Fig. 1.

Microfabrication of a PDMS microfluidic device with photolithography and soft lithography manufacturing processes. Microstructures of a negative photoresist are transferred onto a silicon wafer during photolithography. Similarly, microstructures of positive photoresist can be transferred onto wafers, as shown in the inset (gray box). The width and height (z-dimension) of the microstructure is ≥100 nm. The wafer is used as a mold to produce a PDMS replica during soft lithography. The replica is used to assemble a microfluidic device. Re-drawn based on studies by Duffy et al. (1998).