A dielectric cap, interconnect structure containing the same and related methods are disclosed. The inventive dielectric cap includes a multilayered dielectric material stack wherein at least one layer of the stack has good oxidation resistance, Cu diffusion and/or substantially higher mechanical stability during a post-deposition curing treatment, and including Si--N bonds at the interface of a conductive material such as, for example, Cu. The dielectric cap exhibits a high compressive stress and high modulus and is still remain compressive stress under post-deposition curing treatments for, for example: copper low k back-end-of-line (BEOL) nanoelectronic devices, leading to less film and device cracking and improved reliability.