Paper
12 May 2000 Characterization of excimer lasers for use with optical integrators
Author Affiliations +
Abstract
Excimer lasers are the preferred source of illumination for photolithographic systems. Lenslet array optical integrators are very frequently used to achieve good uniformity of illumination at the plane of the mask--the target to be recorded by the photolithographic system. Lenslet arrays break the incident beam up into subapertures and the resulting beams are overlapped at the plane of the target with variable incident angles. The overlapping of the tilted beams segments results in coherent interference effects leading to fine-scale intensity modulation called orange peel. We show that the ideal method of characterization of excimer lasers for this application is the Young's double hole test with hole spacing set to the lenslet element separation. This method to be superior to other common measures of laser quality such as angular divergence and M2.
© (2000) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
George N. Lawrence and Ying Lin "Characterization of excimer lasers for use with optical integrators", Proc. SPIE 3930, Laser Resonators III, (12 May 2000); https://doi.org/10.1117/12.385393
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KEYWORDS
Spatial coherence

Excimer lasers

Visibility

Modulation

Integrated optics

Relays

Speckle

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