Sealed wafer packaging of microelectromechanical systems
First Claim
1. A MEMS unit comprising:
- a MEMS device on a substrate;
a cover;
an adhesive sheet comprising cutouts for the MEMS device;
the adhesive sheet disposed between the substrate and the cover;
standoff posts spanning between the substrate and the cover; and
the substrate, the adhesive sheet, and the cover bonded together in registration;
whereby the MEMS device is sealed and protected from contamination.
1 Assignment
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Accused Products
Abstract
Multiple microelectromechanical systems (MEMS) on a substrate are capped with a cover using a layer that may function as a bonding agent, separation layer, and hermetic seal. A substrate has a first side with multiple MEMS devices. A cover is formed with through-holes for vias, and with standoff posts for layer registration and separation. An adhesive sheet is patterned with cutouts for the MEMS devices, vias, and standoff posts. The adhesive sheet is tacked to the cover, then placed on the MEMS substrate and heated to bond the layers. The via holes may be metalized with leads for circuit board connection. The MEMS units may be diced from the substrate after sealing, thus protecting them from contaminants.
30 Citations
17 Claims
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1. A MEMS unit comprising:
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a MEMS device on a substrate; a cover; an adhesive sheet comprising cutouts for the MEMS device; the adhesive sheet disposed between the substrate and the cover; standoff posts spanning between the substrate and the cover; and the substrate, the adhesive sheet, and the cover bonded together in registration; whereby the MEMS device is sealed and protected from contamination. - View Dependent Claims (2, 3, 4, 5, 6, 7, 17)
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8. A method of packaging microelectromechanical systems (MEMS) devices, comprising:
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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. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A sealed assembly of MEMS units comprising:
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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. - View Dependent Claims (16)
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Specification