Workpiece processing using ozone gas and chelating agents

A method for processing one or more workpieces having an oxide layer, comprising:

• heating a liquid including de-ionized water and a chelating agent;
• forming a layer of the heated liquid on the surface of the workpiece;
• and
• contacting the surface of the workpiece with ozone gas in the layer of heated liquid, with the ozone chemically reacting with an oxidizable contaminant at the surface of the workpiece, and with the chelating agent chemically reacting with a metal contaminant, to process the workpiece.

A method for cleaning one or more workpieces having an oxide layer on a surface of the workpiece, comprising:

• placing the workpiece into a chamber;
• heating a liquid including de-ionized water, ammonium hydroxide and a chelating agent;
• forming a layer of the heated liquid on the surface of the workpiece;
• and
• providing ozone gas into the chamber, with the ozone gas chemically reacting with a contaminant at the surface of the workpiece, and with the chelating agent chemically reacting with a metal contaminant, to process the workpiece, and with the oxide layer thickness remaining substantially unchanged.

An apparatus for cleaning a workpiece comprising:

• a chamber;
• a workpiece holder in the chamber;
• liquid outlets in the chamber positioned to apply liquid onto at least one surface of a workpiece supported by the workpiece holder;
• a source of aqueous liquid connecting with the liquid outlets, with the aqueous liquid including a chelating agent;
• a heater for heating the aqueous liquid;
• and
• a source of ozone gas connecting into the chamber.