Device encapsulation using physical vapor deposition

A method of forming a microelectromechanical system (MEMS) device, comprising:

• forming a first dielectric layer comprising a first dielectric material over a semiconductor substrate;
• forming a second dielectric layer over the first dielectric layer, the second dielectric layer comprising a different second dielectric material;
• forming a third dielectric layer over the second dielectric layer, the third dielectric layer comprising the first dielectric material;
• forming a plurality of openings in the third dielectric layer that expose the second dielectric layer;
• removing the second dielectric layer, thereby forming a cavity between the first and third dielectric layers and exposing an underside of the third dielectric layer;
• and
• forming a fourth dielectric layer over the third dielectric layer, the fourth dielectric layer comprising a different third dielectric material that seals the openings without depositing on one or more components exposed on the underside of the third dielectric layer.

A device, comprising:

• a microelectromechanical system (MEMS) structure, wherein the MEMS structure comprises a cavity, one or more microscale features disposed in the cavity, and one or more openings extending from a surface of the MEMS structure to the cavity;
• and
• a film disposed on the MEMS structure, wherein the film comprises a dielectric material;
• wherein a portion of the dielectric material is disposed in the cavity of the MEMS structure and contained to a surface area opposite at least one of the one or more openings and away from the one of more microscale features.