In high performance integrated circuits, low dielectric constant (low-ε) materials are required as inter-level dielectric (ILD) for on-chip interconnect to provide advantages in high speed, low dynamic power dissipation and low cross-talk noise. A variety of low dielectric constant materials, which include fluorinated silicon-oxide, porous silica and porous organic materials, chemical vapor deposited and spin-on deposited (SOD) organic materials, have been developed or are under development to fulfill this need. In this paper, we first review the need and integration architecture of low-ε materials for on-chip interconnect. Then, we discuss the consequence of using low-ε materials as ILD in advanced interconnect with emphasis on the ILD electrical characteristics and the interconnect reliability. Although the focus is on several new promising SOD low-ε materials, the developed evaluation methodology is applicable to other type low-ε materials as well.