Removal of Submicrometer Particles from Silicon Wafer Surfaces Using HF-Based Cleaning Mixtures

Abstract

We have studied the particle removal efficiency of HF-based cleaning mixtures used to clean wafer surfaces during semiconductor manufacturing. and metallic oxide particles can be easily removed from silicon wafers using a HF-based clean, whereas the removal of metallic particles and especially Si and polymeric particles is much more difficult. This is explained in terms of surface hydrophobicity effects. For thermal oxide wafer substrates, a low removal efficiency is observed for the positively charged and particles. This has been explained previously by redeposition of the particles from the carry-over layer during the final rinse [R. Vos, I. Cornelissen, M. Meuris, P. Mertens, and M. Heyns, in Cleaning Technology in Semiconductor Device Manufacturing VI, J. Ruzyllo, T. Hattori, and R. E. Novak, Editors, PV 99-36, p. 461, The Electrochemical Society Proceedings Series, Pennington, NJ (1999)]. Surfactants are found to increase the removal of Si and polymeric particles from silicon substrates. This is attributed to the elimination of hydrophobic attraction forces. In addition, the surfactant is also successful in preventing the particles from redepositing during the final rinse treatment, because during the rinse, both the particle and the substrate have the same surface charge. © 2001 The Electrochemical Society. All rights reserved.