Removal of Submicrometre Alumina Particles from Silicon Oxide Substrates

Abstract

In this paper, two techniques were used for the removal of submicrometre sized alumina particles used in post-CMP (chemical mechanical polishing) applications. Alumina particles were deposited onto a silicon oxide wafer by dipping the wafer in the CMP slurry and then spin drying them. Megasonic cleaning and brush cleaning techniques were used to remove the slurry residue. The removal efficiency of each technique (contact and non-contact) was evaluated as a function of the process parameters. The removal of particles was studied as a function of the cleaning parameters including temperature, cleaning time, and megasonic power in the case of megasonic cleaning, and brush pressure, rotational speed, and cleaning time in the case of brush cleaning. The results show that both cleaning techniques can be effective in removing slurry residue under certain conditions. Longer cleaning times and higher pressures had adverse effects on contact cleaning. Similarly, longer times and higher megasonic power had adverse effects on non-contact cleaning.