Fabrication of seamless roller mold with excimer laser direct writing technology

This paper presents a new method for fabricating a seamless roller mold with micrometer-scaled features based on laser direct writing approach. In the process, a glass roller is first coated with a metal thin film. A high-energy pulsed laser directly machines the metal thin film and thus defines the pattern on the roller´s surface. Subsequent wet etching on the patterned roller using the residual metal layer as the etching mask completes the fabrication of seamless glass roller molds. Digital image processing techniques are incorporated into the laser machining processes so that complicated patterns can be successfully transferred. Experimental results demonstrate a smallest feature size down to 20 mum for both linear grating and dot-array patterns. The advantages of this method are: (1). seamless patterns on roller mold, (2). good machining accuracy, (3). easiness in achieving complicated patterns, and (4). low cost. This method opens up many new directions and possibilities in the applications of roller-imprinting for continuous, large-area, and low-cost fabrication of micro-structures.