Characterizing automated handling equipment using discharge current measurements II

Characterizing the ESD performance of Automated Handling Equipment (AHE) can be confusing, subjective, sometimes just plain arbitrary, and much of the time wrong. ESD sensitivity of devices is classified by a set of standards that specify an amplitude and type of discharge mode such as Human Body Model (HBM), Charged Device Model (CDM), or Machine Model (MM). Each of the models has unique circuitry of capacitance, resistance and inductance to provide a specific current, rise time and pulse shape of the discharge at a specific voltage. These are fairly repeatable and reproducible measurements while on the other hand, attempts to classify AHEs based on voltage measurements are most often misleading. This paper deals with the additional results of methods for measuring the discharge currents both on the bench and in the equipment and hopefully answers some questions raised in the related publication from the 2004 EOS/ESD Symposium.