The present invention provides a hardmask that is located on a surface of a low k dielectric material having at least one conductive feature embedded therein. The hardmask includes a lower region of a hermetic oxide material located adjacent to the low k dielectric material and an upper region comprising atoms of Si, C and H located above the hermetic oxide material. The present invention also provides a method of fabricating the inventive hardmask as well as a method to form an interconnect structure containing the same.