Rapid fabrication of embossing tools for the production of polymeric microfluidic devices for bioanalytical applications

In this work we present embossing tools that were fabricated using both UV and X-ray lithography. The embossing tools created were used to emboss microfluidic channels for bioanalytical applications. Specifically, two tools were fabricated. One, using X-ray lithography, was fabricated for electrophoretic separations of DNA restriction fragment analysis. A second tool, fabricated using SU8, was designed for micro PCR applications. Depths of both tools were approximately 100 mum. Both tools were made by directly electroforming nickel on a stainless steel base. Fabrication time for the tool fabricated using X-ray lithography was less than 1 week, and largely depended on the availability of the X-ray source. The SU8 embossing tool was fabricated in less than 24 hours. The resulting nickel electroforms from both processes were extremely robust and did not fail under embossing conditions required for PMMA and/or polycarbonate. Some problems removing SU8 after electroforming were seen for smaller size gaps between nickel structures.