How are MEMS different from semiconductors?
MEMS processes grew from traditional semiconductor technology. Over the last decade, the processing methodology for MEMS devices has evolved independently. While on the surface, both semiconductor and MEMS batch-process wafers patterned by photolithography, MEMS-specific manufacturing creates moving parts on wafers by removing sacrificial layers beneath desired mechanical structures. This fundamental difference has several processing implications. MEMS processing typically involves deeper, more specialized etches, and may fuse wafers into a stack to create a large multilayer device. MEMS devices may often have features on both sides of a wafer. Finally, while semiconductor foundries typically have process lines that are optimized for commodity production, MEMS foundries have become highly specialized and flexible to accommodate newly developed MEMS processes.
