Understanding of wet and alternative particle removal processes in microelectronics: theoretical capabilities and limitations

Abstract

A 2 orders of magnitude range of van der Waals interactions is considered here to take the majority of the variety of shapes and materials of actual particles into account. Comparing these interactions with the repulsive forces generated by electrostatic charges, drag, surface tension, shock waves, high accelerations and aerosol particles, the intrinsic capabilities and limitations of the different cleaning processes can be predicted. Three kinds of particle-removal processes have been identified -- universal processes capable of removing all particle sizes and types, even from patterned wafers, processes that present the same theoretical ability but are actually limited by the accessibility of the particles, and finally cleanings that are not able to remove all particle sizes.