Overlay accuracy limitations of soft stamp UV nanoimprint lithography and circumvention strategies for device applications

An EBL system has also been utilized as a benchmarking tool to measure both stamp distortions and alignment precision of this mix & match approach. By aligning the EBL system to 20 mm × 20 mm and 8 mm × 8 mm cells to compensate pattern distortions of order of 3 μm over 6 in. wafer area, overlay accuracy better than 1.2 μm has been demonstrated. This result can partially be attributed to the flexible SCIL stamp which compensates deformations caused by the presence of particles which would otherwise significantly reduce the alignment precision.