[Fwd: epi backsides]

Nandasiri Samarakone nandasiri.samarakone at asml.com
Fri Feb 1 18:19:05 PST 2008

Hi Binder
Please touch base with me Monday so we can discuss.
What I gather from Mahnaz mail is that thick epi wafers wont hold on the
Usually thats due to wafer warpage 
The picture suggests an area of epi that has a different grain structure
and hence reflectivity.
I expect epi dep to be single sided so it points to some kind of
different grain nucleation mechanism in that area which presumably is
temperature related and hence stress will cause wafer bow.
I am not an expert on epi, however, my involvements in silicon on
sapphire epi dep and poly deposition would suggest that dropping the
deposition temperature and aiming for a slower growth rate may help.
Anyway lets discuss, before we involve Europe. 


From: Mahnaz Mansourpour [mailto:mahnaz at stanford.edu] 
Sent: Friday, February 01, 2008 5:10 PM
To: asml at snf.stanford.edu; Paul Rissman; Mary Tang; Nandasiri Samarakone
Subject: [Fwd: epi backsides]

Hello all,

Here are the pictures of the EPI wafers ( back side)  that lost vacuum
on the asml.
We are looking in to the issue from different angle.
Binder is going to send the pictures to Europe and seek their advise.
One thought was,  that may be one of the pin in EPI  is not performing
well so Maurice went through the trouble to open the system and let me
look in to it,   and things looks to be just fine,  Gary Yama confirmed
it as well. Still Maurice will peruse the issue to see why we see this
problem with thicker deposition.
Apparently few lab members already figure out how to approach  and
resolve the issue for their process; 
Renata  does some sort of CMP, Yuhykr deposit LTO first and that  has
worked for him well. Gary Yama has an idea which we will discuss  next
week.  We are all   trying to find the easiest way  which will work for
every one and does not require many extra steps. So till next week,  be
patient and work with us. 
Thanks to maurice for taking the  pictures.

-------- Original Message -------- 
Subject: 	epi backsides	
Date: 	Fri, 01 Feb 2008 13:22:39 -0800	
From: 	maurice <maurice at snf.stanford.edu>
<mailto:maurice at snf.stanford.edu> 	
To: 	Mahnaz Mansourpour <mahnaz at snf.stanford.edu>
<mailto:mahnaz at snf.stanford.edu> 	

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