Patent ID: 9505614
Filing Date: 2016-11-29
CPC Classification: B81B,B81C

Claim Text:
1. A method of fabricating a microphone having a sealing layer, comprising: providing a substrate wafer having a surface; etching trenches into the surface of the substrate wafer, the trenches to be through holes of a backplate; covering the surface of the substrate wafer with a sacrificial material, the sacrificial material filling the trenches; depositing a seal layer on the sacrificial material, the seal layer having a thickness of not greater than 500 nanometers; etching a seal aperture in the seal layer; adding additional sacrificial material within the seal aperture such that the additional sacrificial material is contiguous with the sacrificial material; depositing a diaphragm layer on the seal layer; etching a spring gap and springs into the diaphragm layer to define a diaphragm region in the diaphragm layer; etching a backside cavity in the substrate wafer to expose the sacrificial material; and removing the sacrificial material and the added sacrificial material to release the diaphragm layer such that the diaphragm layer is suspended by the springs and is movable relative to the backplate wherein the diaphragm layer and the backplate form a variable capacitor of a microphone, and the springs suspend the diaphragm layer when the microphone is in operation, and the seal layer seals the diaphragm region except at the location of the seal aperture.