Transene Company manufactures Tungsten Etchant TFW.  TFW etches W at a rate
of approximately 130 angstroms/second at 30 deg C.  TFW will not attack
SiO2.

Please visit Transene's website, www.transene.com, for technical literature.
I am available if you have additional questions.

Regards,

Christopher Christuk
Transene Company
Tel:  978 777 7860
email:  christopher@transene.com
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