Fabrication and controlled release of structures using etch-stop trenches
AssigneeAnalog Devices, Inc.
InventorsMichael J. Daneman, Behrang Behin
Life of this patent
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Abstract
MEMS structures may be formed on a substrate by forming a series trenches filled with etch-stop material in the device layer, followed by an isotropic etch of the device material stopping on the etch-stop material. This approach provides a controlled release method where the exact timing of the isotropic release etch becomes non-critical. Further, using this method, structures with significant topology may be fabricated while keeping the wafer topology to a minimum during processing until the very end of the process. Using the method of this invention, features with large topology may be formed while keeping the wafer topology to a minimum until the very end of the process.
Claims25
A method for a controlled release of structures comprising:
- a) forming one or more trenches in a layer of device material;
- b) filling one or more selected trenches with an etch-stop material to form one or more etch-stop trenches;
- c) defining one or more structures between the selected trenches;
- d) forming a structural layer proximate one or more exposed areas of the device layer, wherein the structural layer includes one or more structures that are formed directly on top of an etch-stop layer;
- and
- e) etching one or more portions of the device layer between the etch-stop trenches to release the structures, wherein the etching does not etch the etch-stop material.
A process for forming structures comprising:
- i) forming one or more trenches in a layer of device material;
- ii) filling one or more selected trenches with an etch-stop material to form one or more etch-stop trenches;
- iii) masking a surface of the layer of device material to expose one or more selected areas of device material that border one or more of the etch-stop trenches;
- and
- iv) forming one or more structures on one or more of the selected areas of the device material that were exposed;
- and
- v) etching one or more of the selected areas of the device layer to release the structures, wherein the etching does not etch the etch-stop material.
Dependencies are inferred from the claim text.