Cleaning performance of the nitrogen purge process when a Front Opening Unified Pod (FOUP) is contaminated by Hydrogen Fluoride(HF) and Volatile Organic Compound (VOC)

摘要

Front Opening Unified Pod (FOUP), a wafer carrier, is used for storage and transportation of wafers to prevent contamination from external exposure. FOUP is generally used for large size wafers, such as in 300-mm-wafer manufacturing processes. Also, the air inside of the FOUP may be contaminated by the gases from the manufacturing process or by the compounds emitted from the wafers that are stored in the FOUP. The airborne molecular contaminations (AMCs) are a common cause of certain defects and pattern failures of the chip manufacturing. A useful method for reducing these yield-affecting influences is purging the FOUP surface with nitrogen gas. Hydrogen Fluoride (HF) and Volatile Organic Compound (VOC) are by far the AMC found most often due to its presence in process chemicals. The purging procedure of the contaminated FOUP was examined by a continuous measurement of HF and VOC in the purging gas flow. This study aims to evaluate the contamination and purging the FOUP by monitoring concentrations of HF and VOC. by Cavity Ring-Down Spectroscopy (CRDS) and photoionization detector (PID) monitoring system, respectively. The result shows that the concentrations of HF and VOC influence the air directly in the FOUP.