Scheme for bath chemistry measurement and control for improved semiconductor wet processing

摘要

A feedback control system for providing automated and in-situ control of multi-component chemical concentrations in a liquid bath used for semiconductor processing. A sample from the liquid bath is injected into a carrier stream and routed to a conductivity detector and to an amperometric detector. Hydrogen peroxide concentration levels, as well as acidic or basic component concentration levels, are monitored and the measured readings are sent to a processor. If the concentration levels are not within tolerance for a given process, the processor meters in an appropriate amount of a needed chemical or diluting agent in order to bring the bath to an appropriate chemical concentration level. Additional detectors are employed in order to provide other types of analyses of the chemicals or contaminants present in the liquid bath and the amperometric detection need not be necessarily limited to H.sub.2 O.sub.2.