Adhesive Wafer Bonding with SU-8 Intermediate Layers for Microfluidic Applications

Abstract

Recently adhesive wafer bonding using SU-8 has gained a lot of interest for micro-fluidic devices e.g. lab-on-chip applications. Due to its specific properties as well as the capability to pattern thin and thick layers accurately, SU-8 is an ideal candidate for micro-fluidic components like channels, reservoirs and valves, but also for micro-optical components. Wafer bonding enables the capping and encapsulation of the devices. In this paper the state-of-the-art of SU-8 wafer bonding is presented with a higher emphasis on the impact of the pre- processing. Spin-, spray coating and dry film lamination are reviewed and the resulting bond properties are analyzed.