Method of manufacturing polysilicon thin film and method of manufacturing thin film transistor having the same

Abstract

In a method of manufacturing a polysilicon thin film and a method of manufacturing a TFT having the thin film, a laser beam is irradiated on a portion of an amorphous silicon thin film to liquefy the portion of the amorphous silicon thin film. The amorphous silicon thin film is on a first end portion of a substrate. The liquefied silicon is crystallized to form silicon grains. The laser beam is shifted from the first end portion towards a second end portion of the substrate opposite the first end portion by an interval in a first direction. The laser beam is then irradiated onto a portion of the amorphous silicon thin film adjacent to the silicon grains to form a first polysilicon thin film. Therefore, electrical characteristics of the amorphous silicon thin film may be improved.

1 . A method of manufacturing a polysilicon thin film comprising:
 irradiating a laser beam generated from a laser unit onto a first portion of an amorphous silicon thin film to liquefy the first portion of the amorphous silicon thin film, the laser beam having a beam shape including a first width substantially in parallel with a first direction and a second width substantially in parallel with a second direction substantially perpendicular to the first direction;   transporting the substrate or the laser beam for shifting the laser beam in the first direction to form a first polysilicon thin film;   rotating the substrate or the laser beam by a predetermined angle after forming the first polysilicon thin film; and   transporting the substrate or the laser beam for shifting the laser beam in the second direction to liquefy the first polysilicon thin film and to form a second polysilicon film.   
   
   
       2 . The method of  claim 1 , wherein the second width is greater than the first width, the beam shape of the laser unit is substantially the same shape as a shape of the laser beam irradiated onto the first portion. 
   
   
       3 . The method of  claim 2 , wherein the amorphous silicon thin film is formed on the substrate and the second width of the beam is substantially same to a side of the substrate. 
   
   
       4 . The method of  claim 3 , wherein the first width of the beam is about 3 um to about 10 um. 
   
   
       5 . The method of  claim 1 , wherein the amorphous silicon thin film is formed on the substrate and the second width of the beam is substantially same to a side of the substrate. 
   
   
       6 . The method of  claim 5 , wherein the first width of the beam is about 3 um to about 10 um. 
   
   
       7 . The method of  claim 1 , the shifting of the laser beam in the first direction is discrete. 
   
   
       8 . The method of  claim 7 , the discretion interval is same to or less than half of the first width of the laser beam. 
   
   
       9 . The method of  claim 7 , the discretion interval is bigger than half and less than the first with of the laser beam. 
   
   
       10 . The method of  claim 7 , wherein the second width is greater than the first width, the beam shape of the laser unit is substantially the same shape as a shape of the laser beam irradiated onto the first portion. 
   
   
       11 . The method of  claim 10 , wherein the amorphous silicon thin film is formed on the substrate and the second width of the beam is substantially same to a side of the substrate. 
   
   
       12 . The method of  claim 11 , wherein the first width of the beam is about 3 um to about 10 um. 
   
   
       13 . The method of  claim 7 , wherein the amorphous silicon thin film is formed on the substrate and the second width of the beam is substantially same to a side of the substrate. 
   
   
       14 . The method of  claim 13 , wherein the first width of the beam is about 3 um to about 10 um. 
   
   
       15 . A method of manufacturing a thin film transistor comprising:
 forming an amorphous silicon thin film on a substrate;   irradiating a laser beam generated from a laser unit onto the amorphous silicon thin film to change the amorphous silicon thin film into a polysilicon thin film;   partially etching the polysilicon thin film to form a polysilicon pattern;   forming a first insulating layer on the substrate having the polysilicon pattern;   forming a gate electrode on the first insulating layer overlapping a portion of the polysilicon pattern;   forming a second insulating layer on the first insulating layer and the gate electrode;   partially etching the first and second insulating layers to form contact holes;   
     and
 forming a source electrode and a drain electrode on the second insulating layer, the source electrode being spaced apart from the drain electrode, the source and drain electrodes being electrically connected to the polysilicon pattern through the contact holes, 
 wherein the laser beam irradiation scans a first direction to change the amorphous silicon thin film into a first polysilicon thin film, and the laser beam irradiation scans a second direction to change the first polysilicon thin film into a second polysilicon thin film. 
 
   
   
       16 . The method of  claim 15 , the first direction and the second direction are different from each other. 
   
   
       17 . The method of  claim 16 , the first direction and the second direction are substantially perpendicular. 
   
   
       18 . The method of  claim 16 , wherein the beam shape of the laser unit is elongated and substantially the same shape as a shape of the laser beam irradiated onto the first portion. 
   
   
       19 . The method of  claim 18 , wherein the length of the beam is substantially same to a side of the substrate. 
   
   
       20 . The method of  claim 19 , wherein the width of the beam is about 3 um to about 10 um. 
   
   
       21 . The method of  claim 16 , the scanning of the laser beam in the first direction is discrete. 
   
   
       22 . The method of  claim 21 , the discretion interval is same to or less than half of the first width of the laser beam. 
   
   
       23 . The method of  claim 21 , the discretion interval is bigger than half and less than the first with of the laser beam. 
   
   
       24 . The method of  claim 21 , wherein the beam shape of the laser unit is elongated substantially the same shape as a shape of the laser beam irradiated onto the first portion. 
   
   
       25 . The method of  claim 24 , wherein the length of the beam is substantially same to a side of the substrate. 
   
   
       26 . The method of  claim 25 , wherein the width of the beam is about 3 um to about 10 um. 
   
   
       27 . The method of  claim 21 , wherein the beam is elongated and the length of the beam is substantially same to a side of the substrate. 
   
   
       28 . The method of  claim 27 , wherein the width of the beam is about 3 um to about 10 um. 
   
   
       29 . A method of manufacturing a polysilicon thin film comprising:
 irradiating a laser beam generated from a laser unit onto a first portion of an amorphous silicon thin film to liquefy the first portion of the amorphous silicon thin film, the laser beam having a beam shape including a first width substantially in parallel with a first direction and a second width substantially in parallel with a second direction substantially perpendicular to the first direction;   transporting the substrate or the laser beam for scanning the laser beam in the first direction to form a first polysilicon thin film;   rotating the substrate or the laser beam by a predetermined angle after forming the first polysilicon thin film; and   transporting the substrate or the laser beam for scanning the laser beam in the second direction to liquefy the first polysilicon thin film and to form a second polysilicon film.