Lift-off process with bi-layer photoresist patterns for conformal-coated superhydrophilic pulsed plasma chemical vapor deposition-SiOxon SiCxfor lab-on-a-chip applications

In this work, a lift-off process with bi-layer photoresist patterns was applied to the formation of hydrophobic/hydrophilic micropatterns on practical polymer substrates used in healthcare diagnostic commercial products. The bi-layer photoresist patterns with undercut structures made it possible to peel the conformal-coated silicon oxide (SiO x ) films from substrates. SiO x and silicon carbide (SiC x ) layers were deposited by pulsed plasma chemical vapor deposition (PPCVD) method which can form roughened surfaces to enhance hydrophilicity of SiO x and hydrophobicity of SiC x . Microfluidic applications using hydrophobic/hydrophilic patterns were also demonstrated on low-cost substrates such as poly(ethylene terephthalate) (PET) and paper films.