Patent ID: 6878303

Claim:
A substrate processing apparatus for supplying a treatment liquid onto a surface of a substrate to treat the same, comprising: a spin chuck for holding and rotating the substrate; a nozzle for supplying a treatment liquid to the substrate held by the spin chuck; a circulating passage arranged such that the treatment liquid supplied to the substrate from the nozzle and used for substrate treatment is circulated to the nozzle and reutilized for substrate treatment, the circulating passage including a treatment liquid tank which stores the treatment liquid, a treatment liquid supply passage through which the treatment liquid is supplied from the treatment liquid tank to the substrate, and a treatment liquid collecting passage through which the treatment liquid after the substrate treatment is returned to the treatment liquid tank; a metal contamination amount measuring device for measuring a metal contamination amount in the treatment liquid which circulates in the circulating passage and is arranged for sampling said treatment liquid at a part of the circulating passage from the treatment liquid tank through the nozzle; and a judgment processing unit for judging whether or not a value measured by the metal contamination amount measuring device has exceeded a predetermined set value.