FABRICATION BASED ON A POSITIVE ACTING PHASE COMPATIBLE BLEND OF MATRIX POLYMER AND MODIFIER POLYMER

摘要

Abstract of the DisclosureA phase compatible polymer blend serves as a radiationsensitive lithographic resist in the fabrication ofcircuits and circuit elements. Radiation sensitivityis due to inclusion of a "modifier". Resistproperties, notably stability to agents and ambients tobe masked are attributed largely to a second component,the "matrix polymer".In an exemplary embodiment in which the blend ispositive acting, fabrication including dry processingis dependent upon use of a resist blend of a vapordeveloping polysulfone and a novolac. The novolac,inherently soluble in alkaline media is renderedinsoluble in the blend. Radiation initiateddepolymerization results in volatilization of themodifier to render the irradiated portions of theresist soluble in alkaline developers.Modifier may function in other manner; for example, itmay undergo radiation initiated polymerization so as toinsolubilize the blend in irradiated regions, soresulting in a negative acting resist.Effective isolation of lithographic from maskingfunctions permit design of blends with highlithographic sensitivity, as well as good processingstability. The latter is sufficient to permit use inmany dry processing procedures as practiced in directwriting, as well as in mask fabrication of large scaleintegrated silicon circuits.