Diffusion and Solubility of Common Microelectronic Airborne Molecular Contaminants into PEI Thin Polymer Membranes and its Related Contamination Control Applications

Sorption and outgassing mechanisms of corrosive gases in relation with wafers lost yield due to polymer container Front Opening Unified Pod (FOUP), is crucial information to understand the cross contamination between FOUP and wafers. This occurs when FOUPs (made in polymers) outgas contaminants into the wafer surrounding minienvironment. Gas sorption is governed by surface adsorption, followed by diffusion and solubility and then, permeability appears as a key parameter to understanding these cross contamination phenomena. In this work, we present the transport coefficients obtained for gaseous HF and HCl at cleanroom conditions (Patm, 21 ± 2°C & 40% RH) at two different HX concentrations using the sorption kinetic method, based on Fick’s law, for thin films (≈50μm) of PEI. Finally, we establish the relationship between the sorption parameters of a polymer thin film and the potential contamination transfer from a FOUP whose main polymer material is similar.