Adhesive wafer bonding for CMOS based lab-on-a-chip devices

Abstract

Adhesive wafer bonding using laminated photosensitive dry-resist offers many advantages and can be used to realize advanced, CMOS integrated, lab-on-a-chip devices. The low bond-temperatures involved allow the hybrid integration of a range of substrates, e.g. CMOS wafers with structured MEMS glass wafers. The dry-film polymer functions as an adhesive interlayer and can be lithographically patterned to form sealed microfluidic fluid channels and chambers. This approach is well suited for low-cost R&D prototyping, and efforts reported in the past were often limited to proof-of-concept devices. However, all of the involved process steps do have the potential to be scaled up for an industrial volume production. We report on our activities to implement a baseline 8″ process flow, using the ORDYL SY300 series of permanent dry-film resist, to enable the commercial manufacturing of microfluidic devices based on this technology at a MEMS foundry. Advantages and disadvantages of the presented approach are discussed.