Abstract: A thin film battery having a protective package that provides a heat-resistant, hermetic seal for the thin film battery. A thin film battery includes thin film layers of components such as a cathode current collector, a cathode, an electrolyte, an anode, and an anode current collector built up on a substrate. Layers of dielectric material are positioned over the thin film battery. Suitable dielectric materials include aluminum oxide, silicon dioxide, silicon nitride, silicon carbide, tantalum oxide, diamond, and diamond-like-carbon. The dielectric materials are annealed. A layer of epoxy is positioned completely over all layers of the thin film battery and cured under ultraviolet light. Finally, the epoxy is annealed. The resultant thin film battery has a package that provides protection from the atmosphere, high temperatures, undesirable gases and can withstand processes utilized in the semiconductor and other industries to produce printed circuit boards with surface mounted thin film batteries.