Abstract: A purification method for an aqueous hydrogen peroxide solution, includes passing the aqueous hydrogen peroxide solution through a first H-form strong cation exchange resin column 1, a salt-form strong anion exchange resin column 2 and a second H-form strong cation exchange resin column 3. An H-form strong cation exchange resin having crosslinking of 6% or less, an H-form strong cation exchange resin having crosslinking of 9% or more, or an H-form strong cation exchange resin produced by steps (a) and (b) is used as an H-form strong cation exchange resin packed in the second H-form strong cation exchange resin column 3: (a) copolymerizing a monovinyl aromatic monomer with a crosslinkable aromatic monomer having a non-polymerizable impurity content of 3% by weight or less therein using a predetermined amount of a specified radical polymerization initiator at a predetermined polymerization temperature to obtain a crosslinked copolymer; and (b) sulfonating the crosslinked copolymer.

Abstract: A purification method for an aqueous hydrogen peroxide solution, includes passing the aqueous hydrogen peroxide solution through a first H-form strong cation exchange resin column 1, a salt-form strong anion exchange resin column 2 and a second H-form strong cation exchange resin column 3. An H-form strong cation exchange resin having crosslinking of 6% or less, an H-form strong cation exchange resin having crosslinking of 9% or more, or an H-form strong cation exchange resin produced by steps (a) and (b) is used as an H-form strong cation exchange resin packed in the second H-form strong cation exchange resin column 3: (a) copolymerizing a monovinyl aromatic monomer with a crosslinkable aromatic monomer having a non-polymerizable impurity content of 3% by weight or less therein using a predetermined amount of a specified radical polymerization initiator at a predetermined polymerization temperature to obtain a crosslinked copolymer; and (b) sulfonating the crosslinked copolymer.

Abstract: A silicon wafer after being cleaned by using a cleaning liquid is rinsed by using carbonic water. According to such a silicon wafer cleaning method, generation of static due to a rinsing treatment is not caused, so that an electrostatic breakdown is not caused, adhesion of dirt to a cleaned silicon wafer surface due to the static is not caused, adhesion of metal impurities can be prevented in the rinsing treatment of the silicon wafer and, while giving consideration to the cost, furthermore, a rinsing treatment using a clean rinsing liquid free from causing any residue can be performed.

Abstract: A silicon wafer after being cleaned by using a cleaning liquid is rinsed by using carbonic water. According to such a silicon wafer cleaning method, generation of static due to a rinsing treatment is not caused, so that an electrostatic breakdown is not caused, adhesion of dirt to a cleaned silicon wafer surface due to the static is not caused, adhesion of metal impurities can be prevented in the rinsing treatment of the silicon wafer and, while giving consideration to the cost, furthermore, a rinsing treatment using a clean rinsing liquid free from causing any residue can be performed.