Etch process for etching microstructures
AssigneeApplied Materials, Inc.
InventorsJeffrey D. Chinn, Sofiane Soukane
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Abstract
A two-step method of releasing microelectromechanical devices from a substrate is disclosed. The first step comprises isotropically etching a silicon oxide layer sandwiched between two silicon-containing layers with a gaseous hydrogen fluoride-water mixture, the overlying silicon layer to be separated from the underlying silicon layer or substrate for a time sufficient to form an opening but not to release the overlying layer, and the second step comprises adding a drying agent to substitute for moisture remaining in the opening and to dissolve away any residues in the opening that can cause stiction.
Claims8
A method of releasing a microelectromechanical structure comprising a silicon oxide layer sandwiched between two silicon-containing layers, a first, substrate layer and a second, overlying layer to be released from the silicon oxide layer comprising, in sequence,
- a) isotropically etching a partial opening in the silicon oxide layer using a gaseous aqueous hydrogen fluoride etchant;
- and
- b) adding a polar drying agent to replace the moisture remaining in the partial opening, and dissolve away residues remaining therein.
A method of forming a microelectromechanical feature comprising
- a) isotropically etching a silicon oxide layer between two silicon-containing layers with gaseous aqueous hydrogen fluoride for a time period that provides an opening in the silicon oxide layer, but that does not allow the overlying silicon layer to collapse onto and adhere to the underlying silicon-containing layer;
- and
- b) adding a quantity of a drying agent so as to substitute the drying agent for water remaining in the opening and to dissolve residues remaining in the opening;
- and
- c) repeating steps a) and b) until complete release of the feature to be made is achieved.
Dependencies are inferred from the claim text.