Patent ID: 8381964

Claim:
A Sn—Ag bonding method comprising the steps of: providing a first wafer and a second wafer, evaporating a first bonding layer onto the first wafer while the first bonding layer is made of tin or tin alloy, evaporating a second bonding layer onto the second wafer while the second bonding layer is made of silver or silver alloy, cleaning surfaces of the first bonding layer and the second bonding layer, attaching the first bonding layer on the first wafer with the second bonding layer on the second wafer and being sent to a vacuum furnace, and heating the vacuum furnace to a certain temperature and bonding occurring between the first bonding layer and the second bonding layer, wherein bonding time of the bonding occurring between the first bonding layer and the second bonding layer ranges from 30 minutes to 4 hours.