Stabilization of γ-lactam and lactone ring-fused norcaradienes by protonation: DFT calculations of norcaradiene and the corresponding cycloheptatriene structures

Kohmoto, Shigeo; Motomura, Tatsuya; Takahashi, Masahiro; Kishikawa, Keiki

doi:10.1016/j.molstruc.2009.10.049

Cited by 2 publications

(2 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Remarkably, the PAG simultaneously generates both an acid and a lactam that acts as a quencher. 60 This is significant as quencher distribution has been shown to be the most detrimental stochastic aspect of photoresist systems and could be avoided by having the same component generate both acid and base. 61 The EUV mechanism also contrasts with its accepted mechanism under DUV irradiation 62 in which homolytic bond cleavage occurs.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Based on the compounds detected in the EUV exposed resist film and prior information on the EUV process, a rational decomposition mechanism was proposed for PAG 9 in Scheme . Remarkably, the PAG simultaneously generates both an acid and a lactam that acts as a quencher . This is significant as quencher distribution has been shown to be the most detrimental stochastic aspect of photoresist systems and could be avoided by having the same component generate both acid and base .…”

Section: Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

High-Performance Chain Scissionable Resists for Extreme Ultraviolet Lithography: Discovery of the Photoacid Generator Structure and Mechanism

et al. 2022

View full text Add to dashboard Cite

Extreme ultraviolet (EUV) lithography currently dominates the frontier of semiconductor fabrication. Photoresists must satisfy increasingly strict pattern fidelity requirements to realize the significant enhancements in resolution offered by EUV technology. Traditional chemically amplified resists (CARs) have hit a barrier in the form of the resolution, line edge roughness, and sensitivity trade-off. This has been compounded by a lack of understanding of the chemical mechanism associated with the EUV process. Here, we synthesize a series of novel EUV photoresists based on a self-immolative, acid-labile poly(acetal) system. These systems are shown to be commercially viable under current EUV requirements. Careful study of the resists’ degradation pathways has enabled the identification of a remarkable photoacid generator (PAG) that functions as both an acid generator and base quencher, enabling further improvements over previous resists. density functional theory calculations reveal, for the first time, the connection between the PAG activation barrier and resist sensitivity and suggests why attempts to use electron-beam lithography to predict EUV performance have failed.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%