Abstract: This invention is a method for cleaning a semiconductor manufacturing system, which passes a highly volatile liquid agent through the system to remove the impurities and to dissolve chemicals used in the system. The cleaning agent dissolves and washes the chemicals out of the system to keep the chemicals from combining with moisture in the air and forming oxide particles. By washing with a liquid, residual gases and impurities in the system are rapidly removed from the system. After washing the system, the cleaning agent is quickly dried because the cleaning agent is highly volatile. Thereby, the system is cleaned efficiently within a short time by using this method.