Plasma etching method and plasma etching apparatus

An plasma etching apparatus comprising:

• a vacuum container in which an object to be processed made of a member containing silicon is disposed;
• a first gas source that supplies hydrogen fluoride gas into the vacuum container;
• a second gas source that supplies hydrogen nitride gas into the vacuum container;
• a heating device that heats the object to be processed;
• and
• a control unit, wherein
• the control unit repeats a set of steps a plurality of times, the set of steps including
• introducing hydrogen fluoride gas from the first gas source into the processing chamber and supplying hydrogen fluoride molecules to a surface of a film layer of the object to be processed,
• exhausting the interior of the processing chamber while stopping the supply of the hydrogen fluoride gas into the processing chamber to reduce the hydrogen fluoride molecules in said processing chamber, and
• introducing hydrogen nitride gas from the second gas source into the vacuum container to form a compound layer containing nitrogen, hydrogen, and fluorine on the surface of the film layer, and
• heating the object to be processed by the heating device to remove the compound layer formed on the surface of the film layer.

An plasma etching apparatus comprising:

• a vacuum container in which an object to be processed made of a member containing silicon is disposed;
• a first gas source that supplies hydrogen fluoride gas into the vacuum container;
• a second gas source that supplies N2 gas and H2 gas into the vacuum container;
• a plasma device that generates plasma in the vacuum container;
• a heating device that heats the object to be processed;
• and
• a control unit, wherein
• the control unit repeats a set of steps a plurality of times, the set of steps including
• introducing hydrogen fluoride gas from the first gas source into the processing chamber and supplying hydrogen fluoride molecules to a surface of a film layer of the object to be processed,
• exhausting the interior of the processing chamber while stopping the supply of the hydrogen fluoride gas into the processing chamber to reduce the hydrogen fluoride molecules in said processing chamber,
• introducing N2 gas and H2 gas from the second gas source into the vacuum container and generating plasma in the vacuum container by the plasma device to generate NH3 molecules, and
• forming a compound layer containing nitrogen, hydrogen, and fluorine on the surface of the film layer, and
• heating the object to be processed by the heating device to remove the compound layer formed on the surface of the film layer.