Method of measuring nitrogen content, method of forming silicon oxynitride film and process for producing semiconductor device

A method of forming a silicon oxynitride film by nitriding a silicon oxide film formed on a surface of a processing target substrate, comprising:

• nitriding a silicon oxide film formed on a surface of a measurement target substrate to form a silicon oxynitride film;
• measuring a total film thickness T1N of the silicon oxynitride film measurement target substrate and the silicon oxide film remaining thereunder;
• reoxidizing the measurement target substrate;
• measuring a total film thickness T2N of the silicon oxynitride film, the silicon oxide film and a reoxidized silicon oxide film formed on the measurement target substrate after reoxidizing the measurement target substrate;
• reoxidizing a reference substrate having a silicon oxide film formed thereon independently of the measurement target substrate;
• measuring a total film thickness T2 of the silicon oxide film and a reoxidized silicon oxide film formed on the reference substrate after reoxidizing the reference substrate;
• calculating a reoxidation rate reduction ratio of the measurement target substrate from the total film thicknesses T1N, T2N and T2 by using Equation 1;
• determining the nitrogen concentration in the silicon oxynitride film on the measurement target substrate based on the calculated reoxidation rate reduction ratio;
• determining nitriding process conditions for the silicon oxide film on the processing target substrate based on the determined nitrogen concentration;
• and
• nitriding the silicon oxide formed on the surface of the processing target substrate under the determined nitriding process conditions to form the silicon oxynitride film;
• wherein Equation 1 is as follows:
• RORR (%)={(T2−T2N)/(T2−T1N)}×100.

A method of manufacturing a semiconductor device including forming a silicon oxynitride film by nitriding a silicon oxide film formed on a surface of a processing target substrate, wherein said forming the silicon oxynitride film comprises:

• nitriding a silicon oxide film formed on a surface of a measurement target substrate to form a silicon oxynitride film;
• measuring a total film thickness T1N of the silicon oxynitride film measurement target substrate and the silicon oxide film remaining thereunder;
• reoxidizing the measurement target substrate;
• measuring a total film thickness T2N of the silicon oxynitride film, the silicon oxide film and a reoxidized silicon oxide film formed on the measurement target substrate after reoxidizing the measurement target substrate;
• reoxidizing a reference substrate having a silicon oxide film formed thereon independently of the measurement target substrate;
• measuring a total film thickness T2 of the silicon oxide film and a reoxidized silicon oxide film formed on the reference substrate after reoxidizing the reference substrate;
• calculating a reoxidation rate reduction ratio of the measurement target substrate from the total film thicknesses T1N, T2N and T2 by using Equation 1;
• determining the nitrogen concentration in the silicon oxynitride film on the measurement target substrate based on the calculated reoxidation rate reduction ratio;
• determining nitriding process conditions for the silicon oxide film on the processing target substrate based on the determined nitrogen concentration;
• and
• nitriding the silicon oxide formed on the surface of the processing target substrate under the determined nitriding process conditions to form the silicon oxynitride film,
• wherein Equation 1 is as follows:
• RORR (%)={(T2−T2N)/(T2−T1N)}×100.