Patent ID: 9741613
Date: 2017-08-22
CPC Classifications: H01L

Claim:
1. A method comprising: forming a hardmask layer over a dielectric layer; forming mandrels over the hardmask layer; forming first spacers on sides of the mandrels; forming trenches by removing the mandrels and etching through the hardmask layer down into the dielectric layer; removing the first spacers; filling the trenches with a sacrificial layer; forming and etching a block mask over the hardmask and sacrificial layers to form a cut area over a portion of the trenches; forming second spacers at sides of the cut area; removing the sacrificial layer from the portion of the trenches; forming a mask in the cut area and the portion of trenches, the mask selected from a high density plasma (HDP) oxide, silicon carbide (SiC) or silicon carbon nitride (SiCNH); selectively etching the second spacers; and selectively etching the sacrificial layer and the dielectric layer to form self-aligned vias (SAVs).