基于自相干叠栅条纹的光刻机对准技术  

Alignment Technique Using Moire Fringes Based on Self-Coherence in Lithographic Tools

作　　者：杜聚有[1,2] 戴凤钊 步扬[1,2] 王向朝 

机构地区：[1]中国科学院上海光学精密机械研究所信息光学与光电技术实验室,上海201800 [2]中国科学院大学,北京100049

出　　处：《中国激光》2017年第12期177-184,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61405210;61474129)

摘　　要：随着光刻技术向10nm及以下工艺节点的延伸,光刻工艺对套刻精度提出了更高的要求,相应的对准精度的要求已经达到亚纳米量级。提出一种基于自相干叠栅条纹的光刻机对准方法,其原理是利用对准系统的光学结构将位相型光栅对准标记的同级次衍射光束进行分束和转像,在对准系统像面上形成两组周期不同的干涉条纹,这两组干涉条纹进一步干涉叠加形成自相干叠栅条纹,组成自相干叠栅条纹的两组干涉条纹随对准标记的移动向相反方向移动,并将对准标记的位移量进行放大,从而提高对准标记位置测量的精度。通过对自相干叠栅条纹图像进行傅里叶变换和相位提取,分析其相位信息得到对准标记的位置。仿真结果表明,对准精度和对准重复精度分别可以达到0.07nm和0.11nm。As the technology of lithography extending to 10 nm and below process nodes in advanced semiconductor manufacturing,lithography has put forward high requirements for the precision of overlay,and the corresponding alignment accuracy has reached sub-nanometer level.In this paper,a new alignment technique using Moire fringes based on self-coherence in lithographic tools is presented.The principle is that the same diffraction order beams from the alignment mark of the phase grating are split and image-rotated by using optical structure of alignment system.Two groups of interference fringes with different periods are formed on the image plane of the alignment system.The two group of interference fringes are further interfered and superimposed to form self-coherence Moire fringes.The two interference fringes move toward opposite direction when the alignment mark position is displaced,and this displacement of the alignment mark can be enlarged.The position measurement accuracy of the alignment mark is improved.The Fourier transform and phase extraction are carried out by self-coherence Moire fringe image,and the position of alignment mark is got by the analysis of its phase information.Simulation results show that the alignment accuracy and the alignment repetition accuracy can reach 0.07 nm and 0.11 nm respectively.

关 键 词：测量 光刻 套刻 对准 叠栅条纹 

分 类 号：TN0[电子电信—物理电子学]