Controlled contamination of optics under 157-nm laser irradiation

Bloomstein, Theodore M.; Liberman, Vladimir; Palmacci, Stephen T.; Rothschild, M.

doi:10.1117/12.435766

Cited by 8 publications

(3 citation statements)

References 3 publications

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“…The reported cleaning rates are in the range of about 3nm / kJ/cm 2 / 1ppm O 2 [1,2] In the case of removing organic compounds from highly contaminant sensitive 157nm optical elements the cleaning effect is appreciated and explored [3,4,5] But there are also layers purposely deposited on mask surfaces which should not be impacted or even removed during these cleaning procedures: FIB-deposited carbon-containing films. These FIB depositions are state-of-the art for the repair of reticles [6].…”

Section: Introductionmentioning

confidence: 97%

Influence of 157-nm specific cleaning procedures on the quality of FIB repair depositions on reticles

Eisner¹,

Schilz

Williams³

et al. 2002

SPIE Proceedings

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An UV lamp cleaning system (172nm) and a 157nm laser have been used to irradiate Ga-based focused ion beam (FIB) repair depositions on 193nm and 157nm reticles. The thickness change of the depositions due to the irradiation has been measured using an atomic force microscope. For the 193nm reticle additional transmission measurements were realized. These depositions are found to be highly resistant to UV lamp cleaning treatments of up to 18h (2mW/cm 2 , 1% O 2 ). Extended tests were also done with 157nm irradiation (9kJ/cm 2 , 1-10ppm O 2 ). At the end of these tests a film loss of the depositions of 0.4nm /kJ/cm 2 and a transmission change of 10% could be determined.

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Section: Introductionmentioning

confidence: 97%

Influence of 157-nm specific cleaning procedures on the quality of FIB repair depositions on reticles

Eisner¹,

Schilz

Williams³

et al. 2002

SPIE Proceedings

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“…The development of high performance lasers, exposure tools and resists for 157nm lithography requires therefore an evaluation system of 157nm optical materials and outgassed products. Comprehensive research and development related to the evaluation of 157nm optical materials and to controlled contamination of optics under 157nm irradiation has been done by the Lincoln Laboratory, Massachusetts Institute of Technology [1][2][3][4] .…”

Section: Introductionmentioning

confidence: 99%

Study of resist outgassing by F 2 laser irradiation

Itakura

Kawasa

Sumitani

et al. 2003

Advances in Resist Technology and Processing XX

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F 2 laser lithography at 157nm is the most promising candidate of post-ArF excimer laser lithography. A major concern, however, is the deterioration of 157nm optics due to contamination under F 2 laser irradiation. An evaluation of outgassed products of 157nm resist and their effect on optical materials and is therefore indispensable for F 2 laser lithography. Semiconductor Leading Edge Technologies Inc. (Selete) and Komatsu Ltd. designed and constructed a resist outgassing evaluation system in order to develop exposure tools and resists for 157nm lithography. The system determines the negative effects of outgassing resist contaminants on the transmittance of optical materials under F 2 laser irradiation. The system has two units. One unit collects resist outgas and analyzes sampled gas in a gas chromatograph mass spectrometer (GC-MS). The other unit is a resist outgassing adhesion unit, which measures the transmittance change of optical materials due to contamination adhesion in real-time. Our analysis showed that most outgassed products were from the resist protecting groups and photo acid generators (PAG) including small hydrocarbons like isobutene, benzene derivatives and dimethoxymethane. After irradiating a 157nm lithography resist with a total dose of 30J/cm 2 the transmittance of a calcium fluoride (CaF 2 ) substrate decreased from initially 90% to 85%. This was due to adhesion contamination as x-ray photoelectron spectroscopy (XPS) analysis showed an organic contamination deposition of over 5nm thickness on the CaF 2 substrate.

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“…Especially resist outgassing reduces the performance of exposure tools. Comprehensive research related to the analysis of outgassing from resists and to controlled contamination of optical surfaces under 157nm irradiation has been done by the Lincoln Laboratory, Massachusetts Institute of Technology (LL-MIT) [1][2][3][4][5] . In addition, the limited lifetime of soft pellicles used at 157nm is an important issue.…”

Section: Introductionmentioning

confidence: 99%

Evaluation systems of F 2 laser lithography materials

et al. 2004

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In this paper, we present an evaluation system for F 2 laser lithography masks and resists and we report preliminary test results. The evaluation system has two subsystems that are based on very accurate measurement technology. One subsystem is used for mask evaluation, the other subsystem for resist evaluation. The mask subsystem consists of two units. One unit evaluates real size 6025 binary masks placed horizontally as inside steppers. This unit measures three parameters: 1) the real time in-situ transmittance at 157nm during F 2 laser irradiation, 2) the in-situ VUV transmittance using a VUV spectrophotometer and 3) the deformation of the pellicle. The precision of transmittance measurement at 157nm is +/-0.5%. The precision of the pellicle deformation measurement is +/-0.1μ m. The second unit of the mask subsystem collects samples of the mask outgassing and analyzes them in a gas chromatograph mass spectrometer. The resist evaluation subsystem consists of three units. 1) One unit determines negative effects of outgassing resist contaminants on the transmittance of optical materials under F 2 laser irradiation, 2) the second unit analyzes the outgassing from resists and 3) the third unit examines the effectiveness of exposure tool purge nozzles to reduce outgassing contamination.

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Controlled contamination of optics under 157-nm laser irradiation

Cited by 8 publications

References 3 publications

Influence of 157-nm specific cleaning procedures on the quality of FIB repair depositions on reticles

Influence of 157-nm specific cleaning procedures on the quality of FIB repair depositions on reticles

Study of resist outgassing by F 2 laser irradiation

Evaluation systems of F 2 laser lithography materials

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