Lift-off technique for producing metal pattern using single photoresist processing and oblique angle metal deposition

Claim 1

A process for forming on a substrate a patern of metallization significantly finer than the resolution capability of a photoresist material utilizing a single layer of photoresist comprising: (a) forming a single layer of a positive photoresist on the substrate; (b) pattern irradiating the photoresist layer with a dosage of actinic radiation such that, upon development, the irradiated pattern of the photoresist layer will be only partially removed; (c) developing the irradiated photoresist layer, thus forming recesses which extend only partially through the thickness of the photoresist layer; (d) depositing a first layer of metallization onto the irradiated and developed photoresist layer at an oblique angle such that it does not completely cover said recesses; (e) flood irradiating the portion of the photoresist layer not covered by the first layer of metallization, said portion lying within the recesses with actinic radiation and developing by removing said portion of the photoresist layer whereby openings are formed in the recesses of the photoresist layer which extend to the substrate; (f) depositing a second layer of metallization over the substrate and first layer of metallization, wherein the metallization deposited on the substrate through said openings separates from that deposited on the first layer of metallization; (g) contacting the photoresist layer with an organic solvent capable of separating the irradiated, developed and metallized photoresist layer from the substrate; and (h) removing the layer of photoresist and metallization deposited thereover from the substrate leaving the second layer of metallization deposited in the openings.