In this paper,a review of Cu/low-k,carbon nanotube(CNT),graphene nanoribbon(GNR)and optical based interconnect technologies has been done,Interconnect models,challenges and solutions have also been discussed.Of all the four technologies,CNT interconnects satisfy most of the challenges and they are most suited for nanometer scale technologies,despite some minor drawbacks.It is concluded that beyond 32nm technology,a paradigm shift in the interconnect material is required as Cu/low-k interconnects are approaching fundamental limits. In this paper, a review of Cu / low-k, carbon nanotube (CNT), graphene nanoribbon (GNR) and optical based interconnect technologies has been done, Interconnect models, challenges and solutions have also been discussed. Of all four technologies, CNT interconnects satisfy most of the challenges and they are most suited for nanometer scale technologies, despite both minor scales.It is concluded that beyond 32nm technology, a paradigm shift in the interconnect material is required as Cu / low-k interconnects are approaching fundamental limits .