Etching method and plasma processing apparatus

An etching method comprising:

• (a) providing a substrate having an etching target film including a silicon-containing film, and a mask on the etching target film;
• (b) after (a), forming a tungsten-containing deposit on the mask by a first plasma generated from a first processing gas including tungsten hexafluoride gas and a hydrogen-containing gas, the hydrogen-containing gas including at least one of hydrogen gas, hydrocarbon gas, and hydrofluorocarbon gas;
• (c) after (b), deforming or modifying the tungsten-containing deposit by a second plasma generated from a second processing gas different from the first processing gas, the second processing gas including at least one of fluorocarbon gas, hydrofluorocarbon gas, and a halogen-containing gas;
• and
• (d) after (c), etching the etching target film by a third plasma generated from a third processing gas different from the first and second processing gases.

A plasma processing apparatus comprising:

• a chamber;
• and
• a substrate support configured to support a substrate in the chamber;
• a gas supply configured to supply a processing gas into the chamber;
• a plasma generator configured to generate plasma in the chamber;
• and
• a controller,
• wherein the controller is configured to control the gas supply and the plasma generator to perform a process including
• providing the substrate including an etching target film and a mask on the etching target film,
• forming a metal-containing deposit on the mask by a first plasma generated from a first processing gas including a metal-containing gas and a hydrogen-containing gas,
• after forming the metal-containing deposit, deforming or modifying the metal-containing deposit by a second plasma generated from a second processing gas different from the first processing gas, and
• after deforming or modifying the metal-containing deposit, etching the etching target film.