Structures for packaging stress-sensitive micro-electro-mechanical system stacked onto electronic circuit chip

摘要

A packaged micro-electro-mechanical system (MEMS) device (100) comprises a circuitry chip (101) attached to the pad (110) of a substrate with leads (111), and a MEMS (150) vertically attached to the chip surface by a layer (140) of low modulus silicone compound. On the chip surface, the MEMS device is surrounded by a polyimide ring (130) with a surface phobic to silicone compounds. A dome-shaped glob (160) of cured low modulus silicone material covers the MEMS and the MEMS terminal bonding wire spans (180); the glob is restricted to the chip surface area inside the polyimide ring and has a surface non-adhesive to epoxy-based molding compounds. A package (190) of polymeric molding compound encapsulates the vertical assembly of the glob embedding the MEMS, the circuitry chip, and portions of the substrate; the molding compound is non-adhering to the glob surface yet adhering to all other surfaces.