| 摘要 |
The present invention provides a MEMS pressure sensor and a manufacturing method. The pressure is formed by a top cap wafer, a MEMS wafer and a bottom cap wafer. The MEMS wafer comprises a frame and a membrane, the frame defining a cavity. The membrane is suspended by the frame over the cavity. The bottom cap wafer closes the cavity. The top cap wafer has a recess defining with the membrane a capacitance gap. The top cap wafer comprises a top cap electrode located over the membrane and forming, together with the membrane, a capacitor to detect a deflection of the membrane. Electrical contacts on the top cap wafer are connected to the top cap electrode. A vent is extends from outside of the sensor into the cavity or the capacitance gap. The pressure sensor can include two cavities and two capacitance gaps, to form a differential pressure sensor. |
| 主权项 |
1. A MEMS pressure sensor comprising:
a MEMS wafer being electrically conductive and having first and second opposite sides the MEMS wafer having formed therein a frame and a membrane, the frame defining at least one cavity, the membrane being suspended by the frame over said at least one cavity on the first side of the MEMS wafer; a top cap wafer being electrically conductive and having inner and outer sides, the top cap wafer being bonded on its inner side to the first side of the MEMS wafer, the inner side of the top cap wafer having at least one recess defining with the membrane at least one capacitance gap, the top cap wafer having formed therein at least one top cap electrode located over the membrane and forming, together with the membrane, at least one capacitor to detect a deflection of the membrane; at least a first electrical contact and a second electrical contact are provided on the top cap wafer, the first electrical contact being connected to one of said at least one top cap electrode and the second electrical contact being connected to the membrane by way of an insulated conducting pathway extending from the membrane and through the top cap wafer; a bottom cap wafer having inner and outer sides, the bottom cap wafer being bonded on its inner side to the second side of the MEMS wafer and enclosing the at least one cavity; and a vent provided in at least one of the top cap, bottom cap and MEMS wafer, the vent extending from outside of the MEMS pressure sensor into one of said at least one cavity and said at least one capacitance gap. |
