Floating gate EEPROM as EOS indicators during wafer-level GMR processing

Potentially damaging charging currents and voltages in wafer-level giant magentoresistance (GMR) plasma processing tools have been measured using floating gate EEPROM (FG-EEPROM) monitor wafers. Although FG-EEPROM monitors have been used as semiconductor process monitors, this report demonstrates their use in ESD-sensitive GMR head production. Use of FG-EEPROM monitors allows quantification of plasma-induced EOS voltages and currents, and can be used in optimizing process tool EOS performance, as is demonstrated in a case study on an ion mill.