Patent ID: 7807234

Claim:
A plasma processing method applying oxynitridation processing to a silicon substrate in a process vessel by using plasma, comprising the steps of: introducing an inert gas, N 2 , and O 2 into the process vessel; making a mixed gas of the inert gas, N 2 , and O 2 into a plasma by an antenna in the process vessel to form oxygen radicals and nitrogen radicals; and forming a silicon oxynitride film by applying oxynitridation processing to a surface of the silicon substrate by the oxygen radicals and the nitrogen radicals, wherein the flow rate ratio of the O 2 to N 2 is 1:4 to 1:6, and wherein a nitrogen concentration in the silicon oxynitride film has two peaks including a first peak near the surface of the silicon oxynitride film that is higher than a second peak near the interface between the silicon oxynitride film and the substrate.