A substrate inspection apparatus may include a light source, which is configured to emit an incident light. The substrate inspection apparatus may further include a support, a detector, and a light adjuster. The supporting base configured to support a substrate, the detector configured to detect a defect on the substrate, and the light adjuster configured to allow the incident light to be reflected. The detector may be configured to collect a scattering signal. The scattering signal is generated from an optical interaction between an evanescent wave and the defect on the substrate, and to detect the defect. The evanescent wave may be generated when the incident light is totally and/or substantially reflected by the light adjuster.