多层冷压印光刻中超高精度对正的研究

Ultra-Precision Alignment for Room-TemperatureMulti-Layer Imprint Lithography

为满足多层冷压印光刻中套刻的超高精度要求,提出了基于斜纹结构光栅的对正技术.利用光电接收器件阵列组合接收光栅产生莫尔条纹的零级光,得到条纹平面内X、Y方向的对正误差信号.通过调整光栅副的间隙来提高误差信号的对比度.利用高对比度和灵敏度的误差信号作为控制系统的驱动信号,对承片台进行宏微两级驱动控制,并由激光干涉仪作为控制系统的反馈环节在驱动过程中进行全程监测,实现自动对正.最终使在X、Y方向上的重复对正精度达到了±20nm,满足了100nm特征尺寸压印光刻的对正精度要求.

An ultra-precision alignment technique adopting a pair of special slant gratings was presented for room-temperature imprint lithography. The 0th-order beams of moire signals generated by the gratings were received by a photoelectric detector array, and then the misalignment errors in X-Y directions were obtained, respectively. The contrast of moire signals was improved via adjusting the grating gaps, thus the improved signals were chosen to control the alignment of a X-Y stage by means of coarse-fine positioning system. The laser interferometers were considered as the feedback elements of the control system to monitor the process. Finally, the repeatable alignment accuracy (± 20 nm) ensures to meet the requirement of alignment accuracy for sub-100 nm imprint lithography.