Technical noteThermal controlHybrid bonding that heats only the Cu bond interface, not the whole wafer
Hybrid bonding heats an entire wafer for 0.5 to 4 hours to complete the Cu bond, even though the heat is needed only within a few micrometres of the interface. This technical note sets out an approach that transmits 1500 nm light through the silicon substrate and generates heat for nanoseconds only in an absorbing layer behind the Cu pad, together with the reasoning behind the design.