Rapid prototyping process based on the use of an intelligent pinhole mask and 193 nm excimer laser used to fabricate polymer microfluidic devices

Laser use for rapid prototyping of microfluidic devices has proven useful but can have certain drawbacks including variations in channel width, depth and shape when producing complex geometries. We describe our work on an advanced rapid laser prototyping technique, based on the use of an "intelligent pinhole" and 193 nm excimer laser. The pinhole, a dynamic mask, consists of four individually programmable blades and is controlled through a LabVIEW user interface. Each blade has the capability to be positioned with sub-micron repeatability with a response time on the order of 5 ms. Synchronization with the excimer laser software allows the fabrication of more complex microchannel layouts that are not possible with fixed mask techniques. Using the programmability of the pinhole we can eliminate some of the undesirable effects associated with scanning laser ablation, such as ramps leading into and out of microchannels and banking or undercutting effects at microchannel junctions and corners. The paper will demonstrate beam re-configuration techniques which allow the creation of zero lead-ins to microchannels and show the system's potential to rapidly generate varying design iterations by fabricating a working microfluidic device and testing its application.