CVD of nitride layer onto organosilicate glass

Mary Tang mtang at stanford.edu
Thu Jun 5 21:12:44 PDT 2008


Hi Andrew --

After consulting with Maurice, I think there was some confusion about 
the equipment choice.  I believe Maurice thought you were asking about 
the LPCVD Tylan nitride system.  This is a high temperature-activated 
CVD deposition for CMOS clean wafers.  The temperature is 750-850C -- 
typically, organosilicate glasses aren't subject to those temperatures 
-- and generally these glasses are restricted to the metal and 
post-metal processing of devices (i.e., "semiclean" at SNF).  The LPCVD 
furnace is question is restricted to pre-metal CMOS (i,e,m "clean" at 
SNF.)  Thus, his concern.

Looking through the Coral history, it looks like the Dauskardt group has 
not used the LPCVD nitride system.  Several group members have, however, 
used the sts PECVD system.  This system uses plasma to activate the 
deposition process -- and so, the deposition is at about 300-350 C, 
typically.  This would be consistent with use of organosilicate materials. 

SpecMat approval is not required for sts dep -- The sts is a 
"gold-contaminated" tool.and organosilicate glasses are OK'ed for 
processing in this class of tools.  I believe this information is on the 
website, but I'd be first to admit that it may not be easy to find (and 
as webmaster, I should know.)  As we're in the process of redesigning 
it, your suggestions and advice on how to improve it would be appreciated.


Mary

Andrew Thiel wrote:
> Hello,
>
> I'm a graduate student in materials science interested in using CVD at 
> SNF.  I have a silicon wafer topped with a thin film of an 
> organosilicate glass, and I'd simply like a silicon nitride film 
> deposited onto it.  My research group (Dauskardt in MSE) has actually 
> done this exact deposition at SNF several times over the past couple 
> years without any issues, but the current manager of CVD at SNF 
> (Maurice Stevens) is reluctant to allow an organosilicate glass into 
> any chamber without the permission of SpecMat.
>
> The specific organosilicate glass I would be introducing into the CVD 
> chamber is DiEthoxyMethylSilane (DEMS).  My research group has 
> conducted thermal studies and found this material to stable up to 
> temperatures of at least 400 C.
>
> Please let me know of any other additional information you may need.
>
> Thanks,
> Andrew




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