The present invention comprises an interconnect structure including a metal, interlayer dielectric and a ceramic diffusion barrier formed therebetween, where the ceramic diffusion barrier has a composition SivNwCxOyHz, where 0.1≦v≦0.9, 0≦w≦0.5, 0.01≦x≦0.9, 0≦y≦0.7, 0.01≦z≦0.8 for v+w+x+y+z=1. The ceramic diffusion barrier acts as a diffusion barrier to metals, i.e., copper. The present invention also comprises a method for forming the inventive ceramic diffusion barrier including the steps depositing a polymeric preceramic having a composition SivNwCxOyHz, where 0.1<v<0.8, 0<w<0.8, 0.05<x<0.8, 0<y<0.3, 0.05<z<0.8 for v+w+x+y+z=1 and then converting the polymeric preceramic layer into a ceramic diffusion barrier by thermal methods.