Analysis of Resistivity Increase in Copper Nanoscale Interconnects Utilizing Monte Carlo Simulation and Optimum Wiring Structure to Suppress Resistivity Increase

Abstract

The present work investigated the behavior of resistivity increase in Cu interconnects utilizing Monte Carlo simulation. We developed efficient Monte Carlo method to estimate the size effect on resistivity in nanoscale interconnects structure. In the dimension where line width and film thickness becomes a dimension comparable to the electron mean free path, the multiple interface scattering occurred around the corners of interconnects and it became a dominant factor for the resistivity increase. In terms of interface scattering, controlling Line Edge Roughness (LER) and Line Width Roughness (LWR) is important to suppress the resistivity increase. It is preferable that LER wavelength is longer than electron mean free path and subsequently LWR is minimalized. In terms of grain boundary scattering, enhancing the average grain size is an effective method to suppress the resistivity increase.