Effect of Various Surface Treatment for Enhancing Adhesion of Au on Parylene Coated Protein Chip

Deposition of Parylene-c provides an inert biocompatible barrier to chemicals, moisture and biofluids. For the fabrication of electrical protein mass detection system, parylenec was deposited on device for electrical insulation. Parylene coated micromachined devices were then coated e-beam evaporated 30/150 rim thick -Cr/Au layers for protein-protein interaction. In general, For the piranha cleaning of Au for bio applications, poor adhesion of Au on parylene-c surfaces is a major hurdle in the reliable and durable performance in the biosensors. So we described a method for enhancing adhesion of Au on parylene-c coated surfaces. For the ion-beam and plasma effect for enhancing surface energy, ion beam treatment and atmosphere plasma treatment were performed. And for the modification from hydrophobic to hydrophilic surface, piranha, PBST and BSA treatment were performed. Tape-test analysis and piranha treatment were used for qualitative adhesive comparison of Au on parylene-c substrate. Contact angle measurements were performed before and after various treatments. Surface roughness and microstructures were observed using FESEM and AFM. From the results, the increase in adhesion is attributed to increased surface energy rather than hydraulic surface characteristics.