Encapsulated MEMS devices and methods of fabrication with wafer-level fabrication processes are described which address small molecule diffusion into hermetically sealed cavities. In some configurations a small molecule barrier layer, or hydrogen barrier layer, is formed during a back-end-of-the-line (BEOL) processing over a cap wafer including a planarized surface formed during a via reveal griding operation. In some configurations a small molecule barrier layer is not formed over the planarized surface during BEOL processing in order to allow an escape path for small molecules. In some configurations a small molecule barrier layer, or hydrogen barrier layer, is formed on a bottom side of a cap wafer prior to bonding the cap wafer to a device wafer during wafer-level fabrication.

A micro-electro-mechanical system (MEMS) device includes a supporting substrate, a cavity disposed in the supporting substrate, a stopper, and a MEMS structure. The stopper is disposed between the supporting substrate and the cavity, and an inner sidewall of the stopper is in contact with the cavity. The stopper includes a filling material surrounding a periphery of the cavity, and a liner wrapping around the filling material. The MEMS structure is disposed over the cavity and attached on the stopper and the supporting substrate.

A micro electro mechanical system (MEMS) includes a circuit substrate comprising electronic circuitry, a support substrate having a recess, a bonding layer disposed between the circuit substrate and the support substrate, through holes passing through the circuit substrate to the recess, a first conductive layer disposed on a front side of the circuit substrate, and a second conductive layer disposed on an inner wall of the recess. The first conductive layer extends into the through holes and the second conductive layer extends into the through holes and coupled to the first conductive layer.

A microstructure with high bonding strength includes a substrate, a deposition layer, and a first dielectric layer. The substrate has a first surface. The first surface has a covered area and an exposed area. The deposition layer has a plurality of nanoscale metal particles. The deposition layer is disposed on the covered area of the first surface. The exposed area is exposed from the deposition layer. The deposition layer has a bonding face on one side away from the first surface. The first dielectric layer is disposed on the bonding face and contacts the exposed area. With the connection structure between the first dielectric layer and the exposed area of the substrate, a hotspot structure formed by the deposition layer and the first dielectric layer is more stably fixed to the substrate, thereby improving bonding strength of the overall structure.

A method includes forming a microelectromechanical system (MEMS) device wherein the MEMS device includes a cavity and one or more release holes extending from a surface of the MEMS device to the cavity, and sealing at least a portion of the MEMS device including the one or more release holes with a film utilizing a physical vapor deposition (PVD) process.

A device includes one or more layers of a microelectromechanical system (MEMS) structure and a dielectric stack over the one or more layers. The dielectric stack includes a first dielectric layer having a first index of refraction, and a second dielectric layer having a second index of refraction different than the first index of refraction.

A method of fabricating a micro-electro-mechanical system (MEMS) device, the steps include: providing a supporting substrate; etching the supporting substrate to form a trench, where the trench surrounds a portion of the supporting substrate; forming a liner in the trench; filling up the trench with a filling material to form a stopper, wherein the stopper comprises the liner and the filling material; forming a MEMS structure on the stopper and the supporting substrate, wherein the MEMS structure includes a through hole; and etching a portion of the supporting substrate to form a cavity by providing an etchant through the through hole, wherein the stopper is in contact with the cavity.