Patent ID: 8759223

Claim:
A double patterning etching method comprising: (a) forming a plurality of double patterning features on a substrate, by: (i) forming at least one dielectric layer on the substrate; (ii) forming on the substrate, a plurality of first resist features which are spaced apart to form first openings; and (iii) after (ii), forming a second resist feature in each first opening to define second openings that are each between adjacent first and second resist features; (iv) forming a to layer to fill the second openings; and (v) removing the first and second resist features to form a plurality of double patterning features; (b) providing in a process zone of a process chamber, the substrate having the double patterning features; (c) energizing in a remote chamber, an etching gas comprising nitrogen trifluoride, ammonia, and hydrogen; (d) introducing the energized etching gas into the process zone of the process chamber to etch the double patterning features to form a solid residue on the substrate; and (e) sublimating the solid residue by heating the substrate to a temperature of at least about 100° C.