ON-SITE GENERATION OF ULTRA-HIGH-PURITY BUFFERED-HF FOR SEMICONDUCTOR PROCESSING

摘要

A process for preparing ultra-high-purity buffered hydrofluoric acid on-site at a semiconductor manufacturing facility. Anhydrous ammonia is purified by scrubbing (17) in a high-pH liquor, and then combined with high-purity aqueous HF which has been purified by a similar process. The generation is monitored by a density measurement to produce an acid whose pH and buffering are accurately controlled.