Atomic layer etch of tungsten for enhanced tungsten deposition fill

Abstract

Methods of depositing tungsten into high aspect ratio features using a dep-etch-dep process integrating various deposition techniques with alternating pulses of surface modification and removal during etch are provided herein. Methods involve introducing an activation gas at a chamber pressure and/or applying a bias using a bias power selected to preferentially etch the metal at or near the opening of the feature relative to the interior region of the feature. Apparatuses include integrated hardware for performing deposition of metal and atomic layer etching of metal in the same tool and/or without breaking vacuum.

1 - 35 . (canceled) 
     
     
         36 . A method comprising:
 preferentially etching a first amount of a metal in a feature on a substrate at or near the opening of the feature relative to an interior region of the feature by
 (i) exposing the feature to a halogen-containing gas to form a modified surface of the first amount of the metal; 
 (ii) exposing the modified surface to an activation gas; and 
 (iii) applying a bias to the substrate during at least one of (i) and (ii) using a bias power. 
   
     
     
         37 . The method of  claim 36 , wherein the metal contains tungsten or molybdenum. 
     
     
         38 . The method of  claim 36 , wherein the bias power when applied during (i) is greater than 0V and less than about 200 V. 
     
     
         39 . The method of  claim 36 , wherein the bias power when applied during (ii) is less than a threshold bias power. 
     
     
         40 . The method of  claim 36 , wherein the forming of the modified surface of the first amount of the metal is self-limiting. 
     
     
         41 . The method of  claim 36 , further comprising depositing the first amount of the metal in the feature on the substrate, wherein the depositing and the preferentially etching are performed without breaking vacuum. 
     
     
         42 . The method of  claim 41 , wherein the depositing and the preferentially etching are performed in different chambers of the same tool. 
     
     
         43 . The method of  claim 36 , further comprising igniting a plasma during at least one of (i) and (ii). 
     
     
         44 . The method of  claim 36 , further comprising, after preferentially etching the first amount of the metal, depositing a second amount of metal in the feature. 
     
     
         45 . The method of  claim 44 , wherein the metal is tungsten deposited using one or more tungsten precursors or combinations thereof. 
     
     
         46 . The method of  claim 44 , wherein the metal is selected from the group consisting of fluorine-free tungsten, titanium, tantalum, nickel, and cobalt. 
     
     
         47 . The method of  claim 36 , wherein the halogen-containing gas is selected from the group consisting of chlorine, bromine, iodine, and combinations thereof. 
     
     
         48 . The method of  claim 36 , wherein the activation gas is selected from a group consisting of helium, neon, krypton, and argon. 
     
     
         49 . A method comprising:
 preferentially etching a first amount of a metal in a feature on a substrate at or near an opening of the feature relative to an interior region of the feature by
 (i) exposing the feature to a halogen-containing gas to form a modified surface of the first amount of the metal; and 
 (ii) exposing the modified surface to an activation gas at a chamber pressure between about 1 mTorr and about 15 mTorr. 
   
     
     
         50 . The method of  claim 49 , wherein the metal contains tungsten or molybdenum. 
     
     
         51 . The method of  claim 49 , wherein forming of the modified surface of the first amount of the metal comprises a self-limiting reaction. 
     
     
         52 . The method of  claim 49 , further comprising depositing the first amount of the metal in the feature on the substrate, wherein the depositing and the preferentially etching are performed without breaking vacuum. 
     
     
         53 . The method of  claim 49 , further comprising igniting a plasma during at least one of (i) and (ii). 
     
     
         54 . The method of  claim 49 , further comprising, after preferentially etching the first amount of the metal, depositing a second amount of metal in the feature. 
     
     
         55 . An apparatus for processing semiconductor substrates, the apparatus comprising:
 a process chamber comprising a showerhead and a substrate support,   a plasma generator, and   a controller having at least one processor and a memory,   wherein the at least one processor and the memory are communicatively connected with one another,   the at least one processor is at least operatively connected with flow-control hardware, and the memory stores machine-readable instructions for:
 (i) causing introduction of a halogen-containing gas to the process chamber; 
 (ii) causing introduction of an activation gas; and 
 (iii) causing a bias to be applied to the substrate during at least (i) and (ii).