SpecMat Logsheet, 10/12/05

Ed Myers edmyers at stanford.edu
Mon Oct 10 16:01:49 PDT 2005

SpecMat Members,

Tuesday, 10/11 is our normal SpecMat meeting day.  However many of us will 
be involved with our visitors from Korea.  I would like to propose we do 
this meeting by email.  We have three new items to address.

1) Jun-Fei Zheng:  Poly deposition on a Vapor Jet Deposition Si3N4 film 
from outside CIS.  Jun-Fei is willing to provide TXRF data to show the film 
meets our contamination requirements.  The second part of the request is 
"to avoid H2SO4:H2O2 process as our wafer has never been through 
Lithographic process and this is what the H2SO4:H2O2 mainly for but 
H2SO4:H2O2 process might destroy the gate quality Si3N4. We also do not see 
the need for 50:1 HF dip, which is used for clear oxide formed on Silicon 
during H2SO4:H2O2 process. We believe SC1 and SC2 in combination would be 
able to address potential contamination during wafer handling and shipping."

Comments:  The Thermcopoly tube is part of the Clean Equipment set and 
requires a pre-diffusion clean prior to deposition.  The request is use an 
SC1/SC2 clean approach instead of the standard pre-diff clean.  Is there a 
bench were we can use SC1 (NH4OH/H2O2/H2O) and SC2 (HCL/H2O2/H2O) or will 
the work need to be done in beakers?

2) Ching-Huang: McIntyre ALD Hf02 processing in Semiclean Tools.  TXRF 
analysis was provided with the request.  The data shows the sample to be 
above our SemiClean contamination specification for both Fe and Ca (along 
with S).  Do to peak overlap the levels of Ni, Co and Cu (possibly Cl) 
could not be determined.

Comments:  I do not think we should approve the request with this level of 
contamination.  I feel there should be an effort made to reduce the 
contamination level in the ALD system before we assume the contamination 

3) Mike Weimer:  Limiting CF4 Etchs in pQuest.  Etches using CF4 must 
contain high amounts of O2. As a guideline (this number is not perfectly 
strict, but is a good guideline) any etch with CF4 should be ~20% CF4 and 
80% O2. Small variations around this % are OK. No etches containing large 
amounts of CF4 and small amounts of O2 are allowed.  This basically 
eliminates etching of Si3N4 and SiO2 with CF4.

Comments: I do not think we should accept this proposal as presented 
because it is to confining.  I attended the meeting where this proposal was 
developed.  It is based on seen non-responsibility in the GaAs 
etches.  From the data that was presented, I was not convinced all the 
non-reproducibility were caused  by the CF4 etches.   The GaAs community 
was not willing to support testing of the memory effect in the chamber as 
the gas chemistries are switched.  The work was volunteered at not burden 
to the GaAs community.  I did volunteer to email the pQuest community with 
any SpecMat request that come in.  This way they can voice their concerns 
early in the approval process.

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