Replication of large-area microstructures by combining movable induction heating and roller hot embossing

Hot embossing is a low-cost and flexible method for fabricating microstructures and nanostructures on polymers. However, the conventional hot embossing process poses two challenges: First, the plates that are used do not provide uniform pressure, and the size of the chamber limits the imprinting area. Second, heating with thick metal plates significantly lengthens cycle time. Finally, the uniformity of temperature also affects the embossing results. To achieve a high heating rate and uniform pressure over a large area, this study combined an induction heating system and roll-to-plate hot embossing. A movable plate was used to move the mold through the induction coil, increasing the heating area and overcoming limitations related to the embossing area posed by the coil length. The imprinting area reached 100 × 100 mm². In addition, the temperature difference was less than 20°C at each molding temperature range from 150°C to 190°C. The mold and the substrate were placed on a vacuum absorber to prevent deformation and slippage of the mold and provide preloading and packing pressure. Cooling fans were employed to improve cooling efficiency. Experimental replication yielded replication rates higher than 97% at 190°C and 5 kgf/cm² with a cycle time of approximately 2 minutes. To verify the feasibility of the process, V-groove microstructures were successfully fabricated using a movable induction heating roller embossing facility. Highlights: The feasibility of the moving induction heating roller embossing process. A vacuum movable platform prevents deformation and slippage of the substrate. Improve the temperature uniformity of the movable platform.