particles issues of p5000

Matthew W. Messana mmessana at
Tue May 4 16:49:37 PDT 2010

Depending on your etch, p5000 may not etch the silicon in your Al/Si. You should try to do a "freckle etch" to get rid of the Si. John Shott made some suggestions to me for doing the freckle etch in drytek2. The message is below.


From: John Shott

The references that I can find to a freckle etch in drytek2 date to the 
era when we could still use Freon 115 (C2FCl5) so that information is 
not strictly applicable.

It was, however, a short silicon etch using the same recipe as our 
normal poly etch at that time .... just a very short etch:
    pressure = 150 mTorr
    RF power = 500 watts
    Time = 15 sec
    Freon 115 flow = 50 sccm
    SF6 flow = 50 sccm
and that matched the recipe that we normally used for poly silicon in 
that era.

If I am not mistaken, our current poly etch is:
    pressure = 150 mTorr
    RF power = 400 watts
    SF6 flow = 117 sccm
    Freon 22 flow = 51 sccm

I would suggest also trying a short 15 second etch using this recipe and 
think that it should work well to clean up any residual silicon dust 
without doing too much damage to anything else.  Note: you'll want to 
watch this carefully .... I think that there is a trouble report that we 
have not addressed that if the second numbers on the recipe 2 process 
time are set to other than "00" that it will not stop that step at the 
proper time.  So, I'd set a time of 00:15 .... but would be watching it 
like a hawk to hit the "Clear wafer" button (the red one just above the 
green Standby button to terminate the process after 15 seconds in case 
it doesn't terminate when it reaches 15 seconds.  Of course, a test 
wafer is always a good idea.


-----Original Message-----
From: Shu-Lu Chen [mailto:shuluc at] 
Sent: Tuesday, May 04, 2010 4:23 PM
To: p5000etch at
Subject: particles issues of p5000


Is there anyone with the experience of using chamber A to etch Al/Si on top of Ge surface ?
We found some particles after the Al/Si etch and are wondering what those particles could be.
Thanks for any information.


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