Method of forming a large surface area integrated circuit

A method of forming a large area electronic element, e.g., a large area integrated microelectronic circuit which has at least one dimension in excess of three inches, by forming a film of photoresist separate from a surface to be etched, and thereafter depositing the film of photoresist on the surface to be etched. The deposited photoresist film is then exposed to actinic radiation and developed, and the exposed, underlying surface may thereafter be etched. The method for depositing the photoresist involves passing a viscous liquid composed of photoresist and solvent under positive pressure through a very thin elongated orifice that extends across and in close proximity to (e.g., 0.01 inch or less), but spaced apart from the surface to be processed to form a very thin flexible continuous film of liquid photoresist composition issuing from the orifice. The surface to be processed is linearly moved past the orifice so as to deposit the issued film of photoresist on the surface, in a thickness no greater than 100 microns, and preferably much less. The wet deposited film is then heated to drive off the solvent thereby reducing the thickness of the photoresist. The method disclosed herein is particularly suitable for processing large area rectangular substrates and continuous flexible substrates used in roll-to-roll processing equipment.