| abstract |
The total film thickness (T1N) of silicon oxynitride film and silicon oxide film remaining as its underlying layer is measured. Measurement object substrate is re-oxidized, and, after the re-oxidization, the total film thickness (T2N) of the silicon oxynitride film, silicon oxide film and silicon oxide film resulting from the re-oxidization on the measurement object substrate is measured. Separately, a reference substrate provided with silicon oxide film is re-oxidized, and, after the re-oxidization, the total film thickness (T2) of the silicon oxide film and silicon oxide film resulting from the re-oxidization on the reference substrate is measured. Re-oxidization rate reduction ratio (RORR) of the measurement object substrate is calculated by the following formula (1) from the values of total film thickness T1N, T2N and T2. The nitrogen content of the silicon oxynitride film of the measurement object substrate is determined from the calculated re-oxidization rate reduction ratio (RORR). RORR(%) = ((T2-T2N)/(T2-T1N))*100 (1). |