193 NM LITHOGRAPHY USING A NEGATIVE ACTING P(SI-CMS) RESIST

Copolymers of trimethysilylmethyl methacrylate and chloromethylstyrene [P(SI-CMS)] have been formulated as negative resists for exposure at 193 nm. To achieve maximum sensitivity, absorption has been targeted s o that the amount of radiation exposing the base of a given film thick ness is I(0)e(-1), leading to an optimum optical absorbance of log(10) e, or 0.434. Through control of the mole ratio of the monomers in the P(SI-CMS) copolymer, optimum response has been tailored for coating th icknesses from 2000 Angstrom to 5500 Angstrom. Optimal formulations yi eld working sensitivities of from 3 to 20 mJ/cm(2) for materials havin g a <(M)over bar(w)> of 4 x 10(4) g/mole, with resolution demonstrated below 0.4 IJ-m Resists exhibit etching resistance in O-2 RIE and are suitable for application in both single layer and bi-layer processes.