CPC H01L 24/75 (2013.01) [H01L 21/67092 (2013.01); H01L 21/681 (2013.01); H01L 23/544 (2013.01); H01L 21/68 (2013.01); H01L 21/682 (2013.01); H01L 2223/54426 (2013.01); H01L 2224/75703 (2013.01); H01L 2224/75753 (2013.01); H01L 2224/75901 (2013.01); Y10T 29/49 (2015.01); Y10T 29/49002 (2015.01); Y10T 29/49131 (2015.01); Y10T 29/49764 (2015.01); Y10T 29/53022 (2015.01)] | 20 Claims |
1. A method of aligning two wafers during a bonding process, the method comprising:
aligning a first wafer having a plurality of alignment markings with a second wafer having a plurality of alignment markings;
placing a plurality of flags between the first wafer and the second wafer;
detecting movement of the plurality of flags with respect to the first wafer and the second wafer using at least one sensor; and
determining whether the wafers remain aligned within an alignment tolerance based on the detected movement of the plurality of flags relative to the first wafer and the second wafer.
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