CPC H01S 5/0237 (2021.01) [B23K 1/0056 (2013.01); H01S 5/4025 (2013.01); B23K 2101/40 (2018.08)] | 14 Claims |
1. An apparatus for sequential bonding comprising:
a stage to receive a substrate having a plurality of receiving pads, wherein a first and a second receiving pads of said plurality of receiving pads each comprise a first metal alloy;
a first pickup head configured to attach a first semiconductor chip comprising a first metal layer to said first receiving pad;
a first heating unit coupled to said first pickup head to raise a temperature of said first semiconductor chip according to a first temperature profile to cause intermixing of said first metal layer on said first semiconductor chip and said first metal alloy of said first receiving pad to form a second metal alloy having a higher melting point than said first metal alloy;
a second pickup head configured to attach a second semiconductor chip comprising a second metal layer to said second receiving pad; and
a second heating unit coupled to said second pickup head to raise a temperature of said second semiconductor chip according to a second temperature profile to cause intermixing of said second metal layer on said second semiconductor chip and said first metal alloy of said second receiving pad to form a third metal alloy having a higher melting point than said first metal alloy;
wherein said first temperature and said second temperature profiles are based on a common set of temperature set points and time durations and wherein said second temperature profile is executed after a completion of said first temperature profile.
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