Optical module for surface inspection and surface inspection apparatus including the same

An optical module for surface inspection, comprising:

• a first light source unit configured to illuminate first light to an inspected substrate and including a first light source generating the first light and a first dichroic beam splitter changing a path of the first light;
• a second light source unit configured to illuminate second light to the inspected substrate;
• and
• a detection unit configured to detect third light produced by reflecting the first light on the inspected substrate and fourth light produced by scattering the second light on the inspected substrate,
• wherein the third light and the fourth light pass through the first dichroic beam splitter to reach the detection unit, and
• the transmittance of the first dichroic beam splitter for the third light is 50%, and the transmittance of the first dichroic beam splitter for the fourth light is 90% or more.

An optical module for use in inspecting the surface of a substrate, the module comprising:

• a first light source unit that outputs first light along a first optical axis of the module, the first light source unit including a first light source, and a beam splitter oriented to reflect light produced by the first light source along the first optical axis of the module;
• a second light source unit that outputs light polarized in a first direction along a second optical axis that intersects the first optical axis at an imaging plane and is oblique with respect to the first optical axis;
• and
• a detection unit including a light detector,
• wherein the beam splitter is disposed along the first optical axis between the imaging plane and the light detector, and the beam splitter has a transmittance with respect to the first light and the polarized second light,
• whereby the light detector captures light that is a product of the first light reflecting from a surface of a substrate oriented substantially perpendicular to the first optical axis and lying in the imaging plane, and captures light that is a product of the polarized second light scattered from the surface of the substrate.