Saravan:

The fact that you are getting a pinkish plasma suggests to me that you have
a leak in your system. Typically an oxygen plasma should be blueish in color
so you might be getting nitrogen from the leak. Do a leak-back test on your
system, pump down to a base pressure and close the gate valve. Your leakback
rate should be <10 mtorr/minute. There are many places where a leak can form
but check all orings and surfaces first. If you don't have a helium leak
detector you can use iso alcohol and the baratron to show where a leak might
be. Bob Henderson

----- Original Message -----
From: "saravan kallempudi" 
To: 
Sent: Wednesday, December 24, 2008 6:59 AM
Subject: [mems-talk] DRIE Recipe


> Dear all,
> We are using Oxygen plasma from DRIE for ashing.
> The colour of the plasma is bright pinkish at the start but turning dim
within few seconds after getting plasma.
> power: 300W RF
> Pressure: 0.370 m bar
> Oxygen: 50 sccm
> If I need to change my recipe I will!!
> Thanks,
> Saravan