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Proceedings Paper

Light source heat absorption analysis of a Dyson type lithography lens
Author(s): Ming-Ying Hsu; Cheng-Fang Ho; Shenq-Tsong Chang; Ting-Ming Huang
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Paper Abstract

The lithography system in a high energy light source, the system refractive lens, absorbs the heat from the light source. The light source’s power is uniformly distributed on the reticle side. The incident rays’ power density is calculated by radiometry in each lens’ surface. The lens heat absorption ratio depends on the optical glass species, quality, and wavelength. The optical glass’ higher internal transmittance means less heat absorption; meanwhile, in different conditions, the lens’ refractive index will change with temperature. Other researchers have tried to calculate the lens temperature distribution; this study applies the Finite Element Method (FEM), radiometry, and ray tracing to solve the lens temperature distribution. Each incident ray’s path was separated into many sections, and the heat absorption was calculated for each section. Therefore, the heat generated in incident ray sections were weighted to finite element grids and the temperature distribution was solved. The lens’ non uniform temperature distribution will cause the incident ray’s Optical Path Difference (OPD). Each incident ray’s OPD can be fit by Zernike polynomials; the fitting results can be input into optical software to evaluate the thermal effect on lens heat absorption.

Paper Details

Date Published: 2 September 2015
PDF: 14 pages
Proc. SPIE 9573, Optomechanical Engineering 2015, 95730L (2 September 2015); doi: 10.1117/12.2185669
Show Author Affiliations
Ming-Ying Hsu, Instrument Technology Research Ctr. (Taiwan)
Cheng-Fang Ho, Instrument Technology Research Ctr. (Taiwan)
Shenq-Tsong Chang, Instrument Technology Research Ctr. (Taiwan)
Ting-Ming Huang, Instrument Technology Research Ctr. (Taiwan)


Published in SPIE Proceedings Vol. 9573:
Optomechanical Engineering 2015
Alson E. Hatheway, Editor(s)

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