When an interconnect structure is built on porous ultra low k (ULK) material, the bottom of the trench and/or via is usually damaged by a following metallization process which may be suitable for dense higher dielectric materials. Embodiment of the present invention may provide a method of forming an interconnect structure on an inter-layer dielectric (ILD) material. The method includes steps of treating an exposed area of said ILD material to create a densified area, and metallizing said densified area.