Semiconductor Device

Abstract

It is an object of the present invention to connect a wiring, an electrode, or the like formed with two incompatible films (an ITO film and an aluminum film) without increasing the cross-sectional area of the wiring and to achieve lower power consumption even when the screen size becomes larger. The present invention provides a two-layer structure including an upper layer and a lower layer having a larger width than the upper layer. A first conductive layer is formed with Ti or Mo, and a second conductive layer is formed with aluminum (pure aluminum) having low electric resistance over the first conductive layer. A part of the lower layer projected from the end section of the upper layer is bonded with ITO.

1 . (canceled) 
     
     
         2 . A display device comprising a pixel portion, the pixel portion comprising:
 a first conductive layer including molybdenum;   a second conductive layer including aluminum over the first conductive layer;   an insulating film including an opening over the second conductive layer;   a third conductive layer including indium tin oxide over the insulating film; and   an orientation film over the third conductive layer,   wherein the second conductive layer has a region in contact with the first conductive layer,
 wherein a thickness of the first conductive layer is from 20 to 200 nm, 
 wherein a thickness of the second conductive layer is from 0.1 to 2 μm, 
 wherein the third conductive layer has a region in contact with the insulating film, 
 wherein the third conductive layer has a region overlapping an end portion of the first conductive layer in the opening of the insulating film, 
 wherein the third conductive layer has a region overlapping an end portion of the second conductive layer in the opening of the insulating film, 
 wherein the second conductive layer has a tapered side surface, and 
 wherein the orientation film has a region overlapping the third conductive layer in the opening of the insulating film. 
   
     
     
         3 . An electronic device including the display device according to  claim 2 .