Revisit pattern collapse for 14nm node and beyond

Yoshimoto, Kenji; Higgins, Craig; Raghunathan, Ananthan; Hartley, John G.; Goldfarb, Darı́o L.; Katō, Hirokazu; Petrillo, Karen; Colburn, Matthew; Schefske, Jeffrey; Wood, O. R.; Wallow, Thomas I.

doi:10.1117/12.880180

Cited by 13 publications

(13 citation statements)

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“…al 7 . The resist pattern collapse evaluations were carried out the College of Nanoscale Science and Engineering (CNSE) of University of Albany, Albany NY.…”

Section: Exposure Tools and Resist Processingmentioning

confidence: 97%

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New methodology to predict pattern collapse for 14nm and beyond

2012

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Critical aspect ratio induced pattern collapse has been a concern for lithography process engineers since before the 180 nm node. This line bending can lead to pattern deformation or complete substrate adhesion failure. Several process improvements, such as surfactant-laced final rinse, have been proposed to alter surface energies and increase the critical aspect ratio for collapse. The challenge is more severe for sub-60 nm pitch ground-rules that are being developed for the 14 nm technology node, since 30nm and smaller spaces will produce extremely large capillary forces acting on very narrow resist patterns. In previous studies, an analytical model was used to predict pattern collapse of simplified line/space structures. In this work, we propose a new framework to predict pattern collapse of sub-60 nm pitch EUV resist structures by the use of a semi-empirical model. This semi-empirical model is derived from the one-dimensional analytical model, which includes a term dependent on the local pattern geometry and the physical properties of the resist and rinse solution. We calibrate/verify the model with various EUV pattern collapse data collected from onedimensional (e.g., line/space) patterns. Hotspots predicted by the semi-empirical model are compared with those obtained from EUV wafer exposures. Weaknesses in model prediction were then used to adjust the model terms. Determining pattern collapse and identifying hot-spots early in the development cycle is critical for setting restricted design rules and refining DFM/RET solutions.

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“…al 7 . The resist pattern collapse evaluations were carried out the College of Nanoscale Science and Engineering (CNSE) of University of Albany, Albany NY.…”

Section: Exposure Tools and Resist Processingmentioning

confidence: 97%

“…There is a certain dependence upon the mechanical properties of the resist material, but this failure mode impacts optical, immersion, e-beam, and EUV resist systems. In fact, a recent report indicates that it will be challenging to maintain aspect ratios in excess of 2.0 for sub-60 nm pitch EUV patterning 7 .…”

Section: Introductionmentioning

confidence: 99%

New methodology to predict pattern collapse for 14nm and beyond

2012

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“…Due to the finite CD increment between images, an error bar was assigned to each point. Also included in the chart are published CARC data for nested lines (1:1) of KrF, ArF and EUV resists featuring reduced contact angles [25].…”

Section: Surfactant-containing Rinse and Resist Design For Collapse Mmentioning

confidence: 99%

Pattern collapse mitigation strategies for EUV lithography

et al. 2012

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In this study, a comprehensive approach towards assessing pattern collapse challenges and solutions for Extreme Ultraviolet Lithography (EUV) resists beyond the 14nm node is undertaken. The fundamental forces that drive pattern deformation are reassessed in order to propose a generalized design criterion for EUV photoresists and aqueous surfactanated rinses. Furthermore, ultimate pattern collapse solutions such as solvent drying utilizing pressurized fluids (supercritical CO 2 ) are exemplified for sub-60nm pitch EUV patterning. In parallel, alternative EUV integration schemes that use a metal-based hardmask (MHM) are studied using a specifically tailored self-assembled monolayer (SAM) to prevent delamination-driven pattern collapse due to resist-hardmask interfacial adhesion failure. Finally, the marginal image transfer of 40nm pitched L/S of ultrathin EUV resist into a SiARC-underlayer stack appears to be gated by the EUV resist resolution limit and the reduced film thickness budget. An alternative method for achieving improved postetch line width roughness (LWR) with an ultrathin MHM-based integration scheme is herein demonstrated.

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“…It is well known that pattern collapse is improved by decreasing capillary force [10]. Although many researchers have investigated effects of processing conditions such as film thickness and rinse materials on decreasing capillary force [11][12], detailed understanding is still lacking from a perspective of hydrophobicity of resist film.…”

Section: Introductionmentioning

confidence: 99%

EUV Resist Materials for 16 nm And below Half Pitch Applications

Tarutani

Tsubaki

Takizawa

et al. 2012

J. Photopol. Sci. Technol.

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A series of polymer with different hydrophobicity have been synthesized to investigate effects of contact angle on ultimate resolution. Contact angle of these polymers was widely changed by utilizing polymers having a different chemical structure and protection ratio. It is revealed that resolution of 20 nm half-pitch (hp) was limited by pattern collapse and improved by increasing contact angle of polymer under E-beam exposure. It is noteworthy that resolution of 20 nm hp and below for current EUV resists with exposures on a NXE:3100 and a micro-field exposure tool (MET) at SEMATECH Berkeley was also limited by pattern collapse. Low diffusion character of current EUV resists with controlled PAG design, especially polymer bound PAG (PBP), suppressed degradation of resolution by chemical blur. Combination of high contact angle polymer with low diffusivity PAG showed resolution of 16 nm hp using a MET at SEMATECH Berkeley with a LWR of 3.0 nm, sensitivity of 24 mJ/cm 2 , and Z-factor of 4 × 10 -9 mJ·nm 3 . Unfortunately density of blob defect for the hydrophobic polymer was above 100 counts/cm 2 . Hydrophobicity of film surface was found to be a main cause of its poor defectivity. Adding the new EUV additive to the hydrophobic resist reduced density of blob defect from 100 counts/cm 2 to below 0.1 counts/cm 2 .

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Revisit pattern collapse for 14nm node and beyond

Cited by 13 publications

References 0 publications

New methodology to predict pattern collapse for 14nm and beyond

New methodology to predict pattern collapse for 14nm and beyond

Pattern collapse mitigation strategies for EUV lithography

EUV Resist Materials for 16 nm And below Half Pitch Applications

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