Copper-MWCNT Composite: A Solution to Breakdown in Copper Interconnects

Abstract

In this work, Cu-MWCNT composite is recommended as a potential solution to diminish breakdown in copper interconnects caused due to self- heating. Cu-MWCNT composite is less affected by temperature variation as compared to copper interconnect by 33%. To support this deduction, lateral temperature profiles of copper and Cu-MWCNT composite are compared which shows that copper interconnect reaches a higher temperature point due to self-heating as compared to Cu-MWCNT composite interconnect. Delay in Cu-MWCNT composite interconnect turned out to be lesser than copper interconnect. Also, increase in the fraction of MWCNT in Cu-MWCNT composite ($F_{MWCNT}$) leads to decrease in delay. Cu-MWCNT composite with higher $F_{MWCNT}$ experiences lesser Noise Delay Product (NDP) among all the alternatives which makes it most advantageous in terms of signal integrity. NDP of Cu-MWCNT composite interconnects are almost constant with increase in temperature making it immune to thermal effects. MWCNT has the highest reliability in terms of breakdown power ($P_{BD}$) while 1 mm long Cu-MWCNT composite (with $F_{MWCNT}=0.6$) when compared to copper has 61% improvement in breakdown power. Cu-MWCNT composite interconnect is much better than copper interconnect specially for longer wire and higher $F_{MWCNT}$ in terms of $NDP/P_{BD}$ ratio. Our analysis recommends long Cu-MWCNT composite (with $F_{MWCNT}> 0.6$) interconnects to replace copper interconnects as a solution to increased self-heating in copper leading to its breakdown and also improvement in signal integrity aspects.