This article discusses the challenges involved in testing analog and mixed-signal ICs and provides practical guidance and insights on how to deal with them.

Techniques used by failure analysts to provide proper stimuli to diagnose failures in mixed-signal ICs differ from routine digital IC tester stimuli. Mixed-signal parts not only require vector stimulus (i.e., set timing and frequency base), but also analog output sense signals, which are classified by differences in magnitude, frequency, and current. This article explains how a mixed-signal ASIC was analyzed using various signal stimuli.

A wide range of electrical faults are revealed through thermal laser stimulation (TLS). In principle, an electrical parameter, typically current or voltage, is monitored for changes caused by the heating effects of the laser. Most test setups are designed to limit the activity of the device in order to minimize the signal-to-noise ratio, but in some cases, the fault’s electrical footprint can only be detected when the device is stimulated in a dynamic way. This article describes the setup and implementation of various dynamic TLS methods and presents example applications demonstrating the advantages and limitations of each approach.

This article provides a detailed overview of silicon characterization and debug process, describing the intent of each step, the challenges involved, and the FA tools and techniques used. It also discusses the difference between electrical and functional failures, the implementation and use of on-chip debugging resources, the important role of schmoo plots.

Parametric analysis of SRAM cells is widely used to locate faults and analyze device failures, but the pico-probing and bit-line multiplexing required for data acquisition is becoming increasingly difficult. This article explains how the addition of an on-die low-yield analysis circuit eliminates the problem. The simplicity of the measurement circuit and the potential to use a known library of curves, makes low-yield analysis one of the most versatile DFT techniques for cache fault isolation.

Faster time-to-production of a new product is the common goal of design houses and foundries. This article demonstrates how foundries can contribute through post silicon validation, which allows design houses to focus on more complicated issues.

Off-state leakage currents account for roughly half of the total current is today’s ICs, and with each new generation of technology, the problem is getting worse. Failure analysts, however, see things differently. Light emission associated with leakage current is a rich source of information about the operation of ICs. In this article, the authors explain how they use this light to monitor logic states, measure temperatures, analyze cross-talk and power distribution noise, and diagnose broken scan chains. Light emission from off-state leakage current (LEOSLC) is shown to be especially useful for diagnosing faults that reside in scan clock trees, which are otherwise very difficult to detect.

In most cases, microelectronic failure analysis is rooted in the observation of voltage, either as logic levels or as time-based waveforms. This is due largely to the ease of making such measurements. As a result, current measurement is often overlooked. This article discusses aspects of current measurement that can be used during fault localization, often providing information that cannot be obtained by other means.

This article provides a recap and summaries of the EDFAS Virtual User Group Workshop held in January 2021. The summaries cover key participants, presentation topics, and discussion highlights from the Focused Ion Beam, Sample Preparation, Contactless Probing and Nanoprobing, and System on Package virtual group meetings.

This article explains how the success rate of in-line scan chain logic macros can be nearly doubled for certain types of failures with the help of laser voltage imaging and laser voltage probing. The authors provide background information on LVI, LVP, and scan chain logic macros and show how they are used to diagnose skip test, clock-type, and soft single-latch failures.

The 45th International Symposium for Testing and Failure Analysis (ISTFA 2019) was held in Portland, Oregon, November 10-14, 2019. This article gives a brief summary of the highlights and identifies key contributors to the event. It also includes highlights of panel discussions from the inaugural meeting of Women in Electronics Failure Analysis (WEFA) and the panel discussion "What Does Artificial Intelligence Mean to Failure Analysis Engineers?" The article concludes with a brief recap of each of the four User Group meetings that took place during the conference: Sample Prep, System on Package, FIB/Circuit Edit, and Nanoprobing.

This article provides a systematic overview of knowledge-based and machine-learning AI methods and their potential for use in automated testing, defect identification, fault prediction, root cause analysis, and equipment scheduling. It also discusses the role of decision-making rules, image annotations, and ontologies in automated workflows, data sharing, and interoperability.

Scan chains help detect and identify failures in integrated circuits, but they are also susceptible to failure themselves. When scan chains break, it does not necessarily render them useless. Normally, scan chains can be debugged and diagnosed so that they can be fixed or used while masking out vector bits associated with broken or corrupted portions of the chain. This article describes the different ways that scan chains can break and how it tends to affect their performance. It explains how to repair various types of scan chain failures or at least regain partial use for limited testing purposes.