Angle-resolved scattering measurements of polished surfaces and optical coatings at 157 nm

Bloomstein, Theodore M.; Hardy, D. E.; Gomez, Lewis; Rothschild, M.

doi:10.1117/12.485469

Cited by 3 publications

(1 citation statement)

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“…This implies that cleaning is necessary not only for transmission stability, but also for flare stability. Typical transmission loss and flare increase mechanisms include both absorption and surface roughness-induced light scattering [10]. …”

Section: Storage Environment and Contamination Of 157nm Substrates Anmentioning

confidence: 99%

Experimental investigation of fabrication process-, transportation-, storage, and handling-induced contamination of 157-nm reticles and vacuum UV cleaning

Okoroanyanwu¹,

Stepanenko

Vereecke

et al. 2004

SPIE Proceedings

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Mask fabrication process, transportation, storage, and handling contribute to contamination of 157nm reticles and modified fused silica substrates, resulting in transmission loss. A stable VUV cleaning procedure for contaminated binary, alternating, and attenuated phase shift reticles has been developed. This cleaning procedure was verified by lithographic imaging on the 157nm ASML MS-VII exposure scanner. A point-to-point steady state dose transmission uniformity range across a batch of 25 wafers (the exposure conditions of which were equivalent to that of a 300 mm wafer, 26mm×33mm fields, 50mJ/cm 2 ) that were exposed with a modified fused silica substrate, was found to be <0.24% for a reticle that was cleaned prior to exposure using this VUV cleaning process. In-situ laser cleaning of contaminated mask substrates during exposure in the MS-VII resulted in 1% change in transmission at doses of up to 20 J/cm 2 , above which transmission remains stable (<0.24% variation). The cleaning procedure involves exposing the contaminated reticle in the UVO Reticle Cleaning Station for 30 minutes, using a cleaning gas mixture of N 2 /O 2 =99%/1%. Transmission loss due to contamination within the clean room is limited to 1 -2 % and is reversible upon VUV cleaning. Flare levels of 3% were measured on contaminated reticle relative to a clean state of the same reticle. VUV cleaning is not only good for improving and maintaining stable mask transmission, but it is also good for preventing reticle contamination-induced flare. Contamination rate and contaminant type appear to be dependent on the storage environment of mask substrates and reticles. Typical contaminants included molecular acids (halogens, sulfur, sulfates), molecular bases (ammonia, amines), molecular condensables (hydrocarbons, alcohols, ketones, fatty acids, siloxanes, phthalate), molecular dopant (boron) and molecular metals (Ca, Mg, Al, Cu). Contamination of mask substrates appears to be through a competitive adsorption phenomenon, whereby low molecular weight species with high vapor pressure and low adsorption energies are over time replaced by large molecular weight ones with low vapor pressure and high adsorption energies. INTRODUCTIONIt is now well established that reticles exposed to ambient air accumulate a film of contaminants that are mostly of hydrocarbon origin. Even a monolayer of organic contaminants or water can lead up to 1-2% transmission loss in modified fused silica substrates (MFS) [1,2]. Upon exposure in lithography, such contamination introduces exposure variation. This paper assesses the impact of fabrication process-, transportation-, handling-, and inspection-induced contamination of 157nm masks. The impact of storage environment and storage duration on contamination of masks is also assessed in this paper. The toolset used in this study comprises SOPRA PUV SE5 tool and a stand-alone UVO reticle cleaning station (RCS), which is equipped with Xe-lamp at 172nm, the details of which are described below. EXPERIMENTAL2.1 MATERIALS MFS mask subs...

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Section: Storage Environment and Contamination Of 157nm Substrates Anmentioning

confidence: 99%

Experimental investigation of fabrication process-, transportation-, storage, and handling-induced contamination of 157-nm reticles and vacuum UV cleaning

Okoroanyanwu¹,

Stepanenko

Vereecke

et al. 2004

SPIE Proceedings

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Methodology of the Assessment of the Abrasive Tool’s Active Surface Using Laser Scatterometry

Kapłonek

Łukianowicz

Nadolny

2012

Transactions of the Canadian Society for Mechanical Engineering

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Diagnostics of abrasive tools requires the use of modern measurement techniques which allows for fast assessment of a surface in order to determine, for example, the degree of its wear or to detect various type of defects. A wide group of optical measurement methods used for this type of assessment are based on the phenomenon of light scattering. One such method based on imaging and analysis of light scattering from a surface is laser scatterometry. In this paper, by utilizing laser scatterometry supported by image analysis techniques, a proposal for a methodology of assessment of the degree to which smearing of the grinding wheel active surface (GWAS) occurs during the plunge grinding process, was presented and discussed. Select results of experimental investigations carried out on bearing steel 100Cr6 were also presented. The obtained results confirmed the efficacy of the above-mentioned techniques that could be an interesting alternative to other methods already used in such measurements.

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Characterization of Magnetoelectropolished Stainless Steel Surfaces’ Texture by Using the Angle-Resolved Scattering and Image Processing Analysis Methods

Kapłonek

Rokosz

Pimenov

2020

Metals

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In this article, the results of preliminary experimental studies related to a fast, non-contact assessment of the AISI 316L stainless austenitic steel surfaces after electrochemical polishing in a magnetic field have been presented. The experiments were realized with the use of a modified angle-resolved scattering (ARS) method based on the analysis of angular distribution of the scattered light intensity. Digital images of such distribution were acquired for selected areas of examined samples—base surface and surface after magnetoelectropolishing (MEP) process. Parametric analysis oriented toward the calculation of selected key geo- and photometric parameters carried out in Image Pro®-Plus software allowed for characterization of the surface conditions of the assessed samples in terms of their scattering properties. The obtained experimental results confirmed the usefulness of the ARS method used in the presented studies as well as the possibility of its practical use (after appropriate modifications) on a wider scale, especially in industrial applications.

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Angle-resolved scattering measurements of polished surfaces and optical coatings at 157 nm

Cited by 3 publications

References 0 publications

Experimental investigation of fabrication process-, transportation-, storage, and handling-induced contamination of 157-nm reticles and vacuum UV cleaning

Experimental investigation of fabrication process-, transportation-, storage, and handling-induced contamination of 157-nm reticles and vacuum UV cleaning

Methodology of the Assessment of the Abrasive Tool’s Active Surface Using Laser Scatterometry

Characterization of Magnetoelectropolished Stainless Steel Surfaces’ Texture by Using the Angle-Resolved Scattering and Image Processing Analysis Methods

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