Fabrication of Photonic/Microfluidic Integrated Devices Using an Epoxy Photoresist

Using a single layer of SU-8 photoresist to fabricate optical waveguide cores and microfluidic channels on Pyrex glass is an ideal way to achieve photonic/microfluidic integration on a single chip. To address the problem of poor bonding, a thin nanoscale intermediate polymer layer was applied to reduce the stress generated from the material processing while maintaining strong adhesion between the patterning polymer layer and Pyrex. It was found that a 186-600 nm thick intermediate layer of a specialty epoxy photoresist effectively served the purpose without deteriorating the optical performance of the involved waveguides. Quality photonic/microfluidic integrated devices with satisfied optical performance were fabricated.