Fabrication of Patterned Substrate by Wet Process for Biochip

Hydrophobic/hydrophilic patterned substrates were fabricated on a glass substrate by a liquid phase deposition (LPD) method. Hydrophobic surface was obtained by modifying ZnO thin films with a rough surface using a fluoroalkyltrimethoxysilane (FAS) and hydrophilic surface was prepared by decomposing FAS on an exposed to UV light. The hexagonal ZnO rods were perpendicularly grown by LPD method on glass substrates with a ZnO seed layer. The diameter and thickness of hexagonal ZnO rods were increased as a function of increases of immersion time. The surface morphology, thickness, crystal structure, transmittance and contact angle of prepared ZnO thin films were measured by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectrophotometer (UV-vis) and contact angle measurement. Hydrophilic ZnO thin films with a contact angle of 20 degrees similar to 30 degrees were changed to a hydrophobic surface with a contact angle of 145 degrees similar to 161 degrees by a FAS surface treatment. Prepared hydrophobic surface was pattered by an irradiation of UV light using shadow mask with 300 mu m or 3 mm dot size. Finally, the hydrophobic surface exposed to UV light was changed to a hydrophilic surface.