Role of Cu film texture in grain growth correlated with twin boundary formation

Abstract

To understand the role of Cu film texture in grain growth at room temperature (RT) in relation to twin boundary formation, Cu films were deposited on various barrier materials, and Cu film texture was investigated by X-ray diffraction. The Cu grain growth was rapid on the barrierless SiO 2 /Si substrate, and very slow on the Ta barrier due to strong (111) texture. The growth rate and the average grain diameter after keeping at RT up to ~60 days were maximized at the (200) Cu peak to (222) Cu peak area ratio of ~1.0, where the {111}, {100}, and {511} grains coexisted. Such coexistence of three or more orientations of grains is essential for facilitating Cu grain growth at RT. Similarly, average twin boundary (TB) density was maximized when Cu grain growth was facilitated. The TB formation in nano-sized Cu grains was not controlled by grain size, but caused by grain growth. The TBs could be annealing twins caused by irregularities in stacking sequence during relatively fast grain growth. The Cu film texture is concluded to be determined at the early beginning of deposition, and wettability of various barrier materials to the Cu films plays a key role in determining the film texture.

Copper thin films by ion beam assisted deposition: Strong texture, superior thermal stability and enhanced hardness

“…1c and g). This is, however, in contrast to the results in [52], where the texture formation in Cu is solely caused by a clean Ta interlayer and the (5 1 1) and (5 7 1 3) texture components are still presented. This contrast strongly implies that the vanishing of the two texture components in this study is caused by the preferential damage and preferential sputtering processes.…”

“…Cu thin films deposited on a clean Ta interlayer commonly show a strong (1 1 1) texture [51,52] due to the heteroepitaxial growth of hexagonal close-packed Cu (1 1 1) planes on b-Ta (0 0 2) planes with pseudohexagonal atomic arrangement [53]. However, this does not seem to be the case in the current study.…”

Failure of metals III: Fracture and fatigue of nanostructured metallic materials

“…The proposed reason is an indirect effect of the presence of Zr which favours the formation of (1 1 0) grains, leading to the coexistence of three types of orientations, i.e. (1 1 1), (1 0 0) and (1 1 0) grains, whose cooperative interplay is known to encourage grain growth [383]. Note finally that the application of low deformation rates sometimes lead to higher m values such as demonstrated in Au films [151].…”

The influence of pulse plating frequency and duty cycle on the microstructure and stress state of electroplated copper films

“…Furthermore, peak current density has also been shown to affect film orientations [23]. Cu film texture is also dependent on the deposition substrate [22,28]. Stainless steel substrates produced more evenly distributed Cu grain orientations compared to MP35N alloy substrates which resulted in preferential {111} orientations at lower PCD and {110} orientations at higher PCD [22].…”