A new electrostatic discharge failure mode

A new electrostatic discharge failure mode was discovered which affects MOS LSI components in hermetic packages with nonconductive lids. Failure can be induced by spraying package lids with canned coolant. It is shown that charge from the freeze spray causes breakdown in the air-gap between the die surface and the lid. As a result, localized surface charging and field inversion occurs in the array, which produces leakage currents and circuit failure. The failure mode can be characterized by its recovery with either a strong UV exposure to the die surface or a DI water rinse.