Computer-aided profile optimization of ion-milled microstructures

摘要

Ion beam etching is an important patterning technique for target materials without volatile chemical etch products at moderate temperatures and pressures. Prior to the etching a simulation of the profile evolution is often performed in order to evaluate the correct process parameters. To speed up this procedure, we introduce the concept of the 'reduced parameters'. This permits a quick and comprehensive overview of profile etch characteristics. Reduced parameters are characteristic for the etch profile under certain objectives. We introduce three characteristic parameters, the lateral displacement, the trenching depth and the fidelity of pattern transfer. These parameters are evaluated with respect to their dependence on process parameters. Collected in a database they provide a means of making an easy parameter choice without detailed simulations. The etch profiles for the determination of these reduced parameters are calculated using the segment-motion algorithm IBEPM (ion beam etching program), which works with sputtering data generated by the well known Monte Carlo code TRIM (transport of ions in matter). To verify the simulation results we compare calculated trench profiles with experimental fabricated trenches in silicon and gold. [References: 18]