Quasi-differential capacitive MEMS pressure sensor and manufacturing methods thereof
First Claim
1. A quasi-differential capacitive MEMS pressure sensor, comprising:
- a substrate, an insulating layer formed on the substrate, a first lower electrode and a second lower electrode respectively formed on the insulating layer, a first upper electrode supported above the first lower electrode, and a second upper electrode supported above the second lower electrode, wherein the first upper electrode is a pressure-sensitive film, a cavity between the first upper electrode and the first lower electrode is a closed cavity, so that the first upper electrode and the first lower electrode constitute an air pressure-sensitive type capacitor, the air pressure-sensitive type capacitor further comprising an anti-collision projection formed on the first lower electrode and/or an anti-collision projection formed on the insulating layer and penetrating through the first lower electrode to protrude upward, wherein there is a gap between the anti-collision projection and the first upper electrode; and
the second upper electrode and the second lower electrode constitute a reference capacitor whose capacitance does not vary with external air pressure.
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Abstract
The present invention discloses a quasi-differential capacitive MEMS pressure sensor and manufacturing methods thereof. The quasi-differential capacitive MEMS pressure sensor includes a first lower electrode, a second lower electrode, a first upper electrode supported above the first lower electrode, and a second upper electrode supported above the second lower electrode, wherein the first upper electrode is a pressure-sensitive film, and a cavity between the first upper electrode and the first lower electrode is a closed cavity, so that the first upper electrode and the first lower electrode constitute an air pressure-sensitive type capacitor; and the second upper electrode and the second lower electrode constitute a reference capacitor whose capacitance does not vary with external air pressure. The pressure sensor provided by the present invention can at least partially filter out a common-mode interference signal in an output signal of the air pressure-sensitive type capacitor by use of the reference capacitor, thereby improving the stability and resolution of the output signal of the air pressure-sensitive type capacitor.
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Citations
9 Claims
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1. A quasi-differential capacitive MEMS pressure sensor, comprising:
- a substrate, an insulating layer formed on the substrate, a first lower electrode and a second lower electrode respectively formed on the insulating layer, a first upper electrode supported above the first lower electrode, and a second upper electrode supported above the second lower electrode, wherein the first upper electrode is a pressure-sensitive film, a cavity between the first upper electrode and the first lower electrode is a closed cavity, so that the first upper electrode and the first lower electrode constitute an air pressure-sensitive type capacitor, the air pressure-sensitive type capacitor further comprising an anti-collision projection formed on the first lower electrode and/or an anti-collision projection formed on the insulating layer and penetrating through the first lower electrode to protrude upward, wherein there is a gap between the anti-collision projection and the first upper electrode; and
the second upper electrode and the second lower electrode constitute a reference capacitor whose capacitance does not vary with external air pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a substrate, an insulating layer formed on the substrate, a first lower electrode and a second lower electrode respectively formed on the insulating layer, a first upper electrode supported above the first lower electrode, and a second upper electrode supported above the second lower electrode, wherein the first upper electrode is a pressure-sensitive film, a cavity between the first upper electrode and the first lower electrode is a closed cavity, so that the first upper electrode and the first lower electrode constitute an air pressure-sensitive type capacitor, the air pressure-sensitive type capacitor further comprising an anti-collision projection formed on the first lower electrode and/or an anti-collision projection formed on the insulating layer and penetrating through the first lower electrode to protrude upward, wherein there is a gap between the anti-collision projection and the first upper electrode; and
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8. A manufacturing method of a quasi-differential capacitive MEMS pressure sensor, the method comprising the following steps:
- a), depositing a first oxide layer as an insulating layer on a substrate;
b), depositing and etching a first metal layer on the insulating layer to form a first lower electrode and a second lower electrode independent of each other;
c) depositing and etching a second oxide layer on the first lower electrode and the second lower electrode to form a supporting part and a supporting post corresponding to the second lower electrode; and
d), bonding a pressure-sensitive film on the supporting part and the supporting post to form a closed cavity between the pressure-sensitive film and the first lower electrode to enable the pressure-sensitive film, which acts as a first upper electrode, and the first lower electrode to constitute an air pressure-sensitive type capacitor, and to form a second upper electrode supported by the supporting post, to enable the second upper electrode and the second lower electrode to constitute a reference capacitor whose capacitance does not vary with external air pressure.
- a), depositing a first oxide layer as an insulating layer on a substrate;
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9. A manufacturing method of a quasi-differential capacitive MEMS pressure sensor, the method comprising the following steps:
- a), depositing a first oxide layer as an insulating layer on a substrate;
b), depositing and etching a first metal layer on the insulating layer to form a first lower electrode and a second lower electrode independent of each other;
c) depositing and etching a second oxide layer on the first lower electrode and the second lower electrode to form a supporting part;
d), bonding a pressure-sensitive film on the supporting part to form a closed cavity between the pressure-sensitive film and the first lower electrode to enable the pressure-sensitive film, which acts as a first upper electrode, and the first lower electrode to constitute an air pressure-sensitive type capacitor, and to form another closed cavity between the pressure-sensitive film and the second lower electrode; and
e) etching the pressure-sensitive film to enable the another closed cavity to become a cavity communicating with the outside, enabling the pressure-sensitive film, which acts as a second upper electrode, and the second lower electrode to constitute a reference capacitor whose capacitance does not vary with external air pressure.
- a), depositing a first oxide layer as an insulating layer on a substrate;
Specification