Digital holography has proven its ability to acquire high accuracy full field 3D data with one single image acquisition. This means that in principle this technique offers the chance to perform 3D serial inspection processes, as well. However, one limitation in digital holography is its limited ability to measure rough surfaces. In the presence of rough surfaces, the magnification of the image has to be increased to capture the required phase information on each camera pixel. However, this leads to significant reduction of inspection speed. If low magnification is selected, the rough surface produces speckles which cannot be treated properly by digital holography algorithms. In this paper, we describe the extension of digital holography to rough surface applications using speckle interferometry technique. This technique is capable of fast inspection of rough surfaces with sub-micrometer accuracy. The principle of this approach is shown and a practical application for 3D surface inspection of wafer cutting processes is given.

Date Published: 31 January 2013
PDF: 7 pages
Proc. SPIE 8759, Eighth International Symposium on Precision Engineering Measurement and Instrumentation, 87593Q (31 January 2013); doi: 10.1117/12.2014598

Published in SPIE Proceedings Vol. 8759:
Eighth International Symposium on Precision Engineering Measurement and Instrumentation
Jie Lin, Editor(s)