Implementation of COMA type ArF Resist for Sub-100nm Patterning.

Abstract

To accomplish sub-100nm minimum feature size to sub 100nm, new light sources for photolithography are emerging, such as ArF(λ=193nm), F2(λ=157nm), EPL(E-beam Project Lithography) and EUV(Extremely Ultraviolet, 13nm). Among these lithography technologies, ArF lithography will be used for sub 100nm lithography at first. For a few years, ArF resist development has been the key issue for the success of ArF lithography. For this ArF lithography, we have developed COMA (cyclo-olefin/maleic anhydride) type ArF resists in which the base resin consists of cycloolefin and maleic anhydride. Now, this COMA type resist is strong candidate for primary ArF resist. From the patterning results, we can say that the ArF resist is enough to start real device production except contact hole patterning. For the sub 100nm contact hole patterning, more intensive research must be performed in the field of RFP (Resist Flow Process) or RELACS (Resolution Enhancement Lithography Assisted by Chemical Shrink). From the etch resistance point of view, COMA type ArF resists have some problems under oxide etch condition. To solve this oxide etch problem, additional E-beam curing is required. For the more fundamental solution for the oxide etch, new etch equipment or hard mask must be developed for implementation of ArF process. E-beam curing also solves the line slimming due to E-beam attack during SEM measurement.