A method of manufacturing an organic light-emitting display apparatus includes: providing an organic light emission part on a substrate; providing a first inorganic layer including a first low temperature viscosity transition (“LVT”) inorganic material on the substrate to cover the organic light emission part; and adding fluoride into the first inorganic layer using a fluorine group material such that the first inorganic layer is converted into a second inorganic layer comprising a second low temperature viscosity transition inorganic material.