US Patent 8489225 Wafer alignment system with optical coherence tomography

A system for performing alignment of two wafers is disclosed. The system comprises an optical coherence tomography system and a wafer alignment system. The wafer alignment system is configured and disposed to control the relative position of a first wafer and a second wafer. The optical coherence tomography system is configured and disposed to compute coordinate data for a plurality of alignment marks on the first wafer and second wafer, and send that coordinate data to the wafer alignment system.