摘要
针对28nm浸没式扫描光刻机掩模台的光栅干涉仪位移测量系统,开展了系统热漂移研究,并进行了热漂移测试实验与结果分析。该位移测量系统采用外差对称式四细分的光路设计以及栅距为1μm的二维光栅,配合2048倍电子细分的相位计数卡,其系统分辨力达到了0.12nm。热漂移测试结果显示:该系统的热漂移X向为17.86nm/K,Y向为41.43nm/K。在光刻机掩模台的实际测量环境中,测量环境的温度波动稳定在5mK以内,此时系统的热漂移X向可以控制在0.09nm以内,Y向可以控制在0.21nm以内。实验数据表明系统的热漂移误差小于1nm,满足掩模台亚纳米位移测量精度需求。
The grating interferometer displacement measurement system of the 28 nm immersion scanning lithography reticle stage was taken as the research object, the thermal drift study of the system was carried out, and the thermal drift test experiment and result analysis were carried out. The system adopts het-erodyne symmetrical four-division optical path designand a two-dimensional grating with a pitch of 1, with 2048 times electronic subdivision phase counting card, the system resolution reaches0.12 nm. The thermal drift test results show that the thermal drift of the system is 17.86 nm/K in the X-direction, and 41.43 nm/K in the Y-direction. In the actual measurement environment of the lithography reticle stage, the temperature fluctuation of the measurement environment is stable within 5 mK, at which time the thermal drift X-direction of the system can be controlled within 0.09 nm, and the Y-direction can be controlled within 0.21 nm. The experimental data shows that the thermal drift error of the system is less than 1 nm, which meets the requirements of sub-nanometer displacement measurement accuracy of the reticle stage.
引文
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