Jeremy Smallwood

Electrostatic field limits and charge threshold for field induced damage to voltage susceptible devices

We have studied electrostatic field and charge threshold limits for damage to MOSFET devices in order to understand the ESD damage risks during handling in electronics production and assembly processes. The study covers both field induced charged device model (CDM) and charged board model (CBM) cases. The charging electrostatic field for failure can be even two orders of magnitude lower for a device on a board than at component level. The charge level for failure remains approximately constant. Our results show that charge threshold for failure would serve as a good guide for ESD risks of voltage susceptible MOSFETs as discrete components and when assembled to PWBs.

Charged device discharge measurement methods in electronics manufacturing

Electrical components with a lower CDM ESD immunity can require additional protection methods in manufacturing. Discharge current measurements and electromagnetic pulse detection gives valuable data for more detailed ESD risk assessments. However, both methods require sophisticated tools and trained personnel to get accurate data for control purposes.

The main parameters affecting charged device discharge waveforms in a CDM qualification and manufacturing

Charged device model (CDM) discharges in a CDM qualification and charged device discharges in electronics manufacturing are compared to evaluate the main discharge parameters. Accurate charged device ESD risk assessments would require to use discharge current waveform information and tailored measurement methods.

Qualification challenges of footwear and flooring systems

Measurement of body voltage alone can result in erroneous conclusions in qualification of footwear and flooring systems in combination with a person. Measurement uncertainties should be taken into account. We have studied the time dependency and charge generation of some footwear and flooring systems. The most significant inconsistencies of the voltage measurement are discussed in this technical paper.

Electrostatic shock risks in assembly of large wind turbine blades

Electrostatic shocks were reported by personnel manufacturing large fiber reinforced plastic wind turbine blades. Inspection and measurements confirmed these reports. We have estimated the possible discharge energy and likelihood of hazardous ESD in some production steps. Administrative and technical recommendations are given to control static to an acceptable level.