1. A method for evaluating a semiconductor wafer by which LPDs on a surface of a semiconductor wafer are detected with the use of a laser surface inspection apparatus and the detected LPDs are classified into a crystal defect on the surface of the semiconductor wafer and a foreign matter on the surface of the semiconductor wafer, comprising steps of: detecting the LPDs on the surface of a semiconductor wafer as an examination sample in two measurement modes of the laser surface inspection apparatus, the two measurement modes consisting of low-angle incidence/low-angle detection (DWO) and low-angle incidence/high-angle detection (DNO); performing size classification based on size information of the LPDs detected in the two measurement modes; calculating, from detection coordinates of each LPD detected in the two measurement modes, a distance between the detection coordinates and a relative angle to a wafer center in the two measurement modes; presetting, in accordance with each classified size, determination criteria to determine each LPD having the distance between the detection coordinates and the relative angle in the two measurement modes which fall within a predetermined range as a foreign matter and to determine any LPD other than the LPD falling in the predetermined range as a killer defect which is a defect of the semiconductor wafer as an examination sample; detecting the LPDs of a semiconductor wafer as an evaluation target in the two measurement modes; performing size classification based on size information of the LPDs detected in the two measurement modes as to the semiconductor wafer as the evaluation target; calculating, from detection coordinates of each LPD detected in the two measurement modes, a distance between the detection coordinates and a relative angle to a wafer center in the two measurement modes as to the semiconductor wafer as the evaluation target; and classifying the LPDs detected on a surface of the semiconductor as the evaluation target into the killer defect and the foreign matter based on a result of the calculation and the determination criteria.