The term Class 0 has not been defined for manufacturing applications by any industry standard and that there is a growing need for one. We have found that manufacturing failure rates escalate exponentially for devices with ESD withstand voltages below 250 volts for either HBM or CDM and then again at 125 volts and at 50 volts. Thus, escalation of manufacturing counter measures becomes essential at each of these break points. It is also vitally important for the manufacturing process to have well defined trigger points for risk assessments of these ultra-sensitive components. These risk assessments involve verification of manufacturing process capability as well as for any risks that may be passed on to customers. In some instances, risk assessments have resulted in the redesign of components, circuit boards and/or assemblies to improve the ESD performance. Manufacturing process capability tests become increasingly complex the deeper into the Class 0 region the devices are (see Class 0 case study). Note: MM is intentionally omitted from this definition since it is largely redundant to HBM.
Thus, we define Class 0 for manufacturing as any component that falls into one of the three categories below. Control methods escalate with each lower category.
- Class 0
- Component Withstand Voltages Less than 250 volts HBM or CDM
- Class 00
- Component Withstand Voltages Less than 125 volts HBM or CDM
- Class 000
- Component Withstand Voltages Less than 50 volts HBM or CDM