Numerical shaper optimization for sputtered optical precision filters

A novel optimization procedure for optical precision sputter coaters with respect to the f ilm homogeneity is demonstrated. For a coater concept based on dual cylindrical sputtering sources and a rotating turn-table as sample-holder, the inherent radial decay of the film thickness must be compensated by shaper elements. For that purpose, a simulation model of the particle flux within such a coater is set up and validated against experimental data. Subsequently, the shaper design is optimized according to the modeled metal flux profile. The resulting film thickness deviations are minimized down to ±0.35%.