Impact of deposition-rate fluctuations on thin-film thickness and uniformity

Variations in deposition rate are superimposed on a thin-film deposition model with planetary rotation to determine the impact on film thickness. Variations in magnitude and frequency of the fluctuations relative to the speed of planetary revolution lead to thickness errors and uniformity variations up to 3%. Sufficiently rapid oscillations in the deposition rate have a negligible impact, while slow oscillations are found to be problematic, leading to changes in the nominal film thickness. Superimposing noise as a random fluctuation in the deposition rate has a negligible impact, confirming the importance of any underlying harmonic oscillations in the deposition rate or source operation.