METHOD OF IMPROVING LIFETIME OF ETCHING LIQUID AND YIELD IN CU-INTERCONNECTION PROCESS AND CU-INTERCONNECTION ETCHING DEVICE

摘要

A Cu-interconnection etching device includes an etching liquid tank containing therein an etching liquid that is a hydrogen peroxide based solution, a first concentration monitoring device receiving the etching liquid from the etching liquid tank and measuring a copper ion concentration of the etching liquid. The etching liquid is supplied through a filter assembly that filters off copper ions contained in the etching liquid so as to provide a filtered etching liquid. The filter etching liquid is supplied through a second concentration monitoring device that measures a copper ion concentration of the filtered etching liquid and conducts the filtered etching liquid back to the etching liquid tank. A variation between the measurements of the first and second concentration monitoring devices is used to control the operation of the filter assembly in order to maintain a proper level of copper ion concentration in the etching liquid.