NOVELTY - Battery comprises cathode current collector (32), cathode (24), electrolyte (26), anode (28) and anode current collector (34). The battery comprises dielectric thin film layers (38,40) comprising aluminum oxide, silicon dioxide, silicon nitride, silicon carbide, tantalum oxide, diamond and diamond-like-carbon, deposited on substrate (22). A sealing layer is formed on thin film layer (40).    USE - For production of printed circuit board.    ADVANTAGE - The packaging thin film batteries, especially lithium based thin film batteries comprising protective coating, protects the battery form undesirable gases, moisture, high temperature exposure and protects the battery from deterioration when the battery is subjected to assembly and testing procedures in semiconductor industry and other industry. The thin film battery comprises heat-resistant hermetically sealed package, sustains the rigors of solder reflow process, submerged in heated degreaser and water without degradation, and withstands atmospheric gaseous elements for long period of time. The thin film battery is heat-resistant up to 300degreesC. The thin films of aluminum oxide and silicon dioxide are heat-resistant, and thereby inert dielectric materials and amorphous do not react with the underlying thin film battery materials. The aluminum oxide and silicon dioxide act as excellent diffusion barriers. Thus, when a layer of cured epoxy is added to the protective coating, the thin film battery becomes completely impervious to fluids, for e.g. water.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) Method of providing protective coating for thin film battery cell; and    (2) Method of producing thin film battery having protective coating.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic cross-sectional view of the thin film battery having protective coating which is heat-resistant and hermetically seals the thin film battery.    Substrate (22)    Cathode (24)    Electrolyte (26)    Anode (28)    Cathode current collector (32)    Anode current collector (34)    Dielectric thin film layer (38,40)    Sealing layer (42)