A novel SU-8 nanofluidic chip fabrication technique based on traditional UV photolithography

Nanofluidic chips are becoming increasingly important for biological and chemical applications due to the special phenomena only occur in nanochannels. In this study, a simple and low-cost method for fabricating SU-8 nanofluidic chips is proposed based on traditional ultraviolet (UV) photolithography. The thermal-induced cracks (nanochannels) can be automatically formed by thermal stress release during the postbake process. The influence of pattern-shape, pattern-angle and pattern-distance on the maximum stress of the SU-8 patterns was investigated. And the effect of postbake temperature on the maximum stress of the SU-8 patterns was also analyzed. The numerical and experimental results show that when the triangle SU-8 patterns with pattern-angle of 60° is postbaked at 125 °C, the nanocracks can be easily formed between two patterns. With this newly developed technology, simple, low-cost and large scale nanofluidic chips can be fabricated only by traditional UV photolighography, which allows a commercially manufacturing of nano-components.