A real-time exposure dose control algorithm for
DUV excimer lasers
A real-time exposure dose control algorithm for
DUV excimer lasers
Liu Shiyuan, Wu Xiaojian, Qin Xinyi
State Key Laboratory of Digital Manufacturing Equipment and Technology, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology
Abstract：A real-time exposure dose control algorithm for deep ultraviolet (DUV) excimer lasers in a step-and-scan optical lithography is presented. By establishing an abstract scan exposure model and analyzing the pulse-to-pulse energy fluctuation characteristics of DUV excimer lasers, a real-time dose regulation is implemented based on closed-loop feedback control, which especially focuses on reducing the effect of pulse energy overshot and pulse-to-pulse stochastic fluctuation. The experiment conducted on an ArF excimer laser with wavelength of 193 nm, repetition rate of 4 kHz, and pulse energy of 5 mJ confirms that such a real-time dose control algorithm is able to achieve a dose accuracy of above 0.89% even with only 20 pulses. It is fully expected that this algorithm will not only meet increasingly stringent dose accuracy requirements for sub-half-micron lithography, but also be helpful to improve lithography throughput as well as efficiency.
出版日期: 2008-06-05
引用本文:
. A real-time exposure dose control algorithm for
DUV excimer lasers[J]. Frontiers of Optoelectronics in China, 2008, 1(1-2): 123-129.
Liu Shiyuan, Wu Xiaojian, Qin Xinyi. A real-time exposure dose control algorithm for
DUV excimer lasers. Front. Optoelectron., 2008, 1(1-2): 123-129.
Levinson H J . Principles of Lithography. Washington: SPIE Press, 2001
2
Yu M L, Sagle A, Buller B . Exploring the fundamental limit of CD control: a modelfor shot noise in lithography. In: Proceedingsof SPIE, 2005, 5751: 687–698. doi:10.1117/12.613661
3
Inoue S, Fujisawa T, Izuha K . Effective exposure dose measurement in optical microlithography. In: Proceedings of SPIE, 2000, 3998: 810–818. doi:10.1117/12.386445
4
Kivenzor G J . Self-sustaining dose control system: ways to improve the exposureprocess. In: Proceedings of SPIE, 2000, 4000: 835–842. doi:10.1117/12.389077
5
Das P . Excimerlaser as a total light source solution for DUV microlithography. In: Proceedings of SPIE, 2001, 4184: 323–329. doi:10.1117/12.414082
6
Blumenstock G M, Meinert C, Farrar N R, et al.. Evolution of light source technology to supportimmersion and EUV lithography. In: Proceedingsof SPIE, 2005, 5645: 188–195. doi:10.1117/12.577587
7
de Zwart G, van den Brink M A, George R Performance of a step-and-scansystem for DUV lithography. In: Proceedingsof SPIE, 1997, 3051: 817–835. doi:10.1117/12.276002
8
Zschocke W, Albrecht H-S, Schroeder T, et al.. High repetition rate excimer lasers for 193nm lithography. In: Proceedings of SPIE, 2002, 4691: 1722–1733. doi:10.1117/12.474561
9
van den Brink M A, Jasper H, Slonaker S, et al.. Step-and-scan and step-and-repeat: a technologycomparison. In: Proceedings of SPIE, 1996, 2726: 734–753. doi:10.1117/12.240936
