Why Defect based Testing Works for High-Speed I/O Interfaces

摘要

All device segments rely upon High Speed I/O interfaces to deliver functionality and data rate needs. Industry segments include Mobile computing, Automotive, Internet of Things (IoT), edge computing, AI acceleration, Server computers and Personal computers devices. For over a decade, defect-based test methods have provided robust test coverage which permits test factories to deploy low cost ATE. With advanced process nodes, faster data rates and an increase in I/O types on a product some doubt the capabilities of defect-based test methods. The differing transmission lines in a manufacturing test environment and a system environment lay at the heart of the drawbacks. This paper highlights these differences and provides an overview of 20 years experiences with defect-based testing of High-Speed I/O (e.g. PCI Express, DDR). These experiences justify why defect-based test methods implemented with Design for Test (DfT) circuitry can cover the same faulty behaviors as specification based Test. This paper also discusses potential gaps of commonly used High Speed I/O defect-based test approaches and suggests ways to close them.