Processes and Systems for Engineering a Barrier Surface for Copper Deposition

Abstract

An integrated system for processing a substrate in controlled environment to enable deposition of a thin copper seed layer on a surface of a metallic barrier layer of a copper interconnect is provided. The system includes a lab-ambient transfer chamber, a vacuum transfer chamber, a vacuum process module for cleaning an exposed surface of a metal oxide of a underlying metal, a vacuum process module for depositing the metallic barrier layer, and a controlled-ambient transfer chamber filled with an inert gas, wherein at least one controlled-ambient process module is coupled to the controlled-ambient transfer chamber. In addition, the system includes an electroless copper deposition process module used to deposit the thin layer of copper seed layer on the surface of the metallic barrier layer.

1 . An integrated system for processing a substrate in controlled environment to enable deposition of a thin copper seed layer on a surface of a metallic barrier layer of a 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 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 cleaning an exposed surface of a metal oxide of a underlying metal in the integrated system, wherein the underlying metal is part of a underlying interconnect, the copper interconnect is electrically connected to the underlying interconnect, wherein the vacuum process module for cleaning 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 vacuum process module for depositing the metallic barrier layer, wherein the vacuum process module for depositing the metallic barrier layer 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, wherein at least one controlled-ambient process module is coupled to the controlled-ambient transfer chamber; and   an electroless copper deposition process module used to deposit the thin layer of copper seed layer on the surface of the metallic barrier layer, wherein the electroless copper deposition process module is one of the at least one controlled environment process modules coupled to the controlled-ambient transfer chamber.   
     
     
         2 . The integrated system of  claim 1 , further comprising:
 a hydrogen-containing reduction process module used to reduce metal oxide or metal nitride on the surface of the metallic barrier, 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 electroless copper deposition process module is also used to deposit a gap-fill copper layer over the thin copper seed layer. 
     
     
         4 . The integrated system of  claim 1 , wherein another electroless copper deposition process module is used to deposit a gap-fill copper layer over the thin copper seed layer. 
     
     
         5 . The integrated system of  claim 1 , further comprising:
 a substrate cleaning process module used to clean the substrate surface after depositing the gap-fill copper layer over the thin layer copper seed layer, the substrate cleaning process module is one of the at least one vacuum process module coupled to the controlled-ambient transfer module.   
     
     
         6 . 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 being 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; 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 being configured to be operated under vacuum at pressure less than 1 Torr or at lab ambient or to be filled with an inert gas selected from a group of inert gases.   
     
     
         7 . 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 control the exposure of the substrate to oxygen. 
     
     
         8 . The integrated system of  claim 1 , wherein the controlled-ambient transfer chamber and each one the at least one process module coupled to the controlled-ambient transfer chamber are filled with one or more inert gases selected from the group of inert gases to control the exposure of the substrate to oxygen. 
     
     
         9 . 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. 
     
     
         10 . The method of  claim 9 , wherein limiting the exposure of the substrate surface to oxygen enables the thin layer of copper seed layer being selectively deposited on the surface of the metallic barrier layer. 
     
     
         11 . 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 and comes out the at least one process module in a dry state. 
     
     
         12 . The integrated system of  claim 11 , wherein the electroless copper deposition process module is coupled to a rinse and dry system to enable the dry-in/dry-out processing. 
     
     
         13 . An integrated system for processing a substrate in controlled environment to enable selective deposition of a thin copper seed layer on a surface of a metallic barrier layer of a copper interconnect and preparing a planarized copper surface of the copper interconnect to selectively depositing a thin layer of a cobalt-alloy material in an integrated system 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 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;   an Ar sputtering process module to clean an exposed surface of a metal oxide of a underlying metal in the integrated system, wherein the underlying metal is part of a underlying interconnect, the copper interconnect is electrically connected to the underlying interconnect, the Ar sputtering process module one of the at least one vacuum process module is coupled to the vacuum transfer chamber;   an atomic layer deposition (ALD) process module for depositing a thin first metallic barrier layer, wherein the ALD process module is one of the at least one vacuum process module coupled to the vacuum transfer chamber;   a PVD process chamber for depositing a thin second metallic barrier layer, wherein the PVD process module is one of the at least one vacuum process module coupled to the vacuum transfer chamber;   a hydrogen reduction process module for reducing a metal oxide or metal nitride to a metal, wherein the hydrogen reduction process module is one of the at least one vacuum process module coupled to the vacuum transfer chamber;   an oxygen plasma process module for removing organic contaminants from the substrate surface, wherein the oxygen plasma process module is one of the at least one vacuum process module coupled to the vacuum transfer chamber;   a controlled-ambient transfer chamber filled with an inert gas selected from a group of inert gases, wherein at least one controlled-ambient process module is coupled to the controlled-ambient transfer chamber;   an electroless copper deposition process module used to deposit the thin layer of copper seed layer and a gap-fill copper layer on the surface of the metallic barrier layer, the electroless copper deposition process module being one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber;   an electroless cobalt-alloy deposition process module used to deposit the thin layer of the cobalt-alloy material on the prepared planarized copper surface, the electroless copper alloy deposition process module being one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber;   a planarizing process module used to remove a copper overburden and a bather overburden of the copper interconnect, the planarizing process module is one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer module; and   a wet clean process module used to remove metallic contamination on the substrate surface, the wet clean process module is one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer module.   
     
     
         14 . The integrated system of  claim 13 , further comprising:
 a substrate cleaning process module used to clean the substrate surface after depositing and planarizing the gap-fill copper layer over the thin layer copper seed layer and after depositing the thin layer of the cobalt-alloy material, the substrate cleaning process module being one of the at least one controlled-ambient process module coupled to the controlled-ambient transfer module.   
     
     
         15 . The integrated system of  claim 13 , 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 being 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 being configured to be operated under vacuum at pressure less than 1 Torr or at lab ambient 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.   
     
     
         16 . The integrated system of  claim 13 , wherein the controlled-ambient transfer chamber and each one the at least one controlled-ambient process module coupled to the controlled-ambient transfer chamber are filled with one or more inert gas selected from the group of inert gases to limit the exposure of the substrate to oxygen. 
     
     
         17 . The integrated system of  claim 13 , wherein substrate is transferred and processed in the integrated system to limit a duration the substrate is exposed to oxygen. 
     
     
         18 . The integrated system of  claim 13 , wherein limiting the exposure of the substrate surface to oxygen enables the thin layer of copper seed layer being selectively deposited on the surface of the metallic barrier layer. 
     
     
         19 . The integrated system of  claim 13 , 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 and comes out the at least one process module in a dry state. 
     
     
         20 . An integrated system for processing a substrate in controlled environment to enable deposition of a thin copper seed layer on a surface of a metallic barrier layer of a 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 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 reducing the metallic barrier layer, wherein the vacuum process module for reducing the metallic barrier layer one of the at least one vacuum process module is 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, wherein at least one controlled-ambient process module is coupled to the controlled-ambient transfer chamber; and   an electroless copper deposition process module used to deposit the thin layer of copper seed layer on the surface of the metallic barrier layer, wherein the electroless copper deposition process module is one of the at least one controlled environment process modules coupled to the controlled-ambient transfer chamber.