 (en) * | 2016-03-31 | 2017-10-01 | St Microelectronics Srl | PROCESS OF MANUFACTURE OF A MEMS PRESSURE SENSOR AND RELATIVE MEMS PRESSURE SENSOR |
| CN106018879B (en) * | 2016-05-12 | 2019-03-22 | 广东合微集成电路技术有限公司 | A kind of MEMS acceleration transducer and manufacturing method |
| CN109205549A (en) * | 2017-07-03 | 2019-01-15 | 无锡华润上华科技有限公司 | The preparation method of double cavity structures |
| CN109809355B (en) * | 2019-03-06 | 2025-02-28 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor and method for manufacturing the same |
-
2019
- 2019-03-06 CN CN201910166629.6A patent/CN109809355B/en active Active
- 2019-10-24 WO PCT/CN2019/112938 patent/WO2020177339A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103991836A (en) * | 2013-02-19 | 2014-08-20 | 苏州敏芯微电子技术有限公司 | Micro electro mechanical system sensor and manufacturing method thereof |
| CN106744649A (en) * | 2015-11-19 | 2017-05-31 | 意法半导体股份有限公司 | Micro electro mechanical device and its manufacture method with two buried cavities |
| CN105890827A (en) * | 2016-01-18 | 2016-08-24 | 上海芯赫科技有限公司 | Capacitive pressure sensor and manufacturing method thereof |
| CN210559358U (en) * | 2019-03-06 | 2020-05-19 | 苏州敏芯微电子技术股份有限公司 | Pressure sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109809355A (en) | 2019-05-28 |
| WO2020177339A1 (en) | 2020-09-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN206126837U (en) | MEMS pressure sensor with little mechanical structure | |
| US5220838A (en) | Overpressure-protected, differential pressure sensor and method of making the same | |
| US5332469A (en) | Capacitive surface micromachined differential pressure sensor | |
| KR100301097B1 (en) | Acceleration sensor element and method of its manufacture | |
| KR100462569B1 (en) | Semiconductor pressure sensor and its manufacturing method | |
| US8359928B2 (en) | Pressure sensor and method for manufacturing the pressure sensor | |
| US20060260408A1 (en) | Integrated differential pressure sensor and manufacturing process thereof | |
| US20020053242A1 (en) | Surface-micromachined pressure sensor and high pressure application | |
| CN109809355B (en) | Pressure sensor and method for manufacturing the same | |
| GB2276979A (en) | Capacitive surface micromachined absolute pressure sensor | |
| JPH077160A (en) | Method and apparatus for manufacturing integral-type pressure transducer | |
| TW201302598A (en) | Device for measuring environmental forces and method of fabricating the same | |
| CN110044524B (en) | Micro-electromechanical piezoresistive pressure sensor with self-test capability and corresponding manufacturing method | |
| EP0672898A2 (en) | Semiconductor pressure sensor with polysilicon diaphragm and single-crystal gage elements and fabrication method therefor | |
| CN108931321A (en) | Beam-island-film integration resonant mode pressure sensor structure and manufacturing method | |
| JP2002250665A (en) | Capacitance-type sensor and its manufacturing method | |
| CN113063529A (en) | Micromechanical resonant pressure sensor and manufacturing method thereof | |
| JP4918140B2 (en) | Semiconductor pressure sensor | |
| CN1243576A (en) | Micromechanical semiconductor device and method for production thereof | |
| CN111947815A (en) | MEMS pressure chip and preparation method thereof | |
| CN110182753B (en) | Method for manufacturing high-sensitivity acceleration sensor structure | |
| CN110040682B (en) | Preparation method of high-sensitivity acceleration sensor structure | |
| CN210559358U (en) | Pressure sensor | |
| JP2000022168A (en) | Semiconductor acceleration sensor and manufacture thereof | |
| BG66488B1 (en) | A method for pr0ducing devices for mems with electric elements in their lateral walls |
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 |