[labnetwork] ICP etch of LiNbO3

[N . Shane Patrick]

Hello Paul,

We’ve had some experience now with lithium niobate materials in an Oxford Plasmalab 100 ICP tool using fluorine chemistry. The problem we have found is that the by-products are not truly volatile and tend to deposit on everything where they are, in subsequent processes, likely to to be etched and redeposited.

This has lead to micro masking, deposition on other substrates where it is not ideal, and plasma loading to the point of significant degradation of etch rates and uniformity. because of this, we were forced to do a hard, open chamber scrub and clean each time this process was run, followed by a few etch and clean cycles to get mostly back to normal operation. The maintenance time is such that I recommend staying away form this process if at all possible.

We’ve not seen a negative effect on ultimate vacuum pressure or pump lifetime, but we’ve also reduced the frequency at which we allow this process due to the cleaning involved, so it may be we just haven’t had enough material go through to truly evaluate pump performance and lifetime expectancy.

Best of luck. If you’d like more information on what we’ve seen, let me know and I’ll put you in contact with our etch engineer who has been attempting to cope with the matter.

N. Shane Patrick
Research Engineer, Washington Nanofabrication Facility (WNF)
National Nanotechnology Coordinated Infrastructure (NNCI)
University of Washington
Fluke Hall 132, Box 352143
(206) 221-1045
patricns at uw.edu <mailto:patricns at uw.edu>
http://www.wnf.washington.edu/ <http://www.wnf.washington.edu/>
> On Jan 18, 2018, at 11:28 AM, Horng, Paul S. <horng at udel.edu> wrote:
> 
> Hi,
> Has anyone had experience with plasma etching of LiNbO3 films ? It is hard to etch so higher platen power is needed to enhance physical sputtering. What is the impact on etch rate of other processes like etching of Si, SiO2, SiN, etc. in the same chamber ?  How often is chamber liner needed to be scrubbed clean ? Will it shorten the life of turbo pump ?
> 
> Thank You,
> 
> Paul S. Horng, Ph.D
> Process Engineer, UD NanoFab
> 457 ISE Lab
> 221 Academy Street, Newark, DE 19716
> (302)831-4827
> http://udnf.udel.edu <http://udnf.udel.edu/>
> 
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