Wafer level sealing methods with different vacuum levels for MEMS sensors

摘要

The present disclosure relates to a method of forming a plurality of MEMs device having a plurality of cavities with different pressures on a wafer package system, and an associated apparatus. In some embodiments, the method is performed by providing a work-piece having a plurality of microelectromechanical system (MEMs) devices. A cap wafer is bonded onto the work-piece in a first ambient environment having a first pressure. The bonding forms a plurality of cavities abutting the plurality of MEMs devices, which are held at the first pressure. One or more openings are formed in one or more of the plurality of cavities leading to a gas flow path that could be held at a pressure level different from the first pressure. The one or more openings in the one or more of the plurality of cavities are then sealed in a different ambient environment having a different pressure, thereby causing the one or more of the plurality of cavities to be held at the different pressure.

主权项

1. A wafer level packaging (WLP) structure comprising:
a work-piece including a silicon region and including first and second micro-electromechanical system (MEMs) devices thereon; first and second cavities-disposed at least partially in the silicon region of the work-piece, and fluidly coupled to the first and second MEMs devices, respectively, wherein the first cavity retains a first pressure level and the second cavity retains a different second pressure level; a cap work-piece over the work-piece; a gas flow path that couples the second cavity to an opening in the cap work-piece; a sealant in the opening in the cap work-piece and sealing the gas flow path from an ambient environment external to the WLP structure; and a sealing residue that resides at a bottom surface of the second cavity.