Microstructures fabricated by laser-induced polymerization

The application of laser technology has shown great advantages in the fast growing area where electronic and mechanical components are combined to form miniature structures. Use of laser-induced polymerization (LIP) in making microstructures has drawn increasing attention. A focused laser beam can be guided directly to write three-dimensional patterns. The advantages are high cure speed, constant intensity along the curing distance and uniform exposure over the curing area. It will-result in more efficient absorption by selecting an appropriate photoinitiator and reduce the unwanted reactions, which are common in conventional UV light curing. This also leads to a more precise control of the penetration profile. This paper will report on fabrication of three-dimensional microstructures on a laser microfabricating system using the principle of UV LIP. Laser curing parameters were optimized to make micro-sized primitives, including cubes, cylinders, annuluses, and pyramids. By combining primitives, more complicated structures were obtained. A scanning electron microscope and a roughness step tester gave the feature size and surface roughness. The polymerized objects had lateral dimensions of about 200 micrometers and were typically be 300 micrometers in height. The best average surface roughness was 385 nanometers.