Extreme Ultraviolet Interferometric Lithography: A Path to Nanopatterning

Cerrina, F.; Isoyan, Artak; Jiang, Fang; Cheng, Yongpan; Leonard, Quinn J.; Wallace, John; Heinrich, K.; Ho, A. H. P.; Efremov, Mikhail Yu.; Nealey, Paul F.

doi:10.1080/08940880802268236

Cited by 1 publication

(5 citation statements)

References 16 publications

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“…4 ͑At most synchrotron radiation facilities, this asymmetry is by design, to facilitate the use of spectrographs where the image of the electron beam is formed on the entrance slit, usually horizontal-hence, a thin horizontal beam cross section is preferred.͒ This difference in beam cross section has an important effect on image formation. Obviously, it is difficult to image fringes when the period is near to or less than the blur.…”

Section: -D Patterningmentioning

confidence: 98%

“…4, this is easily achieved by stepping the wafer so that the zero order from one of the gratings illuminates the interference fringe region. By timing the two exposures, it is possible to vary the image contrast.…”

Section: Modulation Controlmentioning

confidence: 99%

“…4, the low-stress silicon nitride membrane ͑SiNH͒ supporting the gratings is approximately 100 nm thick. The grating itself is formed by e-beam lithography and thus tends to have a square wave cross section; this creates multiple orders in the diffraction pattern.…”

Section: Diffraction Efficiencymentioning

confidence: 99%

“…6 In this paper, we present the analysis of the image formation process in a typical EUV-IL setup and discuss, in detail, intrinsic ͑e.g., materials, geometry͒ and extrinsic ͑e.g., partial coherence͒ effects; the exposure system and experimental results have been reported elsewhere. 4 Although conceptually simple, the operation of an interferometer system in the EUV presents many challenges that must be overcome to produce high-quality patterns of highvisibility fringes. In this paper, we will often use, interchangeably, the terms "visibility," "contrast," and "modulation" when referring to the image quality; different disciplines use different terminology.…”

Section: Introductionmentioning

confidence: 99%

“…2,3 Spurred by the need for a simpler and easily accessible nanopatterning tool in the EUV, during the last decade a new lithographic technique called extreme ultraviolet interferometric lithography ͑EUV-IL͒ has emerged, specifically to pattern nanometerscale periodic structures. [4][5][6] EUV-IL is an extension of the well-known achromatic interferometric lithography that was developed in the 1980s, using UV laser sources to fabricate large-area gratings of a 50-nm half-period. 7 Since then, various interferometric lithography ͑IL͒ techniques based on diffraction gratings to form the interfering beams have been described and used in the UV/deep UV regions.…”

Section: Introductionmentioning

confidence: 99%

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Engineering study of extreme ultraviolet interferometric lithography

Jiang

Cheng

Isoyan

et al. 2009

J. Micro/Nanolith. MEMS MOEMS

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Extreme ultraviolet interferometric lithography ͑EUV-IL͒ is a powerful nanopatterning technique, exploiting the interference of two beams of short-wavelength radiation ͑ Ϸ 13 nm͒ to form high-accuracy fringe patterns. Transmission diffraction gratings of appropriate period ͑40-100 nm͒ are used to form the beams; the substrate is located in the region of overlap to expose the photoresist material, recording 20-50 nm interference fringe patterns. Although the physics of EUV-IL is simple, its actual implementation is not and requires attention to detail in order to fully exploit the power of the technique. In order to understand the impact of realistic physical conditions on the performance of EUV-IL, we have developed a set of accurate numerical models based on the Rayleigh-Sommerfeld diffraction theory. These modeling tools are then applied to generate a complete and accurate analysis of EUV-IL, taking into account all the relevant physical processes, from finite extent of the gratings to the partial coherence of the source, and including detailed physical structure of the mask. The results are used to guide the design and implementation of EUV-IL exposure systems, down to the sub-11-nm range.

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Section: -D Patterningmentioning

confidence: 98%

Section: Modulation Controlmentioning

confidence: 99%

Section: Diffraction Efficiencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%