Complex micro-patterning in silicon with varied tilt angles realized by advanced plasma etching

The objective of our investigations was to develop a new etching process, which accomplished well defined positive etch profiles in silicon. Using this so-called PPE-process (Positive Profiles Etching process) we realized patterns in silicon with tilt angles of the sidewalls between 60 and 88° and an etch depth up to 200 μm. Etch rates between 3 and 5 μm/min can be achieved and a large number of process parameters enables the variation of the etch profiles in a wide range. Based on these results we could create complex etch profiles by a combination of several silicon etching processes according to application-oriented demands.