[labnetwork] FW: Silicon Nitride question

[Dan Woodie]

Richard,

At the Cornell NanoScale Facility, we use the foreline cold trap method to pull out most of the deposits that would build up in the foreline areas. We have seen that the flammable deposits that can occur have mostly been in areas where you can get partial reactivity of the silanes, such as low oxygen environments like vacuum pump exhaust lines post pump, where the high pump nitrogen purge leads to a low oxygen area. We had a problem here with these deposits and so we added Edwards Gas Reactor Columns (GRC) units immediately after the pump. Attached is a paper we found describing what occurs. The deposits we get in the cold trap have been mostly ammonium chloride which remove easily in warm water.

Dan

Daniel Woodie
Safety Manager, College of Engineering
Cornell University
344 Duffield Hall
Ithaca, NY 14853-2700
(607)254-4891
Off Hour Emergency # - (607)227-2993

From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Morrison, Richard H., Jr.
Sent: Wednesday, April 11, 2012 8:09 AM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Silicon Nitride question

Hi Everyone,

I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated?

Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust?

2nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum.

Thanks
Rick


Rick Morrison
Senior Member Technical  Staff
Group Leader Microfabrication Operations
Draper Laboratory
555 Technology Square
Cambridge, MA  02139

W  617-258-3420
C   508-930-3461

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