JPS6413730A - Lift-off flatting method - Google Patents

Abstract

PURPOSE:To form a flat surface of a thin film without any unnecessary residual groove in the flat surface after lifting off the thin film by applying a positive type photoresist on the thin film substrate, exposing the resulting photoresist to an aromatic series solvent before or after rendering the same photoresist to exposure to light, and thereafter developing the photoresist. CONSTITUTION:A positive type photoresist 3 for example is applied on a sample composed of a niobium substrate 1 and a silicon dioxide thin film 2 deposited on the substrate, and thereafter subjected to a heat treatment at 80 deg.C for 30 minutes in nitrogen gas. The resulting sample is irradiated selectively with UV light for example, and dipped in chlorobenzene for 15 minutes to form a layer 3a difficult to be dissolved in a developing solution. Then, the result sample undergoes a heat treatment in nitrogen gas, and thereafter developing processing using a micro posit developer. Successively, the silicon dioxide thin film is removed selectively by the etching and dipped into a micro posit developer. Hereby, part of the positive type resist 3 except for the layer 3 difficult to be dissolved is dissolved. And, a niobium deposit film 4 is deposited on the sample with sputtering. The deposit film 4 is not deposited below the dissolved portion of the positive type resist. In succession, the sample is dipped into acetone for example and subjected to ultrasonic vibration, whereby the resist 3 is dissolved to remove the silicon dioxide thin film 2 on the resist 3.