Laser micromachining of polymeric mold inserts for rapid prototyping of PMMA devices via photomolding

New technical approaches in biotechnology call for fast, cost efficient and precise patterning techniques in order to realize first polymeric prototypes in a small-scale production. For this purpose a new promising replication procedure was developed: in the first processing step UV- laser radiation is used for direct precision pattering of chemically stable polymer bulk material such as PSU, PEEK, and PI. In the second processing step thin metallic layers are deposited onto the polymer surface. Finally, in the third processing step these laser generated molds are used for replication of PMMA prototypes via UV-light induced reaction injection molding. The metallic layers on the polymeric surface have to suppress or to avoid an undesired chemical interaction between the polymer surface and the MMA/PMMA resin which is used in photo molding. The deposition of a thin Pt/Au layer system leads to a significant increase of mold inset lifetime form 1-5 up to 20 replication cycles for structures with high aspect ratios. Structures with aspect ratios of larger than 10 can be achieved with a minimal lateral dimension of about 6 micrometers . For this rapid tooling technique the actual impressive technical performances compared to other mold insert fabrication techniques will be presented with respect to the prototyping of microdevices made of PMMA.