Feature fill with nucleation inhibition

Abstract

Described herein are methods of filling features with tungsten, and related systems and apparatus, involving inhibition of tungsten nucleation. In some embodiments, the methods involve selective inhibition along a feature profile. Methods of selectively inhibiting tungsten nucleation can include exposing the feature to a direct or remote plasma. Pre-inhibition and post-inhibition treatments are used to modulate the inhibition effect, facilitating feature fill using inhibition across a wide process window. The methods described herein can be used to fill vertical features, such as in tungsten vias, and horizontal features, such as vertical NAND (VNAND) wordlines. The methods may be used for both conformal fill and bottom-up/inside-out fill. Examples of applications include logic and memory contact fill, DRAM buried wordline fill, vertically integrated memory gate and wordline fill, and 3-D integration using through-silicon vias.

1 - 18 . (canceled) 
     
     
         19 . A method comprising:
 (a) exposing a metal layer in a feature to nitrogen species to form an inhibition profile in the feature, wherein nucleation is inhibited according to the inhibition profile; and   (b) after (a), exposing the feature to oxygen species to modify the inhibition profile.   
     
     
         20 . The method of  claim 19 , further comprising depositing tungsten in the feature in accordance with the modified inhibition profile. 
     
     
         21 . The method of  claim 19 , wherein the metal is tungsten. 
     
     
         22 . The method of  claim 19 , wherein (a) forms a metal nitride layer in the feature. 
     
     
         23 . The method of  claim 19 , wherein (a) comprises exposing the metal layer to a nitrogen-containing plasma. 
     
     
         24 . The method of  claim 23 , wherein the nitrogen-containing plasma is a remotely-generated plasma. 
     
     
         25 . The method of  claim 19 , wherein (b) comprises exposing the metal layer to an oxygen-containing plasma. 
     
     
         26 . The method of  claim 25 , wherein the oxygen-containing plasma is a remotely-generated plasma. 
     
     
         27 . The method of  claim 19 , wherein the inhibition profile varies along a feature axis. 
     
     
         28 . The method of  claim 20 , wherein depositing tungsten is performed in a different chamber than operations (a) and (b). 
     
     
         29 . The method of  claim 20 , wherein operations (a) and (b) and depositing tungsten are performed in the same multi-station chamber. 
     
     
         30 . A method comprising:
 exposing a tungsten surface in a feature to nitrogen species to form a tungsten nitride surface;   exposing the tungsten nitride surface to oxygen species to form a modified tungsten nitride surface; and   after exposing the tungsten nitride surface to oxygen species, exposing the modified tungsten nitride surface to a tungsten-containing precursor and depositing tungsten in the feature.   
     
     
         31 . The method of  claim 30 , wherein exposing a tungsten surface in a feature to nitrogen species comprises exposing the feature to a nitrogen-containing plasma. 
     
     
         32 . The method of  claim 31 , wherein the nitrogen-containing plasma is a remotely-generated plasma. 
     
     
         33 . The method of  claim 30 , wherein exposing the tungsten nitride surface to oxygen species comprises exposing the feature to an oxygen-containing plasma. 
     
     
         34 . The method of  claim 33 , wherein the oxygen-containing plasma is a remotely-generated plasma. 
     
     
         35 . A method comprising:
 exposing a metal layer in a feature to an inhibition chemistry to form an inhibition profile in the feature, wherein nucleation is inhibited according to the inhibition profile; and   after (a), exposing the feature to nitrogen and oxygen to modify the inhibition profile.   
     
     
         36 . The method of  claim 35 , wherein (b) decreases the inhibition effect. 
     
     
         37 . The method of  claim 35 , wherein (b) comprises exposing the feature to air.