New high-resolution charge transfer x-ray and electron beam negative resist

A new class of polymeric negative x-ray and electron beam resists is described. Polystyrene-tetrathiafulvalene films doped with a halocarbon acceptor show good sensitivity to x-rays (D1/2=44 mJ/cm2) and electron beams (D1/2=6 μC/cm2), with high contrast values γ≳2.5, and with no evidence for the classical swelling phenomena. In electron beam exposures at 10 μC/cm2, parallel wall patterns are produced with pattern resolution of 1000 Å or better. Reasons for the improvement in lithographic parameters relative to previous negative resists are briefly discussed.