Disclosed are an organic light emitting display and a deposition method for depositing an electrode or a passivation layer by means of a box cathode sputtering method or a facing target sputtering method by mixing Ar with an inert gas heavier than Ar gas. The present embodiments provide an organic light emitting display including a substrate; a thin film transistor formed on the substrate; a first electrode formed on the thin film transistor; an organic layer formed on the first electrode; and a second electrode layer sputter-deposited on the organic layer by mixing Ar gas with an inert gas heavier than said Ar using a box cathode sputtering method or a facing target sputtering method.