Local distribution of particles deposited on patterned surfaces

In many process steps of integrated circuits (IC’s) fabrication, silicon wafers are coming in contact with process liquids such as ultra pure water (UPW) and aqueous and non-aqueous chemical mixtures. During these process steps, liquid-borne particle contamination can deposit on the wafer surface. Particle contamination from UPW is an important factor influencing random yield loss of IC’s [1]. A number of yield models are used to predict yields including Poisson, Murphy, Seeds, and negative binomial models [2,3]. However, these models are based on the assumption that particles are randomly deposited on the wafer surface [4].