The DI-CO2 is used in single substrate cleaning tools for rinsing steps to prevent ESD effects and/or corrosion by creating UPW (ultrapure water) with precisely defined conductivity. It is a compact system for tool integration, providing conductive DI-CO2 water (carbonated ultra-pure water) with closed loop controlled conductivity. The conductivity is kept at a constant value under changing flow conditions by control of the CO2concentration in the DI-CO2 water.