提出了一种基于二维光栅叠栅效应的纳米光刻对准方法,用于接近式光刻实现二维同步对准。该方法采用两组周期接近的二维光栅重叠产生一组周期分布的叠栅条纹,条纹的周期相对于两光栅周期被大幅度放大,将光栅间的位移反应在条纹的相位信息中。利用二维光栅在傅里叶频谱中x、y向相互独立的频谱分布,通过傅里叶变换对正交叠栅条纹横纵两个方向上的相位信息进行解析,可实现高精度二维同步对准。建立了双二维Ronchi光栅对准复振幅分布物理模型,推导了基片、掩模相对位移量与叠栅条纹相位之间的关系。通过计算机模拟对该对准方法进行了仿真分析,考虑噪声情况下,对准精度可以达到2 nm;通过实验系统对该对准方法进行测试,实验结果对准精度可以达到22 nm。 A novel method of nanolithography alignment based on two-dimensional grating stack-gate effect is proposed for two-dimensional synchronization alignment of proximity lithography. In this method, two sets of periodic two-dimensional gratings are overlapped to generate a group of moiré fringes with periodic distribution. The fringes are greatly magnified relative to the two grating periods and the inter-grating displacement is reflected in the phase information of the fringes. Using two-dimensional grating in the Fourier spectrum of x, y to the independent spectral distribution, through the Fourier transform of the orthogonal moat fringes in both horizontal and vertical phase information analysis can be achieved high-precision two-dimensional synchronization alignment. A two-dimensional Ronchi grating alignment complex amplitude distribution physical model was established and the relationship between the relative displacement of substrate and mask and moire phase was derived. The alignment method was simulated by computer simulation, considering the noise, the alignment accuracy can reach 2 nm. By the experimental system, the alignment method is tested, the experimental results can achieve the alignment accuracy of 22 nm.