Patent ID: 6827869
Filing Date: 2004-12-07
Classification: B81B,B81C,H01L

Abstract:
A method of forming a multi-part cavity in a substrate, the method comprising the steps of:a) etching said substrate to a first predetermined depth to form a shaped opening; b) forming a conformal protective layer overlying at least a sidewall of said shaped opening, wherein said protective layer comprises a material having a different etch selectivity than said substrate; and c) etching said substrate to a second predetermined depth to form a shaped cavity using a plasma generated from an etchant source gas which selectively etches said substrate relative to said protective layer, wherein said shaped cavity directly and completely underlies and is in continuous communication with said shaped opening, wherein at least a portion of said shaped cavity exhibits a cross sectional dimension on a plane parallel with the upper surface of said substrate, which cross-sectional dimension is larger than the largest cross-sectional dimension of said shaped opening on a plane parallel with said substrate upper surface, and whereby said protective layer effectively preserves the profile of said shaped opening during etching of said shaped cavity, whereby the shape of said shaped cavity is controlled.