5 August 2015 Accurate measurement of illumination uniformity using spot sensor based 2-dimension scanning method
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Proceedings Volume 9621, 2015 International Conference on Optical Instruments and Technology: Advanced Lasers and Applications; 96210O (2015) https://doi.org/10.1117/12.2192536
Event: International Conference on Optical Instruments and Technology 2015, 2015, Beijing, China
Abstract
Illumination uniformity of the illuminator is significant for achieving stringent critical dimension (CD) control for lithography machine. In order to achieve high uniform illuminating, there is an urgent demand of accurate measurement for illumination uniformity. The difficulty for accurate measurement of illumination uniformity for the illuminator mainly lies in two aspects: the illumination plane is large; excimer laser pulse energy is variable from pulse to pulse. In this work, a spot sensor based 2-dimension scanning method for illumination uniformity measurement is proposed, where the spot sensor in combination with a 2-dimension moveable stage is located in the illumination plane of the illuminator is used to scan the illumination plane point-by-point so as to obtain the whole irradiation distribution. To improve measurement accuracy, the energy sensor of the illuminator serves as the reference and monitors each pulse in real-time showing benefit of excimer laser pulse energy fluctuation eliminating. Secondly, the used spot sensor is modified for strict synchronization control of the spot sensor and the energy sensor so that the measurement precision can be improved. Measurement results show that X direction transient non-uniformity, Y direction transient non-uniformity and X direction integral non-uniformity of the illuminator are 5.14%, 5.55% and 2.16% respectively with a measurement uncertainty of 0.31% (k=2). It is proved that the proposed method is effective and helpful for further system optimizing and alignment.
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Chengke Xie, Chengke Xie, Ming Chen, Ming Chen, Youbao Zhang, Youbao Zhang, Xinghua Ma, Xinghua Ma, Baoxi Yang, Baoxi Yang, Huijie Huang, Huijie Huang, } "Accurate measurement of illumination uniformity using spot sensor based 2-dimension scanning method", Proc. SPIE 9621, 2015 International Conference on Optical Instruments and Technology: Advanced Lasers and Applications, 96210O (5 August 2015); doi: 10.1117/12.2192536; https://doi.org/10.1117/12.2192536
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