Patent ID: 6780277
Filing Date: 2004-08-24
Classification: H01L

Abstract:
An etching apparatus comprising:a process bath for accommodating an object to be processed therein and storing an etching liquid for etching the object; a drain system for draining the etching liquid in the process bath, the drain system being capable of adopting a draining state in which the drain system is draining the etching liquid without returning the drained etching liquid into the process bath again and a non-draining state in which the drain system stops draining the etching liquid; a supply system for supplying a new etching liquid into the process bath, the supply system being capable of adopting a supplying state in which the supply system is supplying the etching liquid and a non-supplying state in which the supply system stops supplying the new etching liquid; and control means for controlling an operation of the drain system to drain a designated amount of the etching liquid in the process bath without returning the drained etching liquid into the process bath again, when the concentration of a specified substance contained in the etching liquid in the process bath reaches a designated value, while leaving the remaining amount of the etching liquid, and for controlling an operation of the supply system to supply the new etching liquid into the process bath, thereby making a mixture of the new etching liquid and the used etching liquid left in the process bath.