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; SC-1 (APM), SC-2 (HPM), SPM, and 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.
Keywords: wet cleaning, photoresist stripping, critical cleaning, SC-1, APM, SC-2, HPM, SPM, Piranha, reaction mechanism, concentration control
2.1 Introduction to Aqueous Cleaning
The majority of cleaning in a microelectronics fabrication area is performed with liquids, primarily water, the most abundant molecule on the earth. On average wet cleaning and surface conditioning are used 2–3 times per masking layer. Other liquids are used for cleaning, but water surpasses all others. Chemicals, both gases and liquids, can be mixed into the water, or water added to dilute chemicals. This Chapter covers the chemistry of aqueous-based cleaning solutions. Chapter 3 ...