Unique freeze cleaning technology

摘要

In this work, a novel chemical-free technique is proposed to remove adsorbed particles of less than 100 nm from a substrate. More specifically, the small particles buried under the "stagnant layer" were removed using a process that relied on the force generated by volumetric expansion on rapid freezing of supercooled water. In the process, water penetrated into the small (narrow) spaces via the capillary force; it then flowed into the narrow intcrfacial gap between the substrate and particles, and lifted the particles off the substrate via the volumetric expansion force on ice formation. Because fine patterns have no such gaps, they are not damaged during this process. In other words, unlike conventional cleaning technologies, such as mega sonic cleaning and two-fluid jet cleaning, this cleaning process is able to specifically target the small particles while the fine patterns are unaffected.