Encapsulation of MEMS devices using pillar-supported caps
AssigneeIC Mechanics, Inc.
InventorsL. Richard Carley, Suresh Santhanam, Hsu Yu-Nu
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Abstract
This invention comprises a process for fabricating a MEMS microstructure in a sealed cavity wherein the etchant entry holes are created as a by-product of the fabrication process without an additional step to etch holes in the cap layer. The process involves extending the layers of sacrificial material past the horizontal boundaries of the cap layer. The cap layer is supported by pillars formed by a deposition in holes etched through the sacrificial layers, and the etchant entry holes are formed when the excess sacrificial material is etched away, leaving voids between the pillars supporting the cap.
Claims26
A method of fabricating a sealed cavity for containing a microstructure comprising the steps of:
- providing a substrate;
- depositing one or more sacrificial layers on said substrate;
- creating a plurality of holes through said one or more layers of sacrificial material to said substrate;
- depositing a cap layer on top of said one or more sacrificial layers, said cap layer forming pillars supporting said cap in said plurality of etched holes;
- and
- introducing an etchant to said device such that said one or more sacrificial layers are etched away by said etchant and wherein said etchant enters the area under said cap layer through holes formed when said one or more sacrificial layers is etched from between said plurality of pillars.
A method of fabricating a sealed cavity for containing a microstructure comprising the steps of:
- providing a substrate;
- depositing a first layer of sacrificial material on said substrate;
- forming a microstructure on said first sacrificial layer of any desired shape;
- depositing a second layer of sacrificial material on said first layer of sacrificial material, covering said microstructure;
- creating a plurality of holes through said one or more layers of sacrificial material to said substrate;
- depositing a cap layer on top of said one of more sacrificial layers, said cap layer forming pillars supporting said cap in said plurality of etched holes;
- introducing an etchant to said device such that said one or more sacrificial layers are etched away by said etchant and wherein said etchant enters said sealed cavity through holes formed when said one or more sacrificial layers is etched from between said plurality of pillars;
- and
- depositing a seal layer on top of said cap layer, said seal layer sealing said etched areas between said plurality of pillars.
Dependencies are inferred from the claim text.