A process of physical vapor depositing mirror layer with improved reflectivity is disclosed. A wafer is loaded into a PVD tool comprising a degas chamber, a Ti/TiN sputter deposition chamber, a cooling chamber, and an aluminum sputter deposition chamber. A wafer degas process is first performed within the degas chamber. The wafer is then transferred to the Ti/TiN sputter deposition chamber and deposition sputtering a layer of titanium onto the wafer. The wafer is transferred to the cooling chamber and gas cooling the wafer temperature down to 40-50° C. The wafer is then transferred to the aluminum sputter deposition chamber and deposition sputtering a layer of aluminum onto the wafer at 40-50° C. with a backside gas turned off. The deposited layer of aluminum over the wafer has a reflectivity of about 0.925 at wavelength of around 380 nm.