2014证件照
Name of the speaker: Jian Liu
Position: Professor                                   
Organization: Ultra-Precision Optoelectronic Instrument Engineering Institute, Harbin Institute of Technology
Nationality: China
 



The Title of Speech: Optical microscopy in nano-metrology and international standardization
Biography of the Speaker: Jian Liu is Prof and vice dean of School of Electrical Engineering and Automation, Harbin Institute of Technology, China, Honorary Prof in University of Nottingham, UK. His academic interests lie in the theories and implementations of optical microscopes, in particular the development of confocal microscopes, applied optics and optical metrology. He is council member of China Optical Society for Engineering and China Instrument and Control Society, member of ISO/TC213 and China SAC/TC240 as well which are both served for geometrical products specifications, and board member of Journal of Microscopy, Surface Topography: Metrology & Properties and Optics Communications.
 Abstract of Speech: Optical microscopes are essential tools on nano metrology as the measurements are contactless and offer large working distance and high 3D resolution, which have been widely applied for metrology on material layers, nano-package alignment, MEMS and micro-optical surfaces etc. However, nano standardization gets more challenging when metrological theory comes into 3D, parts of 2D theories are no longer suitable and new terms, definitions and guidances are required to be formulated. These discussions might be in frame of metrology or optics. For example, in 3D topography, people notice that height fidelity will occurred and principle height error cannot be avoided when measure on tight and deep grooves. But how the height change affected by lateral size is not clear until HIT group give the decoupling criterion. The proposed decoupling criterion can guide users to choose appropriate NA before measurement, and evaluate the possibility avoiding principle error on height when the W and H is roughly known.
In this presentation, a new reading criterion for groove depth measurements based on limited energy loss (LEL) will be presented. It theoretically models the coupling relationship between the groove depth, the decoupled portions that are reliable for height assessment, and the NA of the objective. Through the experiments, the deductions from the model were verified, and the proposed LEL decoupling criterion well predicted the range of the portions that suffered measurement accuracy loss and the minimum measurable width without accuracy loss. And when the groove width is smaller than the predicted width threshold, the measurement results using the W/3 rule lacked fidelity in values and suffered greater STDs. This is a brand new advance accepted by ISO working group and will be involved in international standard.