Detection of focus and spherical aberration by use of a phase grating

Proceedings of SPIE - The International Society for Optical Engineering

Volumn 4346, Issue 2, 2001, Pages 1355-1361

  Kirk, J P ^a   Schank, S ^a   Lin, Chieh Yu ^a  

^a IBM MICROELECTRONICS   (United States)

Author keywords

Focus measurement; Lens stability; Spherical aberration; Three beam interferometer

Indexed keywords

ABERRATIONS; DIFFRACTION GRATINGS; FOCUSING; IMAGE ANALYSIS; INTERFEROMETERS; LENSES; OPTICAL MICROSCOPY;

SPHERICAL ABERRATIONS;

PHOTORESISTS;

EID: 0035758486     PISSN: 0277786X     EISSN: None     Source Type: Conference Proceeding    
DOI: 10.1117/12.435673     Document Type: Conference Paper

References (3)

1. Only aberrations with even azimuthal symmetry are apparent in the image of a grating formed by symmetrical pupil illumination.
2. J.P. Kirk, et. al., SPIE 4346-02, 2001.
3. a) exposing λ=248nm, I-line photoresist is used; for example, THMR-IP3250 by Ohka America Inc. b) exposing λ=193nm, 248 photoresist is used; for example, UV82 Positive DUV photoresist by Shipley Inc.