Patent ID: 7772126

Claim:
A method of patterning a substrate, comprising: (a) providing a substrate including a pattern surface; (b) disposing an interlayer on the pattern surface; (c) providing a buried hard mask on the interlayer, the buried hard mask including a template opening with a template length disposed along a line axis and a template width perpendicular thereto; (d) filling the buried hard mask with a fill material; (e) providing a top mask of amorphous carbon via a plasma-enhanced chemical vapor deposition based amorphous carbon layer above the filled buried hard mask, the top mask including a trim opening crossing the template opening and having a trim width disposed along the line axis and is smaller than the template length; and (f) etching the fill material and the interlayer via the top mask and the buried hard mask such that a process section of the pattern surface is exposed and such that a target length and width of the process section result from the template and trim widths; wherein providing the top mask comprises: disposing an amorphous carbon layer above the buried hard mask; disposing an upper sacrificial mask layer on the amorphous carbon layer; providing a second resist mask on the upper sacrificial mask layer, wherein the second resist mask comprises a resist opening that exposes a section of the upper sacrificial mask layer; removing the exposed section of the upper sacrificial mask layer, thereby exposing a section of the amorphous carbon layer; and removing the exposed section of the amorphous carbon layer, thereby providing the trim opening and the top mask via the amorphous carbon layer.