A new 2D-self-calibration method with large freedom and high-precision performance or imaging metrology devices
Peter Ekberg - Industrial Metrology and Optics, Dept. of Production Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden (plekberg@kth.se)
Monday 14th March, 1.30pm-3pm
A1 Pope Building
Abstract
When calibrating 2D or 3D metrology systems you need to rely on a traceable artifact for the calibration. However if the system you intend to calibrate has smaller uncertainties than the uncertainty of the reference artifact, the uncertainty of the instrument will be dominated by the artifact and not by the instrument. The only way to reveal the performance of the instrument is then to use self-calibration, i.e. a calibration without any externally verified references, except a 1D traceable measurement between two points on an artifact. In this presentation the application of a new general self-calibration algorithm is introduced, allowing a large freedom to the positioning of the artifact, and also less demands on the 2D-structure on it. The algorithm is an enhancement of the self-calibration method already published by P. Ekberg et al. The algorithm has successfully been tested by simulations and by using real data from a white light interference microscope, confocal microscope and an AFM yielding X, Y repeatability of a few nm. The algorithm has also been used for separating distortions in ordinary low cost camera based systems opening up possibilities for accurate measurements in images using very low cost equipment.
Peter Ekberg, Doctor of Technology, at KTH Royal Institute of Technology, Stockholm, Sweden is one of the founders of Micronic Laser Systems, today Mycronic. He has more than 25 years of experience in the technology used in the pattern generators and large area metrology systems developed by the company. He was in charge of the MMS15000 project that today provides large area mask makers with nm measurement uncertainty over square meter sized masks. His main interest today is in the metrology and image processing fields. He also acts as a teacher in advanced metrology and quality courses in Production Engineering at KTH. He has written several articles on large area mask metrology and has presented the topic at several conferences over the years. He has several patents related to self-calibration and nano-metrology, and his published self-calibration research has been highlighted by “Advances in Engineering” in 2014
Prof. Peter Ekberg gave a seminar about absolute calibration by image processing method.