Patent ID: 7876541

Claim:
An electrostatic discharge (ESD) protection method of a semiconductor memory device, comprising steps of: (1) in order to prevent ESD caused by an internal circuit supplied with a power voltage and different first and second ground voltages respectively provided from a power pad and first and second ground pads, connecting the first ESD protector in parallel between the power pad and the second ground pad and connecting the second ESD protector between the first and second ground pads; (2) after supplying an alternating current (AC) corresponding to ESD during an ESD test, measuring a driving voltage of the first ESD protector and a gate oxide breakdown voltage of elements in the internal circuit; and (3) if the measured driving voltage of the first ESD protector is higher than the gate oxide breakdown voltage of the elements in the internal circuit, connecting additionally a third ESD protector between the power pad and the first ground pad in order to decrease the driving voltage of the first ESD protector.