Deconstructing contact hole CD printing variability in EUV lithography

Civay, Deniz; Wallow, Tom; Doganaksoy, Necip; Verduijn, Erik; Schmid, Gerard M.; Mangat, Pawitter J. S.

doi:10.1117/12.2049546

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…The printing of CH patterns is affected by several issues such as illumination conditions, resist, reticle, stochastics, and polarization effects. [1][2][3][4] Different methods have been used to improve the critical dimension uniformity (LCDU) of printed CHs, such as the conventional mask can be improved with phase shift mask or use the leaf hexagonal illumination technique. 2,4 Resist performance for CH patterns can be different from that of the lines/spaces and therefore needs to be addressed.…”

Section: Introductionmentioning

confidence: 99%

Studying resist performance for contact holes printing using EUV interference lithography

Wang

Tseng

Kazazis

et al. 2019

J. Micro/Nanolith. MEMS MOEMS

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Extreme ultraviolet interference lithography (EUV-IL) is a relatively simple and inexpensive technique that can pattern high-resolution line/space and has been successfully used for the resist performance testing. While the aerial image in EUV-IL formed by two beams is straightforward to understand and has contrast of 1, the aerial image formed by four beams providing contact holes is rather complicated. The beam polarization and relative phases of the individual beams play a significant role in the aerial image formation in four-beam interference lithography. In particular, controlling the relative phase of the beams is very difficult to achieve due to short wavelength. To circumvent this problem, we propose an effective double exposure four-beam interference lithography method, by intentionally designing the grating with a slightly different pitch to create an optical path difference that is longer than the coherence length of the EUV light (13.5 nm). We numerically prove the effective double exposure four-beam interference is not sensitive to the phases difference and verify our analytical model by printing both positive tone chemically amplified resist and a negative tone inorganic resist.

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Section: Introductionmentioning

confidence: 99%

Studying resist performance for contact holes printing using EUV interference lithography

Wang

Tseng

Kazazis

et al. 2019

J. Micro/Nanolith. MEMS MOEMS

View full text Add to dashboard Cite

show abstract

“…Contact hole (CH) patterning is an important lithography step and will be one of the key applications in the extreme ultraviolet lithography (EUVL). The printing of CH patterns is affected by several issues such as illumination conditions, resist, reticle, stochastics and polarization effects [1][2][3][4]. Different methods have been used to improve the critical dimension uniformity (LCDU) of printed CHs, such as the conventional mask can be improved with phase shift mask or use the leaf hexagonal illumination technique [2,4].…”

Section: Introductionmentioning

confidence: 99%

Studying resist performance for contact holes printing using EUV interference lithography

Wang

Tseng

Kazazis

et al. 2018

International Conference on Extreme Ultraviolet Lithography 2018

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Extreme ultraviolet interference lithography (EUV-IL) is relatively simple and inexpensive technique that can pattern high resolution line/space and has been successfully used for the resist performance testing. While the aerial image in EUV-IL formed by two beams is straightforward to understand and has contrast of 1, the aerial image formed by four beams providing contact holes (CHs) is rather complicated. The phases of the interfering beams as well as by the polarization play big roles in the image of the interference pattern and its contrast. To understand thoroughly the formation of CH, we investigate theoretically polarization effect on the aerial image generated with two and four-beam interference. We show the coherent four-beam interference provides the highest contrast (1) with zero initial phase. But the interference pattern strongly depends on the phase difference and switch from one to another when the phase difference between the two pairs of gratings is π/2. Consequently, the contrast also decreases and interference pattern could end with random form when the relative phase of the beams cannot be fully controlled. We propose an incoherent four-beam interference model by intentionally designing the grating with a slightly different pitch to create an optical path difference that is longer than the coherence length of the EUV light (13.5 nm). We also discuss the polarization-induced contrast loss. We verify our analytical model by printing both positive tone chemically amplified resist (CAR) and a negative tone inorganic resist.

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Lithographic stochastics: beyond 3σ

Bristol

Krysak

2017

J. Micro/Nanolith. MEMS MOEMS

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Deconstructing contact hole CD printing variability in EUV lithography

Cited by 4 publications

References 2 publications

Studying resist performance for contact holes printing using EUV interference lithography

Studying resist performance for contact holes printing using EUV interference lithography

Studying resist performance for contact holes printing using EUV interference lithography

Lithographic stochastics: beyond 3σ

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