US Patent:
20020187595, Dec 12, 2002
Inventors:
Hans Walitzki - Portland OR, US
Kurt Dichmann - Banks OR, US
Thomas Magee - Lake Oswego OR, US
Claudian Nicolesco - Portland OR, US
Assignee:
Silicon Evolution, Inc. - Vancouver WA
International Classification:
H01L021/338
Abstract:
A method for the production of silicon-on-insulator (SOI) wafers for controlling the device layer thickness variations and improvement of bonding quality at the interface of the wafers is disclosed. Using standard etched wafers, a unique sequence of process steps consisting of 2-step front side grinding, free-floating simultaneous double side polishing prepares wafers with low TTV and reduced edge roll off zones. The much smaller unbonded edge zone eliminates the requirements for edge grinding or etching in most cases. When the same s-step grinding/FFS-DSP sequence is applied after bonding and annealing of a Silicon-on-Insulator package, the resulting thickness variation in the device layer is usually smaller than what would be obtained from prior art processes.