ABSTRACT
The various factors that determine the adhesional force between particles and a surface include particle size and shape, particle and substrate composition, and the choice of cleaning medium. This chapter discusses various experimental methods to measure the force of adhesion and several suggestions on conducting an evaluation of a wafer cleaning system. Particle adhesion in liquids is lower than in air by a factor of 2 to 4. This decrease in the force of adhesion is due to a multitude of factors, which include: lowering of the Hamaker constant in liquids, and presence of ionic, double-layer repulsive forces in liquids. Wafer rinsers/dryers, which are commonly used in the microelectronics industry, use a combination of hydrodynamic drag and centrifugal force to remove particles from wafers. In aerodynamic and hydrodynamic methods, a stream of air or liquid is passed over particles adhering to a solid surface.
