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Primary Examiner—William A. Powell
Attorney, Agent, or Firm—Roger May; Richard D.
A dry-release method for sacrificial layer microstructure fabrication is provided in which a structural layer is anchored to a substrate and deposited on a sacrificial layer located therebetween. Thereafter, holes are etched through the structural layer. Some of the holes are covered with a polymer layer, and portions of the sacrificial layer are then etched through the uncovered holes in the structural layer, creating void areas extending to the substrate. Preferably, the void areas also include undercut areas. The void areas are then filled with a protective polymer layer, creating temporary posts that extend from the surface of the substrate to the structural layer. The sacrificial layer is then removed by means of wet etching. The temporary posts provide support for the structural layer against capillary forces which are created by the evaporation of liquids used in the wet etching process. After wet etching of the sacrificial layer is completed, the temporary posts are removed by a dry etching technique. The resulting microstructure consists of a free-standing structural layer that is anchored to the substrate.
20 Oaims, 4 Drawing Sheets