Effect of amplitude roughness on EUV mask specifications

Claus, Rene A.; Neureuther, Andrew R.; Naulleau, Patrick; Waller, Laura

doi:10.1117/12.2069073

Cited by 1 publication

(1 citation statement)

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“…Low-frequency roughness can potentially increase severely the failure rate of memory devices . On the other hand, high-frequency roughness can cause local variations in voltage in transistors and hence lead to variations in leakage or threshold voltages. , The origins of line edge roughness have been the subject of intense investigation and factors such as acid diffusion, − shot noise, − and mask roughness − identified as major contributors. − However, it has been suggested that the inherent heterogeneity of the photoresist may also strongly contribute to the generation of rough features upon processing. This includes heterogeneity in the distribution of photoacid generator (PAG) or other components such as base quencher and in the resist polymer itself.…”

Section: Introductionmentioning

confidence: 99%

Terpolymerization of Styrenic Photoresist Polymers: Effect of RAFT Polymerization on the Compositional Heterogeneity

et al. 2015

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The heterogeneity of the chemical structure of photoresist polymers, both within and 1 between the polymer chains, is believed to contribute to the phenomenon of line edge roughness 2 in high-resolution lithography. The copolymerization and terpolymerization of three important photoresist monomers, 4-acetoxystyrene (AOST), styrene (Sty) and tertiary-butyl acrylate (tBA) is examined in detail in this work. In particular the effect of the use of a reversible addition fragmentation chain transfer (RAFT) agent in these reactions is reported. The pair-wise copolymerization reactivity ratios for the RAFT polymerizations are close to, but different from those measured under the same conditions but in the absence of the RAFT agent. The differences are suggested to be related to the effect of the RAFT agent on the environment of the locus of polymerization. The course of the terpolymerization reactions can be well predicted from the copolymer reactivity ratios and the classical Alfrey-Goldfinger expression, indicating that the reactions in this system conform to terminal model of reactivity. Calculations of the expected sequence distributions as a function of composition and conversion clearly demonstrate that the polymers prepared under RAFT conditions are significantly more homogeneous that their counterparts prepared using conventional free radical polymerization. The significance of these results for the performance of the RAFT terpolymers in photoresist formulations is highlighted.

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