Hermeticity of Electronic Packages
- Hal Greenhouse, Bendix Aviation Corporation (retired)
This is a book about the integrity of sealed packages to resist foreign gases and liquids penetrating the seal or an opening (crack) in the packageÃ¹especially critical to the reliability and longevity of electronics. The author explains how to predict the reliability and the longevity of the packages based on leak rate measurements and the assumptions of impurities. Non-specialists in particular will benefit from the author's long involvement in the technology. Hermeticity is a subject that demands practical experience, and solving one problem does not necessarily give one the background to solve another. Thus, the book provides a ready reference to help deal with day to day issues as they arise.The book gathers in a single volume a great many issues previously available only in journalsÃ¹or only in the experience of working engineers. How to define the ""goodness"" of a seal? How is that seal measured? How does the integrity of the seal affect circuit reliability? What is the significance of the measured integrity of the seal? What is the relationship of Residual Gas Analysis and the seal integrity? The handbook answers these questions and more, providing an analysis of nearly 100 problems representative of the wide variety of challenges that actually occur in industry today.View full description
Packaging engineers, scientists and technicians as well as novice users, package designers, reliability engineers and those who measure and evaluate the integrity of packages, especially in the field of microelectronics.
- Published: October 2011
- Imprint: WILLIAM ANDREW
- ISBN: 978-1-4377-7877-9
Table of Contents1. Gas Kinetics 1.0 GENERAL CONSIDERATIONS 1.1 Boyle's Law 1.2 Charles's Law (1787) or Gay-Lussac's Law (1802) 1.3 Dalton's Law (1801) 1.4 Avogadro's Law (1811) 1.5 Avogadro's Number 1.6 Loschmidt's Number 2.0 MATHEMATICAL RELATIONSHIPS 3.0 PROBLEMS AND THEIR SOLUTIONS2. Viscous and Molecular Conductance of Gases 1.0 CONDUCTION OF GASES 2.0 VISCOUS CONDUCTION 3.0 MOLECULAR CONDUCTION 4.0 CONDUCTION IN THE TRANSITIONAL RANGE 5.0 COMPOSITE CONDUCTANCE EQUATIONS 6.0 SMALLEST THEORETICAL LEAK 7.0 DISCUSSION 8.0 PROBLEMS AND THEIR SOLUTIONS 3. The Flow of Gases 1.0 GENERAL FLOW CHARACTERISTICS 2.0 MEASURED, STANDARD AND TRUE LEAK RATES 3.0 LEAK RATES FOR DIFFERENT GASES 4.0 CHANGE OF PARTIAL PRESSURE WITH TIME 5.0 VISCOUS FLOW FROM SEALED PACKAGES 6.0 VISCOUS FLOW RATES OF DIFFERENT GASES 7.0 PROBLEMS AND THEIR SOLUTIONS4. The Flow of Gases into Sealed Packages 1.0 MOLECULAR FLOW 2.0 VISCOUS FLOW INTO AND OUT OF SEALED PACKAGES 3.0 THE SIMULTANEOUS FLOW OF GASES IN BOTH DIRECTIONS 4.0 PROBLEMS AND THEIR SOLUTIONS5. Water in Sealed Packages 1.0 WATER RELATED CORROSION AND CIRCUIT FAILURES 2.0 WATER LEAKING INTO A SEALED PACKAGE FROM THE OUTSIDE ENVIRONMENT 3.0 WATER OUTGASSING INSIDE THE PACKAGE 4.0 WATER AS A RESULT OF A CHEMICAL REACTION WITHIN THE PACKAGE 5.0 PROBLEMS AND THEIR SOLUTIONS6. Understanding Helium Fine Leak Testing in Accordance with Method 1014, MIL-STD-883 1.0 PURPOSE OF THE TEST 2.0 BASIS OF THE TEST 3.0 FIXED METHOD OF TESTING 4.0 FLEXIBLE METHOD OF TESTING 5.0 COMPARISON OF THE FIXED AND FLEXIBLE METHODS 6.0 THE EFFECT OF VISCOUS FLOW 7.0 LEAK RATE LIMITS ARE TOO LENIENT 8.0 BACKFILLING THE PACKAGE WITH HELIUM 9.0 BOMBING AFTER BACKFILLING 10.0 PROBLEMS AND THEIR SOLUTIONS7. Fine Leak Measurements Using a Helium Leak Detector 1.0 PRINCIPLE OF OPERATION 2.0 DEFINITIONS 3.0 CALIBRATION USING A STANDARD LEAK 4.0 MEASUREMENT ERRORS, NOT INCLUDING BACKGROUND ERRORS 5.0 BACKGROUND ERRORS 6.0 ERRORS DUE TO HELIUM ON THE EXTERNAL SURFACE OF THE PACKAGE 7.0 MINIMUM DETECTABLE LEAK (MDL) 8.0 CORRELATION OF STANDARD LEAKS 9.0 LOCATING LEAKS IN PACKAGES 10.0 PROBLEMS AND THEIR SOLUTIONS8. Gross Leaks 1.0 INTRODUCTION 2.0 FORCING A LIQUID INTO A PACKAGE 3.0 FLUOROCARBON VAPOR EXITING A PACKAGE 4.0 THE BUBBLE TEST 5.0 THE VAPOR DETECTION TEST 6.0 THE WEIGHT GAIN TEST 7.0 OPTICAL LEAK TEST 8.0 PENETRANT DYE TEST 9.0 FLUOROCARBONS FROM A RESIDUAL GAS ANALYSIS 10.0 QUANTITATIVE COMPARISON OF GROSS LEAK TEST METHODS 11.0 PROBLEMS AND THEIR SOLUTIONS9. The Permeation of Gases Through Solids 1.0 DESCRIPTION OF THE PERMEATION PROCESS 2.0 EFFECT OF TEMPERATURE ON PERMEATION 3.0 TREATING PERMEATION AS A LEAK RATE 4.0 WATER VAPOR PASSING THROUGH PLASTICS 5.0 PROBLEMS AND THEIR SOLUTIONS10 Residual Gas Analysis (RGA) 1.0 DESCRIPTION OF THE TEST 2.0 WHAT THE TEST MEASURES 3.0 CALCULATION OF LEAK RATES FROM RGA DATA 4.0 INTERPRETATION OF RGA DATA 5.0 THE QUALIFICATION OF SMALL PACKAGES USING RGA 6.0 PROBLEMS AND THEIR SOLUTIONSAppendix 1.0 LIST OF SYMBOLS AND DIMENSIONS 2.0 DIMENSIONS 3.0 CONVERSION FACTORS FOR PRESSURE/VACUUMAcknowledgmentIndex