Processes and systems for engineering a copper surface for selective metal deposition

Abstract

An integrated system for transferring and processing a substrate in a controlled environment to enable selective deposition of a thin layer of a cobalt-alloy material on a copper surface of a copper interconnect to improve electromigration performance of the copper interconnect, comprising: a lab-ambient transfer chamber; a substrate cleaning reactor coupled to the lab-ambient transfer chamber, wherein the substrate cleaning reactor cleans the substrate surface to remove metal-organic complex contaminants on the substrate surface; a vacuum transfer chamber; a vacuum process module for removing organic contaminants from the substrate surface; a controlled-ambient transfer chamber filled with an inert gas; and an electroless cobalt-alloy material deposition process module used to deposit the thin layer of cobalt-alloy material on the copper surface of the copper interconnect after the substrate surface has been removed of metallic contaminants and organic contaminants, and the copper surface has been removed of copper oxide.

What is claimed is: 
     
         1 . An integrated system for transferring and processing a substrate in controlled environment to enable selective deposition of a thin layer of a cobalt-alloy material on a copper surface of a copper interconnect to improve electromigration performance of the copper interconnect, comprising:
 a lab-ambient transfer chamber capable of transferring the substrate from a substrate cassette coupled to the lab-ambient transfer chamber into the integrated system;   a substrate cleaning reactor coupled to the lab-ambient transfer chamber, wherein the substrate cleaning reactor cleans the substrate surface to remove metal-organic complex contaminants on the substrate surface;   a vacuum transfer chamber operated under vacuum at a pressure less than 1 Torr, wherein at least one vacuum process module is coupled to the vacuum transfer chamber;   a vacuum process module for removing organic contaminants from the substrate surface; wherein the vacuum process module is one of the at least one vacuum process module coupled to the vacuum transfer chamber, and is operated under vacuum at a pressure less than 1 Torr;   a controlled-ambient transfer chamber filled with an inert gas selected from a group of inert gases, and at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber; and   an electroless cobalt-alloy material deposition process module used to deposit the thin layer of cobalt-alloy material on the copper surface of the copper interconnect after the substrate surface has been removed of metallic contaminants and organic contaminants, and the copper surface has been removed of copper oxide, the electroless cobalt-alloy material deposition process module being one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber and is filled with an inert gas selected from a group of inert gases and having a fluid delivery system where process fluids are de-gassed.   
     
     
         2 . The integrated system of  claim 1 , further comprising:
 a hydrogen-containing reduction process module used to reduce residual copper oxide on the copper surface into copper, wherein the hydrogen-containing reduction process module is coupled to the vacuum transfer chamber, the hydrogen-containing reduction process module is operated under vacuum at a pressure less than 1 Torr.   
     
     
         3 . The integrated system of  claim 1 , wherein the substrate cleaning reactor that cleans the substrate surface to remove metal contaminants on the substrate surface is a wet clean reactor, employing a wet clean solution containing TMAH. 
     
     
         4 . The integrated system of  claim 1 , further comprises a second substrate cleaning reactor coupled to the lab-ambient transfer chamber, wherein the second substrate cleaning reactor cleans the substrate surface to remove metal oxides on the substrate surface, employing a wet clean solution containing one of citric acid, sulfuric acid, or sulfuric acid with hydrogen peroxide. 
     
     
         5 . The integrated system of  claim 1 , further comprising:
 a substrate cleaning process module used to clean the substrate surface after the copper surface of the substrate has been deposited with the thin layer of the cobalt-alloy material.   
     
     
         6 . The integrated system of  claim 5 , wherein the substrate cleaning process module is filled with an inert gas selected from a group of inert gases and is one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer module. 
     
     
         7 . The integrated system of  claim 1 , further comprising:
 a first loadlock coupled to the vacuum transfer chamber and the controlled-ambient transfer chamber, wherein the first loadlock assists the substrate to be transferred between the vacuum transfer chamber and the controlled-ambient transfer chamber, the first loadlock configured to be operated under vacuum at pressure less than 1 Torr or to be filled with an inert gas selected from a group of inert gases to operated under the same pressure as the controlled-ambient transfer module; and   a second loadlock coupled to the vacuum transfer chamber and the lab-ambient transfer chamber, wherein the second loadlock assists the substrate to be transferred between the vacuum transfer chamber and the lab-ambient transfer chamber, the second loadlock configured to be operated under vacuum at pressure less than 1 Torr or at lab ambient.   
     
     
         8 . The integrated system of  claim 1 , wherein the vacuum transfer chamber and the at least one vacuum process module coupled to the vacuum transfer chamber are operated at a pressure less than 1 Torr to limit the exposure of the substrate to oxygen. 
     
     
         9 . The integrated system of  claim 1 , wherein the controlled-ambient transfer chamber and the at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber are filled with one or more of inert gases selected from the group of inert gases to limit the exposure of the substrate to oxygen. 
     
     
         10 . The integrated system of  claim 1 , wherein substrate is transferred and processed in the integrated system to limit a duration the substrate is exposed to oxygen. 
     
     
         11 . The method of  claim 10 , wherein limiting the exposure of the substrate surface to oxygen reduces the induction time of the deposition reaction and enhances the thin layer of the cobalt-alloy material being selectively deposited on the copper surface. 
     
     
         12 . The integrated system of  claim 1 , wherein the at least one process module coupled to the controlled-ambient transfer module enables a dry-in/dry-out processing of the substrate, wherein the substrate goes in a dry state and comes out in a dry state. 
     
     
         13 . The integrated system of  claim 12 , wherein the electroless cobalt-alloy material deposition process module is coupled to a rinse and dry system to enable the dry-in/dry-out processing. 
     
     
         14 . An integrated system for transferring and processing a substrate in a controlled environment to enable selective deposition of a thin layer of a cobalt-alloy material on a copper surface of a copper interconnect to improve electromigration performance of the copper interconnect, comprising:
 a lab-ambient transfer chamber capable of transferring the substrate from a substrate cassette coupled to the lab-ambient transfer chamber into the integrated system;   a substrate cleaning reactor coupled to the lab-ambient transfer chamber, wherein the substrate cleaning reactor cleans the substrate surface to remove metal-organic complex contaminants on the substrate surface;   a vacuum transfer chamber operated under vacuum at a pressure less than 1 Torr, wherein at least one vacuum process module is coupled to the vacuum transfer chamber;   a vacuum process module for removing organic contaminants from the substrate surface; wherein the vacuum process module is one of the at least one vacuum process module coupled to the vacuum transfer chamber, and is operated under vacuum at a pressure less than 1 Torr;   a controlled-ambient transfer chamber filled with an inert gas selected from a group of inert gases, and at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber; and   an electroless cobalt-alloy material deposition process module used to deposit the thin layer of cobalt-alloy material on the copper surface of the copper interconnect after the substrate surface has been removed of metallic contaminants and organic contaminants, and the copper surface has been removed of copper oxide, the electroless cobalt-alloy material deposition process module being one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber and is filled with an inert gas selected from a group of inert gases and having a fluid delivery system where process fluids are de-gassed;   a hydrogen-containing reduction process module used to reduce residual copper oxide on the copper surface into copper, wherein the hydrogen-containing reduction process module is coupled to the vacuum transfer chamber, the hydrogen-containing reduction process module is operated under vacuum at a pressure less than 1 Torr;   wherein the substrate is transferred and processed in the integrated system to limit a duration the substrate is exposed to oxygen;   wherein limiting the exposure of the substrate surface to oxygen reduces the induction time of the deposition reaction and enhances the thin layer of the cobalt-alloy material being selectively deposited on the copper surface;   wherein the at least one process module coupled to the controlled-ambient transfer module enables a dry-in/dry-out processing of the substrate, wherein the substrate goes in a dry state and comes out in a dry state.   
     
     
         15 . The integrated system of  claim 14 , wherein the substrate cleaning reactor that cleans the substrate surface to remove metal contaminants on the substrate surface is a wet clean reactor, employing a wet clean solution containing TMAH. 
     
     
         16 . The integrated system of  claim 14 , further comprises a second substrate cleaning reactor coupled to the lab-ambient transfer chamber, wherein the second substrate cleaning reactor cleans the substrate surface to remove metal oxides on the substrate surface, employing a wet clean solution containing one of citric acid, sulfuric acid, or sulfuric acid with hydrogen peroxide. 
     
     
         17 . The integrated system of  claim 14 , further comprising:
 a substrate cleaning process module used to clean the substrate surface after the copper surface of the substrate has been deposited with the thin layer of the cobalt-alloy material.   
     
     
         18 . The integrated system of  claim 17 , wherein the substrate cleaning process module is filled with an inert gas selected from a group of inert gases and is one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer module. 
     
     
         19 . The integrated system of  claim 14 , further comprising:
 a first loadlock coupled to the vacuum transfer chamber and the controlled-ambient transfer chamber, wherein the first loadlock assists the substrate to be transferred between the vacuum transfer chamber and the controlled-ambient transfer chamber, the first loadlock configured to be operated under vacuum at pressure less than 1 Torr or to be filled with an inert gas selected from a group of inert gases to operated under the same pressure as the controlled-ambient transfer module; and   a second loadlock coupled to the vacuum transfer chamber and the lab-ambient transfer chamber, wherein the second loadlock assists the substrate to be transferred between the vacuum transfer chamber and the lab-ambient transfer chamber, the second loadlock configured to be operated under vacuum at pressure less than 1 Torr or at lab ambient.