High density plasma post-etch treatment for a dielectric etch process

Abstract

The present disclosure pertains to a post-etch treatment which is performed after a dielectric etch process. Using the method of the invention, byproducts formed on the sidewalls of contact vias during the dielectric etch process can be removed efficiently. The method of the invention also reduces or eliminates the problem of polymer accumulation on process chamber surfaces. Typically, after the etch of a dielectric material to define pattern or interconnect filling spaces, a series of post-etch treatment steps is performed to remove residues remaining on the wafer after the dielectric etch process. According to the method of the present invention, a post-etch treatment method including one or more steps is performed after the dielectric etch process, preferably within the same processing chamber in which the dielectric etch process was performed. The post-etch treatment method comprises exposing a semiconductor structure to a plasma generated from a source gas comprising oxygen, a nitrogen-comprising gas, and a reactive gas comprising hydrogen, carbon, and fluorine. Two optional steps, a flushing step prior to the post-etch treatment and a cleaning step subsequent to the post-etch treatment, can be performed, respectively, before and after the post-etch treatment for the purpose of enhancing the fluorine and byproduct removal and post-etch chamber cleaning.

We claim:  
     
         1 . A method for post-etch treatment of a semiconductor structure following a dielectric etch process, wherein said semiconductor structure includes an overlying dielectric layer into which openings have been etched, wherein the method comprises exposing said semiconductor structure to a plasma generated from a source gas comprising oxygen, a nitrogen-comprising gas, and a reactive gas comprising hydrogen, carbon, and fluorine.  
     
     
         2 . The method of  claim 1 , wherein said reactive gas comprises at least one hydrogen-containing fluorocarbon gas.  
     
     
         3 . The method of  claim 2 , wherein said hydrogen-containing fluorocarbon gas is selected from the group consisting of CHF 3 , CH 2 F 2 , CH 3 F, C 3 H 2 F 6 , and combinations thereof.  
     
     
         4 . The method of  claim 1 , wherein said reactive gas comprises at least one fluorocarbon gas and hydrogen.  
     
     
         5 . The method of  claim 4 , wherein said fluorocarbon gas is selected from the group consisting of C 2 F 6 , C 3 F 6 , C 3 F 8 , C 4 F 6 , C 4 F 8 , and combinations thereof.  
     
     
         6 . The method of  claim 1  or  claim 2 , or  claim 4 , wherein said nitrogen-comprising gas is N 2 .  
     
     
         7 . The method of  claim 1 , wherein said method further comprises a flushing step performed prior to said post-etch treatment.  
     
     
         8 . The method of  claim 7 , wherein said flushing step comprises exposing said semiconductor structure to a high-flow plasma comprising oxygen.  
     
     
         9 . The method of  claim 1  or  claim 8 , wherein said method further comprises a cleaning step subsequent to said post-etch treatment.  
     
     
         10 . The method of  claim 9 , wherein said cleaning step is performed while said semiconductor structure is present in said process chamber.  
     
     
         11 . The method of  claim 1 , wherein said cleaning step is performed after said semiconductor structure is removed from said process chamber.  
     
     
         12 . The method of  claim 1 , wherein said post-etch treatment method removes a photoresist layer overlying said dielectric layer.  
     
     
         13 . A method of post-etch treatment of a semiconductor structure following a dielectric etch process, wherein said semiconductor structure includes an overlying dielectric layer into which openings have been etched, wherein the method comprises the steps of: 
 a) a flushing step comprising exposing said semiconductor structure to a high-flow plasma comprising oxygen;    b) a post-etch treatment step comprising exposing said semiconductor structure to a plasma generated from a source gas comprising oxygen, a nitrogen-comprising gas, and a reactive gas comprising hydrogen, carbon, and fluorine; and    c) a cleaning step comprising exposing at least a process chamber in which said dielectric etch process was performed to a medium-flow plasma comprising oxygen.    
     
     
         14 . The method of  claim 13 , wherein said reactive gas comprises at least one hydrogen-containing fluorocarbon gas.  
     
     
         15 . The method of  claim 14 , wherein said hydrogen-containing fluorocarbon gas is selected from the group consisting of CHF 3 , CH 2 F 2 , CH 3 F, C 3 H 2 F 6 , and combinations thereof.  
     
     
         16 . The method of  claim 13 , wherein said reactive gas comprises at least one fluorocarbon gas and hydrogen.  
     
     
         17 . The method of  claim 16 , wherein said fluorocarbon gas is selected from the group consisting of C 2 F 6 , C 3 F 6 , C 3 F 8 , C 4 F 6 , C 4 F 8 , and combinations thereof.  
     
     
         18 . The method of  claim 13 , wherein said nitrogen-comprising gas is N 2 .  
     
     
         19 . A controller apparatus programmed to carry out the method of  claim 1  or  claim 13 .  
     
     
         20 . A medium containing data which enables a controller apparatus to carry out the method of  claim 1  or claim  13 .