Fabrication of seamless roller mould with smooth surface microstructures by rotation lithography and reflow process

In this work, the authors conducted a versatile approach for an innovative fabrication of a seamless micro-stripes array on the roller which is as a mould for roller imprinting lithography. The major steps in the proposed fabrication method include an uniform speed PR-coating process, followed by a digital micromirrors device based maskless lithography projection and an incremental step-and-rotate exposure process. In addition to above-mentioned steps, a following thermal reflow process was performed to transform the micro-stripes into smooth surface microstructures. The study also analysed the mechanism of the reflow process by numerical simulations and experiments. The mechanism includes the gravitational effect and the definition of the four stages of the reflow process. Study results show that the reflow process on the roller is feasible and the proposed method is a promising approach for fabricating three-dimensional smooth surface microstructures on the roller with different requirements.