深紫外准分子激光实时曝光剂量控制算法研究

提出了一种面向步进扫描投影光刻机的深紫外准分子激光实时曝光剂量控制算法。通过建立扫描曝光过程的抽象模型并分析准分子激光器单脉冲能量波动特性,提出采用闭环反馈控制进行实时调节,着重研究了抑制单脉冲能量超调和随机波动的有效算法。在一台波长为193 nm、重复频率为4 kHz、单脉冲能量为5 mJ的ArF准分子激光器上进行了实验研究。结果表明,当脉冲个数仅为20时算法控制下的剂量精度即可达0.89%,不但满足亚微米光刻越来越严的剂量要求,而且有助于提高光刻机生产效率和激光器使用效率。

Real-Time Exposure Dose Control Algorithm for DUV Excimer Lasers

A real-time exposure dose control algorithm for DUV excimer lasers in a step and scan projection 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 feed back control,which especially focuses on reducing the pulse energy overshot and the pulse to pulse stochastic fluctuation.The experiment conducted on an ArF excimer laser with 193 nm of wavelength,4 kHz of repetition rate,and 5 mJ of pulse energy 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 the more and more stringent dose accuracy requirement for sub-half-micron lithography,but also be helpful to improve the lithography throughput as well as the efficiency.