With reduction of design rules, a number of corresponding new technologies, such as i-HOPC, HOWA and DBO have been proposed and applied to eliminate overlay error. When these technologies are in use, any high-order error distribution needs to be clearly distinguished in order to remove the underlying causes. Lens aberrations are normally thought to mainly impact the Matching Machine Overlay (MMO). However, when using Image-Based overlay (IBO) measurement tools, aberrations become the dominant influence on single machine overlay (SMO) and even on stage repeatability performance. In this paper, several measurements of the error distributions of the lens of SMEE SSB600/10 prototype exposure tool are presented. Models that characterize the primary influence from lens magnification, high order distortion, coma aberration and telecentricity are shown. The contribution to stage repeatability (as measured with IBO tools) from the above errors was predicted with simulator and compared to experiments. Finally, the drift of every lens distortion that impact to SMO over several days was monitored and matched with the result of measurements.
[1]
Jianrui Cheng,et al.
New 0.75 NA ArF scanning lithographic tool
,
2011,
Advanced Lithography.
[2]
Tsann-Bim Chiou,et al.
Using intrafield high-order correction to achieve overlay requirement beyond sub-40nm node
,
2009,
Advanced Lithography.
[3]
Peter Vanoppen,et al.
Achieving optimum diffraction based overlay performance
,
2010,
Advanced Lithography.
[4]
Maxime Gatefait,et al.
Overlay breakdown methodology on immersion scanner
,
2010,
Advanced Lithography.
[5]
Jung-Hyeon Lee,et al.
Application results of lot-to-lot high-order and per-shot overlay correction for sub-60-nm memory device fabrication
,
2009
.