Among all the possible alternatives to conventional lithography techniques， nano-imprint lithography(NIL) has been one of the most promising ones due to its high resolution and low cost. It creates patterns by mechanical deformation of imprint resist and subsequent processes. At the same time, it avoids the limits encountered by conventional methods like the special exposure source, high-precision focusing system, extremely short wavelength lens system and the diffraction limit. Nowadays, NIL has successfully created patterns beyond 5 nm. In addition, NIL can be applied in many fields, covering nano-electronics, nano-optoelectronics, nano-biology, high-density disk storage, optical components, etc.
In fact, NIL can’t be realized without the high precision alignment. In UV-NIL, due to the fact that imprint resist has very similar optical properties to the mask material, fused silica, when imprint resist was filled in the alignment marks the Moiré pattern would effectively become invisible. Prof. Wang directed his team to fabricate a series of high contrast alignment marks with high diffraction efficiency, which successfully solves the low contrast problem existing in UV-NIL. This result also can be used in the alignment system in multilevel NIL, which greatly enriches the applications of UV-NIL, making it become more prospecting techniques. What’s more, Prof. Wang also actively leads the team to develop a new roll-to-plate nano-imprint machine. Compared to the imprint devices on the market, it can achieve high-speed, high-precision graphics transfer, which has great commercial value.
Figure. Moiré pattern obtained from the CCD cameral. (a) Using normal alignment mark. (b) Using the alignment mark we fabricated.
QIN Jin and DING Li are the authors of this paper. The financial support to this work by University of Science and Technology of China start up funding and Anhui Provincial Natural Science Foundation are acknowledged.
(WANG Liang,School of Physical Sciences)