Thats right. And to speed up etching that is to further icrease the <100>/SiO2 etch rate ratio, add pyrazine to the EDP. Receipies are available. Good luck, -Ashutosh- On Fri, 12 Apr 2002, Amit Shiwalkar wrote: Hello, 500 um is a hugh depth, I dont know what is your feature size. SiO2 will not withstand KOH and there are problems even with TMAH. My suggestion is that you use Ethylene Diamine + Pyrocatechol mixture, where SiO2 will serve as an effective etch mask. Regards Amit Shiwalkar aslam muhammad wrote: > Hi Friends > > I want to use TMAH and KOH as etchant to > etch bulk silicon ( 500 micron). which one is more > suitable. my etch mask is SiO2. what is the recipe > of a good etching rate KOH and TMAH please. > > Thankx > > M. Aslam "Your reality is a figment of my Imagination" ......... To me you exist because I imagine that you do. _______________________________________________ mems-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.mems-exchange.org/ ================================================================================ Ashutosh Shastry Research Associate, Graduate Student, Microelectronics Group, School of Biosciences and Electrical Engineering Dept., Bioengineering, Phone: 091-22-5721791 I.I.T. Bombay, INDIA 400 076. Email: shastrys@vsnl.com Phone:091-22-5723655 =============================================================================== O Traveller, there is no such thing as PATH... .....paths are MADE by walking. ================================================================================