Reticle haze control: global update and technology roadmap

Adsorption and desorption kinetics of airborne ammonia on chromium-coated wafer in cleanroom depending on humidity and NH3 concentration

“…As a corrosive and reactive agent, undesired outgassing of residual NH3 gas (type of basic AMCs) results in many severe defects on integrated circuits by forming crystal salts (haze on photomask), T-topping defects in resist development or metal layers corrosion. Indeed, a significant yield loss was observed when the wafers are exposed to NH3 airborne even at low concentration (hundreds of part-per-billion ppbv) [6][7][8]. Therefore, it is highly required the control of NH3 outgassing and its cross contamination emerging from cleanroom environments, minienvironment of process tools, and wafer containers to ensure the high quality and high performance of final products.…”