Controlled multi-step magnetron sputtering process

Abstract

A multi-step sputtering process in plasma sputter reactor having target and magnetron operable in two modes, for example, in a substrate sputter etch and a substrate sputter deposition. The target has an annular vault facing the wafer to be sputter coated. Various types of magnetic means positioned around the vault create a magnetic field supporting a plasma extending over a large volume of the vault. An integrated copper via filling process with the inventive reactor or other reactor includes a first step of highly ionized sputter deposition of copper, which can optionally be used to remove the barrier layer at the bottom of the via, a second step of more neutral, lower-energy sputter deposition of copper to complete the seed layer, and a third step of electroplating copper into the hole to complete the metallization. The first two steps can be also used with barrier metals.

1 . A method for depositing a metal seed layer on a wafer substrate comprising a plurality of recessed device features, the method comprising: 
 (a) depositing a first portion of the metal seed layer on the wafer substrate, using a first plasma comprising a plurality of metal ions, said plurality of metal ions impinging on the wafer substrate substantially perpendicular to the wafer substrate work surface; and    (b) depositing a second portion of the metal seed layer.    
   
   
       2 . The method of  claim 1  wherein (b) is performed using a second plasma comprising a plurality of metal atoms and a plurality of inert gas ions, said plurality of metal atoms impinging on the wafer substrate at substantially random angles and said plurality of inert gas ions impinging on the wafer substrate substantially perpendicular to the wafer substrate work surface.  
   
   
       3 . The method of  claim 1 , wherein the metal seed layer comprises copper.  
   
   
       4 . The method of  claim 1 , wherein the metal seed layer consists essentially of copper.  
   
   
       5 . A method for depositing a metal seed layer on a wafer substrate comprising a plurality of recessed device features, the method comprising: 
 (a) depositing a first portion of the metal seed layer on the wafer substrate; and    (b) depositing a second portion of the metal seed layer using a second plasma comprising a plurality of metal atoms and a plurality of inert gas ions, said plurality of metal atoms impinging on the wafer substrate at substantially random angles and said plurality of inert gas ions impinging on the wafer substrate substantially perpendicular to the wafer substrate work surface.    
   
   
       6 . A method for depositing a metal seed layer on a wafer substrate comprising a plurality of recessed device features, the method comprising: 
 (a) depositing a first portion of the metal seed layer using high energy ionized copper; and    (b) depositing a second portion of the metal seed layer using neutral low energy copper.