Densifying films in semiconductor device

Abstract

Methods of densifying films, cross-linking films, and controlling the stress of films are provided herein. Methods include forming a removable film on a substrate comprising a material to be densified, and annealing the substrate to transfer stress from the removable film to the material and thereby densify the material. Some methods involve depositing a tensile capping layer on the material to be densified on a substrate and annealing the substrate at a temperature greater than about 450° C. Some methods include clamping the substrate including the material to be densified to a shaped pedestal using an electrostatic chuck to apply compressive stress to the material to be densified.

1 . A method comprising:
 forming a removable film on a substrate comprising a feature filled with a material to be densified, and   annealing the substrate to transfer stress from the removable film to the material and densify the material.   
     
     
         2 . The method of  claim 1 , wherein the removable film is tensile. 
     
     
         3 . The method of  claim 2 , wherein the removable film is formed over the material to be densified. 
     
     
         4 . The method of  claim 2 , wherein annealing the substrate induces tensile stress in the removable film. 
     
     
         5 . The method of  claim 2 , wherein the annealing the substrate comprises heating the substrate at a temperature greater than at least about 450° C. 
     
     
         6 . The method of  claim 2 , wherein the removable film is selected from the group consisting of silicon nitrides, metals, metal nitrides, carbon-containing dielectrics, silicon, and combinations thereof. 
     
     
         7 . The method of  claim 2 , wherein the tensile stress of the removable film is at least about 1 GPa. 
     
     
         8 . The method of  claim 1 , wherein the material to be densified is an oxide, nitride, or carbide. 
     
     
         9 . The method of  claim 1 , further comprising after annealing the substrate, treating the substrate with ultraviolet radiation or plasma. 
     
     
         10 - 14 . (canceled) 
     
     
         15 . The method of  claim 1 , wherein the removable film is compressive. 
     
     
         16 . The method of  claim 15 , wherein the removable film formed on the substrate is deposited on the backside of the substrate. 
     
     
         17 . (canceled) 
     
     
         18 . The method of  claim 15 , wherein annealing the substrate induces compressive stress in the removable film. 
     
     
         19 . (canceled) 
     
     
         20 . The method of  claim 15 , further comprising forming a removable tensile film over the material to be densified prior to annealing the substrate. 
     
     
         21 . An apparatus for processing semiconductor substrates, the apparatus comprising:
 a) at least one process chamber comprising a heated pedestal for holding a semiconductor substrate;   b) at least one outlet for coupling to a vacuum;   c) one or more process gas inlets coupled to one or more sources; and   d) a controller for controlling operations in the apparatus comprising machine readable instructions for:
 i) receiving the semiconductor substrate comprising a recessed feature and a seam, the recessed feature filled with a material to be densified; 
 ii) depositing a removable film onto the semiconductor substrate comprising the recessed feature filled with the material to be densified; and 
 iii) after depositing the removable film, setting the temperature of the heated pedestal to a temperature greater than at least about 450° C. to heat the semiconductor substrate and transfer stress from the removable film to the material to be densified and densify the material, 
 wherein the removable film is selected from the group consisting of metal-containing nitrides, metal-containing oxides, silicon-containing nitrides, and silicon-containing carbides, and 
 wherein (iii) comprises crosslinking the seam in the recessed feature. 
   
     
     
         22 . The apparatus of  claim 21 , wherein the heated pedestal is curved. 
     
     
         23 . The apparatus of  claim 22 , wherein the heated pedestal comprises an electrostatic chuck and the controller further comprises machine readable instructions for clamping the semiconductor substrate to the heated pedestal. 
     
     
         24 . The apparatus of  claim 21 , further comprising a plasma generator, wherein the controller further comprises machine readable instructions for, after heating the semiconductor substrate, igniting a plasma. 
     
     
         25 . The apparatus of  claim 21 , wherein the controller further comprises machine readable instructions for transferring the semiconductor substrate to an ultraviolet radiation exposure chamber and exposing the semiconductor substrate to ultraviolet radiation.