PURPOSE: To prevent the contamination of display electrodes by plasma film formation and photoetching by executing formation of respective patterns in the state of coating the display electrodes with protective films.

CONSTITUTION: The protective film 30 formed over the entire surface after the formation of ITO of the display electrodes is self-aligned to source electrodes 19 and is removed by etching and, therefore, remains at the junctures between the display electrodes 14 and the source electrodes 19. Since the protective films 30 are formed on the display electrodes 14, etching rates are equaled in the films and at the boundaries and, therefore, the edges are not formed to a reverse taper shape at the time of forming contact holes in a gate insulating film 15 of an upper layer. Metals, such as Cr, Al and Mo, are used for the material of the protective films 30. The protective films 30 on the display electrodes 14 are etched away simultaneously at the time of patterning if the drain and source wirings and the protective films 30 are formed of the same material by using the Al and Mo.