Patent ID: 8822331

Claim:
A method for forming an anchored damascene structure comprising the steps of: providing a material layer having a conductive region on top; forming a dielectric layer on top of said conductive region, said dielectric layer comprises at least two relatively higher density portions and a relatively lower density portion, said relatively lower density portion sandwiched between said at least two relatively higher density portions, said lower density portion forming a contiguous major portion of the dielectric layer, said lower density potion without an intervening etch stop layer; forming an opening in and through a thickness of said dielectric layer; following forming said opening, enlarging a lateral dimension of said opening in the lower density portion in a single etch step to produce an enlarged opening along an entirety of said thickness having said lateral dimension larger than the opening in said at least two relatively higher density portions thereby forming at least one anchoring step, said lateral dimension comprising a second lateral dimension extending laterally on either side of the opening at an interface with each of the relatively higher density portions; filling said opening with a conductive material; and, forming said conductive material to have an uppermost portion substantially co-planar with a respective uppermost portion of said dielectric layer.