Patent ID: 6831013
Filing Date: 2004-12-14
Classification: H01L

Abstract:
a method of forming a dual damascene via, said method comprises:providing a wafer, wherein said wafer comprises a first metal layer; forming a cap layer on said first metal layer; forming a first dielectric constant dielectric layer on said cap layer; forming a middle etching stop layer on said first dielectric constant dielectric layer; forming a second dielectric constant dielectric layer on said middle etching stop layer; forming a dielectric hard mask layer on said second dielectric constant dielectric layer; forming a second metal layer on said dielectric hard mask layer; removing a part of said second metal layer to form a metal hard mask layer on said dielectric hard mask layer; forming a photo mask layer on said second metal layer and said dielectric hard mask layer; removing a part of said dielectric hard mask layer and a part of said second dielectric constant dielectric layer to form a first trench in said dielectric hard mask layer and said second dielectric constant dielectric layer; removing said photo mask layer; removing said middle etching stop layer which is at a bottom of said first trench and said dielectric hard mask layer; removing a part of said second dielectric constant dielectric layer to form a second trench in said second dielectric constant dielectric layer and removing a part of said first dielectric constant dielectric layer to form a third trench in said first dielectric constant dielectric layer, wherein said second trench and said third are connected with each other; removing said cap layer which is at a bottom of said third trench and removing said middle etching stop layer which is at a partial bottom of said second trench; forming a third metal layer on said second metal layer and in said second trench and said third trench and filling of said second trench and said third trench; and removing a part of said third metal layer to expose said second metal layer and making a surface of said third metal layer and said metal layer become a planar surface.