Effects of Diluted-NH4OH as Conductive Rinse Water in Single Wafer Cleaning Processes

We propose diluted-NH4OH to use as a rinse water combined with or instead of CO2-dissolved water (CO2 water) for preventing electrostatic charge in wet cleaning of semiconductor manufacturing processes. We have developed a novel diluted-NH4OH generator featuring a tube injection which enables precise dilution of concentrated NH4OH reagent directly, and confirmed the effect of preventing electrostatic charge on wafer surfaces by diluted-NH4OH. And we have also evaluated the inhibition of copper corrosion on Si wafer by diluted-NH4OH in comparison with CO2 water and deionized water (DI water), and found that diluted-NH4OH is the best rinse water among these three, by which the static charge is prevented and also the corrosion of copper is inhibited especially when the concentration of NH3 in diluted-NH4OH is controlled to be precisely to have the conductivity range of 10 to 20 μS/cm.