Disclosed is a method of making a flat panel display device. The flat panel display device includes a first substrate, an array of pixels formed on the first substrate, a second substrate opposing the first substrate, and a frit formed between the first substrate and the second substrate to encapsulate the array of pixels. On the first substrate, a buffer layer is formed, a first insulating film is formed on the buffer layer, and a first metal line is formed on the first insulating film. A second insulating film is formed, a second metal line is formed on the second insulating film, and a protective film formed on the upper of the second insulating film. A portion of the protective layer is etched to expose a portion of the second electrode. The frit overlaps with the portion of the second electrode.