Structural analysis of TaWN ternary alloy film applicable to Cu orientation control

Abstract

We examine a structure/texture of a thin TaWN film applicable to the Cu(111) orientation by using automated crystal orientation mapping in transmission electron microscopy. The 5 nm thick TaWN film with an fcc-TaN structure shows (111) orientation in spite of being extremely thin. This orientation of the TaWN film results in highly-oriented growth of Cu (111), and also contributes to the increase in Cu grain size. Such structural features have useful that effectively prevent an increase in the resistance of the Cu interconnect.

Fundamental evaluation of orientation and grain size of Cu film in Cu/TaWN/SiO2/Si system

“…On the other hand, we proposed TaWN alloy films with the above two functions in our previous study, 14) and we demonstrated that the 5 nm thick TaWN alloy film is an excellent barrier in the Cu/ TaWN/Si system, which effectively suppresses Cu diffusion. [14][15][16] Furthermore, we demonstrated that a Cu film with a high orientation of Cu(111) on the TaWN/Si system can be obtained using only a 5 nm thick TaWN alloy film without the need for an underlying material for Cu orientation. 16) In ADMETA2022, we reported formation of the Cu film with Cu(111) orientation on the TaWN/SiO 2 /Si system using X-ray diffraction (XRD) and ω-rocking curve measurements.…”

“…[14][15][16] Furthermore, we demonstrated that a Cu film with a high orientation of Cu(111) on the TaWN/Si system can be obtained using only a 5 nm thick TaWN alloy film without the need for an underlying material for Cu orientation. 16) In ADMETA2022, we reported formation of the Cu film with Cu(111) orientation on the TaWN/SiO 2 /Si system using X-ray diffraction (XRD) and ω-rocking curve measurements. 17) In this study, we investigate whether highly-(111) oriented and large-grained Cu films can be obtained on the TaWN/SiO 2 /Si system using a 5 nm thick TaWN alloy film.…”

“…18) Considering this peak shift, it seems that the TaWN alloy lattice expands. While the Cu(200) diffraction peak was observed for the asdeposited Cu/TaWN/Si system, 16) no peak of the Cu(200) plane was observed for the as-deposited Cu/TaWN/SiO 2 /Si system. Moreover, as evident from Figs.…”

“…Notably, the sputtering conditions and film thickness of the TaWN alloy film and Cu film were the same as the sputtering conditions and film thickness in our previous study. 14,16) Some of the specimens were annealed at various temperatures for 1 h under a vacuum of 10 −7 Torr. The heating and cooling rates of the vacuum annealing equipment were both set to 10 °C min −1 .…”