Dear all,

Recently I was trying to etch a 100um deep device by ICP. The mask I used
is photoresist. But it turned out that when the depth reached only about
40um, the photoresist was etched away. Is there anyone who knows how to
solve this problem? Or should I use another material as mask, say SiO2 or
metal. BTW, the gas in the ICP machine is N2. Thanks.

carol