Title: Method of anti-stiction dimple formation under MEMS
US. Patent: 7,919,006
Assignee: Freescale Semiconductor, Inc.
Abstract: A method for making a MEMS structure comprises patterning recesses in a dielectric layer overlying a substrate, each recess being disposed between adjacent mesas of dielectric material. A conformal layer of semiconductor material is formed overlying the recesses and mesas. The conformal layer is chemical mechanically polished to form a chemical mechanical polished surface, wherein the chemical mechanical polishing is sufficient to create dished portions of semiconductor material within the plurality of recesses. Each dished portion has a depth proximate a central portion thereof that is less than a thickness of the semiconductor material proximate an outer portion thereof. A semiconductor wafer is then bonded to the chemical mechanical polished surface. The bonded semiconductor wafer is patterned with openings according to the requirements of a desired MEMS transducer. Lastly, the MEMS transducer is released. Releasing advantageously exposes anti-stiction features formed from outer edges of the dished portion of semiconductor material.
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