Alternating hardmasks for tight-pitch line formation

An integrated circuit manufacturing process comprising:

• providing a substrate having thereon a plurality of layers comprising dielectric layers or other layers suitable for a hardmask;
• forming a seed layer on the plurality of layers;
• forming a protection layer on the seed layer;
• forming a plurality of mandrels on or above the protection layer;
• forming a sidewall-spacer-forming layer over the mandrels;
• anisotropically etching the sidewall-spacer-forming layer to form sidewall spacers on the mandrels;
• removing the mandrels, thereby forming a set of first hardmask fins and a first hardmask fin pattern;
• etching to expose (i) opposing sidewalls of the seed layer and (ii) opposing sidewalls and an upper surface of the protection layer;
• removing the protection layer to form a second set of fins in the first hardmask fin pattern, wherein uppermost layers of the second set of fins comprise the seed layer;
• using a directed self-assembly process to form a two-color fin pattern of alternating colors, wherein the two-color fin pattern of alternating colors comprises alternating fins of fourth and fifth colors, and wherein a pattern formed by every other fourth-color fin corresponds to the first hardmask fin pattern;
• and
• etching, including selectively etching the fins of the fifth color, to form a second hardmask fin pattern, wherein the second hardmask fin pattern comprises fins, and wherein alternating fins have different uppermost material layers.