摘要 |
A first pump collects used slurry which is employed for a CMP technique. A new slurry supply device supplies new slurry having a concentration higher than a concentration of the used slurry, to the used slurry. A sensor measures a concentration of recycled slurry produced by mixing the used slurry with the new slurry. The new slurry supply device stops supplying the new slurry, in a case where the concentration which the sensor measures is equal to or above a predetermined value. A second pump supplies recycled slurry onto a polishing stage, after the used slurry is completely recycled.
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