Evolution of strain energy during recrystallization of plated Cu films

Murray, Conal E.; Rosenberg, R.; Witt, C.; Treger, Mikhail; Noyan, I. C.

doi:10.1063/1.4807409

Cited by 6 publications

(3 citation statements)

References 17 publications

(21 reference statements)

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“…This may be ascribed to the templating process which yields an initially untextured plated Cu layer on the seed, which then recrystallizes rapidly during plating to minimize grain boundary and surface energy terms in the presence of a residual stress field. This forms mildly textured plated films by the end of the plating process [24]. In contrast, the first few Cu layers forming on textured seed are already highly 111 textured.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, the first few Cu layers forming on textured seed are already highly 111 textured. As the film grows thicker, minimization of strain energy causes the formation of some 001 type grains, causing the (thicker) films to have (relatively) lower values [24]. Since, for both types of films, the 50% recrystallization time,  50 , shows a similar dependency on electroplated film thickness (Figure 9-b), the texture data is critical in identifying the mechanisms responsible for room temperature recrystallization.…”

Section: Discussionmentioning

confidence: 99%

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Prediction of recrystallization times in electroplated copper thin films

Treger

Witt

Cabral³

et al. 2016

Thin Solid Films

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Room temperature recrystallization responses of blanket electroplated Cu thin films deposited under various conditions were monitored in real-time using synchrotron x-ray diffraction.Nominal control of electroplating parameters such as plating current, bath chemistry, and plating time was found to be insufficient to ensure repeatability of the 50% recrystallization time,, from sample to sample even though the thickness variations between samples were insignificant. Real-time x-ray analysis of samples from numerous electroplating baths showed that, for a given seed deposition process, a reliable estimation of at room temperature can be obtained from the ratio of the integrated intensities of the 111 and 200 Cu reflections, I ̅ / I ̅ , of the electroplated film at time zero (immediately after plating). Among the plating parameters investigated seed-layer texture most influenced this ratio and, hence, the subsequent room temperature recrystallization behavior of the plated film.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Prediction of recrystallization times in electroplated copper thin films

Treger

Witt

Cabral³

et al. 2016

Thin Solid Films

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“…Typically in blanket films, the 111 direction of copper aligns normal to film surface; this texture development has been attributed to the minimization of Cu surface energy. 16,17 For trench-initiated subsurface grains, however, the surface energy seems an unlikely driving force; here, the energy of the Cu-Ta interface has a stronger influence. Minimization of the Cu-Ta interfacial energy has been hypothesized to cause 111 texture normal to the trench sidewall.…”

mentioning

confidence: 99%

Rapid trench initiated recrystallization and stagnation in narrow Cu interconnect lines

O'Brien

Rizzolo

Prestowitz

et al. 2015

Applied Physics Letters

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Understanding and ultimately controlling the self-annealing of Cu in narrow interconnect lines has remained a top priority in order to continue down-scaling of back-end of the line interconnects. Recently, it was hypothesized that a bottom-up microstructural transformation process in narrow interconnect features competes with the surface-initiated overburden transformation. Here, a set of transmission electron microscopy images which captures the grain coarsening process in 48 nm lines in a time resolved manner is presented, supporting such a process. Grain size measurements taken from these images have demonstrated that the Cu microstructural transformation in 48 nm interconnect lines stagnates after only 1.5 h at room temperature. This stubborn metastable structure remains stagnant, even after aggressive elevated temperature anneals, suggesting that a limited internal energy source such as dislocation content is driving the transformation. As indicated by the extremely low defect density found in 48 nm trenches, a rapid recrystallization process driven by annihilation of defects in the trenches appears to give way to a metastable microstructure in the trenches.

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