Self-organized process for patterning of a thin-film transistor

We studied the self-organized patterning of an insulator by using micro-contact printing (mu-CP) with an OTS (octadecyltrichlorosilane)-treated PDMS (polydimethylsiloxane) soft mold. An OTS monolayer on the patterned PDMS was formed by dipping it into an OTS solution. We transferred the OTS monolayer from the PDMS mold to a Cr layer on glass. The OTS monolayer changed the surface from hydrophilic to hydrophobic. We made self-organized PVP (cross-linked poly-4-vinylphenol) patterns by spin-coating of PVP. The PVP can be coated on the hydrophilic surface of Cr, but not on the OTS-treated Cr. Thus, we could get organic patterns without photolithography rapidly, and we could use organic patterns as etch barriers at a low cost. Using the surface energy difference and a self-organized process, we could make a 12-mu m-wide organic line pattern easily. Our self-organized process can be used as a patterning method for organic insulators and semiconductors in organic TFTs (thin-film transistors) and as an etch barrier for sub-layer etching in non-organic device fabrication.