CAD design of mask compensation patterns

The wet micromachining of silicon mechanical structures for sensors is a widely used process. But compensation of the corner undercutting is frequently needed. Hence a new method to design compensation mask patterns is proposed here that is based on a numerical simulation. New results on the convex corner undercutting in anisotropic etching of (100), [110] and (hhl) silicon are presented for TMAH and KOH etchants. Simulations of the convex undercutting are performed using the simulator TENSOSIM. For this purpose new software applications are developed that allow us to work with more complex mask patterns. Compensating beams are then studied for various orientations. Differently shaped masks patterns are numerically tested (influence of shape, of relative dimensions and of misalignment of mask patterns) showing that the simulator TENSOSIM is a very convenient CAD tool to design compensation structures for convex corner micromachining in silicon.