Hi Shweta, your question is a little bit confusing to me. HF doesn't etch Si at all. And I can just hardly imagine that you oxidize your Si-Wafer with an 80k Angstrom thick oxide. I etched 5k Angstrom thick oxide in HF (approximately 6-7 minutes) and this is no problem with S1813. Why don't you just pattern your SiO2 and etch the trenches into Si with TMAH for about 4 minutes? Andreas Jahn Office: (301)975 4710 -----Original Message----- From: R. Brent Garber [mailto:garber@engr.uconn.edu] Sent: Monday, March 17, 2003 9:49 AM To: shweta@ece.gatech.edu; General MEMS discussion Subject: Re: [mems-talk] HF attack of PR Shipley 1813 I don't know what is on you Si, but I dry etch Si in SF6 @ 5mT in a RIE at 70 watts with a 4min/um rate. Resist will never withstand a 4um etch in my experience and wet etching that deep will not be easy. Brent Shweta Humad wrote: > Hi all, > I was thinking of a process which would involve a last step of HF wet > etching to create 4 micron deep trenches in silicon. I'm not sure how > long the photo resist can withstand the HF. The photo resist would be > Shipley 1813. I could use BOE also instead of HF but that would take > even longer. Has anyone does this before? > > Thank you > -- > Shweta Humad > Office: (404) 385-4306/2400 > > _______________________________________________ > 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.memsnet.org/ -------------- next part -------------- A non-text attachment was scrubbed... Name: garber.vcf Type: text/x-vcard Size: 371 bytes Desc: Card for R. Brent Garber Url : http://mail.mems-exchange.org/pipermail/mems-talk/attachments/20030317/973df ebb/garber.vcf