Patent ID: 8921144

Claim:
A method of forming at least one Micro-Electro-Mechanical System (MEMS), comprising: forming a lower sacrificial material used to form a lower cavity; forming a cavity via connecting the lower cavity to an upper cavity, the cavity via being formed with a top view profile of rounded or chamfered edges prior to venting the lower sacrificial material; and forming an upper sacrificial material within and above the cavity via, which has a resultant surface based on the profile of the cavity via; and wherein: the upper cavity is formed with a lid that is devoid of structures that would interfere with a MEMS beam, comprising: depositing a lid material on the resultant surface of the upper sacrificial material; and venting the upper sacrificial material to form the upper cavity such the lid material forms the lid which conforms with the resultant surface of the upper sacrificial material; the forming of the upper sacrificial material comprises using a non-regressive silicon deposition process to form a profile comprising tapered side walls on an upper surface; the non-regressive silicon deposition process comprises a conformal silicon deposition process including performing multiple plasma vapor deposition (PVD) silicon deposition and rf biased wafer etchback steps; and the non-regressive deposition process eliminates a regressive overhang structure of the lid material.