Plasma etching method, semiconductor device manufacturing method and computer-readable storage medium

A semiconductor device manufacturing method comprising:

• a plasma etching process for forming, via a mask layer, a hole in a silicon dioxide film formed on an etching stopper layer of a processing target substrate accommodated in a processing chamber by using plasma generated from a processing gas introduced into the processing chamber,
• wherein the plasma etching process includes:
• a main etching process for etching the silicon dioxide film using, as the processing gas, a gaseous mixture including C4F6 gas, C4F8 gas, Ar gas, O2 gas and CO gas, wherein the main etching process is stopped upon exposing at least a part of the etching stopper layer;
• and
• a cyclic etching process that is started after at least the part of the etching stopper layer is exposed and after the main etching process is stopped,
• wherein the cyclic etching process that is started after at least the part of the etching stopper layer is exposed includes:
• a first etching process using a gaseous mixture of a C4F6 gas, an Ar gas and an O2 gas as the processing gas;
• and
• a second etching process using a gaseous mixture of a C4F8 gas, an Ar gas and an O2 gas as the processing gas, and
• the first etching process and the second etching process are alternately performed plural times.