| CPC G01R 31/2642 (2013.01) [G01R 31/2623 (2013.01); G01R 31/2644 (2013.01); H10D 30/669 (2025.01)] | 8 Claims |
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1. A failure prediction method of a semiconductor device that includes a semiconductor element having a trench gate structure configured by connecting main cells in parallel, the main cells including first cells and second cells, the second cells having a structure in which gate insulating films are more easily broken by energization than gate insulating films in the first cells in order to predict failure of the first cells, a number of the second cells being smaller than a number of the first cells, the gate insulating films in the second cells are different in breakability from each other, the failure prediction method comprising:
applying a gate drive voltage in common to gate electrodes of the first cells and gate electrodes of the second cells at a time of driving the semiconductor element;
measuring an electrical characteristic and detecting failure of the second cells due to energization at the time of driving;
electrically isolating the gate electrodes of one or more of the second cells that have failed from the gate electrodes of the first cells so that the gate drive voltage is not applied to the one or more of the second cells that have failed; and
predicting the failure of the first cells based on the failure of the second cells.
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