Etching method and etching device

An apparatus for selectively etching a silicon nitride film, comprising:

• a processing container configured to accommodate a target substrate having the silicon nitride film formed thereon, at least during selective etching of the silicon nitride film;
• a partition plate configured to partition the processing container into a plasma production space defined at an upper portion and a processing space defined at a lower portion;
• an ion trap mechanism provided in the partition plate and including at least a first plate-shaped member in which a plurality of first slits are formed and a second plate-shaped member in which a plurality of second slits are formed, the ion trap mechanism being configured to trap ions and allow radicals to pass therethrough, the plurality of first slits and the plurality of second slits being arranged not to overlap each other when the partition plate is viewed from the processing space;
• a first gas source configured to supply an inert gas to the plasma production space;
• a plasma production mechanism configured to produce a plasma of the inert gas in the plasma production space;
• a placement stage provided in the processing space to place the target substrate thereon;
• a second gas source configured to supply a gas containing H and F into the processing space;
• an exhaust mechanism configured to vacuum-exhaust an interior of the processing container;
• and
• a controller configured to perform a control to execute:
• a first step of disposing the target substrate having the silicon nitride film formed thereon in the processing space;
• a second step of introducing the gas containing H and F into the processing space;
• and
• a third step of selectively etching the silicon nitride film by producing the plasma in the plasma production space and introducing the radicals in the plasma into the processing space via the partition plate while trapping the ions in the plasma by the ion trap mechanism,
• wherein an O2 gas is not introduced into the processing space.

A method of selectively etching a silicon nitride film, the method comprising:

• a first step of disposing a target substrate having the silicon nitride film formed thereon in a processing space;
• a second step of introducing a gas containing H and F from an etching gas source directly into the processing space;
• and
• a third step of selectively introducing radicals of an inert gas generated in a plasma production space into the processing space,
• wherein the gas containing H and F is a HF gas,
• wherein the second step and the third step are performed in a state where a temperature of the target substrate falls within a range of −15 to 35 degrees C., and
• wherein an O2 gas is not introduced into the processing space.