Wafer inspection apparatus

A wafer inspection apparatus comprising:

• a light source configured to output first light;
• a spatial light modulator behind an image surface and configured to receive the first light and output second light in a random pattern;
• a beam splitter in a first light path from the light source to the spatial light modulator and configured to transmit the second light toward a wafer behind a sample surface;
• an objective lens configured to focus the second light from the beam splitter onto an illuminated region of the wafer;
• and
• a detector behind a detection surface and configured to acquire a diffraction image formed on the detection surface based on focused third light reflected from a detection region of the wafer,
• wherein each of the sample surface, the detection surface, and the image surface is a virtual plane that is set in a direction perpendicular to a traveling direction of the second light,
• wherein the image surface is in a second light path from the spatial light modulator to the beam splitter, and
• wherein the second light that is in the random pattern forms a random pattern image of a same shape on each of the sample surface, the detection surface, and the image surface.

A wafer inspection apparatus comprising:

• a light source;
• a stage configured to fix a wafer that is behind a sample surface and that comprises a periodic pattern formed on a surface thereof;
• a spatial light modulator behind an image surface and configured to receive first light from the light source and output second light in a random pattern;
• a beam splitter in a first path of the second light and configured to transmit the second light toward the wafer;
• an objective lens configured to focus the second light onto an illuminated region of the wafer;
• and
• a detector behind a detection surface and configured to acquire a diffraction image formed on the detection surface based on focused third light reflected from a detection region of the wafer,
• wherein each of the sample surface, the detection surface, and the image surface is a virtual plane set in a direction perpendicular to a traveling direction of the second light in the random pattern,
• wherein the image surface is in a second light path from the spatial light modulator to the beam splitter, and
• wherein the second light that is in the random pattern forms a random pattern image of a same shape on each of the sample surface, the detection surface, and the image surface.