Cu/low-k BEOL with nonconcurrent hybrid dielectric interface

An interconnect structure having reduced fringing fields at the bottom corners of said interconnect structure, said structure comprising:

• one or more intent levels, one on top of each other, wherein each interconnect level is separated by a diffusion barrier and includes a dielectric stack of at least one low-k interlayer dielectric on at least one hybrid dielectric, said dielectrics having planar interfaces therebetween and said at least one hybrid dielectric having a higher dielectric constant than said at least one low-k interlayer dielectric,
• each interconnect level further comprising metallic lines formed in said low-k interlayer dielectric, with the proviso that bottom horizontal portions of said metallic lines are not coincident with said interface, and said metallic lines are contained solely within said low-k interlayer dielectric,
• wherein said hybrid dielectric is comprised of a different low-k dielectric from said low-k dielectric and is selected from the group consisting of carbon-, hydrogen-, methyl- or fluorine-doped silicate glass, polyaromatic ethers, aerogels, xerogels, silicon-containing polymers, hydrocarbon polymers, parylene polymers and other dielectrics having a relative dielectric constant of less than 4.