Patent ID: 7915102

Claim:
A method of making a flat panel display device comprising a CMOS thin film transistor (TFT), the method comprising: providing a substrate; forming a first gate electrode and a second gate electrode over the substrate; forming an insulating layer over the substrate and the first and second gate electrodes; forming a semiconductor layer over the insulating layer; forming a conductive layer over the semiconductor layer, wherein the conductive layer comprises at least two sublayers stacked over one another, and wherein forming the conductive layer comprises etching portions of the at least two sublayers in a single etching process; forming a photoresist mask having a first pattern over the semiconductor layer; selectively etching the semiconductor layer using the first pattern of the photoresist mask so as to form a first semiconductor layer and a second semiconductor layer, wherein at least a portion of the first semiconductor layer overlies the first gate electrode, and wherein at least a portion of the second semiconductor layer overlies the second gate electrode; projecting light to the first pattern of the photoresist mask in a direction such that the light passes through the substrate before reaching the first pattern of the photoresist mask, wherein the first and second gate electrodes block the light directed thereto, and wherein the light illuminates at least one portion of the first pattern of the photoresist mask; removing the at least one portion of the first pattern of the photoresist mask illuminated by the light, thereby forming a second pattern in the photoresist mask, wherein the second pattern is different from the first pattern; and selectively doping the first and second semiconductor layers with the second pattern of the photoresist mask, the first and second semiconductor layers having been previously formed with the first pattern of the photoresist mask.