This study examines the problem of an ultrasonic cleaner being unable to effectively remove 1 um diameter particles. Used regularly in the semiconductor industry ultrasonic cleaning is an important important process step in the cleaning of contaminated wafers by immersing them in a solvent bath. The study focuses on understanding the net forces applied to the contaminant particles by acoustic waves. This is a difficult analytical problem and the study treats the ultrasonic cleaning operation as a ‘general fluid-structure interaction’ problem and solving the governing equations numerically. This is, in the author’s experience, a first of its application of ‘numerical fluid-structure interaction techniques’ to ultrasonic cleaning.
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