<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hi Chris,<div><br></div><div>We have the occasional person etching HfO2, usually as a piece mounted to Si, and we run straight BCl3. A SiCl4 clean is supposed to work really well to remove Hf residues. What you can do is run a low pressure Cl2 recipe on Si with a decent amount of bias power to get a mix of Cl2 and SiCl4. There’s a really good paper on the topic where they use the air-gap technique and a XPS: <a href="https://pubs.aip.org/avs/jvb/article/26/1/181/468121">https://pubs.aip.org/avs/jvb/article/26/1/181/468121</a></div><div><br></div><div>Thanks,</div><div>Shawn Wright</div><div>Lurie Nanofabrication Facility</div><div>University of Michigan </div><div><div><br><blockquote type="cite"><div>On Mar 19, 2025, at 3:12 PM, Christopher Raum <crraum@gmail.com> wrote:</div><br class="Apple-interchange-newline"><div><div dir="ltr">
<div>Hi all,</div><div><br></div><div>I'm interested in etching roughly
100 nm of Hf on silicon. There's a concern about the etch byproducts
(mainly HfCl4) being difficult to remove and therefore causing chamber contamination
for subsequent users.</div><div><br></div><div>Does anyone out there have experience plasma etching Hf? If so</div><div><br></div><div>1) Can you confirm a Cl based etch is best? Any luck using a F based etch?</div><div>2) What is the post-etch chamber clean recipe that you use?</div><div><br></div><div>Thanks for your help!</div><div><br></div><div>-Chris</div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr">R&D Engineer 3<br>Experimental Cosmology Group<br>Radio Astronomy Lab<br>University of California, Berkeley<br>278 LeConte Hall<br>Berkeley, CA, <br>Email: <a href="mailto:craum@berkeley.edu" target="_blank">craum@berkeley.edu</a></div></div>
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