The typical scheme of electron beam physical vapor deposition of gold for microelectronics is a set of wafers held on a rotating spherical dome. This scheme provides deposition uniformity less than 2% with wafers of diameter D_w < 5".

Tendencies of technology require an increase of the wafer sizes D_w up to 8" and higher. The deficiency of the multi-wafer deposition scheme for large wafer coating is a fast decrease of deposition rate with the increase of the dome radius, as long as the uniformity condition for the deposited film is R_d >>> D_f.  Also, the collection efficiency is one of the critical issues for gold deposition. The problem stated above demands a change of the technological scheme and the possible solution is a single wafer deposition scheme.

The simulation of gold evaporation and vapor transport to the wafer surface is carried out. The multi-wafer, single crucible technological scheme is calculated in order to compare with experiment and to obtain basic characteristics, such as velocity distribution functions of evaporant atoms over the wafer surface, which gives the distribution of deposition intensity and impingement angles over the surface. The comparison with experimental results obtained in BOC Coating Technology (Fairfield California) allowed evaluating the surface reaction parameters.

An alternative single-wafer scheme with a single crucible shifted 5cm outside the symmetry axis was also simulated. The rotating wafer of 8" is suspended 50-80cm above the evaporation plane. Deposition pressure is varied 0.5-3mTorr. In addition a carrier gas (He) is injected through the ring type nozzle at 5-20mTorr pressures.