@inproceedings{24cf298cf74f46b4855fe934c48217b1,
title = "Full-field wafer warpage measurement technique",
abstract = "An innovative moir{\'e} technique for full-field wafer warpage measurement is proposed in this study. The wafer warpage measurement technique is developed based on moir{\'e} method, Talbot effect, scanning profiling method, stroboscopic, instantaneous phase-shift method, as well as four-step phase shift method, high resolution, high stability and full-field measurement capabilities can be easily achieved. According to the proposed full-field optical configuration, a laser beam is expanded into a collimated beam with a 2-inch diameter and projected onto the wafer surface. The beam is reflected by the wafer surface and forms a moir{\'e} fringe image after passing two circular gratings, which is then focused and captured on a CCD camera for computation. The corresponding moir{\'e} fringes reflected from the wafer surface are obtained by overlapping the images of the measuring grating and the reference grating. The moir{\'e} fringes will shift when wafer warpage occurs. The phase of the moir{\'e} fringes will change proportionally to the degree of warpage in the wafer, which can be measured by detecting variations in the phase shift of the moir{\'e} fringes in each detection points on the surface of the entire wafer. The phase shift variations of each detection points can be calculated via the instantaneous phase-shift method and the four-step phase-shift method. By adding up the phase shift variations of each detection points along the radii of the circular gratings, the warpage value and surface topography of the wafer can be obtained. Experiments show that the proposed method is capable of obtaining test results similar to that of a commercial sensor, as well as performing accurate measurements under high speed rotation of 1500rpm. As compared to current warpage measurement methods such as the beam optical method, confocal microscopy, laser interferometry, shadow moir{\'e} method, and structured light method, this proposed technique has the advantage of full-field measurement, high resolution, stability and adaptability.",
keywords = "Moir{\'e}, Phase shift method, Talbot effect, full-field",
author = "Hsieh, {H. L.} and Lee, {J. Y.} and Huang, {Y. G.} and Liang, {A. J.} and Sun, {B. Y.}",
note = "Publisher Copyright: {\textcopyright} 2017 SPIE.; Optical Measurement Systems for Industrial Inspection X 2017 ; Conference date: 26-06-2017 Through 29-06-2017",
year = "2017",
doi = "10.1117/12.2270191",
language = "???core.languages.en_GB???",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Peter Lehmann and Goncalves, {Armando Albertazzi} and Wolfgang Osten",
booktitle = "Optical Measurement Systems for Industrial Inspection X",
}