Patent ID: 6938626

Claim:
An apparatus for wet-cleaning a substrate through the process of storing a cleaning solution prepared by dissolving active components in water in a cleaning bath provided in a cleaning draft, and then immersing substrates to be cleaned in said cleaning solution for cleaning while allowing clean air to flow into the cleaning draft, the apparatus for wet-cleaning a substrate comprising: a clean air supplier for supplying the clean air into the cleaning draft toward the level of the cleaning solution in the cleaning bath downwards vertically; a humidifier for supplying steam or mist-like water drops into the cleaning draft to maintain the relative humidity of the clean air in the cleaning draft at a value within a predetermined range; a hygrometer placed in the neighborhood of the level of the cleaning solution in the cleaning bath and connected to the humidifier; an exhaust piping for allowing exhaust of air of the cleaning draft; and an exhaust rate control means provided on said exhaust piping; wherein an amount of steam or mist-like water drops supplied from the humidifier is controlled within a predetermined range by feed-back of a humidity value measured by the hygrometer to the humidifier; and air in the cleaning draft is exhausted at the rate in a predetermined range by said exhaust rate control means.