Rapid prototyping system with sub-micrometer resolution for microfluidic applications

We report on a maskless lithography rapid prototyping system for fabrication of microfluidic circuits with sub-micrometer resolution in standard i-line photoresists. The micropatterning system uses the laser direct imaging technique with a focused ultraviolet laser beam and an acousto-optic deflector to steer the beam in two dimensions. The use of an acousto-optic deflector results in high patterning speeds due to absence of moving parts and achieves sub-micrometer beam positioning precision on the photoresist surface. Patterns up to 100 cm2 with well defined edges and wall smoothness on the nanometer scale can be obtained. Direct illumination of the photoresist omits high-resolution masks and alignment with the photoresist sample, in turn making the lithography process more time- and cost-effective as well as flexible, with user control throughout the process. The system provides an efficient alternative to existing photolithography techniques and is especially suitable for rapid prototyping and laboratory use.