Acoustic bubble array-induced jet flow for cleaning particulate contaminants on semiconductor wafers

Abstract

The demand for semiconductors and the necessity of developing the next-generation semiconductor haveskyrocketed with recent technological advancements, such as next-generation mobile networks, cloud computing, theInternet of Things, and artificial intelligence. Accordingly, a new type of semiconductor cleaning technique that canminimize environmental impact and physical harm to the exceedingly thin structures in semiconductor chips must bedeveloped. This work proposes a cleaning strategy for particle contamination on semiconductor wafer surfaces by utilizingjet flow created by bubble oscillation constrained in arrays of microcylinders. The variation in the maximum jetflow velocity caused by single bubble oscillation constrained in a microcylinder, which is affected by physical factors,such as applied voltage, frequency, and microcylinder dimensions, has been investigated. A wafer cleaning apparatusthat comprised 9×9 arrays of microcylinders was designed based on experimental data on single bubble oscillationconstrained in a microcylinder. The maximum jet flow velocity for the multi-arrays of microcylinders can be attainedup to 148.5mm/s, which is nearly five times the maximum value obtained from a single cylinder, even with a lowervoltage applied than with a single microcylinder. The wafer cleaning apparatus removes particulates with different wettabilitiesand sizes from contaminated semiconductor wafers successfully with a high cleaning efficiency of up to 92.5%. The current effort makes an important contribution to the development of semiconductor cleaning techniques that canmeet the requirements of current and next-generation semiconductor manufacturing in terms of yield, stability, andenvironmental pollution.