Impacts of the moisture uptake into the damage layer of porous SiOCH low-k film on line capacitance and leakage current were investigated in the 80nm-pitch triple layer interconnect structure. The damage layer thickness was controlled from zero to 8nm by the RIE, wet process and Cu surface treatment. The damage layer thickness is defined by TEM-EELS analysis. The line capacitance and leakage current were increased by moisture uptake. The dielectric constant of damage layer including moisture was estimated 7.6 by the capacitance simulation. The moisture control of the damage layer in porous SiOCH low-k film is very important to reduce the line capacitance and improve the line leakage current as well as damage layer elimination. ©The Electrochemical Society.