TITANIUM SPUTTER-DEPOSITION AT LOW-PRESSURES AND LONG THROW DISTANCES

Sputter deposition of titanium into trench and via topography has been studied under conditions of pressure as low as 0.3 mTorr (0.04 Pa) fo r long (30 cm) and short (9 cm) throw distances, Film resistivity and deposition rates at both distances have been measured for pressures fr om 0.3 mTorr up to 5 mTorr (0.67 Pa). Pinhole experiments have been us ed to examine the evolution of the angular distribution of sputtered f lux as a function of pressure and distance, The experimental results s how that by increasing the throw distance and reducing pressure, the b ottom coverage in high aspect ratio topographical features may be incr eased to almost 90% but thickness nonuniformity under these conditions remains a significant problem due to the size of the target, We have tested for the presence of resputtering in the highly energetic, low c ollision regime which arises at low pressure and no resputtered materi al has been detected.