Method of etching silicon containing films selectively against each other

A method of etching a first silicon containing film and a second silicon containing film selectively against each other, the method comprising:

• preparing a processing target object within a chamber provided by a chamber main body of a plasma processing apparatus;
• etching the first silicon containing film of the processing target object by generating plasma of a processing gas within the chamber in a state that a temperature of the processing target object is set to a first temperature;
• and
• etching the second silicon containing film of the processing target object by generating the plasma of the processing gas within the chamber in a state that the temperature of the processing target object is set to a second temperature higher than the first temperature,
• wherein an etching rate of the first silicon containing film is higher than an etching rate of the second silicon containing film at the first temperature, and
• the etching rate of the second silicon containing film is higher than the etching rate of the first silicon containing film at the second temperature.