Method for forming a metal line and method for manufacturing display substrate having the metal line

Abstract

A method for forming a metal line includes sequentially depositing a low-resistivity metal layer having aluminum on a base substrate and an upper layer having molybdenum on the low-resistivity metal layer, forming a photoresist pattern having a linear shape on the upper layer, etching the upper layer via a mixed gas using the photoresist pattern as a mask, the mixed gas including a chlorine based gas mixed with an additional gas having at least one of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas, and etching the low-resistivity metal layer using the photoresist pattern as the mask thereby removing any stringer that may be caused by a residue of the low-resistivity metal layer.

1 . A method for forming a metal line, the method comprising:
 sequentially depositing a low-resistivity metal layer having aluminum on a base substrate, and an upper layer having molybdenum on the low-resistivity metal layer;   forming a photoresist pattern having a linear shape on the upper layer;   etching the upper layer via a mixed gas using the photoresist pattern as a mask, the mixed gas including a chlorine based gas mixed with an additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas; and   etching the low-resistivity metal layer using the photoresist pattern as the mask.   
   
   
       2 . The method of  claim 1 , wherein a ratio of the additional gas with respect to the chlorine based gas is between about 50% and about 200%. 
   
   
       3 . The method of  claim 2 , wherein the upper layer is etched with conditions that a source power density [W/cm 2 ] is between about 1 and about 2, and a bias power density [W/cm 2 ] is between about 0.3 and about 0.6. 
   
   
       4 . The method of  claim 1 , wherein the low-resistivity metal layer is etched by the mixed gas including the chlorine based gas mixed with the argon gas or the nitrogen gas. 
   
   
       5 . The method of  claim 4 , wherein a ratio of the argon or nitrogen gas with respect to the chlorine based gas is between about 50% and about 150%. 
   
   
       6 . The method of  claim 5 , wherein the low-resistivity metal layer is etched with conditions that a source power density [W/cm 2 ] is between about 0.7 and about 1.8, and a bias power density [W/cm 2 ] is between about 0.7 and about 1.8. 
   
   
       7 . The method of  claim 1 , further comprising removing a corrosive element remaining on the base substrate after etching the low-resistivity metal layer. 
   
   
       8 . The method of  claim 7 , further comprising forming a lower layer including the molybdenum under the low-resistivity metal layer. 
   
   
       9 . The method of  claim 8 , further comprising etching the lower layer using the mixed gas including the chlorine based gas mixed with the additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas, before removing the corrosive element. 
   
   
       10 . The method of  claim 7 , wherein the corrosive element is removed by using at least one selected from the group consisting of H 2 0 gas and H 2  gas. 
   
   
       11 . The method of  claim 7 , wherein the corrosive element is removed by using a fluorine (F) based gas. 
   
   
       12 . The method for manufacturing a display substrate, the method comprising:
 forming a gate insulating layer on a base substrate, a gate pattern having a gate line and a gate electrode formed on the base substrate;   sequentially forming a source metal layer including a lower layer, a low-resistivity layer and an upper layer, the lower layer having molybdenum formed on the gate insulating layer, the low-resistivity metal layer having aluminum formed on the lower layer, the upper layer having molybdenum formed on the low-resistivity metal layer;   forming a source pattern having a source line, a source electrode and a drain electrode by etching the upper layer using a chlorine based gas mixed with an additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas;   forming a protective insulating layer having a contact hole formed in the protective insulating layer, the contact hole partially exposing the drain electrode; and   forming a pixel electrode electrically connected to the drain electrode through the contact hole.   
   
   
       13 . The method of  claim 12 , wherein a ratio of the additional gas with respect to the chlorine based gas is between about 50% and about 200%. 
   
   
       14 . The method of clam  13 , wherein the upper layer is etched with conditions that a source power density [W/cm 2 ] is between about 1 and about 2, and a bias power density [W/cm 2 ] is between about 0.3 and about 0.6. 
   
   
       15 . The method of  claim 14 , wherein forming the source pattern comprises:
 forming an electrode pattern and the source line, via etching the source metal layer;   etching an upper layer of the electrode pattern using the chlorine based gas mixed with the additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas;   etching a low-resistivity metal layer of the electrode pattern using the mixed gas including the chlorine based gas mixed with argon gas or nitrogen gas; and   etching a lower layer of the electrode pattern using the chlorine based gas mixed with the additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas, and sulfur hexafluoride gas.   
   
   
       16 . The method of  claim 15 , wherein the low-resistivity metal layer is etched with conditions that a chamber pressure is between about 10 and about 30, the source power density [W/cm 2 ] is between about 0.7 and about 1.8, and the bias power density [W/cm 2 ] is between about 0.7 and about 1.8. 
   
   
       17 . The method of  claim 14 , wherein forming the source pattern comprises:
 etching an upper layer of the source metal layer using chlorine based gas mixed with the additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas;   etching a low-resistivity metal layer of the source metal layer using the chlorine based gas mixed with argon gas or nitrogen gas; and   forming the source line, the source electrode and the drain electrode by etching a lower layer of the source metal layer using the chlorine based gas mixed with the additional gas having at least one selected from the group consisting of nitrogen gas, argon gas, helium gas and sulfur hexafluoride gas.   
   
   
       18 . The method of  claim 12 , further comprising removing a corrosive element corroding the low-resistivity metal layer, after forming the source pattern. 
   
   
       19 . The method of  claim 18 , wherein the corrosive element is removed by using at least one selected from the group consisting of H 2 0 gas and H 2  gas. 
   
   
       20 . The method of  claim 18 , wherein the corrosive element is removed by using a fluorine (F) based gas.