Fundamental characterization of stochastic variation for improved single-expose extreme ultraviolet patterning at aggressive pitch

Nanometrology for evaluating rare sites for molecular homogeneity

“…12 In the case of single exposure EUV, traditional methods of evaluating the line edge resolution with CD-SEM at 3σ are not sufficiently sensitive to improve the lithographic process window. 10 Experiments examining missing-contact and merging contact cliffs further demonstrate the current limitations of CD-SEM or area inspection SEM, which can inspect 10 6−8 contacts; however, these are 2 to 4 or orders of magnitude away from the extrapolated cliff. 15 Enhancing device yield and improving the performance of EUV resists require a complete understanding of material segregation occurring at the nanoscale.…”

“…[4][5][6][7] In these tiny features, two types of variations affect the device quality: shot noise during irradiation and chemical variability in the resist. [8][9][10] The latter has been generally perceived as a "black box" as it was difficult or impossible to track the molecular composition at the nanoscale. A typical positive-tone CAR contains a photoacid generator (PAG), a base quencher, and a polymer that undergoes a solubility switch due to an acid-catalyzed reaction.…”

“… – 14 However, in many cases, the origin of resist stochastics remains elusive 12 . In the case of single exposure EUV, traditional methods of evaluating the line edge resolution with CD-SEM at 3σ are not sufficiently sensitive to improve the lithographic process window 10 . Experiments examining missing-contact and merging contact cliffs further demonstrate the current limitations of CD-SEM or area inspection SEM, which can inspect 106−8 contacts; however, these are 2 to 4 or orders of magnitude away from the extrapolated cliff 15 .…”