Soft Failure in Integrated Circuits due to ESD Induced EMS Problems

Soft failures due to ESD events must be taken into account for the correct function of integrated circuits. In addition to the ESD characterization of unpowered integrated circuits, especially in the case of hard failures, an ESD characterization of powered ICs is necessary in order to analyze possible soft failures. The poster deals with soft failures in integrated circuits due to interferences in input and output pad cells from the VDD core and IO supplies. A comparison of the influence of addi - tional capacitances to buffer the IO/core supply is also included. An important prerequisite for a suitable ESD test pulse for powered ICs is the repeatability of the measurement. The measurement system used in this poster and the ESD probe head, respectively, shows an accurate repeatability of the measurement. Soft failures occur due to coupling in the padframe from VDDIO and VDDC to signal pins. Dif- ferent examples will be given in the poster. The root cause for those soft failures will be discussed. Scan detector cells are used to analyze ESD events in the core area of the IC. The detector cells are connected using a scan chain.