A method of making a coated article including a transparent conductive oxide (TCO) film supported by a tempered glass substrate is provided. Initially, an amorphous metal oxide film is sputter-deposited onto a non-tempered glass substrate, either directly or indirectly. The glass substrate with the amorphous film thereon is then thermally tempered using high temperatures. The thermal tempering causes the amorphous film to be transformed into a crystalline transparent conductive oxide (TCO) film. The heat used in the thermal tempering of the glass substrate causes the amorphous film to turn into a crystalline film, causes the visible transmission of the film to increase, and/or causes the film to become electrically conductive.