Model-based sub-resolution assist features using an inverse lithography method

Yu, Jue Chin; Yu, Peichen; Chao, Hsueh Yung

doi:10.1117/12.804678

Cited by 8 publications

(8 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To address this problem, we develop an innovative pixel-flipping algorithm where the pixel-flipping is biased by a wavefront expansion technique. 28 We further incorporate a wavefront-based damping scheme and demonstrate that the resulting masks are similar to those obtained by more elaborated algorithms. For its application as a pre-OPC flow, a single iteration is often sufficient to generate SRAFs and to determine the bias of main features.…”

Section: Introductionsupporting

confidence: 52%

Wavefront-based pixel inversion algorithm for generation of subresolution assist features

Yu²,

Chao

2011

J. Micro/Nanolith. MEMS MOEMS

Self Cite

View full text Add to dashboard Cite

The generation of subresolution assist features (SRAFs) using inverse-lithography techniques demands extensive computational resources which limits its deployment in advanced CMOS nodes. In this paper, we propose a wavefront-based pixel inversion algorithm to quickly obtain inverse masks with a high aerial image quality. Further assisted by a flexible pattern simplification technique, we present effective SRAF generation and placement based on the calculated inverse mask. The proposed approach can be easily inserted prior to a conventional mask correction flow for subsequent concurrent optimizations of both drawn patterns and SRAFs. The innovative pixel inversion and pattern simplification techniques allow quality mask corrections as produced by inverse lithography while maintaining the convenience of standardized/validated process flows currently used in the industry. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

show abstract

Section: Introductionsupporting

confidence: 52%

Wavefront-based pixel inversion algorithm for generation of subresolution assist features

Yu²,

Chao

2011

J. Micro/Nanolith. MEMS MOEMS

Self Cite

View full text Add to dashboard Cite

show abstract

“…A few examples of wavefront templates can be found in Ref. [11]. As a result, the indices of boundary pixels end up being the same for individual features.…”

Section: Methodsmentioning

confidence: 97%

“…The generation of the pixel index is adopted from a wavefront expansion technique previously developed by us [11]. For any particular layout, we construct a wavefront from the feature's edges both inwards and outwards.…”

Section: Methodsmentioning

confidence: 99%

Choosing objective functions for inverse lithography patterning

2011

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

Inverse lithography which generates model-based patterns theoretically has superior patterning fidelity comparing to conventional rule-based technique. Cost functions are the determinant of performance inverse lithography that is also an optimization problem. However, the design and know-how of cost functions have rarely been discussed. In this paper, we investigate the impacts of various cost functions and their superposition for inverse lithography patterning exploiting a steepest descent algorithm. We research the most generally used objective functions, which are the resist and aerial images, and also deliver a derivation for the aerial image contrast. We then discuss the pattern fidelity and final mask characteristics for simple layouts with a single isolated contact and two nested contacts. Moreover, the convergences which are expressed by edge-placement error (EPE) and contrast versus iteration numbers rapidly attain to steady sate in most hybrid cost functions. All in all, we conclude that a cost function composed of a dominant resist-image component and a minor aerial-image or image-contrast component can carry out a good mask correction and contour targets when using inverse lithography patterning.

show abstract

“…where I t (r) is the target image as a function of the pixel index r. r is arranged in the radial direction from the geometric center of a drawn pattern, where r 0 is the index of the boundary pixels. The generation of the pixel index is adopted from a wavefront expansion technique previously developed by us [11]. For any particular layout, we construct a wavefront from the feature's edges both inwards and outwards.…”

Section: Methodsmentioning

confidence: 99%

“…Other cost functions, such as edge contours, aerial image contrast, and mask error enhancement factor (MEEF), have also been proposed and can be customized to satisfy strict technological specifications. In our experience, we have observed that given the same cost function and process model, two different optimization algorithms, like a wavefront-based pixel flipping [11], and gradient descent, tend to converge to nearly identical final mask patterns. This phenomenon further highlights the importance of using a favorable cost function.…”

Section: Introductionmentioning

confidence: 99%

Impacts of cost functions on inverse lithography patterning

Yu¹,

Yu²

2010

Opt. Express

Self Cite

View full text Add to dashboard Cite

For advanced CMOS processes, inverse lithography promises better patterning fidelity than conventional mask correction techniques due to a more complete exploration of the solution space. However, the success of inverse lithography relies highly on customized cost functions whose design and know-how have rarely been discussed. In this paper, we investigate the impacts of various objective functions and their superposition for inverse lithography patterning using a generic gradient descent approach. We investigate the most commonly used objective functions, which are the resist and aerial images, and also present a derivation for the aerial image contrast. We then discuss the resulting pattern fidelity and final mask characteristics for simple layouts with a single isolated contact and two nested contacts. We show that a cost function composed of a dominant resist-image component and a minor aerial-image or image-contrast component can achieve a good mask correction and contour targets when using inverse lithography patterning.

show abstract

Model-based sub-resolution assist features using an inverse lithography method

Cited by 8 publications

References 16 publications

Wavefront-based pixel inversion algorithm for generation of subresolution assist features

Wavefront-based pixel inversion algorithm for generation of subresolution assist features

Choosing objective functions for inverse lithography patterning

Impacts of cost functions on inverse lithography patterning

Contact Info

Product

Resources

About