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

1 . A method of determining a depth of a damage layer formed on a back surface of a substrate, comprising:

irradiating the damage layer with a first light and a second light having a different wavelength from the first light;

detecting the first light and the second light reflected or scattered by defects in the damage layer;

determining 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;

determining a number of defects present in a first area corresponding to the first penetration depth or a concentration of defects present in the first area using the detected first light;

determining a number of defects present in a second area corresponding to the second penetration depth or a concentration of defects present in the second area using the detected second light;

determining a number of defects or a concentration of defects present in a third area that is included in the first area but is not included in the second area using the number of defects or the concentration of defects present in the first area and the number of defects or the concentration of defects present in the second area; and

determining the depth of the damage layer based on the number of defects or a graph of the concentration of defects and the depth of the damage layer, the concentration of defects present in each of the first, second, and third areas, wherein the graph represents a normal distribution curve,

wherein when the first wavelength is longer than the second wavelength, the first penetration depth is deeper than the second penetration depth,

wherein in determining the depth of the damage layer, when first information indicated by the detected first light and second information indicated by the detected second light are the same, the second penetration depth is determined as the depth of the damage layer, and

wherein in determining the depth of the damage layer, when the number of defects or the concentration of defects for the first penetration depth and the number of defects or the concentration of defects for the second penetration depth are the same, the second penetration depth is determined as the depth of the damage layer.

2 . The method of claim 1 , further comprising:

determining the concentration of defects in the first area using the number of defects or the concentration of defects present in the first area;

determining the concentration of defects in the second area using the number of defects or the concentration of defects present in the second area; and

determining the concentration of defects in the third area using the number of defects or the concentration of defects present in the third area.

3 . The method of claim 1 , wherein in irradiating the damage layer with the first light and the second light,

the first light and the second light are simultaneously irradiated to the damage layer, and

the first light and the second light correspond to light dispersed from white light.

4 . The method of claim 1 , wherein in irradiating the damage layer with the first light and the second light, the first light and the second light are sequentially irradiated.

5 . The method of claim 1 , wherein the substrate is a silicon substrate.

6 . A measurement system for determining 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 a first light and a 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 a 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 a concentration of defects present in the second area using the detected second light,

determine a number of defects or a concentration of defects present in a third area that is included in the first area but is not included in the second area using the number of defects or the concentration of defects present in the first area and the number of defects or the concentration of defects present in the second area, and

determine the depth of the damage layer based on the number of defects or a graph of the concentration of defects and the depth of the damage layer, the concentration of defects present in each of the first, second, and third areas, wherein the graph represents a normal distribution curver,

wherein when the first wavelength is longer than the second wavelength, the first penetration depth is deeper than the second penetration depth,

wherein when first information indicated by the detected first light and second information indicated by the detected second light are the same, the second penetration depth is determined as the depth of the damage layer, and

wherein when the number of defects or the concentration of defects for the first penetration depth and the number of defects or the concentration of defects for the second penetration depth are the same, the second penetration depth is determined as the depth of the damage layer.