26 March 2015 Wafer to wafer overlay control algorithm implementation based on statistics
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For mass production of DRAM device, a stable and effective overlay control becomes more and more important as DRAM design rule shrinks. Existent technologies were already applied to overcome this situation. Nevertheless, we are still suffered from tight overlay margin and forced to move from lot-based to wafer-based overlay control. However, the wafer-based control method requires a huge amount of measurement resource.

In this paper, we present the insight for the wafer-based overlay correction with optimal measurement resource which is suitable for mass production. The experiment which is the wafer-based overlay correction by several statistical analyses carried out for 2X nm node DRAM. Among them, linear regression is a strong candidate for wafer-based overlay control, which improved up to 0.8 nm of maximum overlay.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Byeong Soo Lee, Byeong Soo Lee, Young Seog Kang, Young Seog Kang, Jeong Heung Kong, Jeong Heung Kong, Hyun Woo Hwang, Hyun Woo Hwang, Myeong Gyu Song, Myeong Gyu Song, "Wafer to wafer overlay control algorithm implementation based on statistics", Proc. SPIE 9426, Optical Microlithography XXVIII, 942614 (26 March 2015); doi: 10.1117/12.2086936; https://doi.org/10.1117/12.2086936

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