CN114674485A - Small-range MEMS capacitive pressure sensor and preparation method thereof - Google Patents
Small-range MEMS capacitive pressure sensor and preparation method thereof Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor
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- 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
- B81B3/0018—Structures acting upon the moving or flexible element for transforming energy into mechanical movement or vice versa, i.e. actuators, sensors, generators
- B81B3/0021—Transducers for transforming electrical into mechanical energy or vice versa
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- 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
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
- B81C1/00166—Electrodes
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- 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
- B81C1/00436—Shaping materials, i.e. techniques for structuring the substrate or the layers on the substrate
- B81C1/00444—Surface micromachining, i.e. structuring layers on the substrate
- B81C1/00468—Releasing structures
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
- C23C16/34—Nitrides
- C23C16/345—Silicon nitride
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
- C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
- C23C16/40—Oxides
- C23C16/401—Oxides containing silicon
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
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- 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
- G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
- G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2201/00—Specific applications of microelectromechanical systems
- B81B2201/02—Sensors
- B81B2201/0264—Pressure sensors
Abstract
The invention relates to the technical field of pressure sensors, and provides a preparation method of a small-range MEMS capacitive pressure sensor, which comprises the following steps: s1, depositing a lower electrode layer on the substrate, and etching the lower electrode layer to form a single array of lower electrodes; s2, depositing a dielectric layer on the lower electrode, wherein the dielectric layer is used as a protective layer of the lower electrode; s3, depositing a sacrificial layer on the dielectric layer; s4, forming a lower electrode lead-out hole by photoetching and etching; s5, continuing to deposit the upper electrode and forming a sacrificial layer release hole on the surface of the upper electrode; s6, releasing the sacrificial layer; and S7, sealing the sacrificial layer release hole to form a sealed cavity. The small-range MEMS capacitive pressure sensor is also provided and is prepared by the preparation method. The invention has mature process, the formed silicon microstructure has good mechanical property, and particularly, the sealing property of a cavity structure formed by depositing Al/Ti side release holes is excellent.
Description
Technical Field
The invention relates to the technical field of pressure sensors, in particular to a small-range MEMS capacitive pressure sensor and a preparation method thereof.
Background
Pressure sensors, one of the most mature MEMS devices, are currently mainly used for measuring pressures above one atmosphere (100kPa), and commercial mass production has been achieved; the sensor for measuring the pressure below 100kPa is not commonly limited by objective factors such as difficult preparation, higher cost and the like. However, the requirement of pressure sensing test is increasing in both civil and military applications, and the application environment is also becoming more and more diverse. Among them, the demand for a small-scale MEMS pressure sensor is mainly in the measurement of atmospheric pressure and pressure inside a living body.
The MEMS pressure sensor has the biggest problem when measuring small-range pressure due to small pressure to be measured and low sensitivity. MEMS pressure sensors are various in types, are classified according to different action mechanisms and mainly have a piezoresistive type and a capacitive type. Motorola MPX5100 series piezoresistive pressure sensors are an important commercial representative of piezoresistive pressure sensors. The piezoresistive pressure sensor is easily affected by external temperature, so that the piezoresistive pressure sensor generally has large temperature drift, low sensitivity and high power consumption, and is not suitable for application fields with low power consumption and high precision. With the maturity of the MEMS processing technology, the capacitive pressure sensor has many advantages such as small size, low cost, good temperature characteristic, high precision, low power consumption, etc., so that the capacitive pressure sensor technology is receiving more and more attention. A capacitive pressure sensor is a transducer that converts a pressure signal into a capacitive signal. The working principle of the variable capacitor is that one or two electrodes of the variable capacitor are formed by pressure sensitive films, and under the action of external pressure, the pressure sensitive films serving as capacitor electrodes deform to cause the change of a capacitor gap, so that the capacitance value is changed. This change in capacitance value becomes a voltage or current signal through processing of subsequent circuits.
In the above-described variable-pitch capacitive pressure sensor, the capacitance value is changed by changing the pitch between the upper and lower electrode plates, and the capacitive pressure sensor has an inherent nonlinear characteristic, and therefore it is desired to design a capacitive pressure sensor having good linearity and high sensitivity. In patent CN105241584A, a capacitive pressure sensor is disclosed, in which a movable mass is bonded to the center of a lower movable plate, and the measurement of pressure is realized by changing the capacitance due to the change of the distance between the movable mass and a fixed electrode. The mass block moves in a whole parallel mode, so that the linearity is high, but a cavity of the sensor is formed through a series of complex processes such as bonding and the like, the long-term air tightness of the cavity cannot be guaranteed, and the mass and the volume of the mass block cannot be suitable for measurement in a large pressure range. In patent CN1484008A, a multilayer film capacitive pressure sensor is disclosed, which is a multilayer film structure to improve the linearity of the sensor, which puts higher demands on the bulk micromachining process of the sensor and is not favorable for the miniaturization and integration of the sensor.
Nowadays, the MEMS industry mainly uses the bulk process to manufacture the pressure-sensitive sensor film, however, the bulk process cannot make the ultra-thin film and is difficult to be compatible with the CMOS process.
Disclosure of Invention
The invention aims to provide a small-range MEMS capacitive pressure sensor and a preparation method thereof, which can at least solve part of defects in the prior art.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions: a preparation method of a small-range MEMS capacitive pressure sensor comprises the following steps:
s1, depositing a lower electrode layer on the substrate, and etching the lower electrode layer to form a single array of lower electrodes;
s2, depositing a dielectric layer on the lower electrode, wherein the dielectric layer is used as a protective layer of the lower electrode;
s3, depositing a sacrificial layer on the dielectric layer;
s4, forming a lower electrode lead-out hole by photoetching and etching;
s5, continuing to deposit the upper electrode and forming a sacrificial layer release hole on the surface of the upper electrode;
s6, releasing the sacrificial layer;
and S7, sealing the sacrificial layer release hole to form a sealed cavity.
Further, a P-type or N-type polished silicon wafer is used as the substrate.
Further, the dielectric layer is prepared by depositing silicon nitride by PECVD, and the thickness of the silicon nitride is controlled to be 700-900 nm.
Further, the sacrificial layer is prepared by depositing silicon oxide by PECVD, the thickness of the silicon oxide is controlled to be 0.5-1.5 mu m, and the shape, the size and the position of the sacrificial layer are determined by photoetching and etching.
Further, next, a second time of PECVD silicon oxide is deposited and its shape, size and location determined by photolithography and etching, the material of the layer acting as a region for opening the sacrificial layer release holes.
Further, Al/Ti is deposited to seal the sacrificial layer release hole.
Further, the sacrificial layer is divided into a first sacrificial layer and a second sacrificial layer, the first sacrificial layer and the second sacrificial layer are symmetrically arranged, and a space is formed between the first sacrificial layer and the second sacrificial layer.
Furthermore, a part of the upper electrode is deposited in a spacing groove between the first sacrificial layer and the second sacrificial layer, the sacrificial layer release holes are formed in the upper electrode located in the spacing groove, the number of the sacrificial layer release holes is two, and the two sacrificial layer release holes are symmetrically arranged.
The embodiment of the invention provides another technical scheme: a small-range MEMS capacitive pressure sensor is prepared by the preparation method.
Further, the device comprises a substrate, a lower electrode deposited on the substrate and a lower electrode arranged on the lower electrode.
Compared with the prior art, the invention has the beneficial effects that:
1. as the process is mature, the formed silicon microstructure has good mechanical property, and particularly, the cavity structure formed by depositing Al/Ti lateral release holes has excellent sealing property.
2. Based on the dielectric stretching effect principle, the capacitance gap, the electrode plate area and the dielectric constant value of the capacitance dielectric material change along with the change of the pressure, and the capacitance pressure sensor has obvious monotonicity, can realize the data detection of pressure or air pressure and the like, and has good linearity like the capacitance pressure sensor with the lower electrode-dielectric layer-upper electrode sandwich structure.
3. Structurally based on the principle of a variable-gap capacitor, the parallel unit array form is adopted, so that the capacitance is improved to deform under the action of pressure, the variation of the capacitance of the sensor is caused, and the dielectric constant of a capacitance dielectric layer is several times higher than that of air, so that the variation of the capacitance along with the pressure is effectively improved, and the sensitivity of the sensor is improved.
4. By combining with MEMS micromachining technology, the capacitive pressure sensor has small volume, low power consumption and short response time.
5. The pressure sensor with the sandwich capacitor structure effectively improves the sensitivity and the linearity of the sensor, has small temperature drift, and is suitable for pressure measurement in a large temperature range.
6. The side surface is opened to release, so that the sacrificial layer can be released and treated cleanly, the difficulty of the hole plugging process is greatly reduced, and an effective and firm sealed cavity environment is formed.
7. The capacitive pressure sensor with the movable electrode plate only 1um in thickness reduces the size of a chip, solves the problem of low sensitivity in small-range pressure measurement, greatly reduces the processing difficulty of the sensor, and is also suitable for being compatible with a standard integrated circuit process to realize a monolithic integrated sensor.
Drawings
Fig. 1 is a flowchart of a method for manufacturing a small-range MEMS capacitive pressure sensor according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a small-range MEMS capacitive pressure sensor according to an embodiment of the present invention;
in the reference symbols: 1-a substrate; 2-an upper electrode; 3-a dielectric layer; 4-a sacrificial layer; 5-a lower electrode; 6, sealing the cavity; 7-sacrificial layer release holes; 8-leading out holes; 9-photoresist.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 and fig. 2, an embodiment of the present invention provides a method for manufacturing a small-range MEMS capacitive pressure sensor, including the following steps: s1, depositing a lower electrode 5 layer on the substrate 1, and etching the lower electrode 5 layer to form a single array of lower electrodes 5; s2, depositing a dielectric layer 3 on the lower electrode 5, wherein the dielectric layer 3 is used as a protective layer of the lower electrode 5; s3, depositing a sacrificial layer 4 on the dielectric layer 3; s4, forming a lower electrode 5 leading-out hole 8 by photoetching and etching; s5, continuing to deposit the upper electrode 2 and forming a sacrificial layer release hole 7 on the surface; s6, releasing the sacrificial layer 4; and S7, sealing the sacrificial layer release hole 7 to form a sealed cavity 6. For convenience of description, the steps in fig. 1 are sequentially defined as step a, step b, step c, step d, step e, step f, step g, step h, step i, step j, step k, step l, step m, step n, step o, step p, step q, step r, step s, step t, step u, step v, step w, and step x according to the preparation order. In this embodiment, the core part of the manufactured pressure sensor is the final sealed cavity 6, and the internal and external pressure differences can be formed through the sealed cavity 6, when the sensitive electrode of the sensor, i.e. the upper electrode 2, senses the internal and external pressure differences, the pressure differences will cause the deformation of the electrode diaphragm (i.e. the upper electrode 2), the deformation of the electrode diaphragm will cause the capacitance change, and the capacitance change and the pressure magnitude will show a one-to-one correspondence relationship, so that the pressure sensor has a stable structure, low cost and a simple processing technology, and has better compatibility with the CMOS-IC technology, and the size of a chip is reduced. The sensitivity and the consistency of the sensor can be accurately controlled, the capacitive pressure sensor is not influenced by the temperature change of the external environment, and the high temperature resistance of the sensor is improved. The preparation process can effectively control the cost due to simple processing process, but can prepare the pressure sensor with stable structure, has better compatibility with the CMOS-IC process and reduces the size of a chip. The dielectric layer 3 is used as an insulating layer to separate the space, and the cavity structure formed by depositing Al/Ti lateral release holes has excellent sealing performance. The capacitance value of the capacitive pressure sensor formed by the method is mainly determined by the thickness of the thin film body. Based on the dielectric stretching effect principle, the values of the capacitance gap, the electrode plate area and the dielectric constant of the capacitance dielectric material change along with the change of the pressure, the capacitance gap, the electrode plate area and the dielectric constant of the capacitance dielectric material are obvious monotonicity, the characteristic can realize the detection of data such as pressure or air pressure, and the like, and the capacitance pressure sensor with the sandwich structure of the lower electrode 5-the dielectric layer 3-the upper electrode 2 also has good linearity. The capacitive pressure sensor with the movable electrode plate of the sensor prepared in the way, which is only 1um in thickness, reduces the size of a chip, solves the problem of too low sensitivity in small-range pressure measurement, greatly reduces the processing difficulty of the sensor, and is also suitable for being compatible with a standard integrated circuit process to realize a monolithic integrated sensor by adopting the structure.
As an optimization scheme of the embodiment of the present invention, please refer to fig. 1, wherein a P-type or N-type polished silicon wafer is used as the substrate 1. Before preparing the substrate 1, determining the area of a capacitor polar plate, a capacitor gap and the thickness of a movable polar plate according to the range requirement of a pressure sensor, and manufacturing a photoetching plate to finish the design.
Referring to fig. 1, as an optimized solution of the embodiment of the present invention, the dielectric layer 3 is made by depositing silicon nitride by PECVD, and the thickness of the silicon nitride is controlled to be 700-900 nm. In this embodiment, 300nm thick metal Au is deposited as the lower electrode 5 of the pressure sensor, while the lower electrode 5 layer is etched to form the shape of the lower electrode 5 of the single array, see steps a-d. Now, as shown in step a, the lower electrode 5 is provided on the substrate 1, as shown in step b, the photoresist 9 is provided on the lower electrode 5, then the lower electrode 5 is etched to form the shape of the lower electrode 5 of the single array, as shown in step c, and then the excess photoresist 9 is removed, as shown in step d.
Referring to fig. 1, as an optimized solution of the embodiment of the present invention, the sacrificial layer 4 is made by depositing silicon oxide by PECVD, the thickness of the silicon oxide is controlled to be 0.5-1.5 μm, and the shape, size and position of the sacrificial layer 4 are determined by photolithography and etching. In this embodiment, the dielectric layer 3 is deposited by PECVD of silicon nitride having a thickness of 800nm, which not only serves as the dielectric layer 3 of the capacitor structure, but also serves as a protective layer for the lower electrode 5 when the sacrificial layer 4 is etched, see step e.
As an optimization of the embodiment of the present invention, referring to fig. 1, next, a second PECVD deposition of silicon oxide is performed and the shape, size and location thereof are determined by photolithography and etching, the material of the layer being used as the region for opening the sacrificial layer release hole 7. In this embodiment, after step e, PECVD deposits 1um thick silicon oxide as the sacrificial layer 4 material, and determines the shape, size and position of the silicon oxide sacrificial layer 4 by photolithography and etching, see step f-i, and then PECVD deposits 300nm thick silicon oxide for the second time, and determines the shape, size and position by photolithography and etching, see step f-m; the layer material is used as an area for opening and releasing the side surface of the whole sensor, so that the height of the release hole 7 of the sacrificial layer is obviously reduced, the sacrificial layer 4 can be completely released, the difficulty of the hole plugging process is greatly reduced, and an effective and firm sealed cavity 6 environment is formed. And step f, depositing a sacrificial layer 4 on the dielectric layer 3, step g, arranging photoresist 9 on the sacrificial layer 4, etching to form a pattern in step h, and removing the redundant photoresist 9 to form a pattern in step i. After that, the silicon oxide is deposited for the second time, as shown in the figure of step j. Then, a photoresist 9 is provided and etching is performed, as shown in step k. And (e) after the etching is finished, forming a pattern in step l. The excess photoresist 9 is then removed as shown in step m.
As an optimization of the embodiment of the present invention, please refer to fig. 1, which is followed by the step of forming the electrode lead-out hole 8, please refer to steps n-p. And in the step n, photoresist 9 is firstly arranged on the basis of the step m, and then etching is carried out according to the pattern. And (e) after the etching is finished, forming a pattern as shown in step o. And removing the redundant photoresist 9, and obtaining the electrode lead-out hole 8 according to the graph shown in the figure p.
As an optimization of the embodiment of the present invention, referring to FIG. 1, Al/Ti is deposited to seal the sacrificial layer release hole 7. The sacrificial layer 4 is divided into a first sacrificial layer 4 and a second sacrificial layer 4, the first sacrificial layer 4 and the second sacrificial layer 4 are symmetrically arranged, and a space is arranged between the first sacrificial layer 4 and the second sacrificial layer 4. A part of the upper electrode 2 is deposited in a spacing groove between the first sacrificial layer 4 and the second sacrificial layer 4, the sacrificial layer release holes 7 are opened on the upper electrode 2 in the spacing groove, and there are two sacrificial layer release holes 7, and the two sacrificial layer release holes 7 are symmetrically arranged. In this example, 200nm thick upper electrode 2Au was deposited on the structural layer and etched to form sacrificial layer release hole 7 regions, see step q-t. And step q, depositing the upper electrode 2 on the basis of the step p, then setting the photoresist 9 and then etching as shown in step r, then removing the redundant photoresist 9 as shown in step s after etching is finished, and finally obtaining the sacrificial layer release hole 7. The sacrificial layer release holes 7 are located on the side face, and two sacrificial layer release holes 7 are symmetrically arranged. The sacrificial layer 4 is then removed by a sacrificial layer 4 release process and the sacrificial layer release holes 7 are sealed by depositing 0.7um thick Al/Ti, see step u-x. Specifically, the sacrificial layer 4 is released through the sacrificial layer release hole 7 as shown in step u, and then the sacrificial layer release hole 7 is sealed by Al/Ti as shown in the graph of step v. Etching is then continued to separate the upper electrode 2 from the lower electrode 5 as shown in the figures of step w and step x.
The embodiment of the invention provides a small-range MEMS capacitive pressure sensor which is prepared by the preparation method. Comprises a substrate 1, a lower electrode 5 deposited on the substrate 1, and a lower electrode 5. The sensor is structurally based on the principle of a variable-gap capacitor, the parallel unit array form is adopted, the variable quantity of the capacitance of the sensor caused by the deformation of the capacitance under the action of pressure is improved, and the dielectric constant of the capacitance dielectric layer 3 is several times higher than the value of the dielectric constant of air, so that the variable quantity of the capacitance along with the pressure is effectively improved, and the sensitivity of the sensor is improved. The pressure sensor with the sandwich capacitor structure effectively improves the sensitivity and the linearity of the sensor, has small temperature drift, and is suitable for pressure measurement in a large temperature range.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A preparation method of a small-range MEMS capacitive pressure sensor is characterized by comprising the following steps:
S1, depositing a lower electrode layer on the substrate, and etching the lower electrode layer to form a single array of lower electrodes;
s2, depositing a dielectric layer on the lower electrode, wherein the dielectric layer is used as a protective layer of the lower electrode;
s3, depositing a sacrificial layer on the dielectric layer;
s4, forming a lower electrode lead-out hole by photoetching and etching;
s5, continuing to deposit the upper electrode and forming a sacrificial layer release hole on the surface of the upper electrode;
s6, releasing the sacrificial layer;
and S7, sealing the sacrificial layer release hole to form a sealed cavity.
2. The method of making a small-range MEMS capacitive pressure sensor of claim 1, wherein: and adopting a P-type or N-type polished silicon wafer as the substrate.
3. The method of making a small-range MEMS capacitive pressure sensor of claim 1, wherein: the dielectric layer is prepared by depositing silicon nitride by PECVD, and the thickness of the silicon nitride is controlled to be 700-900 nm.
4. The method of making a small-range MEMS capacitive pressure sensor of claim 1, wherein: the sacrificial layer is prepared by depositing silicon oxide by PECVD, the thickness of the silicon oxide is controlled to be 0.5-1.5 mu m, and the shape, the size and the position of the sacrificial layer are determined by photoetching and etching.
5. The method of making a small-range MEMS capacitive pressure sensor of claim 4, wherein: next, a second PECVD deposition of silicon oxide is performed, and its shape, size and location are determined by photolithography and etching, the material of the layer acting as the area for opening the sacrificial layer release holes.
6. The method of making a small-range MEMS capacitive pressure sensor of claim 1, wherein: Al/Ti is deposited to seal the sacrificial layer release hole.
7. The method of making a small-range MEMS capacitive pressure sensor of claim 1, wherein: the sacrificial layer is divided into a first sacrificial layer and a second sacrificial layer, the first sacrificial layer and the second sacrificial layer are symmetrically arranged, and a space is formed between the first sacrificial layer and the second sacrificial layer.
8. The method of making a small-range MEMS capacitive pressure sensor of claim 7, wherein: a part of the upper electrode is deposited in a spacing groove between the first sacrificial layer and the second sacrificial layer, the sacrificial layer release holes are opened on the upper electrode positioned in the spacing groove, the number of the sacrificial layer release holes is two, and the two sacrificial layer release holes are symmetrically arranged.
9. A small-range MEMS capacitive pressure sensor is characterized in that: prepared by the preparation method as described in any one of claims 1 to 8.
10. The small-range MEMS capacitive pressure sensor of claim 9, wherein: comprises a substrate, a lower electrode deposited on the substrate, and a lower electrode arranged on the lower electrode.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101554987A (en) * | 2009-04-30 | 2009-10-14 | 华中科技大学 | Wafer-grade vacuum encapsulation process for micro-electro-mechanical system |
| CN202153165U (en) * | 2011-07-14 | 2012-02-29 | 无锡芯感智半导体有限公司 | Capacitive MEMS (Micro-Electro-Mechanical System) pressure sensor |
| US20120235255A1 (en) * | 2011-03-18 | 2012-09-20 | PixArt Imaging Incorporation, R.O.C. | MEMS acoustic pressure sensor device and method for making same |
| EP2557406A1 (en) * | 2011-08-11 | 2013-02-13 | Nxp B.V. | Multilayered nonon membrane in a mems sensor |
| CN107515060A (en) * | 2017-08-29 | 2017-12-26 | 南京工业大学 | A kind of capacitance pressure transducer, linear compensation method and preparation method |
| CN111010109A (en) * | 2019-03-02 | 2020-04-14 | 天津大学 | Packaging of MEMS devices with release holes located outside of the packaging space |
| CN111092604A (en) * | 2019-12-16 | 2020-05-01 | 杭州见闻录科技有限公司 | Cavity structure of bulk acoustic wave resonator and manufacturing method |
| CN112362199A (en) * | 2020-10-30 | 2021-02-12 | 华中科技大学 | Medium insertion type capacitive pressure sensor and preparation method thereof |
| CN112857628A (en) * | 2021-04-02 | 2021-05-28 | 厦门市敬微精密科技有限公司 | MEMS capacitive pressure sensor chip and manufacturing process thereof |
| CN113670485A (en) * | 2021-09-01 | 2021-11-19 | 青岛芯笙微纳电子科技有限公司 | High-performance MEMS pressure sensor and manufacturing method thereof |
-
2022
- 2022-02-21 CN CN202210156339.5A patent/CN114674485A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101554987A (en) * | 2009-04-30 | 2009-10-14 | 华中科技大学 | Wafer-grade vacuum encapsulation process for micro-electro-mechanical system |
| US20120235255A1 (en) * | 2011-03-18 | 2012-09-20 | PixArt Imaging Incorporation, R.O.C. | MEMS acoustic pressure sensor device and method for making same |
| CN202153165U (en) * | 2011-07-14 | 2012-02-29 | 无锡芯感智半导体有限公司 | Capacitive MEMS (Micro-Electro-Mechanical System) pressure sensor |
| EP2557406A1 (en) * | 2011-08-11 | 2013-02-13 | Nxp B.V. | Multilayered nonon membrane in a mems sensor |
| CN107515060A (en) * | 2017-08-29 | 2017-12-26 | 南京工业大学 | A kind of capacitance pressure transducer, linear compensation method and preparation method |
| CN111010109A (en) * | 2019-03-02 | 2020-04-14 | 天津大学 | Packaging of MEMS devices with release holes located outside of the packaging space |
| CN111092604A (en) * | 2019-12-16 | 2020-05-01 | 杭州见闻录科技有限公司 | Cavity structure of bulk acoustic wave resonator and manufacturing method |
| CN112362199A (en) * | 2020-10-30 | 2021-02-12 | 华中科技大学 | Medium insertion type capacitive pressure sensor and preparation method thereof |
| CN112857628A (en) * | 2021-04-02 | 2021-05-28 | 厦门市敬微精密科技有限公司 | MEMS capacitive pressure sensor chip and manufacturing process thereof |
| CN113670485A (en) * | 2021-09-01 | 2021-11-19 | 青岛芯笙微纳电子科技有限公司 | High-performance MEMS pressure sensor and manufacturing method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 毕克允 等: "《RF MEMS器件设计、加工和应用》", pages: 228 - 233 * |
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