Methods of Forming Tungsten Pillars

Abstract

Methods of forming self-aligned patterns are described. A film material is deposited on a patterned film to fill and cover features formed by the patterned film. The film material is recessed to a level below the top of the patterned film. The recessed film is converted to a metal film by exposure to a metal precursor followed by volumetric expansion of the metal film.

What is claimed is: 
     
         1 . A processing method comprising:
 depositing a film at a temperature in the range of about 300° C. to about 550° C. on a substrate with a patterned film forming at least one feature to fill the at least one feature and extend above the top surface of the patterned film;   recessing the film to lower a top of the film to a height equal to or below the top surface of the patterned film to form a recessed film;   converting the recessed film to a tungsten film; and   expanding the tungsten film to form pillars extending from the at least one feature.   
     
     
         2 . The method of  claim 1 , wherein the film comprises amorphous silicon. 
     
     
         3 . The method of  claim 2 , wherein depositing the film comprises exposing the substrate surface to a precursor comprising one or more of silane, disilane, trisilane or tetrasilane. 
     
     
         4 . The method of  claim 1 , wherein depositing the film occurs at a pressure in the range of about 10 Torr to about 600 Torr. 
     
     
         5 . The method of  claim 3 , wherein depositing the film occurs without a co-reactant for the precursor. 
     
     
         6 . The method of  claim 1 , wherein depositing the film occurs without a plasma. 
     
     
         7 . The method of  claim 1 , wherein recessing the film comprises etching the film. 
     
     
         8 . The method of  claim 7 , wherein etching the film comprises a reactive ion etch process using a bromine based etchant. 
     
     
         9 . The method of  claim 7 , wherein recessing the film comprises exposing the film to a hydrogen plasma or hydrogen radicals. 
     
     
         10 . The method of  claim 1 , wherein converting the recessed film to a tungsten film comprises exposing the recessed film to WF 6 . 
     
     
         11 . The method of  claim 10 , wherein exposure to WF 6  occurs at a temperature in the range of about 300° C. to about 550° C. and a pressure in the range of about 10 Torr to about 100 Torr. 
     
     
         12 . The method of  claim 11 , wherein substantially all of the recessed film is converted to tungsten. 
     
     
         13 . The method of  claim 1 , wherein expanding the tungsten film comprises oxidizing the tungsten film. 
     
     
         14 . The method of  claim 13 , wherein the pillars extend substantially straight up from the feature. 
     
     
         15 . A processing method comprising:
 exposing a substrate surface with a patterned film forming at least one feature to a silicon precursor comprising one or more of silane, disilane, trisilane or tetrasilane to deposit an amorphous silicon film a temperature in the range of about 300° C. to about 550° C. on the substrate surface to fill the at least one feature and extend above the substrate surface, the amorphous silicon film deposited by thermal decomposition;   etching the amorphous silicon film with a hydrogen plasma or hydrogen radicals to recess the amorphous silicon film to lower a top of the amorphous silicon film to a height equal to or below the top surface of the patterned film to form a recessed amorphous silicon film;   exposing the recessed amorphous silicon film to a tungsten precursor to react with the recessed amorphous silicon film to convert substantially all of the amorphous silicon film to a tungsten film; and   oxidizing the tungsten film to expand the tungsten film to form tungsten pillars that extending substantially straight up from the at least one feature.   
     
     
         16 . The method of  claim 15 , wherein depositing the film occurs at a pressure in the range of about 10 Torr to about 600 Torr. 
     
     
         17 . The method of  claim 15 , wherein depositing the film occurs without a co-reactant for the precursor. 
     
     
         18 . The method of  claim 15 , wherein depositing the film occurs without a plasma. 
     
     
         19 . The method of  claim 15 , wherein the tungsten precursor comprises WF 6  and conversion occurs at a temperature in the range of about 300° C. to about 550° C. and a pressure in the range of about 10 Torr to about 100 Torr. 
     
     
         20 . A processing method comprising:
 providing a substrate surface with a patterned film forming at least one feature, the at least one feature extending a depth from a top surface to a bottom surface, the at least one feature having a width defined by a first sidewall and a second sidewall;   exposing the substrate surface to a silicon precursor comprising one or more of silane, disilane, trisilane or tetrasilane to deposit an amorphous silicon film by thermal decomposition on the substrate surface to fill the at least one feature and extend above the top surface of the patterned film, the thermal decomposition occurring without a silicon co-reactant and at a temperature in the range of about 300° C. to about 550° C. without a plasma;   etching the amorphous silicon film with a hydrogen plasma or hydrogen radicals to recess the amorphous silicon film to lower a top of the amorphous silicon film to a height equal to or below the top surface of the patterned film to form a recessed amorphous silicon film;   exposing the recessed amorphous silicon film to a tungsten precursor comprising WF 6  at a temperature in the range of about 300° C. to about 550° C. to react with the recessed amorphous silicon film to convert substantially all of the amorphous silicon film to a tungsten film; and   oxidizing the tungsten film to expand the tungsten film to form tungsten pillars that extending substantially straight up from the at least one feature.