Investigation and solution to the early failure of parasitic NPN triggered by the adjacent PNP ESD clamps

The mechanism of PNP-triggered parasitic NPN´s early failure during ESD stress has been clarified for the first time. We proposed two solutions for the high ESD and Latchup-hard requirements. The embedded SCR structure provides high HBM immunity, which can serve pin-to-pin protection such as the differential IO application. For the Latchup-hard solution, a sandwich guard ring structure solves the snapback-induced local ESD damage issue and achieves low substrate current injection. Note that the spacing rule for the parasitic NPN structures is also greatly reduced up to 44.7%.