We have recently begun processing wafers using a new plasma system for doing
deep silicon etch. Since our goal is 100 microns of vertical etch profile in
silicon we are interested in what types of positive photoresists MEMS people
are using. Our initial results with standard positive resist at thicknesses
of around 1.2 microns have not yielded very consistant results. Work that we
have done with SU-8 resist have been very good with respect to profile and
depth of etch using a formulation of around 5 microns thickness. This also
allows us to ash off the SU-8 after etch with little problem. My question is
what type of resists are acceptable within the MEMS community that will yield
at least a 4-5 micron thickness with vertical profiles using stepper or other
alignment tools. Bob Henderson