Liquid crystal display device and method of manufacturing the same

Abstract

The present invention discloses a method of manufacturing a liquid crystal display device including a first photolithography process forming a gate electrode on a substrate; a second photolithography process including: a) depositing sequentially a gate insulating layer, first and second semiconductor layers, and a metal layer; b) applying a first photoresist on the metal layer; c) aligning a first photo mask with the substrate; d) light exposing and developing the first photoresist to produce a first photoresist pattern; e) etching the metal layer using a first etchant, the first etchant ashing the first photoresist pattern on a predetermined portion of the metal layer to produce a second photoresist pattern, thereby exposing the predetermined portion of the metal layer; and f) etching the gate insulating layer, the first and second semiconductor layer, and the predetermined portion of the metal layer using a second etchant according to the second photoresist pattern to form source and drain electrodes, an ohmic contact layer, and an active area; a third photolithography process forming a passivation film and a contact hole; and a fourth photolithography process forming a pixel electrode connecting with the drain electrode through the contact hole.

1. A method of manufacturing a liquid crystal display device, comprising:
 a first photolithography process forming a gate electrode on a substrate;    a second photolithography process including: 
 a) depositing sequentially a gate insulating layer, a semiconductor layer, and a metal layer;  
 b) applying a first photoresist on the metal layer;  
 c) aligning a first photo mask with the substrate;  
 d) light exposing and developing the first photoresist to produce a first photoresist pattern;  
 e) etching the metal layer using a first etchant, the first etchant ashing the first photoresist pattern on a portion of the metal layer to produce a second photoresist pattern, thereby exposing the portion of the metal layer; and  
 f) etching the gate insulating layer, the semiconductor layer, and the portion of the metal layer using a second etchant according to the second photoresist pattern to form source and drain electrodes, an ohmic contact layer, and an active area;  
   a third photolithography process forming a passivation film and a contact hole; and    a fourth photolithography process forming a pixel electrode connecting with the drain electrode through the contact hole.    
     
     
       2. The method of  claim 1 , wherein the first etchant includes Cl 2 /O 2  gas. 
     
     
       3. The method of  claim 2 , wherein the second etchant includes SF 6 /HCl gas. 
     
     
       4. The method of  claim 2 , wherein the second etchant includes SF 6 /H 2 /Cl 2  gas. 
     
     
       5. The method of  claim 1 , wherein the semiconductor layer includes first and second semiconductor layers. 
     
     
       6. The method of  claim 5 , wherein the first semiconductor layer includes amorphous silicon. 
     
     
       7. The method of  claim 5 , wherein the second semiconductor layer includes doped amorphous silicon. 
     
     
       8. The method of  claim 1 , wherein the source and drain electrodes are made of a metal selected from a group consisting of Cr, Mo, Al, and Al alloy. 
     
     
       9. The method of  claim 8 , wherein the semiconductor layer includes first and second semiconductor layers. 
     
     
       10. The method of  claim 9 , wherein the first semiconductor layer includes amorphous silicon. 
     
     
       11. The method of  claim 9 , wherein the second semiconductor layer includes doped amorphous silicon. 
     
     
       12. The method of  claim 1 , wherein the pixel electrode includes indium tin oxide. 
     
     
       13. The method of  claim 12 , wherein the semiconductor layer includes first and second semiconductor layers. 
     
     
       14. The method of  claim 13 , first semiconductor layer includes amorphous silicon. 
     
     
       15. The method of  claim 13 , wherein the second semiconductor layer includes doped amorphous silicon. 
     
     
       16. A liquid crystal display device comprising:
   a thin film transistor made from;      forming a gate electrode on a substrate;        forming a gate insulating layer, a semiconductor layer, and a metal layer over the gate electrode;        forming a photoresist over the metal layer, the photoresist including a central portion having a first thickness and a side portion having a second thickness, the first thickness being smaller than the second thickness; and        selectively removing the metal layer and the semiconductor layer including portions of the metal layer below the central portion of the photoresist to form source and drain electrodes and a channel;          a data line and a gate line defining a pixel region, the data line have a first width, the width of the data line being smaller than a width of the semiconductor layer.     
     
     
       17. The liquid crystal display device according to  claim 16 , wherein the data line and the semiconductor layer extend substantially in parallel from a top of the pixel region to a bottom of the pixel region.