[labnetwork] Helium leak rate on Oxford RIE

[Paolini, Steven]

Hi Vince,
  Sorry for such a late response but I hadn't noticed anyone mentioning the pressure of the cavity behind the wafer. Assuming that your system has that capability, the flow of He should be judged by the backside pressure. As an example, we have many etching systems here with mechanical wafer clamps and we baseline them when new to flow X amount of He for a specified pressure (closed loop system). As you may expect, the flow of He increases as the backside pressure is called to increase. We use this baseline flow as criteria to either change a seal if applicable, clean the wafer backside or clean the chuck if necessary. We have gotten very good with our tool set to have a seal change or chuck clean at PM intervals. Oh yeah, beware of the photo users that neglect edge bead removal after coating, it can cause the wafer to stick to the chuck and when it begins to transfer out, the lift will "pop" it off the chuck and most certainly position it in a bad spot.
  Steve "Equipment Dood" Paolini

Steve Paolini
Principal Equipment Engineer
Harvard University Center for Nanoscale Systems
11 Oxford St.
Cambridge, MA 02138
617- 496- 9816
spaolini at cns.fas.harvard.edu
www.cns.fas.harvard.edu

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Luciani, Vincent (Fed)
Sent: Thursday, February 22, 2018 4:16 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Helium leak rate on Oxford RIE

Hello All,

Thanks for all the great feedback about the backside helium leak rate on the Oxford tools.  To sum up it sounds like most labs strive to keep it less than 10 sccm  and 6 -12 sccm is a typical range.  It is very helpful to see that what we observe is fairly typical.   We have one process that etches at -100 C with very high RF and ICP power that requires < 5 sccm.  We can get it there for this user but keeping it there is difficult.  For those who asked for the drawings of our modified quartz plate,  I will send that to you individually.   I plan to invest in some mechanical design engineering effort to make these cooled chucks perform better.  I'll share anything we come up with.

Thanks again,

Vince


Vincent K. Luciani
NanoFab Manager
Center for Nanoscale Science and Technology<https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cnst.nist.gov_&d=DwMFAg&c=WO-RGvefibhHBZq3fL85hQ&r=-H4Z_jeDfTYjnKPXor15vLwzBllmg8gFrb9m_k9OGks&m=eV4MYPyzZNXtLwpvNj_ge_JTFFzrUWcRFDWe8LwUlSU&s=Km7eUzO368C8Iuhm32kmTVbbDD2kVN2aK_74cNJvPD4&e=>
National Institute of Standards and Technology
100 Bureau Drive, MS 6201
Gaithersburg, MD 20899-6200 USA
+1-301-975-2886




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