We have used BCB-Cyclotene as a self aligned mask with different etching
schemes and chemical agents. As long as BCB is properly cured it will
withstand the KOH wet ecth. I would suggest curing it at 250'C for at least
one hour in forming gas ambient which will suffcicently prepare the BCB.
After the KOH step BCB could be readily removed in O2/CF4 (80%/20%)
plasma using moderate settings. You may consider thinning down BCB
before application to reach higher photo resolution if there are fine features
and/or reduce plasma etching time in the last BCB removing step.
Ivan Shubin
Research Scientist
ECE Department, UCSD
9500 Gilman Drive
La Jolla, CA 92093
ph./fax 858-534-3627