WO2016192360A1 - 一种差分电容式mems压力传感器及其制造方法 - Google Patents

一种差分电容式mems压力传感器及其制造方法 Download PDF

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Publication number
WO2016192360A1
WO2016192360A1 PCT/CN2015/096916 CN2015096916W WO2016192360A1 WO 2016192360 A1 WO2016192360 A1 WO 2016192360A1 CN 2015096916 W CN2015096916 W CN 2015096916W WO 2016192360 A1 WO2016192360 A1 WO 2016192360A1
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fixed electrode
common
sensitive
lower fixed
upper fixed
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English (en)
French (fr)
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郑国光
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Goertek Inc
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Goertek Inc
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Priority to US15/559,331 priority Critical patent/US10495535B2/en
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems ; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems ; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
    • G01L13/02—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements
    • G01L13/025—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements using diaphragms
    • 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
    • G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
    • G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
    • G01L9/0073—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance using a semiconductive diaphragm
    • 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

Definitions

  • the present invention relates to the field of sensors, and more particularly to a differential capacitance type MEMS pressure sensor; the present invention also relates to a method of manufacturing a differential capacitance type MEMS pressure sensor.
  • the MEMS pressure sensor mainly has two types of capacitive and piezoresistive types, wherein the capacitive MEMS pressure sensor includes a pressure sensitive film, a substrate and a contact.
  • the pressure sensitive film and the substrate form a sealed vacuum chamber, and the capacitor plate formed by the pressure sensitive film reacts to external pressure changes; when the external air pressure changes, the pressure sensitive film above the vacuum chamber will bend, Thus, the capacitance value formed by the pressure sensitive film and the substrate changes, and the change in the capacitance is read by the ASIC circuit to characterize the external pressure change.
  • the above capacitive MEMS pressure sensor detects the change of external pressure through a single capacitor.
  • the amount of capacitance change caused by the change of the external air pressure is small, and the error of detecting by using a single capacitor is large.
  • other interference signals will also cause changes in capacitance, such as stress, temperature and other common-mode signals, will affect the value of the capacitance changes, these harmful signals will not be attenuated or Filtered out, but output together with the pressure signal, which affects the accuracy and stability of pressure detection.
  • a differential capacitive MEMS pressure sensor comprising:
  • the sensitive structural layer comprises a public sensitive part located in the middle, and a common supporting part located at the edge of the public sensitive part, the common sensitive part is connected to the side wall of the common supporting part, and the common support
  • the thickness of the portion is greater than the thickness of the common sensitive portion, so that the cross section of the sensitive structural layer is dumbbell-shaped as a whole;
  • the upper fixed electrode structure layer comprises an upper fixed electrode suspended above the common sensitive portion and forming a capacitor structure with the common sensitive portion, and the upper fixed electrode is provided with a corrosion hole;
  • the lower fixed electrode structural layer is consistent with the structure of the upper fixed electrode structural layer, and the two are vertically symmetric along the sensitive structural layer, and the lower fixed electrode structural layer comprises a capacitor structure suspended below the common sensitive portion and formed with a common sensitive portion. a lower fixed electrode; the lower fixed electrode is provided with a corrosion hole;
  • the position of the common support portion connected to the common sensitive portion has a transitional common slope including a first sloped surface on the upper surface of the common support portion and a second inclined surface on the lower surface of the common support portion.
  • the upper fixed electrode structure layer includes an upper fixed electrode support portion connected to an upper fixed electrode edge, and the upper fixed electrode support portion is connected to an upper surface of the common support portion through an insulating layer;
  • the lower fixed electrode structure layer includes a lower fixed electrode support portion that connects the lower fixed electrode edge, and the lower fixed electrode support portion is connected to the upper surface of the common support portion through the insulating layer.
  • the upper fixed electrode structure layer further includes an upper fixed electrode connecting portion which is inclined, the upper fixed electrode is connected to the upper fixed electrode supporting portion through the upper fixed electrode connecting portion, and the upper fixed electrode connecting portion is located Above the first slope and having the same slope as the first slope;
  • the lower fixed electrode structure layer further includes a lower fixed electrode connecting portion which is inclined, the lower fixed electrode is connected to the lower fixed electrode supporting portion through the lower fixed electrode connecting portion, and the lower fixed electrode connecting portion is located at the second inclined surface Below, and has the same slope as the second slope.
  • an insulating layer is respectively disposed between the upper fixed electrode connecting portion and the first inclined surface, and between the lower fixed electrode connecting portion and the second inclined surface.
  • the lower fixed electrode supporting portion is provided with a conductive portion, the conductive portion penetrates the insulating layer, the common supporting portion is connected with the upper fixed electrode supporting portion, and is separated from the upper fixed electrode supporting portion to form a lower fixed electrode.
  • the conductive portion is connected to the upper fixed electrode supporting portion through the insulating layer, and is formed on the upper fixed electrode supporting portion to form a second conductive contact of the common sensitive portion;
  • a third conductive contact of the upper fixed electrode is further disposed on the upper fixed electrode support portion.
  • the substrate is attached to the lower fixed electrode support portion of the lower fixed electrode structure layer through an insulating layer.
  • the substrate is connected to a common support portion of the sensitive structure layer through an insulating layer, and the lower fixed electrode structure layer is suspended in the vacuum chamber.
  • the invention also provides a method for manufacturing the above MEMS pressure sensor, comprising the following steps:
  • step g) the step of thinning the sensitive structural layer to a predetermined thickness is further included.
  • the MEMS pressure sensor of the invention has a differential capacitance structure formed by the upper fixed electrode, the common sensitive part and the lower fixed electrode, thereby enhancing the suppression of the common mode signal of the chip and improving the signal to noise ratio of the output signal; meanwhile, the public support of the invention
  • the thickness of the part is larger than the thickness of the common sensitive part, so that the cross section of the sensitive structural layer is dumbbell-shaped as a whole, which makes the external common support part shield the strain caused by temperature and stress, thereby greatly reducing the transmission due to temperature and stress changes.
  • the strain on the public sensitive part improves the temperature stability and stress stability of the chip.
  • the inventors of the present invention have found that in the prior art, the error of detecting by using a single capacitor is large, and in addition, the external pressure change causes a change in capacitance, and other interference signals may also cause changes in capacitance, such as stress and temperature. And other common-mode signals will affect the change value of the capacitor. These harmful signals will not be attenuated or filtered, but will be output together with the pressure signal, which will affect the accuracy and stability of the pressure detection. Therefore, the technical task to be achieved by the present invention or the technical problem to be solved is not thought of or expected by those skilled in the art, so the present invention is a new technical solution.
  • FIG. 1 is a schematic view showing the structure of a MEMS pressure sensor of the present invention.
  • 2 to 13 are process flow diagrams of a method of fabricating a MEMS pressure sensor of the present invention.
  • Figure 14 is a schematic illustration of another embodiment of a MEMS pressure sensor of the present invention.
  • a differential capacitive MEMS pressure sensor provided by the present invention includes a substrate 1 and a sensitive structure layer 2, an upper fixed electrode structure layer 3, and a lower fixed electrode structure layer 4 supported on the substrate 1, wherein
  • the upper fixed electrode structure layer 3 is located above the sensitive structure layer 2, and the sensitive structure layer 2 can constitute a first detection capacitor, and the lower fixed electrode structure layer 4 is located below the sensitive structure layer 2, and the sensitive structure layer 2 can be configured
  • the second detecting capacitor, the sensitive structure layer 2 serves as a common sensitive plate of the two detecting capacitors, and the upper fixed electrode structure layer 3 and the lower fixed electrode structure layer 4 are symmetric with respect to the sensitive structure layer 2, so that the first detecting capacitor and the second detecting capacitor
  • the detection capacitor constitutes a differential capacitor structure, thereby improving the detection capability of the microcapacitor, enhancing the suppression of the common mode signal by the chip, and improving the signal to noise ratio of the output signal.
  • the sensitive structural layer 2 of the present invention includes a common sensitive portion 22 at the middle portion, and a common support portion 20 at the edge of the common sensitive portion 22, and the common sensitive portion 22 and the common support portion 20 may be Integral, made of single crystal silicon material.
  • the common sensitive portion 22 is a movable plate of a capacitor structure, and the common sensitive portion 22 is bent and deformed under external pressure.
  • the common support portion 20 primarily provides support for the common sensitive portion 22 to maintain the common sensitive portion 22 in a predetermined position.
  • the edge of the common sensitive portion 22 is connected to the side wall of the common support portion 20, Preferably, the connection position is located in the middle of the side wall of the common support portion 20 such that the common sensitive portion 22 is surrounded by the common support portion 20.
  • the thickness of the common supporting portion 20 is greater than the thickness of the common sensitive portion 22, so that the cross section of the sensitive structural layer 2 is dumbbell-shaped as a whole.
  • the upper fixed electrode structure layer 3 of the present invention includes an upper fixed electrode 32 suspended above the common sensitive portion 22, and the upper fixed electrode 32 can be supported and suspended above the common sensitive portion 22 by means well known to those skilled in the art.
  • the common sensitive portion 22 can form a first detecting capacitance with the upper fixed electrode 32 for detecting a pressure change.
  • the upper fixed electrode structure layer 3 further includes an upper fixed electrode support portion 30 located at an edge of the upper fixed electrode 32, and the upper fixed electrode 32 and the upper fixed electrode support portion 30 may be integrated.
  • the upper fixed electrode support portion 30 mainly supports the upper fixed electrode 32 to maintain the upper fixed electrode 32 at a predetermined position.
  • the edge of the upper fixed electrode 32 is coupled to the upper fixed electrode support portion 30 such that the upper fixed electrode 32 is surrounded by the upper fixed electrode support portion 30.
  • the upper fixed electrode support portion 30 is supported on the upper end surface of the common support portion 20 of the sensitive structural layer 2 through the insulating layer 5, so that the upper fixed electrode 32 can be suspended above the common sensitive portion 22 with a gap between the two.
  • the first detecting capacitor operates in the space 23.
  • the lower fixed electrode structure layer 4 of the present invention is located below the sensitive structure layer 2, which is consistent with the structure of the upper fixed electrode structure layer 3, which are vertically symmetrical along the sensitive structure layer 2.
  • a lower fixed electrode 42 suspended below the common sensitive portion 22 is supported, and the lower fixed electrode 42 can be supported and suspended under the common sensitive portion 22 in a manner well known to those skilled in the art such that the common sensitive portion 22 can be
  • the fixed electrode 42 constitutes a second detection capacitor that can be used to detect a change in pressure.
  • the lower fixed electrode structure layer 4 further includes a lower fixed electrode support portion 40 at an edge of the lower fixed electrode 42, and the lower fixed electrode support portion 40 and the lower fixed electrode support portion 40 may be integrated.
  • the lower fixed electrode support portion 40 mainly supports the lower fixed electrode 42 to hold the lower fixed electrode 42 at a predetermined position.
  • the edge of the lower fixed electrode 42 is coupled to the lower fixed electrode support portion 40 such that the lower fixed electrode 42 is surrounded by the lower fixed electrode support portion 40.
  • the lower fixed electrode support portion 40 is connected to the lower end surface of the common support portion 20 of the sensitive structural layer 2 through the insulating layer 5, so that the lower fixed electrode 42 can be suspended below the common sensitive portion 22 with For the second detection capacitor The space made.
  • the lower fixed electrode support portion 40 may be bonded to the substrate 1 through an insulating layer, and a vacuum chamber 7 is formed between the substrate 1 and the lower fixed electrode 42.
  • a plurality of etching holes 33 are disposed on the upper fixed electrode 32, and the common sensitive portion 22 can be made through the plurality of etching holes 33.
  • the outside world is connected.
  • a plurality of etching holes 43 are also disposed on the lower fixed electrode 42.
  • the substrate 1 is bonded to the common support portion 20 of the sensitive structural layer 2 through an insulating layer, which causes the lower fixed electrode structural layer 4 to be entirely suspended. Placed in the vacuum chamber 7. Separating the lower fixed electrode structure layer 4 from the bonding region of the substrate 1 can prevent the bonding process from causing damage to the lower fixed electrode structure layer 4. In addition, it is also possible to etch away portions of the upper and lower fixed electrodes that do not contribute to the sensitivity, and reduce the parasitic capacitance of the upper and lower fixed electrodes to the common sensitive portion 22 to suppress noise. Such a method of reducing parasitic capacitance is well known to those skilled in the art and will not be specifically described herein.
  • the MEMS pressure sensor of the invention has a differential capacitance structure formed by the upper fixed electrode, the common sensitive part and the lower fixed electrode, thereby enhancing the suppression of the common mode signal of the chip and improving the signal to noise ratio of the output signal; meanwhile, the public support of the invention
  • the thickness of the part is larger than the thickness of the common sensitive part, so that the cross section of the sensitive structural layer is dumbbell-shaped as a whole, which makes the external common support part shield the strain caused by temperature and stress, thereby greatly reducing the transmission due to temperature and stress changes.
  • the strain on the public sensitive part improves the temperature stability and stress stability of the chip.
  • the position of the common support portion 20 connected to the common sensitive portion 22 has a transitional common slope including a first slope 21 located on the upper surface of the common support portion 20, and located at a second inclined surface 24 of the lower surface of the common support portion 20, the common sensitive portion 22 is connected with the common inclined surface on the common supporting portion 20, so that the common inclined surface of the common sensitive portion 22 and the common supporting portion 20 form a groove similar to an isosceles trapezoid;
  • the upper fixed electrode structure layer 3 and the lower fixed electrode structure layer 4 are deposited on the sensitive structure having the step slope when the upper electrode structure layer 3 and the lower fixed electrode structure layer 4 are fixed by the common slope provided.
  • the internal stress of the film can be greatly reduced.
  • the upper fixed electrode structural layer 3 further includes an upper fixed electrode connecting portion 31 which is inclined, and the upper fixed electrode 32 passes through the upper fixed electrode connecting portion 31 and the upper fixed electrode supporting portion 30.
  • the entire upper fixed electrode structure layer 3 is selected to have a uniform thickness, that is, the structural orientation of the entire upper fixed electrode structure layer 3 is completely identical to the structure of the upper surface of the sensitive structural layer 2.
  • the upper fixed electrode supporting portion 30 is supported in parallel above the common supporting portion 20 via the insulating layer 5, and the upper fixed electrode connecting portion 31 and the upper fixed electrode 32 are respectively supported in parallel by the upper fixed electrode supporting portion 30.
  • the first slope 21 is above the common sensitive portion 22.
  • an insulating layer may be disposed between the upper fixed electrode connecting portion 31 and the first inclined surface 21, and the insulating layer at the position is integrated with the insulating layer 5 between the upper fixed electrode supporting portion 30 and the common supporting portion 20. .
  • the lower fixed electrode structural layer 4 and the upper fixed electrode structural layer 3 are vertically symmetrical with respect to the sensitive structural layer 2, and the lower fixed electrode structural layer 4 further includes a downwardly fixed electrode connecting portion which is inclined in order to correspond to the sensitive structural layer 2.
  • the lower fixed electrode 42 is connected to the lower fixed electrode support portion 40 via the lower fixed electrode connecting portion 41.
  • the lower fixed electrode connecting portion 41 and the second inclined surface 24 have the same inclination, so that the lower fixed electrode connecting portion 41 is completely parallel to the first inclined surface 21.
  • the entire lower fixed electrode structural layer 4 is selected to have a uniform thickness, that is, the structural orientation of the entire lower fixed electrode structural layer 4 is completely identical to that of the lower surface of the sensitive structural layer 2.
  • the lower fixed electrode supporting portion 40 is connected in parallel below the common supporting portion 20 via the insulating layer 5, and the lower fixed electrode connecting portion 41 and the lower fixed electrode 42 are suspended in parallel by the lower fixed electrode supporting portion 40, respectively.
  • the two inclined surfaces 24 are below the common sensitive portion 22.
  • an insulating layer may be disposed between the lower fixed electrode connecting portion 41 and the second inclined surface 24, and the insulating layer at the position is integrated with the insulating layer 5 between the lower fixed electrode supporting portion 40 and the common supporting portion 20. .
  • the electrical signals of the upper fixed electrode 32, the common sensitive portion 22, and the lower fixed electrode 42 need to be extracted, and the values of the first detecting capacitor and the second detecting capacitor are obtained through the circuit.
  • the signals of the above three plates can be taken out in a manner well known to those skilled in the art.
  • the lower fixed electrode supporting portion 40 is provided with a conductive portion, and the lower end of the conductive portion is connected to the lower fixed electrode supporting portion 40 .
  • the upper end penetrates the insulating layer 5 and the common supporting portion 20, and is connected to the upper fixed electrode supporting portion 30, and the first conductive contact 80 of the lower fixed electrode 42 is formed on the upper fixed electrode supporting portion 30.
  • a conductive portion may be further disposed on the common supporting portion 20, and the conductive portion is connected to the upper fixed electrode supporting portion 30 through the insulating layer 5, and the common sensitive portion 22 is formed at a corresponding position of the upper fixed electrode supporting portion 30.
  • the second conductive contact 81 is further disposed on the upper fixed electrode support portion 30 with a third conductive contact 82 of the upper fixed electrode 32.
  • the three conductive contacts are all disposed on the upper fixed electrode supporting portion 30.
  • the upper fixed electrode supporting portion 30 can be patterned to form the isolation region 9, thereby fixing the upper electrode supporting portion 30.
  • the areas of the upper three conductive contacts are isolated from each other.
  • the above-mentioned conductive portion functions as an electrical conduction, which may be any conductive material well known to those skilled in the art, which may be a metal material or a polysilicon material.
  • the conductive portion between the common support portion 20 and the upper fixed electrode support portion 30 may also be made of a polysilicon material, which is the same material as the upper fixed electrode support portion 30.
  • the conductive portion is integral with the upper fixed electrode support portion 30.
  • the conductive portion between the lower fixed electrode supporting portion 40 and the upper fixed electrode supporting portion 30 includes a metal portion 6 located in the common supporting portion 20, wherein the upper and lower ends of the metal portion 6 respectively pass through the electrical connecting portion and the upper fixed electrode
  • the support portion 30 and the lower fixed electrode support portion 40 are connected together; the electrical connection portion may be a polysilicon material, which is the same material as the upper fixed electrode support portion 30 and the lower fixed electrode support portion 40.
  • the two conductive portions are integral with the upper fixed electrode support portion 30 and the lower fixed electrode support portion 40, respectively.
  • the invention also provides a method for manufacturing the above MEMS pressure sensor, comprising the following steps:
  • the sensitive structural layer 2 may be made of a single crystal silicon material and insulated from the polysilicon conductive material or the metal portion 6 in the through hole through the insulating layer 5;
  • the lower fixed electrode structure layer 4 may be a polysilicon material having a uniform thickness, after the lower fixed electrode structure layer 4 is deposited on the insulating layer 5,
  • the lower fixed electrode supporting portion 40, the lower fixed electrode connecting portion 41, and the lower fixed electrode 42 are formed; and the lower fixed electrode supporting portion 40 is deposited into the etching hole 60, and is connected with the polysilicon conductive material or the metal portion 6, reference drawing 5;
  • the lower fixed electrode support portion 40 may be bonded to the substrate 1 through an insulating layer, or the common support portion 20 may be bonded to the substrate 1 through an insulating layer by changing the structure;
  • the other side of the sensitive structure layer 2 is processed.
  • the surface of the sensitive structure layer 2 is etched or etched to form the common support portion 20.
  • the upper surface, the first slope 21, and the upper surface of the common sensitive portion 22; a groove having an isosceles trapezoidal shape may be formed on the upper surface of the sensitive structural layer 2 by anisotropic etching, and the bottom of the groove is public-sensitive
  • insulating layer 5 growing the insulating layer 5 on the upper surface of the entire sensitive structural layer 2 such that the insulating layer 5 covers the entire upper surface of the sensitive structural layer 2, and graphically etches the insulating layer 5, which will be located at
  • the crystalline silicon conductive material or the insulating layer 5 over the metal portion 6 is etched away to form an etched hole 800 to expose the end surface of the polysilicon conductive material or the metal portion 6; and the insulating layer 5 located at a predetermined position above the common support portion 20 is engraved Etched, forming an etch hole 810 to expose a portion of the common support portion 20, see FIG. 10;
  • the upper fixed electrode structure layer 3 may be a polysilicon material having a uniform thickness, and the upper fixed electrode structure layer 3 is deposited on After the insulating layer 5 is formed, an upper fixed electrode supporting portion 30, an upper fixed electrode connecting portion 31, and an upper fixed electrode 32 are formed; and the upper fixed electrode supporting portion 30 is deposited into the etching holes 800, 810, respectively, with a polysilicon conductive material or The metal portion 6, the common support portion 20 are connected together, refer to FIG. 11;
  • the first conductive contact 80 is located in the etching Directly above the hole 800
  • the second conductive contact 81 is located directly above the etched hole 810;
  • the formation of the sensitive structural layer is completed by etching or etching on the upper and lower surfaces thereof, thereby reducing the processing cost of the chip; meanwhile, the use of single crystal silicon to form the sensitive structural layer can be greatly reduced.
  • the residual stress increases the stability of the chip; the polysilicon layer of the upper fixed electrode structure layer and the lower fixed electrode structure layer is deposited on the stepped surface of the sensitive structure layer, which can greatly reduce the internal stress of the film.

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Abstract

一种差分电容式MEMS压力传感器，敏感结构层（2）包括公共敏感部（22）以及位于公共敏感部（22）边缘的公共支撑部（20），且公共支撑部（20）的厚度大于公共敏感部（22）的厚度；包括相对于敏感结构层（2）上下对称的用于与公共敏感部（22）形成差分电容的上固定电极结构层（3）、下固定电极结构层（4）。该MEMS压力传感器，通过差分电容结构，增强了芯片对共模信号的抑制，提高了输出信号的信噪比；同时，由于公共支撑部的厚度大于公共敏感部的厚度，这就使得外围的公共支撑部可以屏蔽温度和应力所引起的应变，从而大大降低了由于温度和应力变化所传递到公共敏感部上的应变，提高了芯片的温度稳定性和应力稳定性。还公开了一种差分电容式MEMS压力传感器的制造方法。

Description

一种差分电容式MEMS压力传感器及其制造方法 技术领域
本发明涉及传感器领域，更具体地，涉及一种差分电容式的MEMS压力传感器；本发明还涉及一种差分电容式MEMS压力传感器的制造方法。
背景技术
现行的技术方案中，MEMS压力传感器主要有电容式和压阻式两种，其中，电容式MEMS压力传感器包括压力敏感膜、衬底和触点。压力敏感膜与衬底形成密封的真空腔，压力敏感膜形成的电容极板会对外界的压力变化做出反应；当外界的气压变化时，处在真空腔上方的压力敏感膜会发生弯曲，从而压力敏感膜与衬底形成的电容值会发生变化，进而由ASIC电路读出该电容的变化，来表征外界的压力变化。
上述电容式MEMS压力传感器是通过单个电容来检测外界压力变化的，一般来说，外界气压变化所引起的电容变化量都是很小的，采用单个电容进行检测的误差很大。另外，除了外界的压力变化会引起电容变化外，其它干扰信号也会引起电容的变化，如应力、温度及其它的共模信号，都会影响电容的变化值，这些有害的信号不会加以衰减或滤除，而是随压力信号一并输出,进而影响压力检测的精度和稳定性。
发明内容
本发明的一个目的是提供一种差分电容式MEMS压力传感器的新技术方案。
根据本发明的第一方面，提供了一种差分电容式MEMS压力传感器，包括：
敏感结构层，包括位于中部的公共敏感部，以及位于公共敏感部边缘的公共支撑部，所述公共敏感部连接在公共支撑部的侧壁上，且公共支撑 部的厚度大于公共敏感部的厚度，使得敏感结构层的截面整体呈哑铃型；
上固定电极结构层，包括悬置在公共敏感部上方、并与公共敏感部组成电容结构的上固定电极，所述上固定电极上设置有腐蚀孔；
下固定电极结构层，与上固定电极结构层结构一致，二者沿着敏感结构层上下对称，所述下固定电极结构层包括悬置在公共敏感部下方、并与公共敏感部组成电容结构的下固定电极；所述下固定电极上设置有腐蚀孔；
用于支撑的衬底，所述衬底与公共敏感部之间形成了真空腔。
优选地，所述公共支撑部上与公共敏感部连接的位置具有过渡的公共斜面，该公共斜面包括位于公共支撑部上表面的第一斜面，以及位于公共支撑部下表面的第二斜面。
优选地，所述上固定电极结构层包括连接上固定电极边缘的上固定电极支撑部，所述上固定电极支撑部通过绝缘层与公共支撑部的上表面连接；
所述下固定电极结构层包括连接下固定电极边缘的下固定电极支撑部，所述下固定电极支撑部与通过绝缘层与公共支撑部的上表面连接。
优选地，所述上固定电极结构层还包括呈倾斜状的上固定电极连接部，所述上固定电极通过上固定电极连接部与上固定电极支撑部连接，且所述上固定电极连接部位于第一斜面的上方，且与第一斜面具有相同的斜度；
所述下固定电极结构层还包括呈倾斜状的下固定电极连接部，所述下固定电极通过下固定电极连接部与下固定电极支撑部连接，且所述下固定电极连接部位于第二斜面的下方，且与第二斜面具有相同的斜度。
优选地，所述上固定电极连接部与第一斜面之间、所述下固定电极连接部与第二斜面之间分别设有绝缘层。
优选地，所述下固定电极支撑部上设置有导电部，该导电部贯穿绝缘层、公共支撑部与上固定电极支撑部连接在一起，并在上固定电极支撑部上隔离形成下固定电极的第一导电触点；
在所述公共支撑部上设置有导电部，该导电部贯穿绝缘层与上固定电极支撑部连接在一起，并在上固定电极支撑部上隔离形成公共敏感部的第二导电触点；
在所述上固定电极支撑部上还设置有上固定电极的第三导电触点。
优选地，所述衬底通过绝缘层连接在下固定电极结构层的下固定电极支撑部上。
优选地，所述衬底通过绝缘层连接在敏感结构层的公共支撑部上，所述下固定电极结构层悬置在真空腔内。
本发明还提供了一种上述MEMS压力传感器的制造方法，包括以下步骤：
a)在敏感结构层的一端刻蚀贯通其上下两端的通孔，之后在通孔的孔壁上生长绝缘层，并在通孔内填充多晶硅导电材料或金属部；
b)在敏感结构层上表面进行刻蚀或腐蚀，形成公共支撑部的下表面、第二斜面以及公共敏感部的下表面；
c)在整个敏感结构层的上表面生长绝缘层，并对绝缘层进行图形化刻蚀；
d)在绝缘层的上表面沉积下固定电极结构层，形成下固定电极支撑部、下固定电极连接部、下固定电极；且下固定电极支撑部与多晶硅导电材料或金属部连接在一起；
e)在下固定电极上刻蚀形成腐蚀孔；
f)通过腐蚀孔将下固定电极与公共敏感部之间的绝缘层腐蚀掉，将下固定电极从公共敏感部上释放开来；
g)将整个敏感结构层、下固定电极结构层翻转，并键合在衬底上，形成了位于衬底与公共敏感部之间的真空腔；
h)在敏感结构层上表面进行刻蚀或腐蚀，形成公共支撑部的上表面、第一斜面以及公共敏感部的上表面；
i)在整个敏感结构层的上表面生长绝缘层，并对绝缘层进行图形化刻蚀；
j)在绝缘层的上表面沉积上固定电极结构层，形成上固定电极支撑部、上固定电极连接部、上固定电极；且透过图形化的绝缘层，所述上固定电极支撑部与多晶硅导电材料或金属部、公共支撑部连接在一起；
k)在上固定电极支撑部的相应位置制作第一导电触点、第二导电触点、第三导电触点；
l)在上固定电极上刻蚀形成腐蚀孔；并在上固定电极支撑部上进行刻蚀，将第一导电触点、第二导电触点、第三导电触点相互隔离开；
m)通过腐蚀孔将上固定电极与公共敏感部之间的绝缘层腐蚀掉，将上固定电极从公共敏感部上释放开来。
优选地，在所述步骤g)和步骤h)之间，还包括将敏感结构层减薄到预定厚度的步骤。
本发明的MEMS压力传感器，上固定电极、公共敏感部、下固定电极构成了差分电容结构，从而增强了芯片对共模信号的抑制，提高了输出信号的信噪比；同时，本发明公共支撑部的厚度大于公共敏感部的厚度，使得敏感结构层的截面整体呈哑铃型，这就使得外围的公共支撑部可以屏蔽温度和应力所引起的应变，从而大大降低了由于温度和应力变化所传递到公共敏感部上的应变，提高了芯片的温度稳定性和应力稳定性。
本发明的发明人发现，在现有技术中，采用单个电容进行检测的误差很大，另外，除了外界的压力变化会引起电容变化外，其它干扰信号也会引起电容的变化，如应力、温度及其它的共模信号，都会影响电容的变化值，这些有害的信号不会加以衰减或滤除，而是随压力信号一并输出,进而影响压力检测的精度和稳定性。因此，本发明所要实现的技术任务或者所要解决的技术问题是本领域技术人员从未想到的或者没有预期到的，故本发明是一种新的技术方案。
通过以下参照附图对本发明的示例性实施例的详细描述，本发明的其它特征及其优点将会变得清楚。
附图说明
被结合在说明书中并构成说明书的一部分的附图示出了本发明的实施例，并且连同其说明一起用于解释本发明的原理。
图1是本发明MEMS压力传感器的结构示意图。
图2至图13是本发明MEMS压力传感器制造方法的工艺流程图。
图14是本发明MEMS压力传感器另一实施结构的示意图。
具体实施方式
现在将参照附图来详细描述本发明的各种示例性实施例。应注意到：除非另外具体说明，否则在这些实施例中阐述的部件和步骤的相对布置、数字表达式和数值不限制本发明的范围。
以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本发明及其应用或使用的任何限制。
对于相关领域普通技术人员已知的技术、方法和设备可能不作详细讨论，但在适当情况下，所述技术、方法和设备应当被视为说明书的一部分。
在这里示出和讨论的所有例子中，任何具体值应被解释为仅仅是示例性的，而不是作为限制。因此，示例性实施例的其它例子可以具有不同的值。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步讨论。
参考图1，本发明提供的一种差分电容式MEMS压力传感器，其包括衬底1以及支撑在衬底1上的敏感结构层2、上固定电极结构层3、下固定电极结构层4，其中，上固定电极结构层3位于敏感结构层2的上方，其与敏感结构层2可构成第一检测电容，下固定电极结构层4位于敏感结构层2的下方，其与敏感结构层2可构成第二检测电容，敏感结构层2作为两个检测电容的公共敏感极板，而且上固定电极结构层3、下固定电极结构层4相对于敏感结构层2对称，使得第一检测电容和第二检测电容构成了差分电容结构，从而提高了微小电容的检测能力，增强了芯片对共模信号的抑制，提高了输出信号的信噪比。
具体地，参考图1，本发明的敏感结构层2，其包括位于中部的公共敏感部22，以及位于公共敏感部22边缘的公共支撑部20，该公共敏感部22和公共支撑部20可以是一体的，采用单晶硅材料制成。公共敏感部22为电容结构的可动极板，在外界的压力作用下，该公共敏感部22发生弯曲变形。公共支撑部20主要为公共敏感部22提供支撑，使公共敏感部22保持在预定的位置。公共敏感部22的边缘连接在公共支撑部20的侧壁上， 优选其连接位置位于公共支撑部20侧壁的中部，使得公共敏感部22被公共支撑部20环绕起来。其中，所述公共支撑部20的厚度大于公共敏感部22的厚度，使得敏感结构层2的截面整体呈哑铃型。
本发明的上固定电极结构层3，包括悬置在公共敏感部22上方的上固定电极32，上固定电极32可通过本领域技术人员所熟知的方式支撑并悬置在公共敏感部22的上方，使得该公共敏感部22可与上固定电极32构成一可用于检测压力变化的第一检测电容。
在本发明一个具体的实施方式中，所述上固定电极结构层3还包括位于上固定电极32边缘的上固定电极支撑部30，该上固定电极32和上固定电极支撑部30可以是一体的，采用多晶硅材料制成。上固定电极支撑部30主要为上固定电极32提供支撑，使上固定电极32保持在预定的位置上。上固定电极32的边缘与上固定电极支撑部30连接在一起，使得上固定电极32被上固定电极支撑部30环绕起来。其中，上固定电极支撑部30通过绝缘层5支撑在敏感结构层2的公共支撑部20的上端面，使得上固定电极32可以悬置在公共敏感部22的上方，二者之间留有供第一检测电容工作的空间23。
本发明的下固定电极结构层4位于敏感结构层2的下方，其与上固定电极结构层3的结构一致，二者沿着敏感结构层2上下对称。包括悬置在公共敏感部22下方的下固定电极42，下固定电极42可通过本领域技术人员所熟知的方式支撑并悬置在公共敏感部22的下方，使得该公共敏感部22可与下固定电极42构成一可用于检测压力变化的第二检测电容。
在本发明一个具体的实施方式中，所述下固定电极结构层4还包括位于下固定电极42边缘的下固定电极支撑部40，该下固定电极42和下固定电极支撑部40可以是一体的，采用多晶硅材料制成。下固定电极支撑部40主要为下固定电极42提供支撑，使下固定电极42保持在预定的位置上。下固定电极42的边缘与下固定电极支撑部40连接在一起，使得下固定电极42被下固定电极支撑部40环绕起来。其中，下固定电极支撑部40通过绝缘层5连接在敏感结构层2的公共支撑部20的下端面上，使得下固定电极42可以悬置在公共敏感部22的下方，二者之间留有供第二检测电容工 作的空间。
在本发明一个具体的实施方式中，可将下固定电极支撑部40通过绝缘层键合在衬底1上，并使衬底1与下固定电极42之间形成一真空腔7。此时，为了使公共敏感部22可以感应外界压力变化而发生弯曲变形，在所述上固定电极32上设置有多个腐蚀孔33，通过该多个腐蚀孔33，使得公共敏感部22可以与外界连通起来。在本发明一个优选的实施方式中，在所述下固定电极42上也设置有多个腐蚀孔43，此时，可以看成，真空腔7由公共敏感部22和衬底1围成，从而提高了真空腔7的容积，使得公共敏感部22的形变力度更能反应出外界压力变化的力度。
在本发明另一个具体的实施方式中，参考图14，所述衬底1通过绝缘层键合在敏感结构层2的公共支撑部20上，这就使得所述下固定电极结构层4整体悬置在真空腔7内。将下固定电极结构层4与衬底1的键合区域分开，可以防止键合工艺对下固定电极结构层4造成损伤。另外，还可以将上、下固定电极上对灵敏度没有贡献的部分刻蚀掉，降低上、下固定电极对公共敏感部22的寄生电容，以起到抑制噪声的目的。这种降低寄生电容的方法属于本领域技术人员的公知常识，在此不再具体说明。
本发明的MEMS压力传感器，上固定电极、公共敏感部、下固定电极构成了差分电容结构，从而增强了芯片对共模信号的抑制，提高了输出信号的信噪比；同时，本发明公共支撑部的厚度大于公共敏感部的厚度，使得敏感结构层的截面整体呈哑铃型，这就使得外围的公共支撑部可以屏蔽温度和应力所引起的应变，从而大大降低了由于温度和应力变化所传递到公共敏感部上的应变，提高了芯片的温度稳定性和应力稳定性。
在本发明一个优选的实施方式中，所述公共支撑部20上与公共敏感部22连接的位置具有过渡的公共斜面，该公共斜面包括位于公共支撑部20上表面的第一斜面21，以及位于公共支撑部20下表面的第二斜面24，公共敏感部22与公共支撑部20上的公共斜面连接，使得公共敏感部22、公共支撑部20的公共斜面形成了近似等腰梯形的凹槽；同时，通过设置的公共斜面，使得在制作上固定电极结构层3、下固定电极结构层4时，上固定电极结构层3、下固定电极结构层4沉积在具有阶梯坡度的敏感结构 层2上，能够大大降低薄膜的内应力。
为了和敏感结构层2对应起来，所述上固定电极结构层3还包括呈倾斜状的上固定电极连接部31，所述上固定电极32通过上固定电极连接部31与上固定电极支撑部30连接，其中，上固定电极连接部31与第一斜面21具有角度相同的斜度，使得上固定电极连接部31与第一斜面21完全平行。选择整个上固定电极结构层3具有均一的厚度，也就是说，整个上固定电极结构层3的结构走向与敏感结构层2上表面的结构完全一致。其中，上固定电极支撑部30通过绝缘层5平行地支撑在公共支撑部20的上方，所述上固定电极连接部31、上固定电极32通过上固定电极支撑部30分别平行地支撑悬置在第一斜面21、公共敏感部22的上方。进一步优选的是，上固定电极连接部31与第一斜面21之间也可设置绝缘层，该位置的绝缘层与上固定电极支撑部30、公共支撑部20之间的绝缘层5是一体的。
下固定电极结构层4、上固定电极结构层3相对于敏感结构层2上下对称，为了和敏感结构层2对应起来，所述下固定电极结构层4还包括呈倾斜状的下固定电极连接部41，所述下固定电极42通过下固定电极连接部41与下固定电极支撑部40连接。其中，下固定电极连接部41与第二斜面24具有角度相同的斜度，使得下固定电极连接部41与第一斜面21完全平行。选择整个下固定电极结构层4具有均一的厚度，也就是说，整个下固定电极结构层4的结构走向与敏感结构层2下表面的结构完全一致。其中，下固定电极支撑部40通过绝缘层5平行地连接在公共支撑部20的下方，所述下固定电极连接部41、下固定电极42通过下固定电极支撑部40分别平行地悬置在第二斜面24、公共敏感部22的下方。进一步优选的是，下固定电极连接部41与第二斜面24之间也可设置绝缘层，该位置的绝缘层与下固定电极支撑部40、公共支撑部20之间的绝缘层5是一体的。
本发明的MEMS压力传感器，需要将上固定电极32、公共敏感部22、下固定电极42的电信号引出，通过电路来获得第一检测电容、第二检测电容的数值。在此，可通过本领域技术人员所熟知的方式将上述三个极板的信号引出。在本发明一个具体的实施方式中，参考图1，所述下固定电极支撑部40上设置有导电部，该导电部的下端与下固定电极支撑部40连接， 其上端贯穿绝缘层5、公共支撑部20，与上固定电极支撑部30连接在一起，并在上固定电极支撑部30上形成下固定电极42的第一导电触点80。
在所述公共支撑部20上也可设有导电部，该导电部贯穿绝缘层5与上固定电极支撑部30连接在一起，并在上固定电极支撑部30的相应位置上形成公共敏感部22的第二导电触点81；在所述上固定电极支撑部30上还设置有上固定电极32的第三导电触点82。三个导电触点均设置在上固定电极支撑部30上，为了彼此之间的绝缘，可在上固定电极支撑部30上进行图形化处理，形成隔离区9，从而将上固定电极支撑部30上三个导电触点的区域彼此隔离开。
上述的导电部起到电导通的作用，其可以是本领域技术人员所熟知的任意导电材料，其可以是金属材料，也可以是多晶硅材料。应用到本发明的技术方案中，公共支撑部20与上固定电极支撑部30之间的导电部也可以采用多晶硅材料，其与上固定电极支撑部30采用相同的材质，在此，可以理解为该导电部与上固定电极支撑部30是一体的。下固定电极支撑部40与上固定电极支撑部30之间的导电部，包括位于公共支撑部20中的金属部6，其中金属部6的上、下两端分别通过电连接部与上固定电极支撑部30、下固定电极支撑部40连接在一起；该电连接部可以为多晶硅材料，其与上固定电极支撑部30、下固定电极支撑部40上采用相同的材质，在此，可以理解为该两个导电部分别与上固定电极支撑部30、下固定电极支撑部40是一体的。
本发明还提供了一种上述MEMS压力传感器的制造方法，包括以下步骤：
a)在敏感结构层2的一端刻蚀贯通其上下两端的通孔，之后在通孔的孔壁上生长绝缘层5，并在通孔内填充多晶硅导电材料或金属部6，参考图2；敏感结构层2可以采用单晶硅材料，通过绝缘层5与通孔内的多晶硅导电材料或金属部6保持绝缘；
b)在敏感结构层2的上表面进行刻蚀或腐蚀，形成公共支撑部20的下表面、第二斜面24以及公共敏感部22的下表面，参考图3；可通过各向异性腐蚀的方法，在敏感结构层2的上表面形成呈等腰梯形的凹槽，该 凹槽的底部为公共敏感部22的下表面，其侧壁为公共支撑部20的第二斜面24；
c)在整个敏感结构层2的上表面生长一层绝缘层5，使得该绝缘层5覆盖在敏感结构层2的整个上表面；对绝缘层5进行图形化刻蚀，将位于多晶硅导电材料或金属部6上方的绝缘层5刻蚀掉，形成刻蚀孔60，从而将多晶硅导电材料或金属部6的端面露出，参考图4；
d)在绝缘层5的上表面沉积下固定电极结构层4，该下固定电极结构层4可以是多晶硅材料，其具有均一的厚度，该下固定电极结构层4沉积在绝缘层5上之后，形成了下固定电极支撑部40、下固定电极连接部41、下固定电极42；且下固定电极支撑部40沉积至刻蚀孔60中，与多晶硅导电材料或金属部6连接在一起，参考图5；
e)在下固定电极42上刻蚀形成多个腐蚀孔43，参考图6；
f)通过腐蚀孔43将下固定电极42与公共敏感部22之间的绝缘层5腐蚀掉，从而将下固定电极42从公共敏感部22上释放开来，下固定电极42与公共敏感部22之间具有一定的空间23，使得下固定电极42与公共敏感部22可以构成用于检测的电容，参考图7；
g)将整个敏感结构层2、下固定电极结构层4翻转，键合在衬底1上，并形成了位于衬底1与公共敏感部22之间的真空腔7，参考图8；在该步骤中，可以将下固定电极支撑部40通过绝缘层键合在衬底1上，也可以通过改变结构，将公共支撑部20通过绝缘层键合在衬底1上；
h)在上述结构翻转后，对敏感结构层2的另一面进行处理，参考图9的方向，与步骤b)相似，在敏感结构层2上表面进行刻蚀或腐蚀，形成公共支撑部20的上表面、第一斜面21以及公共敏感部22的上表面；可通过各向异性腐蚀的方法，在敏感结构层2的上表面形成呈等腰梯形的凹槽，该凹槽的底部为公共敏感部22的上表面，其侧壁为公共支撑部20的第一斜面21；其中，在该步骤之前，根据需要，还包括将敏感结构层2减薄到预定厚度的步骤；
i)在整个敏感结构层2的上表面生长绝缘层5，使得该绝缘层5覆盖在敏感结构层2的整个上表面，并对绝缘层5进行图形化刻蚀，将位于多 晶硅导电材料或金属部6上方的绝缘层5刻蚀掉，形成刻蚀孔800，将多晶硅导电材料或金属部6的端面露出；同时将位于公共支撑部20上方预定位置的绝缘层5刻蚀掉，形成刻蚀孔810，使部分公共支撑部20露出，参考图10；
j)在绝缘层5的上表面沉积上固定电极结构层3，与步骤d)相似，该上固定电极结构层3可以是多晶硅材料，其具有均一的厚度，该上固定电极结构层3沉积在绝缘层5上之后，形成了上固定电极支撑部30、上固定电极连接部31、上固定电极32；且上固定电极支撑部30沉积至刻蚀孔800、810中，分别与多晶硅导电材料或金属部6、公共支撑部20连接在一起，参考图11；
k)在上固定电极支撑部30的相应位置制作第一导电触点80、第二导电触点81、第三导电触点82，参考图12，具体地，第一导电触点80位于刻蚀孔800的正上方，第二导电触点81位于刻蚀孔810的正上方；
l)在上固定电极32上刻蚀形成腐蚀孔33；并在上固定电极支撑部30上进行刻蚀，形成隔离区9，将第一导电触点80、第二导电触点81、第三导电触点82相互隔离开，参考图13；
m)通过腐蚀孔33将上固定电极32与公共敏感部22之间的绝缘层5腐蚀掉，从而将上固定电极32从公共敏感部22上释放开来，上固定电极32与公共敏感部22之间具有一定的空间23，使得上固定电极32与公共敏感部22可以构成用于检测的电容，参考图1。
本发明的制造方法，敏感结构层的形成是通过在其上、下表面的腐蚀或刻蚀来完成的，降低了芯片的加工成本；同时，采用单晶硅来制作敏感结构层，可以大大降低其残余的应力，提高了芯片的稳定性；上固定电极结构层、下固定电极结构层的多晶硅层沉积在敏感结构层的具有阶梯坡度的表面上，可以大大降低薄膜的内应力。
虽然已经通过例子对本发明的一些特定实施例进行了详细说明，但是本领域的技术人员应该理解，以上例子仅是为了进行说明，而不是为了限制本发明的范围。本领域的技术人员应该理解，可在不脱离本发明的范围和精神的情况下，对以上实施例进行修改。本发明的范围由所附权利要求来限定。

Claims (10)

  1. 一种差分电容式MEMS压力传感器，其特征在于，包括：
    敏感结构层(2)，包括位于中部的公共敏感部(22)，以及位于公共敏感部(22)边缘的公共支撑部(20)，所述公共敏感部(22)连接在公共支撑部(20)的侧壁上，且公共支撑部(20)的厚度大于公共敏感部(22)的厚度，使得敏感结构层(2)的截面整体呈哑铃型；
    上固定电极结构层(3)，包括悬置在公共敏感部(22)上方、并与公共敏感部(22)组成电容结构的上固定电极(32)，所述上固定电极(32)上设置有腐蚀孔(33)；
    下固定电极结构层(4)，与上固定电极结构层(3)结构一致，二者沿着敏感结构层(2)上下对称，所述下固定电极结构层(4)包括悬置在公共敏感部(22)下方、并与公共敏感部(22)组成电容结构的下固定电极(42)；所述下固定电极(42)上设置有腐蚀孔(43)；
    用于支撑的衬底(1)，所述衬底(1)与公共敏感部(22)之间形成了真空腔(7)。
  2. 根据权利要求1所述的MEMS压力传感器，其特征在于：所述公共支撑部(20)上与公共敏感部(22)连接的位置具有过渡的公共斜面，该公共斜面包括位于公共支撑部(20)上表面的第一斜面(21)，以及位于公共支撑部(20)下表面的第二斜面(24)。
  3. 根据权利要求2所述的MEMS压力传感器，其特征在于：
    所述上固定电极结构层(3)包括连接上固定电极(32)边缘的上固定电极支撑部(30)，所述上固定电极支撑部(30)通过绝缘层(5)与公共支撑部(20)的上表面连接；
    所述下固定电极结构层(4)包括连接下固定电极(42)边缘的下固定电极支撑部(40)，所述下固定电极支撑部(40)与通过绝缘层(5)与公共支撑部(20)的上表面连接。
  4. 根据权利要求3所述的MEMS压力传感器，其特征在于：
    所述上固定电极结构层(3)还包括呈倾斜状的上固定电极连接部(31)， 所述上固定电极(32)通过上固定电极连接部(31)与上固定电极支撑部(30)连接，且所述上固定电极连接部(31)位于第一斜面(21)的上方，且与第一斜面(21)具有相同的斜度；
    所述下固定电极结构层(4)还包括呈倾斜状的下固定电极连接部(41)，所述下固定电极(42)通过下固定电极连接部(41)与下固定电极支撑部(40)连接，且所述下固定电极连接部(41)位于第二斜面(24)的下方，且与第二斜面(24)具有相同的斜度。
  5. 根据权利要求4所述的MEMS压力传感器，其特征在于：所述上固定电极连接部(31)与第一斜面(21)之间、所述下固定电极连接部(41)与第二斜面(24)之间分别设有绝缘层(5)。
  6. 根据权利要求3所述的MEMS压力传感器，其特征在于：
    所述下固定电极支撑部(40)上设置有导电部，该导电部贯穿绝缘层、公共支撑部(20)与上固定电极支撑部(30)连接在一起，并在上固定电极支撑部(30)上隔离形成下固定电极(42)的第一导电触点(80)；
    在所述公共支撑部(20)上设置有导电部，该导电部贯穿绝缘层与上固定电极支撑部(30)连接在一起，并在上固定电极支撑部(30)上隔离形成公共敏感部(22)的第二导电触点(81)；
    在所述上固定电极支撑部(30)上还设置有上固定电极(32)的第三导电触点(82)。
  7. 根据权利要求3所述的MEMS压力传感器，其特征在于：所述衬底(1)通过绝缘层连接在下固定电极结构层(4)的下固定电极支撑部(40)上。
  8. 根据权利要求3所述的MEMS压力传感器，其特征在于：所述衬底(1)通过绝缘层连接在敏感结构层(2)的公共支撑部(20)上，所述下固定电极结构层(4)悬置在真空腔(7)内。
  9. 一种如权利要求1至8任一项所述的MEMS压力传感器的制造方法，其特征在于，包括以下步骤：
    a)在敏感结构层(2)的一端刻蚀贯通其上下两端的通孔，之后在通孔的孔壁上生长绝缘层，并在通孔内填充多晶硅导电材料或金属部(6)；
    b)在敏感结构层(2)上表面进行刻蚀或腐蚀，形成公共支撑部(20)的下表面、第二斜面(24)以及公共敏感部(22)的下表面；
    c)在整个敏感结构层(2)的上表面生长绝缘层(5)，并对绝缘层(5)进行图形化刻蚀；
    d)在绝缘层(5)的上表面沉积下固定电极结构层(4)，形成下固定电极支撑部(40)、下固定电极连接部(41)、下固定电极(42)；且下固定电极支撑部(40)与多晶硅导电材料或金属部(6)连接在一起；
    e)在下固定电极(42)上刻蚀形成腐蚀孔(43)；
    f)通过腐蚀孔(43)将下固定电极(42)与公共敏感部(22)之间的绝缘层(5)腐蚀掉，将下固定电极(42)从公共敏感部(22)上释放开来；
    g)将整个敏感结构层(2)、下固定电极结构层(4)翻转，并键合在衬底(1)上，形成了位于衬底(1)与公共敏感部(22)之间的真空腔(7)；
    h)在敏感结构层(2)上表面进行刻蚀或腐蚀，形成公共支撑部(20)的上表面、第一斜面(21)以及公共敏感部(22)的上表面；
    i)在整个敏感结构层(2)的上表面生长绝缘层(5)，并对绝缘层(5)进行图形化刻蚀；
    j)在绝缘层(5)的上表面沉积上固定电极结构层(3)，形成上固定电极支撑部(30)、上固定电极连接部(31)、上固定电极(32)；且透过图形化的绝缘层，所述上固定电极支撑部(30)与多晶硅导电材料或金属部(6)、公共支撑部(20)连接在一起；
    k)在上固定电极支撑部(30)的相应位置制作第一导电触点(80)、第二导电触点(81)、第三导电触点(82)；
    l)在上固定电极(32)上刻蚀形成腐蚀孔(33)；并在上固定电极支撑部(30)上进行刻蚀，将第一导电触点(80)、第二导电触点(81)、第三导电触点(82)相互隔离开；
    m)通过腐蚀孔(33)将上固定电极(32)与公共敏感部(22)之间的绝缘层(5)腐蚀掉，将上固定电极(32)从公共敏感部(22)上释放开 来。
  10. 根据权利要求9所述的制造方法，其特征在于：在所述步骤g)和步骤h)之间，还包括将敏感结构层(2)减薄到预定厚度的步骤。
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