MEMS device and manufacturing process thereof
First Claim
1. A MEMS device, having associated therewith at least one cavity, on a substrate, comprising:
- a sacrificial layer formed over the substrate;
a lid comprising a thin film atop said sacrificial layer, wherein said lid at least partially covers said sacrificial layer, and wherein said lid includes at least one selected from the group consisting of a slit, a beam, and a spring, for relaxing an internal stress on said lid; and
a sealing film for filling filling a plurality of openings in said lid, wherein said sealing film at least partially seals the cavity from an opposing side of said lid.
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Accused Products
Abstract
MEMS devices require special cavity formation and sealing steps such as wafer bonding which reduce the yield and increase the cost. In addition, it is difficult to form a cavity of a large area by the LSI process owing to a residual stress of a sealing film which will be a lid. This leads to a difficulty of realizing an integrated MEMS having a MEMS and a high-performance LSI mounted on one substrate. The lid (or diaphragm) covering therewith a cavity is equipped with slits or beams. During the formation of the cavity, the slits are deformed to absorb and relax the internal stress of the thin sealing film. Then, the cavity is sealed by filling the open portions of the film overlying the cavity between the inside and outside of the cavity. The cavity is formed by removing a portion of the interlayer film of LSI multilevel interconnects and the lid is made of a LSI-process thin film.
136 Citations
15 Claims
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1. A MEMS device, having associated therewith at least one cavity, on a substrate, comprising:
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a sacrificial layer formed over the substrate; a lid comprising a thin film atop said sacrificial layer, wherein said lid at least partially covers said sacrificial layer, and wherein said lid includes at least one selected from the group consisting of a slit, a beam, and a spring, for relaxing an internal stress on said lid; and a sealing film for filling filling a plurality of openings in said lid, wherein said sealing film at least partially seals the cavity from an opposing side of said lid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A manufacturing process for a MEMS device having at least one cavity and a movable body, comprising:
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stacking a second thin film over a first thin film, wherein the first thin film is formed over a substrate, forming a plurality of slits, and at least one beam defined by the slits, in the second thin film, removing a portion of the first thin film via the slits to form a cavity in the first thin film below the second thin film, and deforming at least one of the slits and the beam during said removing to form the cavity, wherein residual stress in the second thin film is relaxed by said deforming. - View Dependent Claims (12, 13, 14)
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15. A manufacturing process of an MEMS device, further comprising:
leaving the first thin film in a portion of the cavity to allow the first film to serve as a support for the second thin film.
Specification