Patent ID: 8796150

Claim:
A method for forming a trench pattern in a structure, comprising: forming a dielectric hardmask layer over a dielectric substrate, said dielectric substrate comprising a stack of, from bottom to top, a patterned dielectric substrate layer and a dielectric layer; forming a metal hardmask layer over the dielectric hardmask layer; forming a capping hardmask layer over the metal hardmask layer, wherein a stress in the capping hardmask layer is configured to counter balance a stress in the metal hardmask layer; forming at least one organic layer over the capping hardmask layer; forming an initial trench pattern through the at least one organic layer, the capping hardmask layer, and the metal hardmask layer and into the dielectric hardmask layer; removing the at least one organic layer; and extending the initial trench pattern into the dielectric layer of the dielectric substrate to form a trench pattern, wherein the capping hardmask layer is present during an initial stage of said forming the trench pattern to protect the metal hardmask layer from erosion.