Method for applying metal features onto metallized layers using electrochemical deposition and electrolytic treatment

Abstract

The present invention is directed to a process for producing structures containing metallized features for use in microelectronic workpieces. The process treats a barrier layer to promote the adhesion between the barrier layer and the metallized feature. Suitable means for promoting adhesion between barrier layers and metallized features according to the invention include an acid treatment of the barrier layer, an electrolytic treatment of the barrier layer, or deposition of a bonding layer between the barrier layer and metallized feature. The present invention thus modifies an exterior surface of a barrier layer making it more suitable for electrodeposition of metal on a barrier, thus eliminating the need for a PVD or CVD seed layer deposition process.

1 . A method for forming a metallized feature on a surface of a microelectronic workpiece comprising: 
 providing a workpiece having a metallized layer;    contacting a surface of the metallized layer with an electrolyte solution;    applying electrical power to the metallized layer and an electrode in contact with the electrolyte solution to produce an electrolytically treated surface of the metallized layer without depositing metal onto the metallized layer; and    electrochemically forming a metallized feature on the electrolytically treated surface of the metallized layer.    
   
   
       2 . The method of  claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the metallized layer comprises: 
 electrochemically forming a seed layer on the electrolytically treated surface of the metallized layer.    
   
   
       3 . The method of  claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the metallized layer comprises electrochemically depositing copper.  
   
   
       4 . The method of  claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the metallized layer comprises electrochemically depositing a copper alloy.  
   
   
       5 . The method of  claim 4 , wherein the copper alloy includes copper as a first metal and a second metal selected from the group consisting of chromium, nickel, cobalt, zinc, aluminum, boron, magnesium, and cerium.  
   
   
       6 . The method of  claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the metallized layer comprises electrochemically depositing ruthenium.  
   
   
       7 . The method of  claim 4 , further comprising the step of rinsing the surface of the microelectronic workpiece carrying the electrolytically treated metallized layer before electrochemically forming the metallized feature thereon.  
   
   
       8 . The method of  claim 7 , further comprising rinsing and thermally treating the surface of the microelectronic workpiece carrying the electrolytically treated metallized layer and the electrochemically formed metallized feature.  
   
   
       9 . The method of  claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the metallized layer comprises contacting the electrolytically treated surface of the metallized layer with an electrolyte solution containing metal species to be deposited onto the electrolytically treated metallized layer.  
   
   
       10 . The method of  claim 1 , wherein the step of electrochemically forming a metallized feature comprises: 
 contacting the electrolytically-treated surface of the metallized layer with an electroplating solution including a source of metal ions as a principal metal species to be deposited during electroplating and providing electroplating power to electroplate the principal metal species onto the electrolytically-treated surface of the metallized layer.    
   
   
       11 . The method of  claim 10 , wherein the electroplating solution comprises a metal ion complexing agent.  
   
   
       12 . The method of  claim 11 , wherein the principal metal species comprises copper, and the metal ion complexing agent is selected from the group consisting of ethylene diamine, ethylene diamine tetraacetic acid, and a polycarboxylic acid.  
   
   
       13 . The method of  claim 12 , wherein the complexing agent is ethylene diamine.  
   
   
       14 . The method of  claim 12 , wherein the complexing agent is citric acid.  
   
   
       15 . The method of  claim 12 , wherein the complexing agent is ethylene diamine tetraacetic acid.  
   
   
       16 . The method of  claim 10 , wherein the principal metal species comprises copper, and the electroplating solution further comprises boric acid.  
   
   
       17 . The method of  claim 10 , wherein the source of the metal ions is selected from the group consisting of copper sulfate, copper gluconate, copper cyanide, copper sulfamate, copper chloride, copper citrate, copper fluoroborate, copper pyrophosphate, and combinations thereof.  
   
   
       18 . The method of  claim 10 , wherein the principal metal species comprises copper, and the electroplating solution further comprises boric acid and a complexing agent selected from the group consisting of ethylene diamine, ethylene diamine tetraacetic acid, and a polycarboxylic acid.  
   
   
       19 . The method of  claim 10 , wherein the electroplating power has a current density in the range of about 20-50 mA/cm 2 .  
   
   
       20 . The method of  claim 10 , wherein the electroplating power has a pulse waveform.  
   
   
       21 . The method of  claim 10 , wherein the electroplating power has a current density in the range of about 20-50 mA/cm 2  and a pulse waveform.  
   
   
       22 . A process for applying a metal structure to a workpiece comprising: 
 providing a workpiece having a metallized layer;    contacting a surface of the metallized layer with an electrolyte solution having an electrode in contact with the electrolyte solution to produce an electrolytically treated surface of the metallized layer without depositing metal onto the metallized layer; and    electrochemically depositing a metal species onto the treated metallized layer to form a composite layer composed of the treated metallized layer and the electrochemically deposited metal species.    
   
   
       23 . A method for forming a copper feature on a surface of a microelectronic workpiece comprising: 
 providing a workpiece having a metallized layer;    contacting a surface of the metallized layer with an electrolyte solution;    applying electrical power to the metallized layer and an electrode in contact with the electrolyte solution to produce an electrolytically treated surface of the metallized layer without depositing metal onto the metallized layer; and    electrochemically forming a copper feature on the electrolytically treated surface of the metallized layer.    
   
   
       24 . The method of  claim 23 , wherein the step of electrochemically forming a copper feature on the electrolytically treated surface of the metallized delayer comprises: 
 electrochemically forming a copper seed layer on the electrolytically treated surface of the metallized layer.    
   
   
       25 . The method of  claim 23 , wherein the step of electrochemically forming a copper feature on the electrolytically treated surface of the metallized layer comprises contacting the electrolytically treated surface of the metallized layer with an electrolyte solution containing copper species to be deposited onto the electrolytically treated metallized layer.  
   
   
       26 . The method of  claim 23 , wherein the step of electrochemically forming a copper feature comprises: 
 contacting the electrolytically treated surface of the metallized layer with an electroplating solution including a source of copper ions as a principal metal species to be deposited during electroplating and providing electroplating power to electroplate the principal metal species onto the electrolytically treated surface of the metallized layer.    
   
   
       27 . The method of  claim 26 , wherein the electroplating solution comprises a copper ion complexing agent.  
   
   
       28 . The method of  claim 27 , wherein the copper ion complexing agent is selected from the group consisting of ethylene diamine, ethylene diamine tetraacetic acid, and a polycarboxylic acid.  
   
   
       29 . The method of  claim 28 , wherein the complexing agent is ethylene diamine.  
   
   
       30 . The method of  claim 28 , wherein the complexing agent is citric acid.  
   
   
       31 . The method of  claim 28 , wherein the complexing agent is ethylene diamine tetraacetic acid.  
   
   
       32 . The method of  claim 26 , wherein the electroplating solution further comprises boric acid.  
   
   
       33 . The method of  claim 26 , wherein the source of copper ions is selected from the group consisting of copper sulfate, copper gluconate, copper cyanide, copper sulfamate, copper chloride, copper citrate, copper fluoroborate, copper pyrophosphate, and combinations thereof.  
   
   
       34 . The method of  claim 26 , wherein the electroplating solution further comprises boric acid and a complexing agent selected from the group consisting of ethylene diamine, ethylene diamine tetraacetic acid, and a polycarboxylic acid.  
   
   
       35 . The method of  claim 26 , wherein the electroplating power has a current density in the range of about 20-50 mA/cm 2 .  
   
   
       36 . The method of  claim 26 , wherein the electroplating power has a pulse waveform.  
   
   
       37 . The method of  claim 26 , wherein the electroplating power has a current density in the range of about 20-50 mA/cm 2  and a pulse waveform.