A device of inspecting defects of a wafer diced or aligned, the wafer including, after being diced or aligned, a silicon wafer layer and a blue film affixed to the bottom of the silicon wafer layer, the device including: an immersion liquid detector having a casing, the casing having a transparent lid, allowing a liquid to flow through and fill between the blue film and the transparent lid; a lens assembly disposed in the casing and below the transparent lid; an optical lens assembly disposed in the casing and below the lens assembly; a light source for generating visible light and infrared light; and a visible-light camera and an infrared camera, both adapted to perform imaging on the bottom of the silicon wafer layer.