Patent ID: 7439543

Claim:
An electronic equipment having a display device comprising: a substrate; a pixel TFT only in a pixel portion which can display a picture over the substrate; a driving circuit over the substrate; an interlayer insulating film; and a pixel electrode, wherein the driving circuit is located outside the pixel portion, wherein the pixel TFT comprises: a first semiconductor island including at least a first channel formation region, a second channel formation region, lightly doped regions and source and drain regions; a first gate insulating film formed over the first semiconductor island; a first gate electrode formed over the first channel formation region with the first gate insulating film interposed therebetween; and a second gate electrode formed over the second channel formation region with the first gate insulating film interposed therebetween, wherein the driving circuit comprises a thin film transistor, said thin film transistor comprising: a second semiconductor island including at least a third channel formation region; a second gate insulating film formed over the second semiconductor island; and a third gate electrode formed over the third channel formation region with the second gate insulating film interposed therebetween, wherein the interlayer insulating film covers the first, second and third gate electrodes and said first and second semiconductor islands, wherein the pixel electrode is formed over the interlayer insulating film and electrically connected to one of the source and drain regions of the first semiconductor island, and wherein each of the first, second and third gate electrodes has tapered edges with a taper angle in a range of 3° to 60°.