Does anyone know a stable resist for protecting silicon wafers, which
can
be stripped after processing?

The resist will be applied by spin-coating. It must be stable for short
time (60s) at pH 13 and for 2 h at 90 C and pH 4.5. After the
wet-chemical
processes it has to be stripped. The stripping solution should not etch
Al.
Also it should not kill immediately the operator.