Photo-assisted deposition of flowable films

Abstract

A method and apparatus for forming a flowable film are described. The method includes providing an oxygen free precursor gas mixture to a processing chamber containing a substrate. The oxygen free precursor gas is activated by exposure to UV radiation in the processing chamber. Molecular fragments resulting from the UV activation are encouraged to deposit on the substrate to form a flowable film on the substrate. The substrate may be cooled to encourage deposition. The film may be hardened by heating and/or by further exposure to UV radiation.

1 . A method of processing a substrate, comprising:
 disposing the substrate on a substrate support in a processing chamber;   cooling the substrate;   providing a precursor gas to the chamber;   activating the precursor gas by exposing the precursor gas to UV radiation in the chamber; and   forming an oxygen free flowable film on the substrate from the activated precursor gas.   
     
     
         2 . The method of  claim 1 , wherein the UV radiation has energy below an ionization potential of the precursor gas. 
     
     
         3 . The method of  claim 1 , further comprising curing the oxygen free flowable film. 
     
     
         4 . The method of  claim 1 , wherein the precursor gas is oxygen free. 
     
     
         5 . The method of  claim 2 , wherein the activating the precursor gas comprises reacting the precursor gas to form oligomers in the gas phase and condensing the oligomers on the substrate. 
     
     
         6 . The method of  claim 5 , wherein cooling the substrate comprises flowing a cooling fluid through the substrate support. 
     
     
         7 . The method of  claim 3 , wherein curing the oxygen free flowable film comprises exposing the oxygen free flowable film to thermal and UV energy. 
     
     
         8 . The method of  claim 1 , wherein the precursor gas comprises a silane, an aminosilane, an organosilane, a carbosilane, an n-substituted silicon containing pyrrol, a silicon containing hydrazone, a silicon containing azide, or a silicon containing pyrazoline. 
     
     
         9 . The method of  claim 8 , wherein the precursor gas comprises a tetrasilane, an N-silyl pyrrol, an N-sila pyrrol, or 2,4-disila-1-pyrazoline. 
     
     
         10 . The method of  claim 9 , wherein the UV energy is radiation having a wavelength of about 308 nm. 
     
     
         11 . A method of processing a substrate, comprising:
 disposing the substrate on a substrate support in a processing chamber;   cooling the substrate;   providing a precursor gas to the chamber;   decomposing the precursor gas by exposing the precursor gas to UV radiation in the chamber; and   forming an oxygen free flowable film on the substrate from the decomposed precursor gas.   
     
     
         12 . The method of  claim 11 , wherein the precursor gas is oxygen free. 
     
     
         13 . The method of  claim 12 , wherein the precursor gas comprises a silane, an aminosilane, an organosilane, a carbosilane, an n-substituted silicon containing pyrrol, a silicon containing hydrazone, a silicon containing azide, or a silicon containing pyrazoline. 
     
     
         14 . The method of  claim 13 , wherein the precursor gas comprises a tetrasilane, an N-silyl pyrrol, an N-sila pyrrol, or 2,4-disila-1-pyrazoline. 
     
     
         15 . The method of  claim 14 , wherein forming an oxygen free flowable film on the substrate from the decomposed precursor gas comprises forming oligomers in the gas phase and condensing the oligomers on the substrate. 
     
     
         16 . The method of  claim 15 , wherein cooling the substrate comprises maintaining the substrate at a temperature no greater than about 50° C. 
     
     
         17 . The method of  claim 16 , further comprising curing the oxygen free flowable film by exposing the oxygen free flowable film to thermal and UV energy. 
     
     
         18 . The method of  claim 17 , wherein exposing the oxygen free flowable film to thermal energy comprises heating the substrate to a temperature of at least 250° C. 
     
     
         19 . A method of processing a substrate, comprising:
 disposing the substrate on a substrate support in a processing chamber;   maintaining the substrate at a temperature of no more than about 50° C. by flowing a coolant through the substrate support;   providing a precursor gas comprising a silane, an aminosilane, an organosilane, a carbosilane, an n-substituted silicon containing pyrrol, a silicon containing hydrazone, a silicon containing azide, or a silicon containing pyrazoline to the chamber;   activating the precursor gas by exposing the precursor gas to UV radiation in the chamber;   forming oligomers in the gas phase;   condensing the oligomers from the activated precursor gas onto the substrate to form an oxygen free flowable film; and   exposing the oxygen free flowable film to UV radiation while heating the substrate to a temperature of at least 250° C.   
     
     
         20 . The method of  claim 19 , wherein the precursor gas comprises a tetrasilane, an N-silyl pyrrol, an N-sila pyrrol, or 2,4-disila-1-pyrazoline.