Resistivity-microstructure correlation of self-annealed electrodeposited copper thin films

The microstructure evolution of electrodeposited copper thin films was studied at room temperature where self-annealing occurs with a transition from a nano to micrograin structures. The effect of deposition current density on the self-annealing rate of 1 μm-thick films was characterized by resistivity and in situ electron backscatter diffraction (EBSD). The progress of self-annealing at the film surface was captured during the first 10 h after deposition. The recrystallized grains appeared to have relatively high image quality, high twin density and low local orientation spread. The correlation between resistivity, image quality, grain average image quality and local orientation spread during self-annealing was investigated. A grain size threshold was used as a criterion to assess the fraction recrystallized of the microstructure as a function of time after deposition. The fractions recrystallized from resistivity and EBSD for films deposited at 30 and 40 mA/cm2 current densities were then compared. The self-annealing rate estimated from EBSD is in reasonable agreement with the rate of resistivity drop.

Figure optionsDownload as PowerPoint slideHighlights
► We studied self-annealing in copper thin films using resistivity and in situ EBSD.
► Recrystallized grains have high image quality and low local orientation spread.
► There is reasonable correlation between resistivity and microstructure.
► Recrystallization initiates near the substrate then proceeds towards film surface.