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介绍亚半微米分步重复投影光刻机同轴对准系统的成像机理和工作过程。该系统在掩模和硅片上均刻有时准光栅标记。经光栅衍射后形成干涉信号,使对准信噪比大大提高,并实现了掩模和硅片之间的直接对准,同时利用光弹性调制器组件对光学信号进行了光学调制,由电路实施解调,提供了一种保持高信噪比,又使弱信号探测不降低精度的对准方案;并通过计算机辅助分析的手段,讨论了SAVART的剪切量、工件台运动速度等对该系统输出信号的影响。
This paper introduces the imaging mechanism and work process of the sub-semi-micron step-and-repeat projection co-axial alignment system. The system is engraved on the mask and silicon are quasi-grating markings. The interference signal is formed after diffraction by the grating, the alignment signal-to-noise ratio is greatly increased, and the direct alignment between the mask and the silicon wafer is realized. Meanwhile, the optical signal is optically modulated by the photoelastic modulator component and is implemented by the circuit Demodulation to provide a high signal to noise ratio, but also to enable the detection of weak signals does not reduce the accuracy of the alignment program; and by means of computer-aided analysis of the SAVART shear rate, the workpiece table speed of the system The effect of the output signal.