Method for manufacturing an electrooptical device

Abstract

An object of the present invention is to provide an electrooptical device having high operation performance and reliability, and a method of manufacturing the electrooptical device. Lov region 207 is disposed in n-channel TFT 302 that comprises a driver circuit, and a TFT structure which is resistant to hot carriers is realized. Loff regions 217 to 220 are disposed in n-channel TFT 304 that comprises a pixel section, and a TFT structure of low off current is realized. An input-output signal wiring 305 and gate wiring 306 are formed by laminating a first wiring and a second wiring having lower resistivity than the first wiring, and wiring resistivity is steeply reduced.

1 . A display device comprising: 
 a semiconductor film formed over a substrate;    a gate insulating film formed over the semiconductor film;    a gate electrode formed over the gate insulating film; and    a gate wiring comprising a first wiring and a second wiring,    wherein a portion of the first wiring extends over the semiconductor film and functions as the gate electrode, while any portion of the second wiring does not function as the gate electrode.    
   
   
       2 . A display device according to  claim 1 , wherein the first wiring comprises at least one material selected from the group consisting of tantalum, titanium, molybdenum, tungsten, chromium, niobium and silicon.  
   
   
       3 . A display device according to  claim 1 , wherein the second wiring comprises at least one material selected from the group consisting of aluminum, copper and silver.  
   
   
       4 . A display device according to  claim 1 , wherein a resistivity of the first wiring is 10 to 500 μΩcm.  
   
   
       5 . A display device according to  claim 1 , wherein a resistivity of the second wiring is 0.1 to 10 μΩcm.  
   
   
       6 . An electronic apparatus having the display device according to  claim 1 , wherein the electronic apparatus is selected from the group consisting of a portable phone, a video camera, a mobile computer, a goggle-type display, a front-type projector, a rear-type projector, a personal computer, a game player, a recording medium, and a digital camera.  
   
   
       7 . A display device comprising: 
 a semiconductor film formed over a substrate;    a gate insulating film formed over the semiconductor film;    a gate electrode formed over the gate insulating film; and    a gate wiring comprising a first wiring and a second wiring,    wherein a resistivity of the second wiring is lower than that of the first wiring,    wherein a portion of the first wiring extends over the semiconductor film and functions as the gate electrode, while any portion of the second wiring does not function as the gate electrode.    
   
   
       8 . A display device according to  claim 7 , wherein the first wiring comprises at least one material selected from the group consisting of tantalum, titanium, molybdenum, tungsten, chromium, niobium and silicon.  
   
   
       9 . A display device according to  claim 7 , wherein the second wiring comprises at least one material selected from the group consisting of aluminum, copper and silver.  
   
   
       10 . A display device according to  claim 7 , wherein a resistivity of the first wiring is 10 to 500 μΩcm.  
   
   
       11 . A display device according to  claim 7 , wherein a resistivity of the second wiring is 0.1 to 10 μΩcm.  
   
   
       12 . An electronic apparatus having the display device according to  claim 7 , wherein the electronic apparatus is selected from the group consisting of a portable phone, a video camera, a mobile computer, a goggle-type display, a front-type projector, a rear-type projector, a personal computer, a game player, a recording medium, and a digital camera.  
   
   
       13 . A display device comprising: 
 a semiconductor film formed over a substrate;    a gate insulating film formed over the semiconductor film;    a gate electrode formed over the gate insulating film; and    a gate wiring comprising a first wiring and a second wiring,    wherein a resistivity of the second wiring is 1/10 to 1/100 of that of the first wiring,    wherein a portion of the first wiring extends over the semiconductor film and functions as the gate electrode, while any portion of the second wiring does not function as the gate electrode.    
   
   
       14 . A display device according to  claim 13 , wherein the first wiring comprises at least one material selected from the group consisting of tantalum, titanium, molybdenum, tungsten, chromium, niobium and silicon.  
   
   
       15 . A display device according to  claim 13 , wherein the second wiring comprises at least one material selected from the group consisting of aluminum, copper and silver.  
   
   
       16 . A display device according to  claim 13 , wherein a resistivity of the first wiring is 10 to 500 μΩcm.  
   
   
       17 . A display device according to  claim 13 , wherein a resistivity of the second wiring is 0.1 to 10 μΩcm.  
   
   
       18 . An electronic apparatus having the display device according to  claim 13 , wherein the electronic apparatus is selected from the group consisting of a portable phone, a video camera, a mobile computer, a goggle-type display, a front-type projector, a rear-type projector, a personal computer, a game player, a recording medium, and a digital camera.  
   
   
       19 . A display device comprising: 
 a semiconductor film formed over a substrate;    an LDD region formed in the semiconductor film;    a gate insulating film formed over the semiconductor film;    a gate electrode formed over the gate insulating film so as not to overlap the LDD region; and    a gate wiring comprising a first wiring and a second wiring,    wherein a portion of the first wiring extends over the semiconductor film and functions as the gate electrode, while any portion of the second wiring does not function as the gate electrode.    
   
   
       20 . A display device according to  claim 19 , wherein the first wiring comprises at least one material selected from the group consisting of tantalum, titanium, molybdenum, tungsten, chromium, niobium and silicon.  
   
   
       21 . A display device according to  claim 19 , wherein the second wiring comprises at least one material selected from the group consisting of aluminum, copper and silver.  
   
   
       22 . A display device according to  claim 19 , wherein a resistivity of the first wiring is 10 to 500 μΩcm.  
   
   
       23 . A display device according to  claim 19 , wherein a resistivity of the second wiring is 0.1 to 10 μΩcm.  
   
   
       24 . An electronic apparatus having the display device according to  claim 19 , wherein the electronic apparatus is selected from the group consisting of a portable phone, a video camera, a mobile computer, a goggle-type display, a front-type projector, a rear-type projector, a personal computer, a game player, a recording medium, and a digital camera.  
   
   
       25 . A display device having a plurality of pixels, the display device comprising: 
 a first thin film transistor and a second thin film transistor formed in each of the pixels;    a semiconductor film formed in each of the first thin film transistor and the second thin film transistor;    an LDD region formed in the semiconductor film of at least one of the first thin film transistor and the second thin film transistor;    a gate insulating film formed over the semiconductor film;    a gate electrode formed over the gate insulating film so as not to overlap the LDD region; and    a gate wiring comprising a first wiring and a second wiring,    wherein a portion of the first wiring extends over the semiconductor film and functions as the gate electrode, while any portion of the second wiring does not function as the gate electrode.    
   
   
       26 . A display device according to  claim 25 , wherein the first wiring comprises at least one material selected from the group consisting of tantalum, titanium, molybdenum, tungsten, chromium, niobium and silicon.  
   
   
       27 . A display device according to  claim 25 , wherein the second wiring comprises at least one material selected from the group consisting of aluminum, copper and silver.  
   
   
       28 . A display device according to  claim 25 , wherein a resistivity of the first wiring is 10 to 500 μΩcm.  
   
   
       29 . A display device according to  claim 25 , wherein a resistivity of the second wiring is 0.1 to 10 μΩcm.  
   
   
       30 . An electronic apparatus having the display device according to  claim 25 , wherein the electronic apparatus is selected from the group consisting of a portable phone, a video camera, a mobile computer, a goggle-type display, a front-type projector, a rear-type projector, a personal computer, a game player, a recording medium, and a digital camera.