Patent ID: 7427520

Claim:
A method of measuring a thickness of a thin film formed on a substrate, comprising: a correction-data preparing step of preparing correction data indicating a relationship between a decrement in a measurement value of a thickness by removal of organic contamination adsorbed onto a substrate and an amount of adsorbed organic contamination corresponding to a difference between a true film thickness and a measurement value, said difference being caused due to organic contamination adsorbed onto said substrate before or after said removal of organic contamination; a first film-thickness measuring step of obtaining a first measurement value of a film thickness on a substrate before removal of organic contamination; a removing step of performing said removal of organic contamination on said substrate; a second film-thickness measuring step of obtaining a second measurement value of a film thickness on said substrate after said removal of organic contamination; an amount calculating step of obtaining an amount of adsorbed organic contamination before or after said removal of organic contamination, based on a difference between said first measurement value and said second measurement value and said correction data; and a film-thickness obtaining step of obtaining a thickness of a thin film formed on said substrate, based on said first measurement value and an amount of adsorbed organic contamination before said removal of organic contamination, or based on said second measurement value and an amount of adsorbed organic contamination after said removal of organic contamination.