Conductivity control of water content in solvent strip baths

摘要

A system and method for control of water content in a strip bath. The method to control water content in a solvent bath used for cleaning of semiconductor parts in the back end of semiconductor manufacturing requires addition of water to replace evaporated water. This is done by periodically adjusting a conductivity setpoint at least in part based on the elapsed chemical bathlife and at least in part based on the number of semiconductor parts that have been processed in the bath. The conductivity of the strip bath solution is then continuously measured (as by using an electrodeless conductivity probe). Water is added (as by a DI water injection system) into the bath solution whenever the solvent conductivity falls below the conductivity set point.