Method and apparatus of distributed plasma processing system for conformal ion stimulated nanoscale deposition process

Abstract

A deposition system and method of operating thereof is described for depositing a conformal metal or other similarly responsive coating material film in a high aspect ratio feature using a high density plasma is described. The deposition system includes a plasma source, and a distributed metal source for forming plasma and introducing metal vapor to the deposition system, respectively. The deposition system is configured to form a plasma having a plasma density and generate metal vapor having a metal density, wherein the ratio of the metal density to the plasma density proximate the substrate is less than or equal to unity. This ratio should exist at least within a distance from the surface of the substrate that is about twenty percent of the diameter of the substrate. A ratio that is uniform within plus or minus twenty-five percent substantially across the surface of said substrate is desirable. The ratio is particularly effective for plasma density exceeding 10 12 cm −3 , and for depositing film on substrates having nanoscale features with maximum film thickness less than half of the feature width, for example, at ten percent of the feature width.

1 . A deposition system for forming a thin film in a high aspect ratio feature on a substrate comprising: 
 a process chamber;    a substrate holder coupled to said process chamber, and configured to support said substrate;    a plasma source coupled to said process chamber, and configured to form a plasma in said process chamber; and    a metal source coupled to said process chamber, and configured to introduce a metal to said process chamber,    wherein said plasma source and said metal source are configured to produce a ratio between a metal density and a plasma density of less than unity above said substrate.    
   
   
       2 . The deposition system of  claim 1 , further comprising: 
 a gas injection system coupled to said process chamber, and configured to introduce an inert gas.    
   
   
       3 . The deposition system of  claim 2 , wherein said inert gas includes a Noble gas.  
   
   
       4 . The deposition system of  claim 1 , wherein said plasma density is characterized by an electron density, or an ion density.  
   
   
       5 . The deposition system of  claim 1 , wherein said ratio is substantially uniform across said surface of said substrate.  
   
   
       6 . The deposition system of  claim 1 , wherein said ratio varies as a function of time.  
   
   
       7 . The deposition system of  claim 1 , wherein a spatial distribution of said plasma density above said substrate is represented by ƒ(x,y), a spatial distribution of said metal density is represented by g(x,y), and x and y represent a two-dimensional rectilinear coordinate system parallel with said surface of said substrate, where said function g(x,y) is a substantially similar function as said function ƒ(x,y).  
   
   
       8 . The deposition system of  claim 1 , wherein said plasma source includes one or more plasma generating elements.  
   
   
       9 . The deposition system of  claim 8 , wherein said one or more plasma generating elements is selected from the group consisting of a capacitively coupled plasma generating element, an inductively coupled plasma generating element, a helicon plasma generating element, an electron cyclotron resonance plasma generating element, and a surface wave plasma generating element.  
   
   
       10 . The deposition system of  claim 1 , wherein said plasma source includes at least one of an electrode, or a helical coil, or both.  
   
   
       11 . The deposition system of  claim 1 , wherein said plasma source is configured to produce a high density plasma.  
   
   
       12 . The deposition system of  claim 1 , wherein said plasma source is configured to produce a plasma density exceeding 10 12  cm −3 .  
   
   
       13 . The deposition system of  claim 1 , wherein said plasma source includes a first plasma generating element and a second plasma generating element, where said first generating element and said second generating element are coupled to said process chamber in order to perform at least one of adjusting or controlling a spatial distribution of said plasma density above said substrate.  
   
   
       14 . The deposition system of  claim 13 , wherein said first plasma generating element is coupled to a periphery of a lower portion of said process chamber, and said second plasma generating element is coupled to a periphery of an upper portion of said process chamber.  
   
   
       15 . The deposition system of  claim 13 , wherein said first plasma generating element is coupled to a periphery of a lower portion of said process chamber, and said second plasma generating element is coupled to an upper surface of said process chamber.  
   
   
       16 . The deposition system of  claim 1 , wherein said metal source includes a distributed metal source configured to perform at least one of adjusting or controlling a spatial distribution of said metal density above said substrate.  
   
   
       17 . The deposition system of  claim 16 , wherein said distributed metal source includes one or more metal targets positioned about a periphery of said process chamber.  
   
   
       18 . The deposition system of  claim 16 , wherein said one or more metal targets are coupled to a direct current (DC) power source.  
   
   
       19 . The deposition system of  claim 16 , wherein said one or more metal targets include a plurality of targets coupled to a power source, said power source configured to alternatingly and sequentially power each of said plurality of targets.  
   
   
       20 . The deposition system of  claim 1 , wherein said metal source includes a metal target coupled to a direct current (DC) power source.  
   
   
       21 . The deposition system of  claim 1 , wherein said metal source comprises a source of at least one of aluminum, copper, tantalum, or titanium.  
   
   
       22 . The deposition system of  claim 1 , further comprising: 
 a buffer device coupled to said process chamber, and configured to adjust at least one of said metal density or said plasma density above said substrate in said process chamber.    
   
   
       23 . The deposition system of  claim 22 , wherein said buffer device is coupled to an upper surface of said process chamber.  
   
   
       24 . The deposition system of  claim 22 , wherein said buffer device includes at least one of a flat, convex, or concave shape.  
   
   
       25 . The deposition system of  claim 22 , wherein said buffer device is electrically biased with at least one of direct current (DC) or alternating current (AC) power.  
   
   
       26 . The deposition system of  claim 22 , further comprising: 
 a magnet system coupled to said buffer device, and configured to adjust at least one of said metal density or said plasma density above said substrate in said process chamber.    
   
   
       27 . The deposition system of  claim 26 , wherein said magnet system includes at least one of a permanent magnet array, or an electromagnet.  
   
   
       28 . The deposition system of  claim 26 , wherein said magnet system includes at least one of a rotating magnet system, or a stationary magnet system.  
   
   
       29 . The deposition system of  claim 22 , wherein said buffer device is translatable.  
   
   
       30 . The deposition system of  claim 29 , wherein said buffer device translates in a direction substantially perpendicular to said substrate.  
   
   
       31 . The deposition system of  claim 22 , wherein said buffer device is coupled to a cooling system, a heating system, or both.  
   
   
       32 . The deposition system of  claim 1 , further comprising: 
 a magnet system coupled to said process chamber, and configured to adjust at least one of said metal density or said plasma density above said substrate in said process chamber.    
   
   
       33 . The deposition system of  claim 32 , wherein said magnet system includes at least one of a permanent magnet array, or an electro-magnet.  
   
   
       34 . The deposition system of  claim 32 , wherein said magnet system includes at least one of rotating magnet system, or a stationary magnet system.  
   
   
       35 . The deposition system of  claim 1 , wherein said substrate holder is configured to electrically bias said substrate.  1   
   
   
       36 . The deposition system of  claim 35 , wherein substrate holder is coupled to a radio frequency (RF) generator.  
   
   
       37 . The deposition system of  claim 1 , further comprising: 
 a control system coupled to said process chamber, said substrate holder, said plasma source, and said metal source, and configured to perform at least one of adjusting, monitoring, or controlling said deposition system.    
   
   
       38 . The deposition system of  claim 1 , wherein said process chamber is configured to produce a pressure ranging from approximately 1 mTorr to 100 mTorr, said plasma source is configured to produce said plasma density approximately equal to or exceeding 10 12  cm 3 , said metal source is coupled to a direct current (DC) power source and configured to produce said metal density approximately equal to or less than 10 12  cm −3  using approximately 1 to 4 kW of DC power, and said substrate holder is coupled to a radio frequency (RF) generator and configured to bias said substrate with approximately 0 to 1000 W of RF power.  
   
   
       39 . The deposition system of  claim 1 , wherein said process chamber is configured to produce a pressure ranging from approximately 1 mTorr to 100 mTorr, said metal source is coupled to a direct current (DC) power source and configured to produce said metal density using approximately 2 to 6 kW of DC power that is approximately equal to said plasma density produced by said plasma source, and said substrate holder is coupled to a radio frequency (RF) generator and configured to bias said substrate with approximately 300 to 800 W of RF power.  
   
   
       40 . The deposition system of  claim 1 , wherein said process chamber is configured to produce a pressure ranging from approximately 1 mTorr to 100 mTorr, said metal source is coupled to a direct current (DC) power source and configured to produce said metal density using approximately 1 to 6 kW of DC power that is approximately equal to said plasma density produced by said plasma source, and said substrate holder is coupled to a radio frequency (RF) generator and configured to bias said substrate with approximately 0 to 1000 W of RF power.  
   
   
       41 . A method of depositing a thin metal film in a high aspect ratio feature on a substrate comprising: 
 disposing said substrate on a substrate holder in a deposition system;    forming a plasma having a plasma density within said deposition system using a plasma source;    introducing metal having a metal density within said deposition system using a metal source;    establishing a ratio of said metal density to said plasma density above said substrate, said ratio being approximately equal to or less than unity; and    performing within said feature on said substrate a conformal deposition having a uniformity of plus or minus twenty-five percent.    
   
   
       42 . The method of  claim 41 , wherein said establishing said ratio includes adjusting said plasma density using said plasma source.  
   
   
       43 . The method of  claim 41 , wherein said establishing said ratio includes adjusting said metal density using said metal source.  
   
   
       44 . The method of  claim 41 , wherein said establishing said ratio above said substrate includes establishing said ratio locally above said substrate.  
   
   
       45 . The method of  claim 44 , wherein said establishing said ratio locally above said substrate includes establishing said ratio in a temporary manner.  
   
   
       46 . The method of  claim 41 , wherein said establishing said ratio above said substrate includes establishing said ratio in a temporary manner.  
   
   
       47 . The method of  claim 41 , wherein said depositing of a comformal deposition includes depositing a film having a maximum thickness on the substrate that is less than half the width of the feature.  
   
   
       48 . The method of  claim 47 , wherein said depositing of a comformal deposition includes depositing a film having a maximum thickness on the substrate that is less than approximately one-tenth of the width of the feature.  
   
   
       49 . A method of depositing a thin film in a high aspect ratio feature on a substrate comprising: 
 disposing said substrate on a substrate holder in a deposition system;    providing said deposition system with a coating material source of a coating material having a coating material ionization potential;    introducing into said deposition system a processing gas having an ionization potential greater than said coating material ionization potential;    forming with said processing gas a plasma having a plasma density within said deposition system using a plasma source;    introducing coating material having a coating material density within said deposition system using said coating material source;    establishing a ratio of said coating material density to said plasma density above said substrate, said ratio being not more than unity; and    performing within said feature on said substrate a conformal deposition of said coating material having a uniformity of plus or minus twenty-five percent.    
   
   
       50 . The method of  claim 49 , wherein said ratio is substantially uniform across said surface of said substrate.  
   
   
       51 . The deposition system of  claim 49 , wherein said plasma source is configured to produce a plasma density exceeding 1012 cm-3.  
   
   
       52 . The method of  claim 49 , wherein said depositing of a conformal deposition includes depositing a film having a maximum thickness on the substrate that is less than half the width of the feature.  
   
   
       53 . The method of  claim 49 , wherein said depositing of a conformal deposition includes depositing a film having a maximum thickness on the substrate that is less than approximately one-tenth of the width of the feature.  
   
   
       54 . A deposition system for forming a thin film in a high aspect ratio feature on a substrate comprising: 
 means for performing the method of  claim 49 .    
   
   
       55 . The deposition system of  claim 54  wherein said means for performing the method comprises: 
 a process chamber;    a substrate holder coupled to said process chamber, and configured to support said substrate;    a plasma source coupled to said process chamber, and configured to form a plasma in said process chamber; and    a source of said coating material coupled to said process chamber, and configured to introduce said coating material to said process chamber.