Method of processing target object

A method for processing a substrate comprising:

• (a) providing a substrate including a target layer having a recess;
• (b) supplying a silicon-containing precursor to the substrate and forming an adsorbed precursor layer on the substrate;
• (c) exposing the substrate to plasma generated from oxygen-containing gas and fluorocarbon-containing gas;
• and
• (d) repeating (b) and (c) more than one time,
• wherein in (c), an oxygen active species in the plasma reacts with the adsorbed precursor layer to form a protection film while a fluorine active species in the plasma etches a bottom of the recess,
• wherein the target layer further includes a first protrusion and a second protrusion, and the recess is defined by the first protrusion and the second protrusion, and
• wherein a height of the first protrusion is different from a height of the second protrusion.

An apparatus for processing a substrate comprising:

• a chamber having a gas inlet and a gas outlet;
• a plasma generator;
• and
• a controller configured to cause:
• (a) providing a substrate including a target layer having a recess;
• (b) supplying a silicon-containing precursor to the substrate and forming an adsorbed precursor layer on the substrate;
• (c) etching a bottom of the recess by exposing the substrate to plasma generated from oxygen-containing gas and fluorocarbon-containing gas and reacting an oxygen active species in the plasma with the adsorbed precursor layer to form a protection film while a fluorine active species in the plasma etches the bottom of the recess;
• and
• (d) repeating (b) and (c) more than one time.