Table of Contents
Chapter 1 The Importance of High-Reliability Products at Market Introduction—How and Why to Do a HALT
Introduction
An Overview of HALT
Comparisons of Products with and without HALT
The HALT Process
Cold and Hot Step Stress
Rapid Thermal Transitions
Vibration Step Stress
Combined Stresses in HALT
Other HALT Stresses and Special Situations
Verification HALT
A Perspective on Implementing Corrective Action as a Result of HALT
A Proposal for Managing HALT Limits and Issues
Using the Process
Vibration
Comments Regarding the Various Vibration Tables
Conclusion
HALT Summarized
Illustrating the Value of HALT
Some Thoughts Regarding Ruggedizing a Product Prior to HALT
The Recording of Failures and Corrective Action
Troubleshooting Products under Stress Conditions
Conclusion
Chapter 2 Highly Accelerated Stress Screen—HASS
Introduction
The ABCs of Building Robust Products
Production Product Stress Screen HASS
Why Does HASS Work?
Vibration
Rate of Change of Temperature
Acceleration Factor for Thermal Cycling
Which Stress Levels Are Appropriate?
Precipitation and Detection Screens
Precipitation Screens
Detection Screens
A Comment on HASS Profiles or Screens
Proof of Screen
Fixture Characterization
The HASS Profile
Defect Detection
Life Determination in Proof of Screen
Screen Tuning
Cables for HASS
HASS Summarized
Some HASS Successes
A Word of Caution
Conclusion
Chapter 3 Beyond the Paradigm of Environmental Stress
Screening—Using HASA
Introduction
Background
Statistical Process Overview
Statistics—The System
Scenario 1
Scenario 2
A Control Chart for the HASA Process
The Monitoring System Issues
Problems Uncovered through HASA
An Observation on Using Equation 3.1
Conclusion
Chapter 4 Refinements on Highly Accelerated Stress
Audit (HASA)
Introduction
Background and Assumptions
Application of the Statistics
A Graphical Tool for Detecting Defect Level Changes
Conclusion
Introduction to an Improved HASA Process
HASA Process Flow
Typical Lot Acceptance Sampling Plan
HASA Acceptance Sampling Plan
Chapter 5 The Equipment Required to Perform
Efficient Accelerated Reliability Testing
Overview
System Block Diagram
Temperature
Turbulence
Heating
Cooling .
A Comparison of LN2 Systems and Compressor Systems for HALT and HASS .
Vibration
Control Systems
The Chamber
Product Accessibility
Ducting Air
Work-Area Audible Noise Level
Serviceability
Service
Maximum System Capabilities
Post-Sales Support
Auxiliary Equipment, Operator Safety, and ESD
Failure Analysis Lab
Why Develop an In-House Failure Analysis Capability?
Initial Analysis
Metallographic Sample Preparation
Advanced Techniques
Failure Analysis Conclusion
Conclusion
Chapter 6 How to Sell New Concepts to Management
Introduction
Overview
The Situation Today
The Proposed Program
Addressing Potential Management Concerns
The Savings
Conclusion
Chapter 7 Some Commonly Asked Questions and Observations
How Would Someone Compare ESS and HASS?
What Is HALT in a Few Words?
How Would One Compare Product Qualification Methods and HALT?
Is HALT for Quality Improvement or Is It Intended to Replace RGT and MTBF Tests?
Is There Any Merit to Subjecting a Product to Stresses Far Beyond Its Design Specifications?
What Are Product Specific and Generic Stresses?
If HALT and HASS Are So Great, Why Isn’t Everyone Using HALT and HASS?
Is One HALT Enough?
At What Product Level Should HALT Be Performed?
Who Should Be Involved with the Accelerated Reliability Program?
Physically, Where Should HALT Be Performed?
How Many Units Are Required, and What Can Be Done With Them Once We’re Finished with HALT?
Why a Cultural Change May Be Required in Order to Perform a Successful HALT
Can a Conventional Chamber and Vibration Table Be Used to Perform a HALT?
Are All Six Degrees of Freedom Shakers the Same?
Are There Any Known Problems in Applying Product Temperature Ramp Rates of 60°C per Minute?
Are There Any Advantages to Performing Sequential Rather Than Combined Stress Regimens?
Do HALT and HASS Just Uncover Electronic Defects?
Can HASS Eliminate My Production Steady State, Elevated Temperature Burn-in?
At What Levels of Temperature and Vibration Can I Consider the Product Robust?
How Can You Justify Doing HALT on Products with a Very Short Field Life?
What Are the Yearly Maintenance Costs for the HALT Chambers?
Can the Results of HALT Be Used to Accurately Estimate Field Life?
Appendix A The Derivation of Equation 3.1
Glossary
References
Trademarks and Service Marks