Study of electron-scattering mechanism in nanoscale Cu interconnects

Abstract

This paper presents a study of electron scattering in damascene-processed Cu interconnects. To understand the leading electron-scattering mechanism responsible for the size effect, Cu interconnects with varying physical widths, 80-750 nm, were made, and their resistivity characterized as a function of temperature, ranging from liquid He temperature (4.2 K) to 500 K. The resulting data suggest that surface scattering, contrary to expectations, was not the primary cause of the size effect observed in this investigation. Surface scattering was found to weaken with decreasing line width. Further analysis leads to the conclusion that a substantial fraction of the size effect originates from impurity content scaling inversely with width in these samples.

Electrical Resistivity of Epitaxial Au Films Surface‐Modulated by Arrays of Pt Nanoparticles

“…Thus, although the thin film resistivity is enhanced by surface scattering as compared to the bulk resistivity, the above analysis provides insight into the morphology of the thin film by means of impurity/defect concentrations, which is an important issue for the design of metallic interconnects [15,18] in microelectronics. In Table 1, both parameters θ D and l imp do not vary significantly when the properties of the sample surface are changed.…”

Influence of Minimum Barrier Metal Thickness at Trenches on Void Formation in 50-nm-wide Cu Wiring

“…Therefore, the development of Cu filling process without voids is mandatory for producing very narrow Cu wiring with low resistivity and high reliability. [5][6][7][8] The dual damascene process is widely used for Cu wiring. In this process, Cu wiring is fabricated by repeatedly filling Cu in narrow trenches followed by chemical mechanical polishing (CMP).…”

Microstructures of 50-nm Cu Interconnects along the Longitudinal Direction

“…1) However, there is a significant increase in resistivity in copper interconnects when line widths are less than 100 nm. [1][2][3][4][5][6][7] This is becoming a critical issue and is mainly due to the fact that the line widths are comparable to the mean free path of an electron (39 nm), which causes an increase in resistivity by electron scattering occurring at the grain boundaries of the Cu interconnects. Therefore, it is necessary to develop a grain coarsening process to achieve low resistivity in very narrow Cu interconnects.…”