Layout Consideration and Circuit Solution to Prevent EOS Failure Induced by Latchup Test in a High-Voltage Integrated Circuits

This paper presented a practical industry case of electrical overstress (EOS) failure induced by the latchup test in high-voltage integrated circuits (ICs). By using proper layout modification and additional circuit, the unexpected EOS failure, which is caused by negative-current-triggered latchup test, can be successfully solved. The new design with proposed solutions has been verified in the 0.6-μm 40-V Bipolar CMOS DMOS (BCD) process to pass the test for at least 500-mA trigger current, which shows high negative-current-latch-up immunity without overstress damage, compared with the protection of only the guard ring. Such solutions can be adopted to implement high-voltage-applicable IC product to meet the industry requirement for the mass production of IC manufactures and applications.