Method for monitoring surface treatment of copper containing devices

Abstract

Determining the presence of a corrosion inhibitor on exposed surfaces during manufacture of a microelectronic device subjected to one or more cleaning operations using a cleaning solution containing a corrosion inhibitor where a subsequent manufacturing or handling step requires no corrosion inhibitor residue on the device. A sacrificial copper test piece or coupon is subjected to the cleaning operation along with the device is exposed to hydrogen sulfide gas. The degree of color change in the surface of the copper test piece is a qualitative means of indicating the presence or absence of a corrosion inhibitor residue on exposed copper surfaces of the microelectronic device.

1 . A method for detecting the presence of a residual amount of corrosion inhibitor on a copper surface subjected to a cleaning solution containing a corrosion inhibitor comprising exposing said copper surface to a reactant that will attack said copper surface causing a pronounced color change of said copper surface, said color change indicating an absence of said corrosion inhibitor on said copper surface.  
     
     
         2 . A method according to  claim 1  including using a gaseous reactant.  
     
     
         3 . A method according to  claim 2  including exposing said copper surface to hydrogen sulfide gas.  
     
     
         4 . A method according to  claim 2  including introducing acetic acid into a solution of sodium sulfide in deionized water at room temperature to generate hydrogen sulfide gas as said reactant.  
     
     
         5 . A method for determining the presence of residual corrosion inhibitor on copper surfaces or copper components of a microelectronic device having been subjected to a cleaning prior to a subsequent fabrication operation comprising: 
 including a sacrificial copper coupon or test piece in a group or batch of said devices during said cleaning process;    removing said test piece from said batch and exposing said test piece to a gaseous reactant selected to react with said test piece to produce a visible color change of a surface said test piece in the absence of corrosion inhibitor on said surface of said test piece.    
     
     
         6 . A method according to  claim 5  including using hydrogen sulfide as said gaseous reactant.  
     
     
         7 . A method according to  claim 6  including producing said hydrogen sulfide gas by reacting acetic acid with an aqueous solution of sodium sulfide.  
     
     
         8 . An apparatus for detecting the presence of a residual amount of corrosion inhibitor on a copper surface subjected to a cleaning solution containing a corrosion inhibitor comprising in combination: 
 a first receptacle adapted to receive a test piece or pieces that have been exposed to cleaning solution,    a second receptacle placed inside said first receptacle proximate and said test pieces, said second receptacle adapted to receive reactants to produce a hydrogen sulfide gas; and    means to cover said first receptacle and direct said hydrogen sulfide gas at said test piece or pieces.    
     
     
         9 . An apparatus according to  claim 1  including sodium sulfide solution in said second receptacle.  
     
     
         10 . An apparatus according to  claim 9  including means to introduce an acid into said second receptacle prior to covering said first receptacle.