Method for polishing copper on a workpiece surface

Abstract

A method for polishing a metal layer (e.g. copper) on a workpiece is provided wherein relative motion is produced between the metal layer and a polishing surface and wherein the metal layer has a polish resistant film thereon. The metal layer is first pre-treated to substantially remove the polish resistant film. Next, the metal layer is polished at low pressure between the metal layer and the polishing surface in the presence of a polishing solution. The pretreating may be accomplished by, for example, sputtering, polishing the polish-resistant film in the presence of abrasive polishing solution, polishing the polish-resistant film at higher pressures between the film and the polishing surface and/or maintaining the temperature of the pretreating step to be substantially between 10 degrees Centigrade and 30 degrees Centigrade.

1 . A method for polishing a metallized surface on a workpiece, said metallized surface having a polish-resistant film thereon, said method comprising; 
 pretreating said metallized surface to substantially remove said film; and    polishing said metallized surface by creating relative movement between said metallized surface and a polishing surface at a first pressure in the presence of a polishing solution.    
     
     
         2 . A method according to  claim 1  wherein said metallized surface is copper.  
     
     
         3 . A method according to  claim 2  wherein said first pressure is substantially between 0.1 psi and 3.0 psi.  
     
     
         4 . A method according to  claim 3  wherein said first pressure is between 0.5 psi and 2.0 psi.  
     
     
         5 . A method according to  claim 3  wherein the steps of pretreating and polishing occur at a temperature substantially between 10 degrees Centigrade and 30 degrees Centigrade.  
     
     
         6 . A method according to  claim 2  wherein the pretreating comprises sputtering to remove said film.  
     
     
         7 . A method according to  claim 6  wherein the sputtering occurs in an argon chamber.  
     
     
         8 . A method according to  claim 1  wherein the relative movement is rotary movement.  
     
     
         9 . A method according to  claim 1  wherein the relative movement is orbital movement.  
     
     
         10 . A method according to  claim 4  wherein the pretreating comprises creating relative motion between said film and a polishing surface at a second pressure which is higher than said first pressure.  
     
     
         11 . A method according to  claim 10  wherein said second pressure is substantially between 3 psi and 10 psi.  
     
     
         12 . A method according to  claim 11  wherein said second pressure is between 5 psi and 6 psi.  
     
     
         13 . A method according to  claim 11  where the step of polishing the film occurs at a temperature between 10 degrees Centigrade and 30 degrees Centigrade.  
     
     
         14 . A method according to  claim 1  wherein the step of polishing the film occurs in the presence of a substantially non-abrasive polishing solution.  
     
     
         15 . A method according to  claim 14  wherein said non-abrasive polishing solution contains less than one percent by weight of polishing abrasive.  
     
     
         16 . A method according to  claim 11  wherein the step of polishing the film occurs in the presence of an abrasive polishing solution.  
     
     
         17 . A method according to  claim 11  wherein the step of pretreating occurs for approximately one to twenty seconds.  
     
     
         18 . A method according to  claim 2  wherein the step of pretreating occurs in the presence of an abrasive polishing solution.  
     
     
         19 . A method according to  claim 18  wherein the step of pretreating occurs at a temperature between 10 degrees Centigrade and 30 degrees Centigrade.  
     
     
         20 . A method for polishing a metallized surface on a workpiece, said metallized surface having a polish-resistant film thereon, said method comprising; 
 sputtering said metallized surface to substantially remove said film; and    polishing said metallized surface by creating relative motion between said metallized surface and a polishing surface at a first pressure in the presence of a substantially non-abrasive polishing solution.    
     
     
         21 . A method according to  claim 20  wherein said relative motion is primarily non-orbital motion of the polishing pad.  
     
     
         22 . A method according to  claim 20  wherein said metallized surface is copper.  
     
     
         23 . A method according to  claim 22  wherein said sputtering takes places in an argon chamber.  
     
     
         24 . A method according to  claim 23  wherein said first pressure is substantially between 0.1 and 3.0 psi.  
     
     
         25 . A method according to  claim 24  wherein said first pressure is substantially between 0.5 psi and 2.0 psi.  
     
     
         26 . A method according to  claim 22  wherein the step of polishing takes place in the presence of a non-abrasive polishing solution.  
     
     
         27 . A method according to  claim 26  wherein said polishing solution contains less than one percent by weight of abrasive polishing material.  
     
     
         28 . A method for polishing a metallized layer on a workpiece, said metallized layer having a polish-resistant film thereon, said method comprising; 
 polishing said film by creating relative motion between said film and a polishing surface at a first pressure until said polish-resistant film is substantially removed; and    polishing said metallized surface by creating relative motion between said metallized surface and a polishing surface at a second pressure in the presence of a substantially non-abrasive polishing solution.    
     
     
         29 . A method according to  claim 28  wherein said relative motion comprises primarily non-orbital motion of the polishing pad.  
     
     
         30 . A method according to  claim 28  wherein said metallized layer is copper.  
     
     
         31 . A method according to  claim 30  wherein said second pressure is substantially between 0.1 psi and 3.0 psi.  
     
     
         32 . A method according to  claim 29  wherein the non-orbital motion comprises rotational motion.  
     
     
         33 . A method according to  claim 29  wherein the non-orbital motion comprises linear motion of a linear belt-type polishing pad  
     
     
         34 . A method according to  claim 30  wherein said first pressure is substantially between 3 psi and 10 psi.  
     
     
         35 . A method according to  claim 28  wherein the first and second polishing steps are performed with different polishing heads.  
     
     
         36 . A method according to  claim 29  wherein the different polishing heads are on a carousel apparatus.  
     
     
         37 . A method according to  claim 28  wherein the first and second polishing steps are performed on the same polishing station.  
     
     
         38 . A method for polishing a metallized surface on a workpiece, said metallized surface having a polish-resistant film thereon, said method comprising; 
 polishing said metallized surface by creating relative movement between said metallized surface and a polishing surface at a first polishing velocity to substantially remove said film; and    polishing said metallized surface by creating relative movement between said metallized surface and a polishing surface at a second, reduced polish velocity in the presence of a polishing solution.    
     
     
         39 . The method of  claim 38 , wherein the first polish velocity is two to three times the second polish velocity.  
     
     
         40 . The method of  claim 39 , wherein the relative movement between said metallized surface and a polishing surface comprises rotational motion of the polishing surface.  
     
     
         41 . The method of  claim 39 , wherein the relative movement between said metallized surface and a polishing surface comprises primarily linear motion of a linear belt-type polishing pad.  
     
     
         42 . A method for polishing a metallized surface on a workpiece, said metallized surface having a polish-resistant film thereon, said method comprising; 
 chemically stripping said polish-resistant film from said metallized surface using an etching solution; and    polishing said metallized surface by creating relative movement between said metallized surface and a polishing surface in the presence of a polishing solution.    
     
     
         43 . The method of  claim 42 , wherein said step of chemically stripping comprises dipping the workpiece in a bath of the etching solution.  
     
     
         44 . The method of  claim 42 , wherein the step of chemically stripping comprises polishing said metallized surface by creating relative movement between said metallized surface and a polishing surface in the presence of the etching solution.  
     
     
         45 . The method of  claim 42 , wherein the etching solution comprises dilute inorganic acid.  
     
     
         46 . The method of  claim 42 , wherein the etching solution comprises dilute organic acid.