Metal patterning process on rigid and flexible substrates using nanoimprint lithography and resist pattern transfer technique.

Fabrication of high aspect ratio metal patterns without rabbit ear shaped defects on rigid Si and flexible polyethylene terephthalate (PET) substrates was demonstrated. This process is composed of UV nanoimprint lithography (UV-NIL), resist pattern transfer step, and lift-off process. The imprinted resist pattern with a positive pattern profile on a water soluble polyvinyl alcohol (PVA) coated transparent substrate was transferred to Si and PET substrates in order to create an undercut profile for the high fidelity lift-off process using an UV curable adhesive. After the pattern transfer step, the PVA coated substrate was released by water soaking. The adhesive residue on the substrate was removed by short O2 reactive ion etching (RIE) without significant change of the resist pattern profile. Subsequently, the metal film was deposited by e-beam evaporation on the sample and the resist pattern was removed by acetone solution. As a result, the metal patterns with 250 nm of linewidth and 80 nm of thickness were formed by this process on Si and flexible PET substrates without rabbit ear shaped defects.