A strategy of reducing the power consumption to cure gate dielectric damage by electrothermal annealing (ETA) is proposed. A tri-gate FinFET was fabricated to demonstrate the damage curing by the ETA. Localized Joule heat induced by high current flowing through dual gate electrodes successfully annealed the damaged gate dielectric. Furthermore, a design methodology to save power consumption during the ETA was explored. Electrical measurements and simulations were performed considering scaling-down and material engineering points of view. This work contributes to improving the reliability of the FinFET by developing the ETA approach with reduced power consumption.