ESD Susceptibility of High Gauge Factor Thick Film Piezoresistors

CTS began manufacturing pointing devices in 1994 for use as cursor controls, mounted in the keyboards of notebook computers. While completed keyboards were robust against ESD, many precautions were required during manufacture and assembly to protect against the effects of ESD. While these ESD “protective” controls were effective in controlling ESD, they did not eliminate the ESD susceptibility of the pointing sticks. ESD Susceptibility of high gauge factor thick film resistors was investigated. The thick film resistor processing and the resistor design parameters were studied. Improvements in the thick film resistor paste and strain gauge resistor design have produced pointing sticks capable of withstanding an ESD of 20KV.