METHODS FOR SETTING HIGH VOLTAGE TRIMMING VALUE AND TIME TRIMMING VALUE FOR NONVOLATILE MEMORY, INSPECTION EQUIPMENT FOR NONVOLATILE MEMORY, AND NONVOLATILE MEMORY

摘要

PPROBLEM TO BE SOLVED: To provide a method for setting a high voltage trimming value for a nonvolatile storage for improving reliability life of the nonvolatile storage by relieving an electric stress to a memory cell transistor. PSOLUTION: First, by the design profile of a writing high voltage, a first writing high voltage trimming value based on the design standard is decided (step S201), data are written by a voltage following the first writing high voltage trimming value (step S202), and the threshold voltage of the memory cell transistor after writing is measured (step S203). Then, by the measured threshold voltage, the threshold voltage, and the trimming profile for the writing high voltage, a second writing high voltage trimming value optimum for making the threshold voltage coincide with a target value (the minimally required threshold voltage after data writing) is determined (step S204). PCOPYRIGHT: (C)2004,JPO