Fabrication of masks for electron-beam projection lithography

Lercel, Michael J.; Magg, Chris; Barrett, Monica; Collins, Kevin; Trybendis, Michael J.; Caldwell, Neal; Jeffer, R.; Bouchard, Lucien

doi:10.1116/1.1314370

Cited by 7 publications

(7 citation statements)

References 14 publications

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“…[14] A similar axially dependent distortion is seen on continuous membrane masks. [13] The Sematech funded study also confirmed University of Wisconsin modeling results that pattern density gradients have the worst impact on IP. [15] For example, a subfield that was half-filled with a dense pattern (the other half being unpatterned) caused a large image placement distortion along the line of highest pattern density gradient.…”

Section: Pattern and Materials Requirementssupporting

confidence: 81%

“…Using the support ring provided almost 12 times better repeatability in absolute image placement than not using the ring. [13] This does not indicate that a support ring is necessary, but rather that the chucking format (the mask shape during use) should be standardized for EPL mask use.…”

Section: Pattern and Materials Requirementsmentioning

confidence: 98%

“…This resulted in a 35% higher distortion in the less stiff axis. [13] This can result in anisotropic magnification components. For stencil masks, such shapes would, ideally, be fractured into complementary pairs that not only balanced the overall subfield pattern density but also resulted in a split into isotropic complementary pairs.…”

Section: Pattern and Materials Requirementsmentioning

confidence: 99%

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Analysis of critical parameters for EPL mask fabrication

Lercel¹

2002

Emerging Lithographic Technologies VI

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Electron projection lithography (EPL) requires mask formats that are significantly different from those used in traditional optical lithography. These masks must consist of a thin membrane that is either patterned with transmissive perforations for stencil masks or patterned with a scatterer layer to form a continuous membrane mask. In this paper, the critical requirements for fabrication of EPL masks are discussed. Challenges for mask blank fabrication, image size uniformity, image placement accuracy, and defect control are presented with examples from mask fabrication. The impact of these parameters on EPL mask cost is then discussed. The mask cost is compared for different critical device levels and for different chip sizes. The influence of mask parameters and need for complementary masks drives higher mask costs for certain device levels. By examining the factors influencing mask cost for certain levels, the areas of mask technology that are most critical to controlling mask cost can be identified.

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Section: Pattern and Materials Requirementssupporting

confidence: 81%

Section: Pattern and Materials Requirementsmentioning

confidence: 98%

Section: Pattern and Materials Requirementsmentioning

confidence: 99%

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Analysis of critical parameters for EPL mask fabrication

Lercel¹

2002

Emerging Lithographic Technologies VI

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“…Image placement distortions result not only from the patterning of the membrane (IPD) but also from the differences in the chucking methodology between the e-beam writer, image placement measurement tool and the final exposure tool (out of plane distortions). Factors such as the clamping forces have been shown to lead to large out of plane distortions [7]. However, by using the subtractive technique all image placement caused external to pattern transfer are eliminated.…”

Section: Mask Patterning and Metrologymentioning

confidence: 99%

Image Placement Distortions in EPL Masks

Thiel¹,

Kindt²,

Lawliss³

2002

SPIE Proceedings

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Electron projection lithography (EPL) is a promising candidate for the next generation lithography choice. There are several advantages to EPL, such as a large depth of focus and a lower relative mask cost. Significant challenges also face this technology, including the limitation of the membrane format of the mask. One of the obstacles with the membrane format is image placement distortions, which can be very sensitive to the stress of the membrane as well as the pattern density. This paper studies how the stress of various types of films effects image placement distortions, as well as examines the effect of final mask cleans on image placement distortions.

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“…Improvements are needed in image size uniformity control across large mask areas and image placement control. First, tomask, and can distort based on the chucking forces [9]. Experiments performed for the Scalpel program show the feasibility of this concept,[10] and further experiments are underway to refine the requirements of the mask chucking scheme.All of the small format EPL masks at the MCoC have been formed using a wet etch removal of the silicon wafer to define the membranes.…”

mentioning

confidence: 99%

Mask availability for next-generation lithography

et al. 2002

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The Next Generation Lithography (NGL) Mask Center of Competency (MCoC) has been developing mask technology to support all of the major next generation lithographies for several years. Cross-cutting process development has been applied to generate progress in both the membrane and reflective mask formats. The mask technology has been developed to early capability stage for all of the mask formats. Proximity x-ray masks, although only for certain niche applications, are a very developed mask format. This information has been used to produce electron beam projection masks, in both continuous membrane and stencil formats, and extreme ultraviolet lithography masks. In this paper, we disucss the status of the lithography technology development and the obstacles that remain between the current early development capability and the availability for manufacturing.

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Fabrication of masks for electron-beam projection lithography

Cited by 7 publications

References 14 publications

Analysis of critical parameters for EPL mask fabrication

Analysis of critical parameters for EPL mask fabrication

Image Placement Distortions in EPL Masks

Mask availability for next-generation lithography

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