Method of manufacturing a semiconductor device

A method of manufacturing a semiconductor device including a wafer using a plasma etching device which includes a chamber, a chuck provided in the chamber to dispose the wafer to be processed thereon, a focus ring disposed at a peripheral edge portion of the chuck to surround the wafer disposed on the chuck, and a gas supplying mechanism configured to separately supply various types of gases, the method comprising:

• providing a shower head having a plurality of regions including a central region and a peripheral edge region surrounding the central region, each region configured to selectively supply one of the various types of gases from the gas supplying mechanism to each of a plurality of regions of the wafer along a radial direction of the wafer;
• placing a wafer covered with an organic film on the chuck;
• introducing, from the gas supplying mechanism through the central region of the shower head to a central portion of the wafer, an etching gas which includes at least O2 gas and etches the organic film on the wafer;
• introducing, from the gas supply mechanism through the peripheral edge region of the shower head to a peripheral edge portion of the wafer, an etching inhibiting factor gas having a property of reacting with O radicals which do not react with the organic film and exists on the focus ring when a plasma etching is performed;
• and
• performing the plasma etching on the wafer using the etching gas by generating plasma with the etching gas while eliminating the O radicals and thereby suppressing etching in the peripheral edge portion of the wafer,
• wherein the etching inhibitor gas includes at least a CxFy gas.