摘要
光刻对准中,一般将硅片和掩模对准标记制作成周期接近的光栅,通过光栅标记叠加形成的叠栅条纹的相位信息,探测掩模和硅片的相对位置关系。在实际的应用中,叠栅条纹的方向不仅与对准标记的几何位置有关,而且还与CCD的位置有关。为了将叠栅条纹的光刻对准方法推向实际应用,从矩形光栅到叠栅条纹,分析了一般光栅的相位分布规律。根据叠栅条纹相位特性分析了掩模、基片和CCD的几何位置对对准精度的影响;建立了实际对准偏差与理论值的数学关系模型。研究表明,没有角位移的情况下,当位移值小于0.4pixel时,理论上最大对准误差低于0.002pixel。
In lithographic alignment, alignment labels located on the mask and wafer are generally made by two gratings of slightly different periods. The relative position between the mask and wafer is detected by phase information of moire fringes. In practical application, the direction of moire fringes is not only related to geometric position of alignment labels, but also position of CCD. To propel the method of lithographic alignment into practice, phase distribution law of general gratings is analyzed from rectangle gratings to moire fringes. Based on phase characteristics of moire fringes, effects of geometric positions are emphatically analyzed. Mathematical-relation models of the template, wafer and CCD on alignment precision between the alignment deviation and theoretical displacement are also established. Research results show that the maximal alignment error is theoretically less than 0. 002 pixel without an angular displacement when the displacement is less than 0.4 pixel.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2012年第9期109-116,共8页
Acta Optica Sinica
基金
国家自然科学基金(60976077
61076099)资助课题
关键词
测量
光刻对准
角位移
叠栅条纹
相位分析
measurement
lithographic alignment
angular displacement
fringes analysis
phase analysis
