[labnetwork] ICP etch of LiNbO3

[Deng, Jiangdong]

HI, Paul,
We in CNS evaluated different chambers and ICP systems for LiNbO3 etching, and it turned out Ulvac ICP NLD-570 gave us better results.  Instead of fluorine, we just used Ar (physical sputtering). Redeposition is always an issue for LiNbO3 etching, and it is critical to tune the power, pressure and temperature.  This etching process/recipe have been used for LiNbO3 high speed modulator application for about 2 years (please check Prof. Marko Loncar group's recent publication).
Our ULVAC NLD-570 RIE is dedicated for oxide material etching, we haven’t seen too much impact to the SiO2, SiN etching. We have different chamber for Si device process. the tool is relative new (2 years old), we just opened the chamber for deep PM once.
Please feel free to contact us (Kenlin- cced and myself) if you need more detailed information…

Best!


-JD


-- Jiangdong Deng (JD), Ph.D,

Associate Director
Senior Principal Scientist,
Center for Nanoscale Systems,
Head of Nanofabrication Facility
Harvard University,
Cambridge, MA 02138
Tel: 617-495-3396



From: <labnetwork-bounces at mtl.mit.edu<mailto:labnetwork-bounces at mtl.mit.edu>> on behalf of "patricns at uw.edu<mailto:patricns at uw.edu>" <patricns at uw.edu<mailto:patricns at uw.edu>>
Date: Thursday, January 18, 2018 at 4:57 PM
To: "Horng, Paul S." <horng at udel.edu<mailto:horng at udel.edu>>
Cc: "labnetwork at mtl. Network" <labnetwork at mtl.mit.edu<mailto:labnetwork at mtl.mit.edu>>
Subject: Re: [labnetwork] ICP etch of LiNbO3

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/

On Jan 18, 2018, at 11:28 AM, Horng, Paul S. <horng at udel.edu<mailto: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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