Patent ID: 7901869

Claim:
A double patterning method comprising: forming on a substrate a multi-layered mask including a carbonaceous mask layer, a first cap layer on the carbonaceous mask layer and a second cap layer on the first cap layer, wherein the first cap layer is silicon dioxide formed at a temperature above 250° C. and wherein the second cap layer is amorphous silicon; etching a first lithographically defined pattern into the second cap layer, stopping on the first cap layer, to form two features in the second cap layer; forming a photoresist layer over the second cap layer and contacting the first cap layer; lithographically defining in the photoresist layer a third feature disposed between the two features; etching the third feature to form a double pattern comprising the three features into the first cap layer and the carbonaceous mask layer; etching the double pattern into the substrate; and removing any remaining portion of the multi-layered mask.