[labnetwork] Question on hafnium etching and the post-etch chamber clean.

[Shawn Wright]

Hi Chris,

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:  https://pubs.aip.org/avs/jvb/article/26/1/181/468121

Thanks,
Shawn Wright
Lurie Nanofabrication Facility
University of Michigan 

> On Mar 19, 2025, at 3:12 PM, Christopher Raum <crraum at gmail.com> wrote:
> 
> Hi all,
> 
> 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.
> 
> Does anyone out there have experience plasma etching Hf? If so
> 
> 1) Can you confirm a Cl based etch is best? Any luck using a F based etch?
> 2) What is the post-etch chamber clean recipe that you use?
> 
> Thanks for your help!
> 
> -Chris
> -- 
> R&D Engineer 3
> Experimental Cosmology Group
> Radio Astronomy Lab
> University of California, Berkeley
> 278 LeConte Hall
> Berkeley, CA,     
> Email: craum at berkeley.edu <mailto:craum at berkeley.edu>
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