A novel soft-mold roller embossing method for the rapid fabrication of micro-blocks onto glass substrates

This paper reports a novel UV soft-mold roller embossing technique for the rapid fabrication of polymeric micro-block arrays onto glass substrates. A soft-mold roller embossing facility with UV exposure capacity has been designed, constructed and tested in our laboratory. To fabricate the soft mold with an array of micro-block cavities, a silicon mold with a micro-cavity array was first fabricated by photolithography and deep reactive ion etching. A polycarbonate film was gas pressurized hot embossed against the silicon mold to obtain a master of micro-blocks. The soft mold for the roller stamp was obtained by casting the polydimethylsiloxane over the polycarbonate master to obtain an array of micro-block cavities. During rolling operation, a step motor drove the roller and pressed the UV-curable photopolymer layer on the glass substrate through the rolling zone. A micro-block array was obtained. At the same time, the micro-block array was cured by the UV light radiation while traveling through the rolling zone. The effect of various processing parameters on the replicability of the micro-blocks was investigated. Under the proper processing conditions, 100 x 140 arrays of polymeric micro-blocks, with a dimension of 100 mu m x 80 mu m x 40 mu m can be successfully fabricated. The experimental results in this study suggest that UV soft-mold roller embossing provides an effective way of fabricating microstructures onto glass substrates. The technique can eventually be developed to be used as an effective roll-to-roll process at room temperature and with low pressure. This would provide significant advantages in terms of a shorter cycle time as well as improved product quality.