Search Results for root cause analysis

Statistics, data analysis, root cause analysis, and problem-solving processes play a key role in failure investigations. This chapter explains how to collect failure investigation data, how to build and maintain a database for company-related failures, and how to use corresponding statistics including type of failure, material, and root cause. It describes the purpose and benefits of conducting a root cause analysis and the factors, namely relative failure importance and company value, that determine when an investigation should be performed. The chapter also discusses the four-step problem-solving process as it applies to failure investigation, how to assemble an investigation team, and the details of organization and planning. It concludes with a case history of the Firestone 500 steel-belted tire failure, stressing the importance of a systematic approach to failure investigations.

In embedded systems, the separation between system level, board level, and individual component level failure analysis is slowly disappearing. In order to localize the initial defect area, prepare the sample for root cause analysis, and image the exact root cause, the overall functionality has to be maintained during the process. This leads to the requirement of adding additional techniques that help isolate and image defects that are buried deeply within the board structure. This article demonstrates an approach of advanced board level failure analysis by using several non-destructive localization techniques. The techniques considered for advanced fault isolation are magnetic current imaging for shorts and opens; infrared thermography for electrical shorts; time-domain-reflectometry for shorts and opens; scanning acoustic microscopy; and 2D/3D X-Ray microscopy. The individual methods and their operational principles are introduced along with case studies that will show the value of using them on board level defect analysis.

This chapter describes some common pitfalls encountered in failure investigations and provides guidance to help engineers recognize processes and “quick fixes” that companies often try to substitute for failure analysis. It discusses three important skills and characteristics that a professional engineer must improve to conduct an effective and successful failure investigation, namely technical skills, communication skills, and technical integrity. The chapter also provides information on the additional basic tools available for failure investigation and root cause determination: the Kepner-Tregoe structured problem-solving method, PROACT software for root cause analysis developed by the Reliability Center, Inc., and other processes and methods developed by the Failsafe Network, Inc., and Shainin LLC.

Over the revolutionary era of semiconductor technology, Computer-Aided Design Navigation (CADNav) tools have played an increasingly critical role in silicon debug and failure analysis (FA) in efforts to improve manufacturing yield while reducing time-to-market for integrated circuit (IC) products. This article encompasses the key principles of CADNav for various aspects of semiconductor FA and its importance for improved yield and profitability. An overview of the required input data and formats are described for both IC and package devices, along with key considerations and best practices recommended for fast fault localization, accurate root cause analysis, FA equipment utilization, efficient cross-team collaboration, and database management. Challenges with an FA lab ecosystem are addressed by providing an integrated database and software platform that enable design layout and schematic analysis in the FA lab for quick and accurate navigation and cross-tool collaboration.

This chapter is a brief bibliography of content sources that provide information related to the subject matter of the book.

Designs and materials continue to become more complex, with novel technologies developed to create them, and novel instruments invented to analyze them. Engineers at all stages of the design and manufacturing process should appreciate the reasons why formal failure analysis is performed. This chapter describes why failure analysis is conducted and outlines the responsibilities of the failure analyst.

Root cause of failure in automotive electronics cannot be explained by the failure signatures of failed devices. Deeper investigations in these cases reveals that a superimposition of impact factors, which can never be represented by usual qualification testing, caused the failure. This article highlights some of the most frequent early life failure types in automotive applications. It describes some of the critical things to be considered while handling packages and printed circuit board layout. The article also provides information on failure anamnesis that shows how to use history, failure signatures, environmental conditions, regional failure occurrences, user profile issues, and more in the failure analysis process to improve root cause findings.

The first step in die-level failure analysis is to narrow the search to a specific circuit or transistor group. Then begins the post-isolation process which entails further localizing the defect, determining its electrical, physical, and chemical properties, and examining its microstructure in order to identify the root cause of failure. This chapter assesses the tools and techniques used for those purposes and the challenges brought on by continued transistor scaling, advanced 3D packages, and new IC architectures. The areas covered include sample preparation, nanoprobing, microscopy, FIB circuit edit, and scanning probe microscopy.

This chapter describes the nine steps of a failure investigation. The steps add detail to the problem-solving process introduced in Chapter 3. The first five steps are (1) understanding and negotiating the investigation goals, (2) obtaining an understanding of the failure, (3) objectively and clearly identifying all possible root causes, (4) evaluating the likelihood of each root cause, and (5) converging on the most likely root cause(s). Many failure investigations stop at this point, but significant value is provided in the next four steps, which are (6) identifying all possible corrective actions, (7) evaluating each corrective action, (8) selecting the optimal corrective action(s), and (9) evaluating the effectiveness of each corrective action. Each step is discussed in detail with examples along with information on the procedures to be followed and resources needed for the investigation.

Semiconductor memories are superb drivers for process yield and reliability improvement because of their highly structured architecture and use of aggressive layout rules. This combination provides outstanding failure signature analysis possibilities for the entire design, manufacturing, and test process. This article discusses five key disciplines of the signature analysis process that need to be orchestrated within the organization: design for test practices, test floor data collection methodology, post-test data analysis tools, root cause theorization, and physical failure analysis strategies.

Failure investigation is an integral part of any design and manufacturing operation, providing critical information to solve manufacturing problems and assist in redesigns. This chapter addresses several aspects of failure investigation, beginning with the challenges of organizing such efforts and the need to define a clear and concise goal, direction, and plan prior to the investigation. It covers the causes of failure and the training and education organizations require to understand and prevent them. The chapter emphasizes the importance of discovering the root cause of failures, and uses examples to explain the factors involved and how to recognize them when the first appear.

Diagnosing the root cause of a failure is particularly challenging if the symptom of the failure is not consistently observable. This article focuses on Laser Assisted Device Alteration/Soft Defect Localization (LADA/SDL), a global fault isolation technique, for detecting such failures. The discussion begins with a section describing the three steps in LADA/SDL analysis setup: create the test loop with the fail flag and loop trigger, select the laser dwell time, and select the shmoo bias point. An overview of LADA/SDL workflow is then presented followed by a brief section on time-resolved LADA. The closing pages of the article consider in detail SDL laser interaction physics and LADA laser interaction physics.

In the second step of the four-step problem-solving process, the failure analysis team should identify all potential failure causes. This chapter discusses the steps involved in five such techniques for identifying potential causes of failure, namely brainstorming, mind mapping, Ishikawa diagrams, the “five whys” technique, and flow charting.

A turbine blade in an aircraft engine failed, fracturing at the root above the fir tree region. Fractography indicated that a fatigue crack initiated at the trailing edge of the blade and the final fracture occurred when the crack reached critical length. Although the exact cause of crack initiation could not be established, material defects, improper root loading, and high operating temperatures were ruled out. This chapter describes how investigators came to their conclusions and what they learned through visual and SEM examination and qualitative elemental analysis. It includes images of the microstructure and fracture surfaces and explains what some of the details reveal about the failure.

The ultimate goal of the failure analysis process is to find physical evidence that can identify the root cause of the failure. Transmission electron microscopy (TEM) has emerged as a powerful tool to characterize subtle defects. This article discusses the sample preparation procedures based on focused ion beam milling used for TEM sample preparation. It describes the principles behind commonly used imaging modes in semiconductor failure analysis and how these operation modes can be utilized to selectively maximize signal from specific beam-specimen interactions to generate useful information about the defect. Various elemental analysis techniques, namely energy dispersive spectroscopy, electron energy loss spectroscopy, and energy-filtered TEM, are described using examples encountered in failure analysis. The origin of different image contrast mechanisms, their interpretation, and analytical techniques for composition analysis are discussed. The article also provides information on the use of off-axis electron holography technique in failure analysis.

This report describes the failure of a gas turbine in a combined-cycle power plant and the examination and tests that were conducted to determine the cause. Based on microstructural analysis, hardness measurements, and tensile tests, the failure was attributed to inadequate clearances in the seal land region between two stages in the compressor section of the rotor. The report also recommends changes to remediate the problem.

Passive components can be broadly divided into capacitors, resistors, and inductors. Failure analysis of these components helps determine the root cause and improve the overall quality and reliability of the electronic systems. This article describes different failure analysis approaches used for these components. It discusses different types of capacitors along with their constructions and failure modes. The types include tantalum, aluminum electrolytic, multi-layered ceramics, film, and super capacitors. The article then provides a discussion on the two common types of inductors, namely, common mode choke coil and surface mount powder choke coil.

This chapter details the vibration limits for gearboxes. It focuses on critical speed and peak load. The chapter presents vibration measurement and analysis, which provides a quick and relatively inexpensive way to detect and identify mechanical problems before they become more serious and costly.