Semiconductor device, and manufacturing method thereof

Abstract

In a display device such as a liquid crystal display device, a large sized display screen is realized under low power consumption. A surface of a source wiring line of a pixel portion employed in an active matrix type liquid crystal display device is processed by way of a plating process operation so as to lower a resistance value of this source wiring line. The source wiring line of the pixel portion is manufactured at a step different from a step for manufacturing a source wiring line of a drive circuit portion. Further, electrodes of a terminal portion are processed by a plating process operation so as to reduce a resistance value thereof.

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 a first semiconductor layer;   a second semiconductor layer over the first semiconductor layer, the second semiconductor layer comprising an impurity element applying one conductive type;   a third semiconductor layer over the first semiconductor layer, the third semiconductor layer comprising an impurity element applying one conductive type;   a first wiring electrically connected to the second semiconductor layer, the first wiring comprising a region extending to a first direction; and   a second wiring comprising a region overlapping with the first semiconductor layer, the second wiring comprising a region extending to a second direction intersecting with the first direction,   wherein the first wiring comprises a first conductive layer comprising Cu, and   wherein the first conductive layer is electrically connected to the second semiconductor layer through a second conductive layer, the second conductive layer not comprising Cu.   
     
     
         3 . A semiconductor device comprising:
 a first semiconductor layer;   a second semiconductor layer over the first semiconductor layer, the second semiconductor layer comprising an impurity element applying one conductive type;   a third semiconductor layer over the first semiconductor layer, the third semiconductor layer comprising an impurity element applying one conductive type;   a first wiring electrically connected to the second semiconductor layer, the first wiring comprising a region extending to a first direction; and   a second wiring comprising a region overlapping with the first semiconductor layer, the second wiring comprising a region extending to a second direction intersecting with the first direction,   wherein the first wiring comprises a conductive layer comprising Cu, and   wherein the conductive layer is not in contact with the second semiconductor layer.   
     
     
         4 . The semiconductor device according to  claim 2 ,
 wherein the first semiconductor layer comprises a first region overlapping with the second semiconductor layer, a second region overlapping with the third semiconductor layer, and a third region between the first region and the second region, and   wherein the third region is thinner than each of the first region and the second region.   
     
     
         5 . The semiconductor device according to  claim 2 ,
 wherein the one conductive type of the impurity element in the second semiconductor layer is N-type, and   wherein the one conductive type of the impurity element in the third semiconductor layer is N-type.   
     
     
         6 . An electronic device comprising:
 the semiconductor device according to  claim 2 ; and   at least one of an operation switch, a body, an antenna, a recording medium, and a speaker section.   
     
     
         7 . The semiconductor device according to  claim 3 ,
 wherein the first semiconductor layer comprises a first region overlapping with the second semiconductor layer, a second region overlapping with the third semiconductor layer, and a third region between the first region and the second region, and   wherein the third region is thinner than each of the first region and the second region.   
     
     
         8 . The semiconductor device according to  claim 3 ,
 wherein the one conductive type of the impurity element in the second semiconductor layer is N-type, and
 wherein the one conductive type of the impurity element in the third semiconductor layer is N-type. 
   
     
     
         9 . An electronic device comprising:
 the semiconductor device according to  claim 3 ; and   at least one of an operation switch, a body, an antenna, a recording medium, and a speaker section.