Sealed wafer packaging of microelectromechanical systems

A method of packaging microelectromechanical systems (MEMS) devices, comprising:

• forming multiple MEMS devices and electrical contact pads therefor on a first side of a MEMS substrate;
• forming first and second etching masks on respective first and second sides of a cover;
• reducing parts of the second side of the cover by etching through the second etching mask, thus forming standoff posts on the second side of the cover;
• depositing a working layer on the second side of the cover;
• reducing parts of the first side of the cover by etching through the first etching mask to the working layer, thus forming through-holes in the cover for vias;
• stripping the working layer and the etching masks from the cover;
• patterning an adhesive sheet to match the cover and the MEMS substrate with respective cutouts in the adhesive sheet for the MEMS devices, the vias, and the standoff posts;
• bonding the second side of the cover to the first side of the MEMS substrate using the adhesive sheet as a bonding layer, with the through-holes of the cover in registration with the respective cutouts in the adhesive sheet and with the pads of the MEMS substrate;
• metalizing the through-holes in the cover and the respective cutouts in the adhesive sheet for the vias to form leads;
• and
• singulating the now-sealed MEMS devices into individual packages after the above steps are complete.

A sealed assembly of MEMS units comprising:

• a plurality of MEMS devices on a substrate;
• a cover for the plurality of MEMS devices, the cover comprising standoff posts and through-holes for vias;
• an adhesive sheet comprising respective cutouts for the MEMS devices, the standoff posts, and the vias;
• the adhesive sheet disposed between the substrate and the cover;
• the standoff posts spanning between the substrate and the cover, providing separation therebetween, and providing registration between the cover and the adhesive sheet;
• the substrate, the adhesive sheet, and the cover bonded together in registration;
• and
• the vias metalized;
• whereby the MEMS devices are sealed and protected from contamination.