Abstract: The present invention reduces adhesion of trace metals in ultrapure water for cleaning products, and inhibits the metal contamination of an object to be cleaned. Provided is a metal contamination inhibitor that contains a polymer having an ion-exchange group, such as a polystyrene sulfonate having a molecular weight of at least 100,000. Trace metals in ultrapure water are adsorbed through an ion-exchange reaction of the polymer having the ion-exchange group, and can thus be inhibited from adhering to products. Also provided is a method for cleaning a product with ultrapure water to which the metal contamination inhibitor has been added. Preferably, the ultrapure water to which the metal contamination inhibitor has been added flows through a separation membrane module, and the products are cleaned with permeated water.

Abstract: The present invention reduces adhesion of trace metals in ultrapure water for cleaning products, and inhibits the metal contamination of an object to be cleaned. Provided is a metal contamination inhibitor that contains a polymer having an ion-exchange group, such as a polystyrene sulfonate having a molecular weight of at least 100,000. Trace metals in ultrapure water are adsorbed through an ion-exchange reaction of the polymer having the ion-exchange group, and can thus be inhibited from adhering to products. Also provided is a method for cleaning a product with ultrapure water to which the metal contamination inhibitor has been added. Preferably, the ultrapure water to which the metal contamination inhibitor has been added flows through a separation membrane module, and the products are cleaned with permeated water.

Abstract: The invention provides a wafer washing technique which does not require complicated operations and by which a wafer is washed with ultrapure water through relatively simple operations without contaminating the wafer surface with metals even if the ultrapure water contains metal ions on the ng/L (ppt) level. Wafer washing water includes ultrapure water to which a substance having an affinity for metal ions has been added. A wafer washing method uses this wafer washing water. A substance that exhibits an affinity for metal ions is added beforehand to wafer washing ultrapure water. As a result, the substance captures metal ions present in the ultrapure water and stabilizes them in water, thereby effectively preventing the metal ions from migrating toward the wafer surface and becoming attached to the wafer surface during washing.