Copolymer approach to charge-dissipating electron-beam resists

During electron-beam lithographic exposure on insulating substrates, patter n distortions and displacements are observed due to charging of the surface . To alleviate these displacements, conducting polymers have been investiga ted in the past decade as negative-tone resists and as unimageable top or b ottom layers in a multilayer stack. Our approach uses a graft copolymer: an acrylic backbone for the imaging performance of the resist and a conductin g polymer grafted onto the backbone for the charge-dissipating performance. By using this system, the respective properties of the two components can be individually optimized for such properties as speed, etch resistance, so lubility, and conductivity. This system also permits positive-tone single-l ayer imaging, which has not been achievable previously. High-resolution fea tures (<0.10 mu m): minimal pattern distortions, and no change in the clear ing dose, were observed for graft copolymers containing <1% of the charge-d issipating component that were processed identically to commercially availa ble PMMA resist. (C) 1998 American Vacuum Society. [S0734-211X(98)02906-0].