A Mathematical Model Forecasting HF Adsorption onto Cu-Coated Wafers as a Function of the Airborne Concentration and Moisture

Abstract:

In order to better understand and model the whole sorption behavior of the HF when in contact with a Cu surface inside a FOUP and thus control the related yield losses, Cu-coated wafers have been exposed to varying HF (ppbv) and H₂O (% RH) airborne concentrations. These experiments have yielded a HF-Cu sorption empirical-mathematical model that may be used as an industrial tool for queue-time or fluoride surface concentration predictions. Besides, the formation of CuF₂ only in case of corrosion is evidenced by the XPS measurements whereas the key role of the H₂O is further confirmed by the desorption experiments. The H₂O retained by the surface is actually responsible for promoting the HF adsorption/desorption onto/from Cu and enables a HF threshold concentration that separates the two well differenced uptake regimes; adsorption and corrosion.

• Periodical: Solid State Phenomena (Volume 255)
• Pages: 323-328
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.255.323
• Online since: September 2016
• Authors: Fernando Herrán*, Hervé Fontaine, Paola González-Aguirre, Carlos Beitia, Jim Ohlsen, Jorgen Lundgren
• Keywords: AMC, Cross-Contamination, Desorption, Molecular, Volatile Acids, Water

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