Formation mechanism of 193nm immersion defects and defect reduction strategies

Wei, Yayi; Brandl, S.; Goodwin, Frank

doi:10.1117/12.771221

Cited by 4 publications

(5 citation statements)

References 10 publications

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“…So far, it has been shown that nanobubbles contribute to the attraction between hydrophobic surfaces in water [1][2][3], rupture of thin liquid films [37,38], and hydrodynamic slip [29]. Moreover, they play a role in froth-flotation [39], immersion lithography [40], and are a useful tool for cleaning surfaces fouled with proteins or nanoparticles [41,42].…”

Section: Introductionmentioning

confidence: 99%

The effect of PeakForce tapping mode AFM imaging on the apparent shape of surface nanobubbles

Walczyk

Schön

Schönherr

2013

J. Phys.: Condens. Matter

109

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Until now, TM AFM (tapping mode or intermittent contact mode atomic force microscopy) has been the most often applied direct imaging technique to analyze surface nanobubbles at the solid-aqueous interface. While the presence and number density of nanobubbles can be unequivocally detected and estimated, it remains unclear how much the a priori invasive nature of AFM affects the apparent shapes and dimensions of the nanobubbles. To be able to successfully address the unsolved questions in this field, the accurate knowledge of the nanobubbles' dimensions, radii of curvature etc is necessary. In this contribution we present a comparative study of surface nanobubbles on HOPG (highly oriented pyrolytic graphite) in water acquired with (i) TM AFM and (ii) the recently introduced PFT (PeakForce tapping) mode, in which the force exerted on the nanobubbles rather than the amplitude of the resonating cantilever is used as the AFM feedback parameter during imaging. In particular, we analyzed how the apparent size and shape of nanobubbles depend on the maximum applied force in PFT AFM. Even for forces as small as 73 pN, the nanobubbles appeared smaller than their true size, which was estimated from an extrapolation of the bubble height to zero applied force. In addition, the size underestimation was found to be more pronounced for larger bubbles. The extrapolated true nanoscopic contact angles for nanobubbles on HOPG, measured in PFT AFM, ranged from 145° to 175° and were only slightly underestimated by scanning with non-zero forces. This result was comparable to the nanoscopic contact angles of 160°-175° measured using TM AFM in the same set of experiments. Both values disagree, in accordance with the literature, with the macroscopic contact angle of water on HOPG, measured here to be 63° ± 2°.

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Section: Introductionmentioning

confidence: 99%

The effect of PeakForce tapping mode AFM imaging on the apparent shape of surface nanobubbles

Walczyk

Schön

Schönherr

2013

J. Phys.: Condens. Matter

109

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“…In order to achieve defectivity levels similar to that of dry lithography, an enormous effort was directed toward identifying, classifying, and determining the root cause of various defects associated with immersion lithography. ,,,,,,,,,− As shown in Figure , typical defects can be classified into nonimmersion defects (particles, microbridging, and coating defects) and immersion-related defects (air bubbles, topcoat blister/resist swelling, drying stains, and watermarks). Since the mechanisms of defect formation in 193 nm immersion lithography and process-related defect reduction strategies have been recently reviewed by Wei and Brainard, , only a brief overview will be presented here.…”

Section: Materials For 193 Nm Water Immersion Lithographymentioning

confidence: 99%

“…Microbridging between lines is a nonimmersion-specific defect typically attributed to resist nonuniformity (e.g., gels) or BARC defects, which may generally be reduced by proper filtration . Microbridging defects also increase as the resolution is pushed beyond the capability of the original dry photoresist .…”

Section: Materials For 193 Nm Water Immersion Lithographymentioning

confidence: 99%

“…The impact of an air bubble on imaging performance depends upon the bubble lifetime as fraction of exposure time and the relative distance of the bubble from the wafer. Bubbles closer to the wafer are more problematic due to their stronger shadow and the longer residence time over a position on the wafer (due to the slower fluid flow near the wafer surface). , Many simulations have been performed to assess the impact of various free and surface-bound air bubbles on immersion lithography. ,,− Surface-bound air bubbles have been found to produce defects characterized by significant underexposure ,,, and geometry-dependent pattern distortion (i.e., magnification) . This class of defects has been largely addressed by fluid degassing and improvements in tool and showerhead design, which have been reviewed elsewhere …”

Section: Materials For 193 Nm Water Immersion Lithographymentioning

confidence: 99%

“…Prior to exposure, water may penetrate the topcoat (often through small pinholes) and form circular blisters or induce swelling of the resist . The blister or swelling causes a lensing defect during exposure, which is exhibited by a circular region with narrower pitch. ,,,, The topcoat blister defect was predominantly observed with early base-soluble topcoats, and improvements in topcoat materials have largely eliminated this type of defect. , …”

Section: Materials For 193 Nm Water Immersion Lithographymentioning

confidence: 99%

See 2 more Smart Citations

Advances in Patterning Materials for 193 nm Immersion Lithography

2010

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Defect gallery and bump defect reduction in the self Aligned Double Patterning module

Cai¹,

Padhi²,

Seamons³

et al. 2010

2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference (ASMC)

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The Self Aligned Double Patterning (SADP) module is one scheme to form 3X or 2X line structures by using a dry scanner or immersion scanner. After reliable processes are developed, defect data collection, understanding, characterization, and reduction become important. The learning we obtained at the Mayden Technology Center at Applied Materials reduced ramp time at our customer sites and provided new directions to improve our processes. In this paper, the defect type and evaluation per process to the final 3X or 2X structures in SADP flow are discussed. An in-depth study of the impact of bump defects, bump formation, and a potential solution involving an improved film deposition process are presented.

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Formation mechanism of 193nm immersion defects and defect reduction strategies

Cited by 4 publications

References 10 publications

The effect of PeakForce tapping mode AFM imaging on the apparent shape of surface nanobubbles

The effect of PeakForce tapping mode AFM imaging on the apparent shape of surface nanobubbles

Advances in Patterning Materials for 193 nm Immersion Lithography

Defect gallery and bump defect reduction in the self Aligned Double Patterning module

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