Patent ID: 9490136
Filing Date: 2016-11-08
CPC Classification: H01L

Claim Text:
1. A method comprising: forming a hard mask (HM) stack over a material layer, wherein the HM stack includes a first HM layer disposed over the material layer, a second HM layer disposed over the first HM layer, a third HM layer disposed over the second HM layer and a fourth HM layer disposed over the third HM layer; forming a first trench in the fourth HM layer; forming a first spacer in the first trench; removing the fourth HM layer adjacent to the first spacer to form a second trench; removing at least a portion of the first spacer to form a cut by using the third HM layer as an etch-stop layer; removing a portion of the third HM layer and the second HM layer exposed by the first trench, second trench, and cut to form an extended first trench, extended second trench, and extended cut, respectively; forming second spacers in the extended first trench, the extended second trench, and the extended cut; removing another portion of the second HM layer to form a third trench; and removing a portion of the first HM layer exposed by the extended first trench, extended second trench, extended cut, and third trench, respectively.