Patent ID: 8105949

Claim:
A substrate processing method that processes a substrate in which a to-be-processed layer, an intermediate layer, and a mask layer are stacked in this order, and in which the mask layer has an opening to which part of the intermediate layer is exposed, comprising: performing a shrinking etching by carrying out the following steps in one step: reducing an opening width by accumulating deposit on a side wall surface of the opening in the mask layer using plasma produced from a mixed gas of a deposition gas and an anisotropic etching gas, and etching the intermediate layer that forms a bottom of the opening; and etching a to-be-processed layer by transferring the opening in the intermediate layer corresponding to the opening in the mask layer reduced in opening width in said shrinking etching step onto the to-be-processed layer using plasma produced from a non-deposition gas, wherein the anisotropic etching gas is a gas that has a higher molecular weight than the deposition gas and contains a halogen element of a higher atomic number than bromine (Br), or sulfur (S) or an element of a higher atomic number than sulfur (S) in the 16th group of the periodic system.