Grooves in a desired circuit configuration are formed in the surface of a substrate to pre-pattern the area to receive material forming an organic thin film transistor (OTFT) structure and interconnecting conductive paths. The OTFT material is deposited in the pre-patterned area using printing techniques such as ink jet printing. In one embodiment, the grooves are formed in the surface substrate during the injection molding process of the substrate. Inter-exchangeable device covers carry different substrates to provide different functionalities of an electronic device with which the covers are used.