Patent ID: 7462560

Claim:
A process of physical vapor depositing mirror layer with improved reflectivity, comprising: loading a wafer into a PVD tool comprising a degas chamber, a Ti/TiN sputter deposition chamber, a cooling chamber, and a aluminum sputter deposition chamber; performing a wafer degas process within the degas chamber to pre-clean the wafer; transferring the wafer to the Ti/TiN sputter deposition chamber and deposition sputtering a layer of titanium or titanium nitride onto the wafer; and transferring the wafer to the aluminum sputter deposition chamber and during deposition sputtering a layer of aluminum onto the wafer at 40-50° C. to form the physical vapor depositing mirror layer, a backside gas is off, wherein the surface of the physical vapor depositing mirror layer is formed when the backside gas is off.