Patent ID: 7919391

Claim:
A method of enhancing bonding energy between a first wafer surface and a second wafer surface, while reducing or minimizing transfer defects, to facilitate transfer of a layer from the first wafer to the second wafer, which comprises: providing the first wafer as a donor wafer, wherein the donor wafer includes an implanted species that forms a zone of weakness at a predetermined depth beneath a surface of the donor wafer to be bonded that defines a layer to be transferred; providing the second wafer as a receiving wafer; providing one or both of the first and second wafers with a silicon oxide layer, wherein the first wafer and second wafer or their silicon oxide layer(s) present a bonding surface for bonding the wafers together; cleaning one or both bonding surfaces before applying the activation solution; applying an activating solution to one or both bonding surfaces immediately prior to bonding for a period of 10 seconds to 2 minutes for activating the bonding surface(s), wherein the activating solution comprises ammonia in water (NH4OH) in a concentration by weight in the range from about 0.05% to 0.8% without any hydrogen peroxide (H 2 O 2 ) while brushing the bonding surface(s) to be activated in order to enhance bonding energy between the wafers; bonding the donor and receiving wafers together at the bonding surfaces by contacting the at least one activated bonding surface and the other bonding surface; and detaching the layer at the weakened zone to transfer it to the receiving wafer.