Electron resists for microcircuit fabrication

The edge resolution of electron exposed resists was investigated in order to determine the suitability of these resists for microcircuit fabrication. Both negative and positive resists have been evaluated including KTFR (Kodak Thin Film Resist), Shipley AZ-1350 and polymethyl methacrylate. Of these, KTFR in layer thicknesses of 5000Å has been found to require a charge density of approximately
3 \times 10^{-5}
coul/cm
²
at 10-15 kv, for optimum exposure. Edge resolutions were investigated by exposing lines and observing cross sections in the scanning electron microscope. It was found that a 10 micron wide line of KTFR exposed at 10 kv, shows a smoothly sloping edge af about 2 microns on either side after development. For this reason KTFR was considered unsuitable for submicron device fabrication.