A Sensitive, Etch Resistant, Positive Tone E-Beam Resist System

We have developed a highly sensitive, dry etch resistant, positive resist system that is useful for both E-beam and x-ray lithography. The resist consists of a radiation sensitive poly(olefin sulfone) and a cresol novolac resin together with an appropriate solvent system. The polysulfone sensitizer is a terpolymer of sulfur dioxide, 2-methyl-1-pentene, and one of a variety of methallyl ether derivatives. This terpolymer structure is essential for establishing homogeneous mixing with the cresol novolac resin and for achieving a high glass transition temperature. The synthesis and characterization of the sulfone terpolymers and lithographic evaluation of the resist are presented. © 1988, The Electrochemical Society, Inc. All rights reserved.