Abstract: A wafer fabrication monitoring/control system and method is disclosed. The invention utilizes Multiple Internal Reflection Infrared Detection (MIR-IR) to provide a highly sensitive (sub-10 nm, in-situ, ex-situ) on-wafer monitoring and characterization apparatus and method. The disclosed system and method has many practical applications to the development of advanced microfabrication technologies for sub-32 nm node CMOS semiconductor devices and provides support for formulation design, photolithographic patterning, etching/ashing of photoresists, plasma reactive ion etching (RIE) for trench/via patterning of low k dielectric, bottom anti-reflective coatings (BARCs), etch stop layers, and minimization/removal of plasma-etch polymers, development/confirmation of wet cleaning formulations and effectiveness for post CMP and post-etch cleaning.