METHOD OF EVALUATING TRENCH AVERAGE DEPTH AND SWITCHING CHARACTERISTICS OF TRENCH GATE TYPE MOS SEMICONDUCTOR DEVICE, AND METHOD OF SELECTING SEMICONDUCTOR CHIP

摘要

PROBLEM TO BE SOLVED: To provide a method of evaluating a trench average depth of a trench gate type MOS semiconductor device capable of evaluating and selecting a trench average depth and switching characteristics of a semiconductor chip in a wafer state by non-destruction and by a simple test circuit without using a high-voltage power supply, with respect to a wafer that undergoes a wafer process of the trench gate type MOS semiconductor device.SOLUTION: After termination of a step of burying a gate electrode 8 via a gate insulating film 7 in a trench 11 provided on a surface side of a semiconductor wafer 21 and a step of forming metal main electrodes 5 and 6 on both principal surfaces, a rectangular pulse voltage is applied from a predetermined negative voltage value to a predetermined positive voltage value, between the gate electrode 8 in a semiconductor chip 10 formed in the semiconductor wafer 21 and the rear face metal electrode 5 to measure a gate charging time A when a voltage reaches the predetermined positive voltage value. A trench average depth of the semiconductor chip 10 corresponding to the measured gate charging time A is calculated from a calibration curve indicating a relation between a known trench average depth and a gate charging time.