Open AccessRapid and precise characterization of sub-µm surface defects using laser scatterometer devising a polygonal-shaped waveguide with double-slit aperture
Author(s) -
Vu Tien Dung,
Hyunchul Kim,
Joohyung Lee
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.036923
Subject(s) - optics , scatterometer , materials science , waveguide , aperture (computer memory) , laser , image resolution , pixel , interferometry , physics , acoustics , satellite , astronomy
We present a method of various defects detection on a flat surface using a polygonal-shaped waveguide devised laser scatterometer capable of providing sub-µm precision. The optimized polygonal shape of the waveguide with double-slit aperture substantially improves the detection efficiency of scattered beam more than 10 times compared to that of the conventional circular-shaped waveguide. The scatterometer enables quantification of sub-µm lateral size and height of defects by counting the number of pixels and peak intensity, respectively. We validated the performance of the proposed inspection system by measuring a standard defective specimen and successfully apply to a pilot production line for inspection of 250×140 mm 2 size glass panels providing 31,250 × 16,000 spatial resolution with the capability of a measuring time less than 10 s.