Patent ID: 9150408
Filing Date: 2015-10-06
Classification: B81B,B81C,H01L

Abstract:
1. A method of etching a plurality of cavities in a wafer, the method comprising: providing a wafer having a patterned hard mask layer on a side of the wafer, the patterned hard mask layer having open areas to define locations for first cavities and second cavities; applying a mask over the side of the wafer, thereby covering the patterned hard mask layer; after applying the mask, etching the wafer to remove wafer material from areas defining the second cavities; removing the mask; after removing the mask, performing a step of etching, wherein removal of wafer material is prevented by the hard mask layer at areas covered by the hard mask layer and removal of wafer material takes place in areas not covered by the hard mask layer so as to form a plurality of first cavities in the side of the wafer, the first cavities having a first depth, and to further deepen a plurality of second cavities in the side, such that each of the second cavities has a greater depth than the first depth.