STRUCTURE TO IMPROVE ADHESION BETWEEN TOP CVD LOW-K DIELECTRIC AND DIELECTRIC CAPPING LAYER

An interconnect structure in which the adhesion between an upper level low-k dielectric material, such as a material comprising elements of Si, C, O, and H, and an underlying diffusion capping dielectric, such as a material comprising elements of C, Si, N and H, is improved by incorporating an adhesion transition layer between the two dielectric layers. The presence of the adhesion transition layer between the upper level low-k dielectric and the diffusion barrier capping dielectric can reduce the chance of delamination of the interconnect structure during the packaging process. The adhesion transition layer provided herein includes a lower SiOx- or SiON-containing region and an upper C graded region. Methods of forming such a structure, in particularly the adhesion transition layer, are also provided.