Hidden CD errors due to reticle imperfection

Mark, Zvi; Zheng, Sandra

doi:10.1117/12.435790

Cited by 4 publications

(4 citation statements)

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“…To some extent, equation (1) takes these considerations into account by using the partial derivation, which perturbs only one of the wafer CD arguments (parameters upon which it depends), presumably, a correspondent mask CD. Still, differences in how a particular mask CD or a particular proximity curve is chosen significantly impacts MEEF value.…”

Section: Introductionmentioning

confidence: 99%

“…The MEEF definition presented in 2,3 takes the form of a partial derivative: MEEF = (1) aCDm where CD is the critical dimension on the wafer; CDm is the critical dimension on the mask (in a wafer scale).…”

Section: Introductionmentioning

confidence: 99%

“…The first column of the figure shows three 160 nm lines separated by 160 nm. CD ofthe center line is subjected to the derivation (1). To carry out the derivation, we have to vary the middle line width by perturbing the line shapes.…”

Section: Introductionmentioning

confidence: 99%

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MEEF as a matrix

Granik

Cobb

2002

21st Annual BACUS Symposium on Photomask Technology

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Mask error enhancement factor (MEEF) depends on the two groups of factors. The first group is process-related, and includes parameters such as illumination settings and exposure dose. The second group is mask-related and includes feature sizes, feature shapes, and proximity interactions between features. Factors from the second group have not been studied to the same depth as factors of the first group. Only simple shapes like dense lines, isolated lines, and contact holes, each with only one degree of the distortion freedom, have been addressed by the traditional MEEF theory. We present here a comprehensive MEEF theory for arbitrary 2D mask shapes, with multiple degrees of the distortion freedom. This theory provides a rigorous formal framework for studying impact of the complex mask errors. We introduce mask error enhancement matrix (MEEM) to capture self-and cross-enhancement effects when neighboring mask distortions collectively contribute into the wafer errors. The norm of this matrix is called a generalized MEEF (G-MEEF), an important characteristic of the pattern transfer process. The Singular Value Decomposition of MEEM naturally groups edges of the mask shapes into the proximity-related sets, each with a distinct G-MEEF value. Ranking mask areas by this value helps to identify difficult-to-print regions and to design MEEF-sensitive test patterns. An application ofmatrix MEEF theory is shown to be iterative feedback techniques for model-based OPC.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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MEEF as a matrix

Granik

Cobb

2002

21st Annual BACUS Symposium on Photomask Technology

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“…The tolerable size of defects is an important parameter used to determine the reticle cost [1]. For k 1 values larger than 0.7 the tolerable defect size was evaluated by a simple rule of thumb: "a defect on a 4× reticle could be counted on to print at about one-forth its size on the wafer" [2].…”

Section: Introductionmentioning

confidence: 99%

Mask defect printing mechanisms for future lithography generations

et al. 2006

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Mask defects are of increasing concern for future lithography generations. The improved resolution capabilities of immersion and EUV systems increase also the sensitivity of these systems with respect to small imperfections of the mask. Advanced mask technologies such as alternating phase shift masks (AltPSM), chromeless phase shift lithography (CPL), or "thick" absorbers on EUV masks introduce new defect types.The paper presents an application of rigorous electromagnetic field modeling for the study of typical defect printing mechanisms in ArF immersion lithography and in EUV lithography. For standard imaging and mask technologies, such as binary masks or attenuated phase shift masks, small defects usually print as linewidth or critical dimension (CD) errors with the largest effect at best focus. For AltPSM, CPL masks, and EUV masks this is not always the case. Several unusual printing scenarios were observed: placement errors due to defects can become more critical than CD-errors, defects may print more critical at defocus positions different from the center of the process window, the defect printing may become asymmetric through focus, and the risk of defect printing depends on the polarization of the used light source.Several simulation examples will demonstrate these effects. Rigorous EMF simulations in combination with vector imaging simulations are very useful to understand the origins of the observed defect printing mechanisms.

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Generalized mask error enhancement factor theory

Granik

2005

J. Micro/Nanolith. MEMS MOEMS

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Hidden CD errors due to reticle imperfection

Cited by 4 publications

References 0 publications

MEEF as a matrix

MEEF as a matrix

Mask defect printing mechanisms for future lithography generations

Generalized mask error enhancement factor theory

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