Wafer crack detection device and detection method

The invention provides a wafer crack detection device and a wafer crack detection method. The wafer crack detection device comprises a light shield; the detection assembly is located in the light shield, the detection assembly comprises a photosensitive sensor and a light source which are oppositely arranged, a gap is formed between the photosensitive sensor and the light source, and a wafer to be detected extends into the gap; wherein the wafer to be detected comprises an area to be detected, and the central axis of the photosensitive sensor and the central axis of the light source intersect in the area to be detected. If the crack exists in the to-be-detected area, the light emitted by the light source enters the photosensitive sensor after being reflected by the crack interface, so that the output information of the photosensitive sensor is different from the conventional information, and whether the crack exists in the wafer can be accurately detected based on the obtained output information of the photosensitive sensor; the detection efficiency, the detection precision and the accuracy are high, and the photosensitive sensor and the light source do not directly contact the wafer, so that the cleanliness of the wafer is ensured.