High pressure rf-dc sputtering and methods to improve film uniformity and step-coverage of this process

Abstract

Embodiments of the invention generally provide a processing chamber used to perform a physical vapor deposition (PVD) process and methods of depositing multi-compositional films. The processing chamber may include: an improved RF feed configuration to reduce any standing wave effects; an improved magnetron design to enhance RF plasma uniformity, deposited film composition and thickness uniformity; an improved substrate biasing configuration to improve process control; and an improved process kit design to improve RF field uniformity near the critical surfaces of the substrate. The method includes forming a plasma in a processing region of a chamber using an RF supply coupled to a multi-compositional target, translating a magnetron relative to the multi-compositional target, wherein the magnetron is positioned in a first position relative to a center point of the multi-compositional target while the magnetron is translating and the plasma is formed, and depositing a multi-compositional film on a substrate.

We claim: 
     
         1 . A plasma processing chamber, comprising:
 a target having a first surface in contact with a processing region and a second surface opposite the first surface, wherein the target is configured for coupling to a radio frequency (RF) power supply and a direct current (DC) power supply;   a substrate support having a substrate receiving surface; and   a magnetron disposed adjacent to the second surface of the target, wherein the magnetron comprises:
 an outer pole comprising an outer plurality of magnets; and 
 an inner pole comprising an inner plurality of magnets, wherein the outer pole and the inner pole are substantially parallel, and the outer pole and the inner pole form a portion of an arc. 
   
     
     
         2 . The plasma processing chamber of  claim 1 , further comprising a center feed that is electrically coupled to the target. 
     
     
         3 . The plasma processing chamber of  claim 2 , wherein:
 the center feed includes a length (A), an inner diameter (D 1 ), and an outer diameter (D 2 ),   a surface area aspect ratio of the center feed is between about 0.001/mm and about 0.025/mm, and   the surface area aspect ratio is calculated by A/(πD 1 A+πD 2 A).   
     
     
         4 . The plasma processing chamber of  claim 2 , wherein the center feed is positioned over a central axis of the target. 
     
     
         5 . The plasma processing chamber of  claim 1 , further comprising:
 a grounded shield;   a cover ring; and   a deposition ring disposed over a portion of the substrate support, wherein during processing the cover ring is disposed on a portion of the deposition ring, and the deposition ring and the cover ring are disposed below the substrate receiving surface disposed below the target.   
     
     
         6 . A plasma processing chamber comprising:
 a target having a first surface that is in contact with a processing region and a second surface that is opposite the first surface, wherein the target is configured for coupling to a radio frequency (RF) power supply and a direct current (DC) power supply;   a substrate support having a substrate receiving surface; and   a center feed electrically coupled to the target, wherein:
 the center feed includes a length (A), an inner diameter (D 1 ), and an outer diameter (D 2 ), 
 a surface area aspect ratio of the center feed is between 0.001/mm and 0.025/mm, and 
 the surface area aspect ratio is calculated by A/(πD 1 A+πD 2 A). 
   
     
     
         7 . The plasma processing chamber of  claim 6 , further comprising a magnetron disposed adjacent to the second surface of the target, wherein the magnetron comprises:
 an outer pole comprising an outer plurality of magnets; and   an inner pole comprising an inner plurality of magnets.   
     
     
         8 . The plasma processing chamber of  claim 6 , wherein the center feed is positioned over a central axis of the target. 
     
     
         9 . The plasma processing chamber of  claim 6 , further comprising:
 a grounded shield;   a cover ring; and   a deposition ring disposed over a portion of the substrate support, wherein during processing the cover ring is disposed on a portion of the deposition ring, and the deposition ring and the cover ring are disposed below the substrate receiving surface disposed below the target.   
     
     
         10 . The plasma processing chamber of  claim 9 , further comprising:
 a variable capacitor; and   a controller configured to adjust a capacitance of the variable capacitor during processing.   
     
     
         11 . The plasma processing chamber of  claim 6 , further comprising:
 a cover ring disposed below the substrate receiving surface; and   a motor having a shaft that has a rotation axis.   
     
     
         12 . The plasma processing chamber of  claim 11 , further comprising:
 a magnetron disposed adjacent to the second surface of the target, wherein the magnetron comprises:
 a cross arm coupled to the shaft; 
 a plate coupled to the cross arm at a pivot point, wherein the pivot point is a distance from the rotation axis; and 
 an outer pole and an inner pole coupled to the plate. 
   
     
     
         13 . The plasma processing chamber of  claim 12 , wherein a center of mass of the plate is configured to move a first distance from the rotation axis when rotated in a first direction, and the center of mass of the plate is configured to move a second distance from the rotation axis when rotated in a second direction. 
     
     
         14 . The plasma processing chamber of  claim 12 , wherein a center of mass of the plate is configured to rotate about the pivot point in a third direction when the shaft is rotated in a first direction, and the center of mass of the plate is configured to rotate in a fourth direction about a pivot axis of the pivot point when the shaft is rotated in a second direction that is opposite to the first direction. 
     
     
         15 . The plasma processing chamber of  claim 12 , wherein the outer pole and the inner pole form a portion of an arc. 
     
     
         16 . A plasma processing chamber comprising:
 a target having a first target surface in contact with a processing region and a second target surface opposite the first surface, wherein the target is configured for coupling to a radio frequency (RF) power supply;   a grounded shield that at least partially encloses a portion of the processing region, the grounded shield configured for electrical coupling to a ground;   a substrate support assembly comprising:
 a support having a substrate receiving surface below the target; 
 a cover ring; and 
 a deposition ring disposed over a portion of the support, wherein when a substrate is disposed on the substrate receiving surface during processing the cover ring is disposed on a portion of the deposition ring, the cover ring is electrically isolated from the ground, and the deposition ring and the cover ring are disposed below the substrate receiving surface; and 
   a center feed electrically coupled to the target, wherein:
 the center feed has a first feed surface and a second feed surface, 
 the first feed surface is configured for coupling to the RF power supply and the second feed surface is coupled to the target, and 
 the center feed is positioned over a central axis of the target. 
   
     
     
         17 . The plasma processing chamber of  claim 16 , further comprising:
 a motor having a shaft that has a rotation axis; and   a magnetron disposed adjacent to the second surface of the target, wherein the magnetron comprises:
 an outer pole and an inner pole concentric about a first axis that extends through a center point and form a closed-loop magnetron assembly, wherein a plurality of magnets disposed in the inner and outer poles is not symmetric about a second axis that extends through the center point, the second axis perpendicular to the first axis. 
   
     
     
         18 . The plasma processing chamber of  claim 16 , further comprising:
 an electrode disposed in the support;   a variable capacitor disposed between the electrode and a ground; and   a controller configured to adjust a capacitance of the variable capacitor during processing.   
     
     
         19 . The plasma processing chamber of  claim 16 , further comprising:
 a motor having a shaft that has a rotation axis; and   a magnetron disposed adjacent to the second surface of the target, wherein the magnetron comprises:
 an outer pole comprising an outer plurality of magnets; and 
 an inner pole comprising an inner plurality of magnets, wherein the outer and inner poles form an open-loop magnetron assembly. 
   
     
     
         20 . The plasma processing chamber of  claim 16 , wherein:
 the center feed has a cross-section surface that extends between the first feed surface and the second feed surface,   the cross-section surface is symmetric about a first axis,   the center feed includes a length (A), an inner diameter (D 1 ), and an outer diameter (D 2 ),   the center feed has a surface aspect ratio between about 0.001/mm and about 0.025/mm, and   the surface area aspect ratio is calculated by A/(πD 1 A+πD 2 A).