Oxidizing filler material lines to increase width of hard mask lines

Abstract

A starting semiconductor structure includes a layer of filler material, a hard mask layer over the layer of filler material, and filler material lines over the hard mask layer. The starting semiconductor structure is placed in an etching chamber, and oxygen gas and high plasma power are inserted into the etching chamber and oxidizing, resulting in one or more of the filler material lines being oxidized, the filler material line(s) increasing in width from oxidizing, and etching the hard mask layer with a chemistry that is non-selective to the oxidized filler material lines and hard mask layer, and which has a stronger lateral etch selectivity to the oxidized filler material lines than the hard mask layer.

1 - 10 . (canceled) 
     
     
         11 . A semiconductor structure, comprising:
 a layer of filler material;   a hard mask layer over the layer of filler material; and   a plurality of filler material lines having one or more first widths over the hard mask layer, forming a tri-layer structure.   
     
     
         12 . The semiconductor structure of  claim 11 , further comprising:
 an etching chamber with the tri-layer structure therein;   a first inlet to the etching chamber for a first gas; and   a second inlet to the etching chamber for a second gas.   
     
     
         13 . The semiconductor structure of  claim 12 , wherein one or more of the filler material lines comprise at least one outer oxidation layer, the one or more filler material lines with at least one outer oxidation layer together having one or more second widths larger than the corresponding one or more first widths. 
     
     
         14 . The semiconductor structure of  claim 13 , wherein a thickness of the at least one outer oxidation layer comprises about 1 nm to about 10 nm. 
     
     
         15 . The semiconductor structure of  claim 12 , wherein the first gas is one of oxygen and plasma, and wherein the second gas is the other of oxygen and plasma. 
     
     
         16 . A semiconductor structure, comprising:
 a layer of filler material;   a hard mask layer over the layer of filler material; and   a plurality of filler material lines over the hard mask layer, wherein one or more of the plurality of filler material lines comprise at least one outer oxidation layer, the layer of filler material, the hard mask layer and the plurality of filler material lines forming a tri-layer structure.   
     
     
         17 . The semiconductor structure of  claim 16 , wherein a thickness of the at least one outer oxidation layer comprises about 1 nm to about 10 nm. 
     
     
         18 . The semiconductor structure of  claim 16 , further comprising:
 an etching chamber with the tri-layer structure therein;   a first inlet to the etching chamber coupled to a source of oxygen gas to form the at least one outer oxidation layer of the one or more of the plurality of filler material lines;   a second inlet to the etching chamber coupled to a source of plasma for etching the hard mask layer using the one or more of the plurality of filler material lines as mandrels.   
     
     
         19 . The semiconductor structure of  claim 18 , wherein a thickness of the outer oxidation layer comprises about 1 nm to about 10 nm.