Patent ID: 9728407
Date: 2017-08-08
CPC Classifications: H01L

Claim:
1. A method comprising: forming a first, a second, a third and a fourth mandrel over a material layer, wherein the first and the second mandrels are formed over a first region of the material layer and spaced away by a first distance D forming spacers along sidewalls of the first, second, third and fourth mandrels without covering top surfaces of the first, second, third, and fourth mandrels; forming a patterned hard mask to cover the first region; depositing a filling layer in the second region while the patterned hard mask covers the first region, wherein a space between two adjacent spacers in the second region is filled in by the filling layer; recessing the filling layer to form a filling block in the space between two adjacent spacers in the second region; removing the patterned hard mask; removing the first, second, third and fourth mandrels; and etching the material layer by using spacers and the filling block as an etch mask to form material features in the first region and the second region, respectively.