The process of fabrication of microfluidic structure was showed as figure 3

The process of fabrication of microfluidic structure
was showed as figure 3: Firstly, OFP film is mechanically
folded to form an 8 layers thick resist. Then it followed a
pre-bake process. After it the thick photoresist was
exposured and development. Before add the resist film to
the substrate, the wafer was cleaned in acetone and dried
for Smin in an oven at a temperature of 120°C. For easily
handling, the polyethylene layer was glue to the substrate
with the photoresist layer and the polyester layer was
removed. Then other layer of the dry-film photoresist film
was added on it followed a roll press to eliminate air
bubbles. The remaining protective polyethylene layer had
to be removed. Multiple layers resist films were obtained
to realize higher thickness structure. But as the layer
increasing the exposure process becomes more difficult.
8-layers OFP is a maximum and it results in the total