[labnetwork] Pegasus - Rapier Esc question

[Morrison, Richard H., Jr.]

Draper installed a new Rapier last summer. This our current process control on the ESC chuck:

3-6 sccm flow at 10 Torr
We clean the chamber with O2 plasma when the flow rate gets to  8- 10sccm at 10Torr pressure.
If He flow does not reduce, we open chamber and clean the ESC chuck manually.

We have very tight specs on cleaning the wafer backside to remove particles. Our tool is setup for either 100mm or 150mm wafer size.

Rick


Draper
Principal  Member of the Technical Staff
555 Technology Square
Cambridge Ma, 02139-3563

www.draper.com
rmorrison at draper.com
W 617-258-3420
C 508-930-3461



From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Kevin Owen
Sent: Monday, June 13, 2016 4:17 PM
To: LaFleur, David W <dlafleur at cns.fas.harvard.edu>
Cc: labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Pegasus - Rapier Esc question

We have 2 Pegasus systems, one 4" and one 6", and a 6" APS, all with 6kV esc's. Assuming the same software and recipe format, it's in the "leak check" step defined for each recipe. There should be a warning level and a fault level. Ours is set for 125 mTorr/min warning, 150 mTorr/min fault. On the APS, it's higher (200 mTorr/min fault), since that chuck is older and more worn and we don't get as good leak checks on it. It doesn't really affect process as long as the chuck and wafer are clean so you are getting consistent results wafer-to-wafer.

We typically run 10 Torr backside pressure, most recipes are either 10C or 20C (although temperature doesn't really seem to matter for this). With brand new, shiny ESCs, we've seen anywhere from 10-40 mTorr/min. Leak rates then slowly increase over time as the chucks wear. With proper care, they seem to last a few years before it gets uncomfortably high (to me, uncomfortable is ~150 mTorr/min) and we replace them. Currently, both Pegasus tools are somewhere in the 40-70 mTorr/min range, and the APS is at 100-120.

I'd say the biggest factor that will affect this is the cleanliness of the back of the wafer. Many years ago, when our tools were still new, we would have very regular (probably once per day) leak check failures due to particulate on the back of their samples. What sort of leak rates are you seeing? What's your chamber leak rate?

-Kevin

On Mon, Jun 13, 2016 at 2:03 PM, LaFleur, David W <dlafleur at cns.fas.harvard.edu<mailto:dlafleur at cns.fas.harvard.edu>> wrote:
To Engineers who maintain Pegasus – Rapier Systems with Esc

Where do  you set your 15 Torr leak up rate pass/fail limit for the Esc. Does anyone have success in achieving the factory spec of 50mt/min on a 150mm chuck for 15 torr @15degC ?
What is your max flow you like to see for 15 Torr?
Thanks in advance.

David LaFleur
Equipment Engineer
Harvard University

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--
Kevin Owen
Senior Engineer in Research
Operations Group, Lurie Nanofabrication Facility
University of Michigan
(734) 545-4014
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