Hello,

 You can try  H2O2 which is used to etch TiW. It should work well with W
etching also.

 Regards,

Anil Agiral (M.Sc.)
PhD student Mesofluidics
Hogekamp 10256
MESA+ Institute for Nanotechnology
TNW Faculty
University of Twente
P.O. Box 217
NL-7500 AE Enschede,
The Netherlands
phone:+31 (0)53 489 25 94
e-mail:a.agiral@ewi.utwente.nl