US Patent 7854365 Direct die attach utilizing heated bond head

A method is provided for bonding a die comprising a solder layer which has a melting point Tm. A bond head is heated to a bond head setting temperature T1, which is higher than Tm, and a substrate is heated to a substrate setting temperature T2, which is lower than Tm. The bond head then picks up the die and heats the die towards temperature T1 so as to melt the solder layer. The solder layer of the die is pressed onto the substrate so as to bond the die to the substrate, and thereafter the bond head is separated from the die so that the solder layer is cooled towards T2 and solidifies.