TXRF results for continued processing on semi-clean tools...

Mary Tang mtang at stanford.edu
Fri Oct 9 09:21:14 PDT 2009


And Robert?

Mary

Robert Huang wrote:
>
> Dear SNF Specmat Committee Members:
>
>  
>
> I would like to ask for the committee’s approval to run 4” silicon 
> wafers on SNF semi-clean tools (mainly the AG4100 RTA machine) that 
> have been deposited with titanium oxide via e-beam evaporation through 
> an external vendor.  We have worked with this vendor to reduce metal 
> contamination levels below the 1e12/cm2 “semi-clean” specification 
> limit.  As you will see in the attached file, prior to taking 
> corrective action, there were locations on a test wafer that clearly 
> exhibited Fe and Cu levels above the 1e12/cm2 limit.  However, after 
> detailed investigation, several steps were taken to clean up the tool 
> with the positive results shown in the attached file from the last 
> test wafer.  Note that the TXRF results were provided by Evans 
> Analytical Group (EAG) using a W source which can detect elements from 
> S-Zn and Mo-Hf.  If an element is not listed in the table, it was not 
> detected in the analysis.  Evans has a detailed procedure for 
> calibration of their TXRF equipment and guarantee reproducibility to 
> within the reported results (uncertainty values in the table are 
> 1sigma standard deviations) through use of calibrated Vanadium and 
> Nickel references.  Also note that due to overlap in emission 
> energies, EAG can only report upper bounds for some of the elements 
> (specifically the Cu and Hf energy peaks overlap) and the background 
> matrix Ti energy peak interferes with the Cl, K, and Ca peaks.
>
>  
>
> If there are any questions, please do not hesitate to contact me.
>
>  
>
> Sincerely,
>
>  
>
> Robert Huang
>
> Director, Process and Device Technology
>
> QuSwami, Inc.
>
> 505 Montgomery St., Suite 300
>
> San Francisco, CA 94111
>
> 415-834-9910 (Office)
>
> 408-854-0450 (Cell)
>
> roberth at quswami.com <mailto:roberth at quswami.com>
>


-- 
Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
(650)723-9980
mtang at stanford.edu
http://snf.stanford.edu




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