Influence of CO2 Gas Atmosphere on the Liquid Filling of Superhydrophobic Nanostructures

Abstract

The introduction of 3-D nanostructures in semiconductor manufacturing may create wetting issues in aqueous processing. In this work we evaluated the use of a CO2 gas atmosphere to promote the wetting of superhydrophobic nanopillars, relying on the high solubility of CO2 in aqueous solutions. The patterned surface was first flushed with CO2 gas, before dispensing the aqueous solution that was saturated with N2 and switching the gas flow from CO2 to N2. The liquid penetration was characterized by monitoring the disappearance of CO2 gas using ATR-FTIR. Results showed only a modest improvement in wetting, presumably due to a fast N2-CO2 gas exchange at the wetting front.