Workshops are application-oriented and structured to combine field experience with scientific research to solve everyday problems. They are offered on Thursday, December 1.


Light Emitting Diode (LED) Failure Mechanisms, Reliability, and Qualification

Diganta Das, Ph.D., CALCE, University of Maryland
Thursday, December 1, 2016 | 8:30am-5:00pm


This course will cover the latest progress in understanding of failure mechanisms of LEDs that occur at the die, interconnects, and within the package including electrostatic discharge, delamination, and phosphor thermal quenching. The driving factors for precipitating these mechanisms will be discussed to help the developers and users of LEDs control the mechanisms and assess reliability. The course will also inform on the relevant standards for LED testing and reliability assessment, the qualification methods currently in use by major LED manufacturers, and the qualification philosophies that will be most suitable to meet future needs for LED lighting applications.

Course Outline

1. Introduction to LEDs

  • Characteristics
  • Application Areas
  • History
  • Supply Chain
  • Structure
  • Types

2. LED Packaging

  • Lens types
  • Phosphors
  • Wire bonded and flip chip LEDs
  • Light distribution
  • Comparison of different manufacturers
  • Cross-sectioning LEDs

3. Assessing Reliability

  • Current Methods by LED manufacturers
  • Reliability and Physics-of-Failure (PoF) approach
  • Failure Modes, Mechanisms, and Effects Analysis (FMMEA)

4. Failure Modes and Mechanisms in LEDs

  • Die level
    • Defects (Dislocation, Dark-line, and Dark-spot)
    • Diffusion of Dopants/Impurities into Quantum Well
  • Interconnect level
    • Wirebond Fatigue
    • Delamination
  • Package level (90 minutes)
    • Carbonization of Encapsulant
    • Encapsulant Yellowing
    • Cracking (Epitaxial, Lens, Substrate)
    • Solder Joint Fatigue
    • Tarnishing
    • Electrochemical Migration

5. Qualification methods for LEDs

  • LED lifetime
  • Current Standards and Test procedures for LEDs
  • Issues with current qualification methods

6. PHM technology of LEDs

  • Diagnostic Techniques
  • Prognostic Techniques

7. Summary

Who Should Attend?

  • Design Engineers Using LEDs
  • Component Engineers
  • Reliability Engineers
  • Test and Qualification Engineers

Instructor Bio
Dr. Diganta Das (Ph.D., Mechanical Engineering, University of Maryland, College Park, B.Tech, Manufacturing Science and Engineering, Indian Institute of Technology) is an Associate Research Scientist at the Center for Advanced Life Cycle Engineering. His expertise is in reliability, environmental and operational ratings of electronic parts, uprating, electronic part reprocessing, counterfeit electronics, technology trends in the electronic parts and parts selection and management methodologies. He performs benchmarking processes and organizations of electronics companies for parts selection and management and reliability practices.

His current research interests include electronic parts supply chain, counterfeit electronics avoidance and detection, light emitting diode failure mechanisms, cooling systems in telecommunications infrastructure and their impact on reliability, and power electronics reliability. In addition, Dr. Das is involved in prognostics based risk mitigation of electronics. Dr. Das has published more than 75 articles on these subjects, and presented his research at international conferences and workshops.

Dr. Das leads the Educational Outreach of CALCE with responsibility to develop inter-organizational agreements on joint educational programs, training and internship program, and professional development. He is an Associate Editor of the journal Microelectronics Reliability. He is a Six Sigma Black Belt and a member of IEEE, IMAPS and SMTA.

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