New Process Approval

Blaise Anne Pinaud bapinaud at
Thu Dec 2 10:31:37 PST 2010


I recently completed the safety training at SNF and I would like to know if my non-standard process can be cleanroom approved.  I would like to chemically polish/etch tantalum metal foils in a ternary mixture of nitric acid, sulfuric acid and hydrofluoric acid.  From going through the MSDSs available on the SNF website, it appears that all three of these acids have been used before in the cleanroom.

The substrates will be mechanically polished prior to beginning work in SNF and will be 1 cm by 1 cm in size.  The mixture would be a 5:2:2 ratio of sulfuric:nitric:HF in concentrated form.  This mixture would be prepared on a relatively small scale (mixing 100 mL or less at a time, etching in approximately 10 mL at a time).  I believe Teflon beakers are the most appropriate for use with these chemicals.  The process would be carried out at room temperature and the polish/etch times will be on the order of minutes.  Based on the equipment listings on the SNF website, the 'wet bench general' wbgen seems most appropriate for this work.

I have attached a publication in which this cleaning procedure for tantalum foils is mentioned.  Please let me know if there are any questions or additional information/forms I must provide.

Thank you,

Blaise A. Pinaud
PhD Candidate
Jaramillo Group
Chemical Engineering
Stanford University
bapinaud at
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