Polishing monitoring method, polishing method, and polishing monitoring apparatus

A method of polishing a substrate having a film, said method comprising:

• polishing the substrate by providing sliding contact between the substrate and a polishing pad;
• directing light to the substrate during polishing of the substrate;
• receiving reflected light from the substrate;
• measuring intensity of the reflected light at each wavelength;
• producing spectrum indicating relationship between intensity and wavelength from measured values of the intensity;
• calculating an amount of change in the spectrum per predetermined time;
• integrating the amount of change in the spectrum with respect to polishing time to obtain an amount of cumulative change in the spectrum;
• and
• monitoring progress of polishing of the substrate based on the amount of cumulative change in the spectrum.

A polishing monitoring apparatus, comprising:

• a light-applying unit configured to direct light to the substrate during polishing of the substrate;
• a light-receiving unit configured to receive reflected light from the substrate;
• a spectroscope configured to measure intensity of the reflected light at each wavelength;
• and
• a processing device configured to process measurement data from said spectroscope,
• wherein said processing device is configured to
• produce spectrum indicating relationship between intensity and wavelength from measured values of the intensity,
• calculate an amount of change in the spectrum per predetermined time,
• integrate the amount of change in the spectrum with respect to polishing time to obtain an amount of cumulative change in the spectrum, and
• monitor the progress of polishing of the substrate based on the amount of cumulative change in the spectrum.

A program for enabling a computer to execute the steps of:

• producing spectrum indicating relationship between intensity and wavelength of reflected light from a substrate;
• calculating an amount of change in the spectrum per predetermined time;
• integrating the amount of change in the spectrum with respect to polishing time to obtain an amount of cumulative change in the spectrum;
• and
• monitoring progress of polishing of the substrate based on the amount of cumulative change in the spectrum.