The Chemistry of Wet Cleaning

Aqueous-based cleaning for microelectronics fabrication is the most prevalent process step in integrated circuit manufacturing, approximately 2-3 times per masking layer. These steps are composed of one or more cleaning processes that can be used in different order to provide different results depending on the sequence and the chemicals used. This chapter provides in depth discussions of the chemistry of the primary cleaning solutions; standard clean -1 (SC-1) or ammonia hydrogen peroxide mixture (APM), SC-2 or hydrochloric acid hydrogen peroxide mixture (HPM), sulfuric acid hydrogen peroxide mixture (SPM), and hydrofluoric acid (HF); their composition and purpose. The reaction mechanism, the chemical reactions and reactivity and the sensitivity of chemical composition with respect to each of these processes are explained. The chapter discusses the specific cleaning problems: hydrogen passivation of silicon surfaces, etching rate control for critical cleans, metal-ion contamination, and surface roughening. Controlled Vocabulary Terms ammonia; cleaning; hydrogen compounds; Silicon