Method of cleaning substrate holder

A method of cleaning a substrate holder comprising:

• suspending a substrate holder in a substrate holder cleaning bath, the substrate holder holding a dummy substrate with a sealing member sealing a peripheral portion of the dummy substrate;
• and
• supplying a cleaning liquid into the substrate holder cleaning bath until the substrate holder is immersed in the cleaning liquid to clean the substrate holder,
• wherein different types of cleaning liquids are individually and sequentially supplied into the substrate holder cleaning bath to clean the substrate holder sequentially with the cleaning liquids, and
• wherein the cleaning liquids comprise a first cleaning liquid containing a mixture of sulfuric acid and hydrogen peroxide solution, a second cleaning liquid containing an aqueous solution of sodium hydroxide, and a third cleaning liquid containing methanesulfonic acid, and
• said supplying a cleaning liquid into the substrate holder cleaning bath comprises:
• supplying the first cleaning liquid into the substrate holder cleaning bath until the substrate holder, holding the dummy substrate, is immersed in the first cleaning liquid to clean the substrate holder;
• supplying the second cleaning liquid into the substrate holder cleaning bath until the substrate holder, holding the dummy substrate, is immersed in the second cleaning liquid to clean the substrate holder;
• and
• supplying the third cleaning liquid into the substrate holder cleaning bath until the substrate holder, holding the dummy substrate, is immersed in the third cleaning liquid to clean the substrate holder.