Advanced electrical analysis of embedded memory cells using atomic force probing

To identify the failure cause of embedded memory cells - e.g. SRAM with 6 transistors - it is often necessary to measure the electrical parameters of each transistor. Until now, on integrated circuits with small feature size and pitch, this was only possible using FIB probing pads or SEM probers, but both methods are complex and error-prone. Today Atomic Force Probing (AFP) provides a powerful alternative, allowing fast and non-destructive characterization of single transistors. In this paper the functional principle of the technique is introduced. Three case studies of SRAM, ROM and NVM cells illustrate the successful application of this nano-probing tool.