Simulation of X-ray mask repair by means of FIB-technology

The angular dependence of the sputter yield of a 100 keV gallium FIB (focused ion beam) on gold was determined by evaluating the sufficient ion dose for complete removal of a 0.8 mym thick electroplated gold layer. For two angles of incidence (O degree, 45 degree), the redeposition characteristics of sputtered gold particles were measured. They can be approximated by a cos high 2 function. With these data included, simulations of FIB-processes were carried out, both concerning the structuring of III-V compounds and the repair of opaque defects in X-ray masks. By parameter variation in the simulations, the sticking coefficient of sputtered gold particles was found to be my = 0.5 plus minus 0.1.