Capacitive pressure sensor and method
AssigneeRobert Bosch GmbH
InventorsAndo Feyh, Andrew B. Graham
Life of this patent
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Abstract
In one embodiment, a method of forming a MEMS device includes providing a silicon wafer with a base layer and an intermediate layer above an upper surface of the base layer. A first electrode is defined in the intermediate layer and an oxide portion is provided above an upper surface of the intermediate layer. A cap layer is provided on an upper surface of the oxide portion and a second electrode is defined in the cap layer. The method further includes etching the oxide portion to form a cavity such that when the second electrode and the cavity are projected onto the intermediate layer, the projected second electrode encompasses the projected cavity.
Claims20
A method of forming a MEMS device comprising:
- providing a base layer;
- providing an intermediate layer above an upper surface of the base layer;
- defining a first electrode in the intermediate layer;
- providing an oxide portion above an upper surface of the intermediate layer;
- providing a cap layer on an upper surface of the oxide portion;
- defining a second electrode in the cap layer;
- and
- etching the oxide portion to form a cavity such that when the second electrode and the cavity are projected onto the intermediate layer, the projected second electrode encompasses the projected cavity.
A MEMS device with a highly impermeable cap layer comprising:
- a base layer;
- an intermediate layer above an upper surface of the base layer;
- a first electrode defined in the intermediate layer;
- a cap layer above an upper surface of the intermediate layer;
- a cavity defined by the cap layer and the intermediate layer, the cavity at least partially directly above the first electrode;
- and
- a second electrode in the cap layer, the second electrode extending laterally beyond the cavity such that when the second electrode and the cavity are projected onto the intermediate layer, the projected second electrode encompasses the projected cavity.
Dependencies are inferred from the claim text.