APPLICATION OF POLY(ALKENYLSILANE SULFONE)S AS POSITIVE ELECTRON BEAM RESISTS FOR TWO-LAYER SYSTEMS.

Alternating copolymers of sulfur dioxide and vinyltrimethylsilane (VTMS) and terpolymers with allyltrimethylsilane (ATMS) and 1-butene have been synthesized by low-temperature, free radical-initiated polymerization. The copolymers with VTMS were soluble but hydrolytically unstable. Whereas the copolymer from ATMS was insoluble, terpolymers containing less than 75 mol-% ATMS (relative to butene) were soluble in a variety of organic solvents. Moreover, they were stable against hydrolysis and had good film forming properties. Their electron beam sensitivity was 1. 5 mu C/cm**2 at 20 keV, and their contrast was approx. 2. The terpolymers have been used as a top imaging layer in a two-layer resist system to transfer half-micron features into a 1. 2 mu m-thick Novolac planarizing layer by oxygen reactive-ion etching.