Rapid fabrication of microstructures onto plastic substrates by infrared hot embossing

This paper proposes a rapid fabrication technique of polymeric micro-block arrays using an IR hot embossing process. A pneumatically actuated embossing facility with conventional IR heating was designed, constructed and tested in our laboratory. To mold micro-blocks onto the plastic plates, a silicon mold with an array of micro-block cavities was fabricated by photolithography and deep reactive ion etching. During the embossing process, a PMMA plate was first placed above the mold. A ceramic IR heater was placed above the PMMA plate to heat the mold. The IR passed through the transparent PMMA to reach and heat up the mold surface. After retrieval of the IR heater, the pneumatically actuated embossing facility pressed the plastic plate against the hot master mold. A microblock array was obtained. The effect of various processing parameters on the replicability of the micro-blocks was investigated. Under the proper processing conditions, the arrays of polymeric micro-blocks, with a dimension of 100 μm × 80 μm × 40 μm, could be successfully fabricated. The experimental results in this study suggest that IR heated embossing could provide an effective way of fabricating large-area micro-structures onto plastic plates. This would provide significant advantages in terms of a shorter cycle time as well as improved product quality.