PAG segregation during exposure affecting innate material roughness

Fedynyshyn, Theodore H.; Astolfi, David K.; Cabral, Alberto; Cann, Susan G.; Pottebaum, Indira; Roberts, J. M.

doi:10.1117/12.814811

Cited by 10 publications

(6 citation statements)

References 14 publications

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“…This behavior seems to be in harmony with similar recent studies on contacts 3 and overall LER dependencies and can be attributed to the reduced shot noise effects when dose increases. On the other hand, at fixed doses, a slightly reduced (increased) CD variation is observed at high concentrations of PAG (quencher) in agreement with LER behavior when no segregation effects take place [22][23][24] [Fig. Indeed, this is the result exhibited by the experimental data [see Fig.…”

Section: Effects On Cdusupporting

confidence: 71%

“…[22][23][24] In one of these, a similar resist to that used in this paper was utilized and the effects of different exposure wavelengths (248 nm, 193 nm and EUV) and sensitizer loadings on acid kinetics, quantum yield and LWR were studied. [22][23][24] In one of these, a similar resist to that used in this paper was utilized and the effects of different exposure wavelengths (248 nm, 193 nm and EUV) and sensitizer loadings on acid kinetics, quantum yield and LWR were studied.…”

Section: Introductionmentioning

confidence: 99%

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Critical dimension uniformity and contact edge roughness in extreme ultraviolet lithography: effect of photoacid generator, sensitizer and quencher

Kuppuswamy

Constantoudis

Gogolides

et al. 2013

J. Micro/Nanolith. MEMS MOEMS

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Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 05/15/2015 Terms of Use: http://spiedl.org/termsCritical dimension uniformity and contact edge roughness in extreme ultraviolet lithography: effect of photoacid generator, sensitizer and quencher Abstract. One of the main challenges for developing extreme ultraviolet resists is to satisfy critical dimension uniformity (CDU) and sidewall roughness of contacts to the allowable limit. To this end, further understanding of the effects of resist ingredients on CDU and contact edge roughness (CER) is required. We investigate the effects of a photoacid generator (PAG), sensitizer and quencher concentrations on the CDU and CER. We find that the dependencies of CDU on sensitizer and quencher are dominated by photon shot noise (PSN) effects whereas a more complicated interplay between PSN and PAG distribution statistics should be considered in the dependence of CDU on PAG concentration. The estimated CER parameters [root mean square (RMS) value and correlation length ξ] exhibit a merging trend when plotted against the final critical dimension (CD). In addition, RMS value increases with exposure dose and PAG loading contrary to shot noise expectations. Power spectrum analysis reveals the dominant contribution of low-frequency undulations to CER, which is attributed to the enhanced interaction along specific directions between the aerial image and/or acid kinetics of nearby contacts. This inter-contact effect is further intensified with CD for fixed pitch and may explain the observed CER behavior.

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Section: Effects On Cdusupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Critical dimension uniformity and contact edge roughness in extreme ultraviolet lithography: effect of photoacid generator, sensitizer and quencher

Kuppuswamy

Constantoudis

Gogolides

et al. 2013

J. Micro/Nanolith. MEMS MOEMS

View full text Add to dashboard Cite

show abstract

“…Finally, it should be noted that the resist formulation also consists of additives such as the photoacid generator (PAG) and base quencher and that the distribution of these components may also profoundly affect the lithographic processes and impact negatively on the roughness of the features. For example, Fedynyshyn and colleagues have investigated the effect of PAG segregation on LER and speculated that changes in the rates of dissolution on the nanometer scale can be significant. These and other observations have led to intensive studies of polymer-bound PAGs which can show improved roughness compared with resists containing low molar mass PAG molecules. − In summary, these studies clearly demonstrate that control over the molecular structure of the polymer, and in particular of the distribution of ionizable groups, can have a significant impact on the performance of lithographic polymers.…”

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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“…This acid diffuses, primarily during the subsequent post-exposure-bake step, and causes deprotection of the polymer leading to the desired dissolution switch of the resist in the liquid developer. While there are other options to improve the performance of the photoresist including binding the PAG to the polymer [2][3][4][5] backbone and replacing the base with a photo decomposable quencher, [6][7][8][9][10] the main issue of resist chemical stochastics is that this is a multi-component system so distributions of molecules can lead to local variations in resist sensitivity and dissolution rate. 5,[11][12][13][14][15][16]…”

Section: Introductionmentioning

confidence: 99%

Understanding the onset of EUV resist chemical stochastics

Denbeaux

Azhari

et al. 2023

Jpn. J. Appl. Phys.

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The ability of chemically amplified resists to transfer an aerial image at increasingly smaller dimensions is critical to extreme ultraviolet (EUV) lithography success at increasingly smaller process nodes. Stochastic inhomogeneities in resist exposure and patterning have been studied, which include photon shot noise and resist surface roughness. However, previous work has indicated that inhomogeneities and defectivity are present in multicomponent resists beyond those predicted by random statistics. This is thought to be due to self-segregation of components in the multi-component chemically amplified resist (CAR). The results in this paper show that the most critical part of the resist chemical segregation occurs during the spin coating process after a significant amount of the solvent has evaporated, but while there is still enough solvent to enable molecular mobility within the resist.

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PAG segregation during exposure affecting innate material roughness

Cited by 10 publications

References 14 publications

Critical dimension uniformity and contact edge roughness in extreme ultraviolet lithography: effect of photoacid generator, sensitizer and quencher

Critical dimension uniformity and contact edge roughness in extreme ultraviolet lithography: effect of photoacid generator, sensitizer and quencher

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

Understanding the onset of EUV resist chemical stochastics

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