Abstract This paper presents a new method for improving the quality and effectiveness of scan-based tests. The method, called statistical diagnosis, leverages defect likelihoods learned from analyzing populations of failing die instead of analyzing each die independently as traditionally done. The method was validated in a large silicon study that showed significant improvement in diagnosis resolution with minimal impact on diagnosis accuracy. Statistical diagnosis, as the paper explains, can also be used to predict or identify the dominant defect mechanism in low yielding wafers.

Abstract Focused ion beam (FIB) tools for backside circuit edit play a major role in the validation of integrated circuit (IC) design modifications. Process scaling is one of many significant challenges, because it reduces the accessible area to modify transistors and IC interconnects in the design. This paper examines the geometries available for FIB nanomachining, via milling/etching, and deposited metal jumpers by analyzing polygon data from computer aided design (CAD) virtual layers gathered across four process technologies, from 180nm down to 28nm. The results of this analysis demonstrate that the combination of silicon nanomachining box length and FIB via box length identifies the most challenging aspects of the FIB edit. The smallest geometries include a 300 nanometer silicon access area with a FIB milled 200 nanometer via inside it. More advanced technology nodes will require the ability to make smaller geometries without the help of integrated design features typically referred to as design for FIB/Debug.