Development of Novel Materials for 193-nm Dry and Immersion Lithography

Abstract

We earlier developed new monocyclic fluoropolymers (FUGU) for F2 resist materials. But, it is necessary for FUGU to be improved in their characteristics, especially in the dry-etching resistance, in order to apply to ArF lithography at fine design rules. We have tried to combine FUGUs with Adamntyl methacrylates based conventional ArF resist polymer. In this paper, we have investigated the role of cyclic fluorinated unit, FUGU, in 193 nm resist polymers by analyzing the dissolution behavior. We found that FGEAM showed high sensitivity and good dissolution contrast, compared with acrylate based conventional samples at low PEB temperature (100oC). And this difference of sensitivity was clearly found when weak acidity PAGs were used. From the dissolution behaviors of FGEAM, FUGU unit can work to improve the resist sensitivity in acrylate based ArF resist polymers. These result shows that FUGU unit has a unique characteristics of the sensitivity with 193 nm exposure. We also investigated a new series of fluorinated copolymers for 193-nm lithography, combination of FUGU monomer and acrylate units which are used in conventional ArF resist. Six ter-polymers of FUGU, combination of FUGU monomers and EAdMA, GBLMA and HAdMA were prepared. We found that FUGU ter-polymers had a good dry etching resistance keeping high transparency at 193 nm. And FUGU ter-polymers showed high sensitivity toward 193 nm exposure. So we expect FUGU ter-polymers to be useful for ArF dry and immersion lithography.