Method for measuring depth of damaged layer and concentration of defects in damaged layer, and system for performing same method

A measurement system for measuring a depth of a damage layer formed on a back surface of a substrate, comprising:

• a light irradiator configured to irradiate the damage layer with first light and second light having a different wavelength from the first light;
• a light detector configured to detect the first light and the second light reflected or scattered by defects in the damage layer;
• and
• a determination device configured to receive information on the first light and information on the second light from the light detector,
• wherein the determination device is configured to:
• determine a first penetration depth of the first light and a second penetration depth of the second light based on a first wavelength of the first light and a second wavelength of the second light,
• determine a number of defects present in a first area corresponding to the first penetration depth or concentration of defects present in the first area using the detected first light,
• determine a number of defects present in a second area corresponding to the second penetration depth or concentration of defects present in the second area using the detected second light,
• determine a number of defects present in a third area that is not included in the second area among the first areas or concentration of defects present in the third area using the number or the concentration of defects present in the first area and the number or the concentration of defects present in the second area, and
• determine the depth of the damage layer based on the number or the concentration of defects
• present in each of the first area, the second area, and the third area.