T. Kane, S. Pendyala, M. Tenney, R. Oldrey, M. Villalobos, J. Sylvestri, IBM, Hopewell Junction, NY

Summary: Root cause analysis of frequency sensitive AC “soft” failures in 32nm SRAM arrays pose unusal challenges to the failure analyst. Conventional atomic force probe (AFP) DC measurements cannot reliably identfy the failure source. The employment of tester based schmoo screening coupled with AFP capacitance voltage AC measurements have been shown to identify subtle dopant type defects subsequently confirmed by transmission electron microscopy (TEM). This paper describes in detail the technique employed to find the root cause of such frequency sensitive soft fails