Dear MEMS-Talk Community,

I am looking for references on isotropic dry etching of sacrificial
photoresist layers for surface micromachined MEMS. The etch should be
selective for resist (Shipley S1827 in our case) over silicon, oxide, and --
especially -- aluminum. I have seen O2 and O2/CF4 plasmas referred to as
"standard" processes, but those mentions did not give details like maximum
undercut, etch rate, and selectivity. We have tried pure O2, and the etch
rate was unacceptably slow. Our desired undercut is tens of microns, while
the sacrificial layer thickness is about 3 um.

We have developed a good process using an O2/CHF3 plasma, and I would like
to see how its performance compares. Can anyone direct me to some relevant
papers?

Thanks!
Jordan