The repeatability of system level ESD test and relevant ESD generator parameters

Some system level ESD tests do not repeat well if different ESD generators are used. For improving the test repeatability, ESD generator specifications were considered to be changed and a world wide Round Robin test were performed in 2006 to compare the modified and unmodified ESD generators. The test results show the failure level variations up to 1:3 for an EUT among eight different ESD generators. Multiple ESD parameters including discharge currents and transient fields have been measured. This paper tries to find which parameters would predict the failure level the best in general. The transient fields show large variations among different ESD generators. The voltage induced in a semi-circular loop and the ringing after first discharge current peak show the best correlation to failure levels. The regulation on the transient field is expected to improve the test repeatability.