Dual damascene integration of ultra low dielectric constant porous materials

A dual damascene interconnect structure having a patterned multilayer of spun-on dielectrics on a substrate is provided. The structure includes: a patterned multilayer of spun-on dielectrics on a substrate, including: a cap layer; a first non-porous via level low-k dielectric layer having thereon metal via conductors with a bottom portion and sidewalls; an etch stop layer; a first porous line level low-k dielectric layer having thereon metal line conductors with a bottom portion and sidewalls; a polish stop layer over the first porous line level low-k dielectric; a second thin non-porous via level low-k dielectric layer for coating and planarizing the line and via sidewalls; and a liner material between the metal via and line conductors and the dielectric layers. Also provided is a method of forming the dual damascene interconnect structure.