Partially Coherent Quantitative Phase Retrieval for EUV Lithography

Claus, Rene A.; Wang, Yow-Gwo; Benk, Markus P.; Goldberg, Kenneth A.; Naulleau, Patrick; Neureuther, Andrew R.; Waller, Laura

doi:10.1364/isa.2015.ith2a.4

Cited by 3 publications

(7 citation statements)

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“…(20) and (21) are, when taken together, also sufficient conditions for linearizing partially coherent imagery. Because the Rytov approximation is known to be sensitive to the phase gradient and not its magnitude, the "weak object" terminology in WOTF is perhaps a misnomer, and the aforementioned successful reconstruction results [50][51][52][53] are made plausible. Because the intensity contrast matters most, it follows that the magnitudes of H OA A ρ and H OA ϕ ρ as ρ approaches 0 are of critical importance in determining the validity of linearization because the amplitudes of most naturally occurring objects are strongest for lower spatial frequencies.…”

Section: Research Articlementioning

confidence: 99%

“…One presumed drawback of methods based on the WOTF is reliance on the first-order Born approximation in which the magnitude of the scattered light is much smaller than the magnitude of the incident light [76], hence the use of "weak object" in WOTF. Interestingly, however, although each of the aforementioned authors acknowledge this approximation, the corresponding experimental results seem to indicate that recovery is possible even for objects in which the first Born approximation is not satisfied [50][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

“…Within the context of phase retrieval from micrographs recorded under varying conditions, methods may be broadly categorized as iterative [6,[38][39][40][41][42][43][44] or deterministic [45][46][47][48][49][50][51][52][53]. Iterative methods account for the inherent nonlinearity of the image formation process; however, because the problem is nonconvex [54], they cannot be proven to converge, thus adding additional complexity and constraints.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, microscopic WOTF phase reconstructions have been demonstrated using defocus under the paraxial approximation for small [50] and large defocus [51]. In addition to defocus, WOTF phase recovery was achieved using differential phase contrast (DPC) [52] realized via asymmetric illumination as well as Zernike phase contrast in the extreme ultraviolet [53]. One presumed drawback of methods based on the WOTF is reliance on the first-order Born approximation in which the magnitude of the scattered light is much smaller than the magnitude of the incident light [76], hence the use of "weak object" in WOTF.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative phase microscopy via optimized inversion of the phase optical transfer function

Jenkins

Gaylord

2015

Appl. Opt.

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Although the field of quantitative phase imaging (QPI) has wide-ranging biomedical applicability, many QPI methods are not well-suited for such applications due to their reliance on coherent illumination and specialized hardware. By contrast, methods utilizing partially coherent illumination have the potential to promote the widespread adoption of QPI due to their compatibility with microscopy, which is ubiquitous in the biomedical community. Described herein is a new defocus-based reconstruction method that utilizes a small number of efficiently sampled micrographs to optimally invert the partially coherent phase optical transfer function under assumptions of weak absorption and slowly varying phase. Simulation results are provided that compare the performance of this method with similar algorithms and demonstrate compatibility with large phase objects. The accuracy of the method is validated experimentally using a microlens array as a test phase object. Lastly, time-lapse images of live adherent cells are obtained with an off-the-shelf microscope, thus demonstrating the new method's potential for extending QPI capability widely in the biomedical community.

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Section: Research Articlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quantitative phase microscopy via optimized inversion of the phase optical transfer function

Jenkins

Gaylord

2015

Appl. Opt.

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“…We have previously applied our algorithm to EUV photomasks to study multilayer defects [28,29]. In this paper we describe the algorithm in depth, providing a description of convergence and validity.…”

Section: Introductionmentioning

confidence: 99%

Quantitative phase retrieval with arbitrary pupil and illumination

et al. 2015

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We present a general algorithm for combining measurements taken under various illumination and imaging conditions to quantitatively extract the amplitude and phase of an object wave. The algorithm uses the weak object transfer function, which incorporates arbitrary pupil functions and partially coherent illumination. The approach is extended beyond the weak object regime using an iterative algorithm. We demonstrate the method on measurements of Extreme Ultraviolet Lithography (EUV) multilayer mask defects taken in an EUV zone plate microscope with both a standard zone plate lens and a zone plate implementing Zernike phase contrast. Am. 73, 1434Am. 73, (1983. 5. J. R. Fienup, "Phase retrieval algorithms: a comparison," Appl. Opt. 21, 2758Opt. 21, -2769Opt. 21, (1982. 217, 408-432 (1953). 32. C. Chang, A. Sakdinawat, P. Fischer, E. Anderson, and D. Attwood, "Single-element objective lens for soft x-ray differential interference contrast microscopy," Opt. Lett. 31, 1564Lett. 31, -1566Lett. 31, (2006. 33. F. Zernike, "Phase contrast, a new method for the microscopic observation of transparent objects," Physica 9, 686-698 (1942

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Simple phase retrieval method based on two intensity measurements on a single plane

Zhou

2021

Appl. Opt.

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In this work, a simple phase retrieval method is proposed by observing two intensity patterns on a single plane, which are generated with and without a lens. Rigorous theoretical derivations show that the two fields constitute the Fourier transform pairs, and a modified Gerchberg–Saxton algorithm is proposed to recover the phase patterns from the Fourier pairs. The proposed method does not require the intensity patterns to be measured on two different planes along the propagation distance, and this is quite beneficial in a system with a phase tuning element like a spatial light modulator, which can form a virtual lens by creating a parabola-like phase distribution. Experiments are conducted to demonstrate the effectiveness of the proposed phase retrieval method.

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Partially Coherent Quantitative Phase Retrieval for EUV Lithography

Cited by 3 publications

References 0 publications

Quantitative phase microscopy via optimized inversion of the phase optical transfer function

Quantitative phase microscopy via optimized inversion of the phase optical transfer function

Quantitative phase retrieval with arbitrary pupil and illumination

Simple phase retrieval method based on two intensity measurements on a single plane

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