Etching method of multilayer film

An etching method of a multilayer film including a first oxide film, a second oxide film, and an organic film formed between the first oxide film and the second oxide film in a plasma processing apparatus, the etching method comprising:

• etching the first oxide film by generating plasma of a first processing gas in a processing space of the plasma processing apparatus in which a target object having the multilayer film and a resist mask formed on the first oxide film is accommodated;
• etching the organic film by generating plasma of a second processing gas in the processing space after the etching of the first oxide film;
• and
• etching the second oxide film by generating plasma of a third processing gas in the processing space after the etching of the organic film,
• wherein each of the plasma of the first processing gas, the plasma of the second processing gas, and the plasma of the third processing gas is generated by applying a high frequency power to one of a lower electrode serving as a mounting table configured to mount thereon the target object and an upper electrode provided above the lower electrode,
• the high frequency power in the etching of the organic film is set to be higher than the high frequency power in the etching of the first oxide film and the high frequency power in the etching of the second oxide film,
• in each of the etching of the first oxide film, the etching of the organic film, and the etching of the second oxide film, a high frequency bias power is applied to the lower electrode,
• the high frequency bias power in the etching of the first oxide film and the high frequency bias power in the etching of the second oxide film are set to be higher than the high frequency bias power in the etching of the organic film,
• in each of the etching of the first oxide film, the etching of the organic film, and the etching of the second oxide film, a magnetic field is generated such that horizontal magnetic field components in a radial direction with respect to a central axis line of the target object have an intensity distribution having a peak value at a position far from the central axis line, and
• a position of the peak value of the horizontal magnetic field components in the etching of the organic film is closer to the central axis line than a position of the peak value of the horizontal magnetic field components in the etching of the first oxide film and a position of the peak value of the horizontal magnetic field components in the etching of the second oxide film.