Abstract
This paper describes a method for fabricating micronozzles using low-temperature wafer-level adhesive bonding with SU-8. The influence of different parameters on the bonding of structured wafers has been investigated. The surface energies of bonded wafers are measured to be in the range of 0.42–0.56 J m−2, which are comparable to those of some directly bonded wafers. Converging–diverging nozzle structures with throat widths as small as 3.6 µm are formed in an SU-8 film bonded with another SU-8 intermediate layer to produce sealed micronozzles. A novel interconnection technique is developed to interface and test the micronozzles with a macroscopic fluid delivery system to demonstrate the feasibility of the fabrication process. Leakage test results show that this low-temperature wafer bonding process is a viable MEMS fabrication technique for microfluidic applications.