Method for applying metal features onto barrier layers using electrochemical deposition
View Patent ↗The present invention is directed to a process for producing structures containing metallized features for use in microelectric 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 the 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 steps of:
forming a barrier layer on the workpiece;
contacting a surface of the barrier layer with an electrolyte solution;
applying electrical power to the barrier layer and an electrode in contact with the electrolyte solution to produce an electrolytically treated surface of the barrier layer without depositing metal onto the barrier layer; and
electrochemically forming a metallized feature on the electrolytically-treated surface of the barrier layer.
2. The method of claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the barrier layer comprises:
electrochemically forming a seed layer on the electrolytically treated surface of the barrier layer.
3. The method of claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the barrier 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 barrier 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 forming a barrier layer on the workpiece comprises depositing titanium nitride, tantalum nitride, titanium, tantalum, or any combination thereof onto the workpiece.
7. The method of claim 1 , further comprising the step of rinsing the surface of the microelectronic workpiece carrying the electrolytically treated barrier 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 barrier 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 barrier layer comprises contacting the electrolytically treated surface of the barrier layer with an electrolyte solution containing metal species to be deposited onto the electrolytically treated barrier layer.
10. The method of claim 1 , wherein the step of electrochemically forming a metallized feature comprises:
contacting the electrolytically-treated surface of the barrier 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.
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 metal ions is selected from the group consisting of copper sulfate, copper gluconate, sodium 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/cm2.
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/cm2 and a pulse waveform.
22. The method of claim 1 , wherein the step of electrochemically forming a metallized feature on the electrolytically treated surface of the barrier layer comprises electrochemically depositing ruthenium.