EUV masks under exposure: practical considerations

Gallagher, Emily; McIntyre, Gregory; Wallow, Tom; Raghunathan, Sudharshanan; Wood, O. R.; Kindt, Louis; Whang, John; Barrett, Monica

doi:10.1117/12.880755

Cited by 7 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The total analyzed line length is approximately 1 m. The correlation of the line edge data from exposure to exposure is a measure of the mask contributions since any resist contributions would certainly be expected to be uncorrelated from exposure to exposure. These effects have further been verified in a full field Alpha Demo Tool using a conventional discharge source and a partial coherence of 0.5 [3].…”

Section: Mask Multilayer Roughnessmentioning

confidence: 99%

“…This roughness directly maps to phase roughness in the reflected field which in turn maps to image plane speckle and LER [4][5][6][7]. The concern over, this problem has recently increased since its experimental demonstration in printed wafers at EUV [8] in both an microfield exposure tool [9] and a full field EUV alpha tool [3]. The coupling from roughness to LER depends on many factors including roughness magnitude, roughness correlation length, illumination partial coherence, aberrations, defocus, and numerical aperture (NA) [10].…”

Section: Mask Multilayer Roughnessmentioning

confidence: 99%

“…The non-telecentric nature of EUV masks due to the requisite off-axis illumination, raises a variety of EUV specific problems. A thorough survey of the various sources of mask-induced CDU has been presented by Gallagher et al [3].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Accelerating EUV learning with synchrotron light: mask roughness challenges ahead

Naulleau

Goldberg²,

Gullikson

et al. 2011

SPIE Proceedings

View full text Add to dashboard Cite

Despite significant progress in the commercialization of extreme ultraviolet (EUV) lithography, many important challenges remain, including in the area of masks. The issue of EUV phase roughness that can arise from either multilayer or capping layer roughness has recently garnered increasing concern. The problem with mask phase roughness is that it couples line-edge roughness (LER) through the formation of image plane speckle. The coupling from phase roughness to LER depends on many factors including roughness magnitude, roughness correlation length, illumination partial coherence, aberrations, defocus, and numerical aperture. Analysis shows that only on the order of 50 pm multilayer roughness may be tolerable at the 22-nm half-pitch node. Results also show that Atomic Force Microscopy (AFM) may not be a suitable method for measuring mask phase roughness due to its sensitivity to the surface only. Capping layer roughness is another significant concern especially given that it has been shown to increase with cleaning cycles. In this case, however, AFM does provide a reasonable metric.

show abstract

Section: Mask Multilayer Roughnessmentioning

confidence: 99%

Section: Mask Multilayer Roughnessmentioning

confidence: 99%

See 1 more Smart Citation

Accelerating EUV learning with synchrotron light: mask roughness challenges ahead

Naulleau

Goldberg²,

Gullikson

et al. 2011

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…The visibility of, and concern over, this problem has recently increased since its experimental demonstration at EUV [12] in both an microfield exposure tool [13] and a full field EUV alpha tool [7]. The coupling from roughness to LER, however, depends on many factors including roughness magnitude, roughness correlation length, illumination partial coherence, aberrations and defocus, and numerical aperture (NA).…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mask roughness challenges in extreme ultraviolet mask development

Naulleau¹,

McClinton²,

Goldberg³

et al. 2011

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

View full text Add to dashboard Cite

Despite significant progress in the commercialization of extreme ultraviolet (EUV) lithography, many challenges remain. Although availability of a reliable high power source is arguably the most daunting of these challenges, important mask issues are also of major concern. The issues of EUV phase roughness that can arise from either multilayer or capping layer roughness has recently become of increasing concern. The problem with mask phase roughness is that it couples to image plane speckle and thus line-edge roughness (LER). The coupling, however, depends on many factors including roughness magnitude, roughness correlation length, illumination partial coherence, aberrations and defocus, and numerical aperture. Analysis shows that only on the order of 50 pm multilayer roughness may be tolerable at the 22-nm half-pitch node. The analysis, however, also shows that the difficulty does not scale with future node reductions.Moreover, it is found that ruthenium is a particularly bad choice for capping layer from the perspective of phase roughness and that cleaning damage in such a multilayer could lead to unacceptable image-plane LER.

show abstract

EUV mask black border evolution

et al. 2014

Self Cite

View full text Add to dashboard Cite

The black border is a frame created by removing all the multilayers on the EUV mask in the region around the chip. It is created to prevent exposure of adjacent fields when printing an EUV mask on a wafer. Papers have documented its effectiveness [1] . As the technology transitions into manufacturing, the black border must be optimized from the initial mask making process through its life. In this work, the black border is evaluated in three stages: the black border during fabrication, the final sidewall profile, and extended lifetime studies.This work evaluates the black border through simulations and physical experiments. The simulations address concerns for defects and sidewall profiles. The physical experiments test the current black border process. Three masks are used: one mask to test how black border affects the image placement of features on mask and two masks to test how the multilayers change through extended cleans. Data incorporated in this study includes: registration, reflectivity, multilayer structure images and simulated wafer effects.By evaluating the black border from both a mask making perspective and a lifetime perspective, we are able to characterize how the structure evolves. The mask data and simulations together predict the performance of the black border and its ability to maintain critical dimensions on wafer. In this paper we explore what mask changes occur and how they will affect mask use.

show abstract

EUV masks under exposure: practical considerations

Cited by 7 publications

References 0 publications

Accelerating EUV learning with synchrotron light: mask roughness challenges ahead

Accelerating EUV learning with synchrotron light: mask roughness challenges ahead

Mask roughness challenges in extreme ultraviolet mask development

EUV mask black border evolution

Contact Info

Product

Resources

About