Hi Dlee

You will not get very far using CF4 or SF6 to etch either Au or Cr.  Au and
Cr can be dry etched using a mainly physical process, using RIE with Ar gas.
You can add Cl2 to increase the rate if you have a load-locked system or a
glove-box.  In either case, the metal is likely to etch more slowly than the
PMMA.  PMMA is not very good at resisting plasma, especially if it gets hot.
Ideally, you want to clamp and cool the wafer, but not many systems offer
this.  Expect a rate of around 20nm/min or less (depending on process
conditions and loading).

Martin Walker B.Sc.(Tech.) M.Sc.
Oxford Instruments Plasma Technology
North End, Yatton, Bristol, BS49 4AP UK
T.+44 (0)1934 837031  F.+44 (0)1934 837001
E. 
W. 


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