Patent ID: 8828649

Claim:
A method of patterning a thin film layer, comprising: depositing an intermediate, irradiation sensitive, layer on a substrate; depositing the thin film layer on the intermediate layer; before or after deposition of the thin film layer; exposing the intermediate layer to patterned radiation in order to initiate a chemical reaction therein: removing, by soaking in a developer in a single developmental step, patterned radiation-defined parts of the intermediate layer along with corresponding thin film, to leave patterned thin film and patterned intermediate layer on the substrate; and in which the substrate comprises a polyethyleneterpthalate (PET) film, the intermediate layer comprises epoxidized bisphenol-A/formaldehyde novolac co-polymer (SU8); and the thin film comprises poly(3,4-ethylenedioxythiophene):poly(styrenesulphonate) (PEDOT:PSS).