The calibration of process window model for 55-nm node

Wu, Te; Huang, Sheng Chieh; Huang, Chia Wei; Tsai, Pei Ru; Yang, Chuen Huei; Su, Irene; Falch, Brad

doi:10.1117/12.715496

Cited by 2 publications

(1 citation statement)

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“…11 which reveals a marginal process window. the off-focus dimensions has been beneficial for Scatter Bar (SBAR) rule optimization [1] as well for OPC correction in advanced memory chip production [2] as well as random logic design manufacturing [3]. It is also a powerful tool to improve design and OPC verification: Readily available modeling strategies including variable threshold models used in this study as well as compact models [2] yield accurate process window models by adding a relatively small number of additional SEM measurements characterizing the process window.…”

Section: Resultsmentioning

confidence: 96%

A novel methodology for model-based OPC verification

Huang

Liao

Chou³

et al. 2008

SPIE Proceedings

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Model-based optical proximity correction (OPC) is an indispensable production tool enabling successful extension of photolithography down to sub-80nm regime. Commercial OPC software has established clear procedures to produce accurate OPC models at best focus condition. However, OPC models calibrated at best focus condition sometimes fail to prevent catastrophic circuit failure due to patterning short & open caused by accidental shifts of dose/ focus within the corners of allowed processes window.A novel model-based OPC verification methodology is presented in this work, which precisely pinpoints post OPC photolithography failures in VLSI circuits through the entire lithographic process window. By application of a critical photolithography process window model in OPC verification software, we successfully uncovered all weak points of a design prior tape out, eliminating high risk of circuits open & shorts at the extreme corner of the lithographic process window in any complex circuit layout environment. The process window-related information is usually not taken into consideration when running OPC verification procedures with models calibrated at nominal process condition. Intensive review of the critical dimension (CD) and top-view SEM micrographs from the weak points indicate matching between post OPC simulation and measurements. Using a single highly accurate process window resist model provides a reliable OPC verification methodology when used in a field-or grid-based simulation engine ensuring manufacturability within the largest possible process window for any modern critical design.

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