Contact ring spin during idle time and deplate for defect reduction

Abstract

Embodiments of the invention provide a method for removing contaminants from a plating bath contained in a weir-type plater during idle times. The method broadly includes positioning a lower portion of a substrate support assembly into the plating bath and rotating the substrate support assembly at a rotation rate of between about 1 rpm and about 60 rpm for between about 5 seconds and about 30 seconds to circulate the plating solution such that contaminants accumulating on the surface of the plating solution are urged to flow over a weir of the weir-type plater.

1 . A method for removing contaminants from a plating bath contained in a weir-type plater during idle times, comprising: 
 positioning a lower portion of a substrate support assembly into the plating bath; and    rotating the substrate support assembly at a rotation rate of between about 1 rpm and about 60 rpm for between about 5 seconds and about 30 seconds to circulate the plating solution such that contaminants accumulating on the surface of the plating solution are urged to flow over a weir of the plater.    
     
     
         2 . The method of  claim 1 , wherein the lower portion of the substrate support assembly comprises a contact ring.  
     
     
         3 . The method of  claim 2 , further comprising positioning a lower portion of the contact ring and scallops formed onto a lower surface of the contact ring into the plating bath.  
     
     
         4 . The method of  claim 2 , further comprising positioning the contact ring in the plating bath such that electrical contact pins on the contact ring are immersed in the plating process.  
     
     
         5 . The method of  claim 4 , further comprising deplating the electrical contact pins during the rotation.  
     
     
         6 . The method of  claim 5 , further comprising applying a reverse bias to the contact pins, the reverse bias having a voltage of between about 100 mv and about 10 volts.  
     
     
         7 . The method of  claim 6 , wherein the reverse bias has a duration of between about 1 second and about 360 seconds.  
     
     
         8 . The method of  claim 6 , wherein the reverse bias is at least one of a constant bias, a ramping bias, and a pulsed bias.  
     
     
         9 . The method of  claim 1 , further comprising filtering the plating solution urged to flow over the weir.  
     
     
         10 . A method for filtering surface contaminants from a plating solution in a weir-type plater, comprising: 
 lowering an empty contact ring assembly into the plating solution;    rotating the contact ring assembly to circulate an upper layer of the plating solution;    receiving at least a portion of the upper layer of the plating solution over a weir;    filtering the received portion of the upper layer of the plating solution to remove contaminants therefrom; and    recirculating the filtered plating solution to the weir-type plater.    
     
     
         11 . The method of  claim 10 , wherein rotating comprises rotating the contact ring at between about 5 rpm and about 35 rpm.  
     
     
         12 . The method of  claim 10 , further comprising tilting the contact ring in the plating solution.  
     
     
         13 . The method of  claim 11 , wherein lowering comprises positioning the contact ring such that a lower surface of the contact ring having a plurality of scallops positioned thereon is immersed in the plating solution and a plurality of electrical substrate contact pins are positioned above an upper surface of the plating solution.  
     
     
         14 . The method of  claim 11 , wherein lowering comprises positioning a plurality of electrical substrate contact pins on an upper surface of the contact ring in the plating solution.  
     
     
         15 . The method of  claim 14 , further comprising applying a deplating bias to the electrical substrate contact pins while the pins are immersed in the plating solution.  
     
     
         16 . The method of  claim 15 , wherein the deplating bias is between about 1 volt and about 5 volts.  
     
     
         17 . The method of  claim 11 , wherein filtering the received portion of the upper layer of the plating solution comprises passing the solution through a filter, the filter having a filtration porosity of between about 0.05 microns and about 2 microns.  
     
     
         18 . A method for removing surface contaminants from a plating solution during idle time periods, comprising: 
 positioning a lower portion of a contact ring having a plurality of electrical substrate contact pins extending therefrom in contact with the plating solution;    rotating the contact ring to urge the surface contaminants to flow over a weir;    collecting the plating solution flowing over the weir; and    filtering the collected plating solution to remove the surface contaminants therefrom.    
     
     
         19 . The method of  claim 18 , wherein rotating comprises rotating at between about 5 rpm and about 45 rpm.  
     
     
         20 . The method of  claim 19 , wherein positioning the contact ring comprises immersing a plurality of scallops formed onto a lower surface of the contact ring and the plurality of electrical substrate contact pins in the plating solution.  
     
     
         21 . The method of  claim 20 , further comprising applying a deplating bias to the plurality of electrical contact pins once immersed in the plating solution.  
     
     
         22 . The method of  claim 21 , wherein the deplating bias has a voltage of between about 0.1 volts and about 10 volts.  
     
     
         23 . The method of  claim 18 , further comprising tilting the contact ring at an angle of between about 3° and about 10° from horizontal.