A method for inputting a foreign substance inspection map created by foreign substance inspection for a wafer surface after each processing process in a wafer processing process, inputting a die sort map created by a die sort test after the wafer processing process, setting region segments in the wafer, setting a region number for each segment, calculating foreign substance density of the region segments, based on the foreign substance inspection map, and plotting the foreign substance density, using the region numbers, to calculate a foreign substance inspection map waveform characteristic amount, calculating failure density in the region segments, based on the die sort map, and plotting the failure density, using the region numbers, to calculate a die sort map waveform characteristic amount, calculating similarity between the foreign substance inspection map waveform characteristic amount and the die sort map waveform characteristic amount, and identifying a processing process cause of failure occurrence.