New process models for OPC at sub-90-nm nodes

Granik, Yuri; Cobb, Nicolas B.

doi:10.1117/12.485321

Cited by 30 publications

(17 citation statements)

References 13 publications

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“…Compact models used for OPC, are calibrated from experimental data 7,8 ; therefore, it is extremely important that the metrology methods provide the level of accuracy required by the process requirements and thus imposed to the model. We have mainly focused on vector optical models and VT5 TM process models created by Calibre® WorkBench TM .…”

Section: Methodsmentioning

confidence: 99%

Calibration of OPC models for multiple focus conditions

Schacht¹,

Herold²,

Zimmermann³

et al. 2004

SPIE Proceedings

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Ability to predict process behavior under defocus has until now relied on explicit calculations, which while accurate, cannot be realistically used in full-chip optical and process correction strategies due to the long run times. In this work, we have applied a vector model for the optics, and a compact model for the resist development process. Simulations with these models are fast enough to be the basis of full-chip OPC. We verify this strategy with an independent set of measurements, and compare it to current lithographic process fitting strategies. The results indicate that by describing optical processes as accurately as possible, the model accuracy improves over a wider range of defocus conditions when compared to the traditional calibration method.As long as the calibration process successfully decouples optical and resist effects, relatively simple resist models deliver excellent accuracy within the noise level of the metrology measurements. Our data are based on onedimensional and two-dimensional results using a 193nm system using 0.75 NA and off axis illumination with 6% attenuated phase shift mask. In all cases, a wide variety of sub-resolution assist feature rules were used in order to further test the ability of the models to predict various optical and resist environments.

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Section: Methodsmentioning

confidence: 99%

Calibration of OPC models for multiple focus conditions

Schacht¹,

Herold²,

Zimmermann³

et al. 2004

SPIE Proceedings

Self Cite

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show abstract

“…In other work [1], VT5 type models which incorporate both a variable bias and a variable threshold have been created to overcome the modeling challenges down to at least 65 nm. In a similar vein, state-of-the-art OPC tools now use vector imaging models which incorporate vector effects, film stack, source map, pupil map, polarization, and a non-air ambient medium [2], [3].…”

Section: Model Accuracymentioning

confidence: 99%

“…The OPC scaling law [1] states that from one product generation to the next CDs shrinks faster than interaction ranges of the proximity effects. More and more layout features are "crammed" into the OPC interaction region, challenging modeling accuracy and OPC runtime.…”

Section: Model Accuracymentioning

confidence: 99%

New concepts in OPC

Cobb

Granik

2004

SPIE Proceedings

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In this paper, we will discuss two new concepts to be used in model-based OPC: model-based fragmentation, and model tagging to account for long-range proximity effects. In model-based fragmentation we create an initial fragmentation consisting of small fragmentation across the design. Then, specific fragments are removed according to image criteria in order to keep only those fragmentation points which affect the aerial image the most. Optical flare and long-range etch effects are challenging because they have long interaction ranges. We describe here an edge tagging technique that binds different models to different regions on the layout enabling aberration-or density-sensitive corrections. We show application of this technique on a layout section. We discuss how to implement these techniques in practice and what impact they have on OPC speed and accuracy.

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“…This kernel-based method is well suited for the OPC and replaces the slower Abbe-based formulations. Fast empirical methods for modeling resist such as the variable threshold model (VTM) [9] or the kernel-based compact model such as CM1 [10] were developed to approximate resist threshold variation. These empirical models require extensive model calibration to provide predictive power.…”

Section: History Of Simulation Softwarementioning

confidence: 99%

Review of computational lithography modeling: focusing on extending optical lithography and design-technology co-optimization

Lai

2012

Advanced Optical Technologies

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Advances in computational lithography over the last 10 years have been instrumental to the continued scaling of semiconductor devices. Competitive scaling requires two types of complementary models: fast predictive empirical models that can be used for pattern correction and verification; rigorous physical models that can be used to identify key physical effects that must be considered to ensure pattern fidelity, but are too resource intensive to use for full chip applications. Today, all computational lithography efforts such as the optical proximity correction (OPC) and the optical rules check (ORC) depend on the ability to predictively model the lithography and metrology processes. We discuss some of the current modeling practices in optics, mask, resist and etching, leading to the " Holy Grail " of predictively modeling entire patterning process which we call " virtual fab " . Extreme ultraviolet (EUV) modeling is discussed due to its potential to extend optical lithography scaling for future nodes. Modeling of novel technologies such as Diblock Copolymer patterning is also discussed to demonstrate new opportunities for continued scaling. Complexity of the " virtual fab " approach is extremely high as there are multiple dimensions in this approach. The need to overcome this complexity, by reducing the number of dimensions of the problem, is evident. Lastly, the ability to leverage lithography modeling in design co-optimization is an important element of semiconductor device scaling.

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New process models for OPC at sub-90-nm nodes

Cited by 30 publications

References 13 publications

Calibration of OPC models for multiple focus conditions

Calibration of OPC models for multiple focus conditions

New concepts in OPC

Review of computational lithography modeling: focusing on extending optical lithography and design-technology co-optimization

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