Hi Martyn,
          Two possible answers may be 1) Image reversal which allows the
resist image to have controllable side walls.  This allows vertical side
walls not sloping which buys you about 20% increase in resolution.
                                   Or 2) Metal lift off which allows
metal lines down to 0.1 microns.  Contact me for technical papers on
either process.
Bill Moffat, CEO
Yield Engineering Systems, Inc.
2185 Oakland Rd., San Jose, CA  95131
(408) 954-8353