Storage water used for storage of a silicon wafer in water is disclosed.
The storage water contains Cu at a concentration of 0.01 ppb or less. A method
of storing a silicon wafer in water is also disclosed. In the method, water containing
Cu at a concentration of 0.01 ppb or less is used. In another method, a wafer is
stored in water or a chemical solution, to which a chelating agent is added. The
storage water and the storage methods can prevent degradation of oxide dielectric
breakdown voltage which would otherwise occur due to Cu contamination from the
storage water.
