Patent ID: 8109390

Claim:
A wafer container comprising: a top housing and a bottom housing that nest together to form a clam shell housing with an inner cavity for storage for at least one semiconductor wafer; said top housing having an essentially planar rectangular base with at least one rib that extends perpendicular from said base in an essentially circular orientation; said bottom housing having an essentially planar rectangular base with a plurality of inner and outer arc sector ribs that extend perpendicular from said base wherein said inner and outer arc sectors ribs are arranged concentric with said at least one rib that extends perpendicular from said base of said top housing, and said inner and outer arc sector ribs are formed such that the arc sector of at least one inner rib overlaps the arc sector of at least two outer ribs wherein said overlap of said at least one inner arc sector rib and said at least two outer arc sector ribs is an overlap of between 5 and 15 degrees when measured from a concentric origin of said arc sector ribs.