SUBMICRON WAFER ALIGNMENT

摘要

Certain aspects relate to systems and techniques for submicron alignment in wafer optics. One disclosed method of alignment between wafers to produce an integrated lens stack employs a beam splitter (that is, a 50% transparent mirror) that reflects the alignment mark of the top wafer when the microscope objective is focused on the alignment mark of the bottom wafer. Another disclosed method of alignment between wafers to produce an integrated lens stack implements complementary patterns that can produce a Moiré effect when misaligned in order to aid in visually determining proper alignment between the wafers. In some embodiments, the methods can be combined to increase precision.

主权项

1. An optical wafer stack comprising:
a first transparent wafer including at least a first lens; a second transparent wafer including at least a second lens; a first spacer wafer positioned between the first transparent wafer and the second transparent wafer and including at least a first cell comprising a first perimeter around a first opening, the first lens and the second lens protruding at least partially into the first opening; a first alignment mark provided on the first transparent wafer; a second alignment mark provided on the second transparent wafer; and a first beam splitter layer disposed on a surface of the first spacer layer at a midpoint between an optical path between the first alignment mark and the second alignment mark.