Moon-Hwan Chang a, Diganta Das a, P.V. Varde a,c, Michael Pecht a,b,*
a CALCE Center for Advanced Life Cycle Engineering, University of Maryland, College Park, MD 20742, United States
b Center for Prognostics and System Health Management, City University of Hong Kong, Hong Kong, China
c Homi Bhabha National Institute, Reactor Group, Dhruva Complex, Bhabha Atomic Research Centre, Mumbai 400 085, India
The increasing demand for light emitting diodes (LEDs) has been driven by a number of application categories, including display back-lighting, communications, medical services, sign-age, and general illumination. The construction of LEDs is somewhat similar to microelectronics, but there are functional requirements, materials, and interfaces in LEDs that make their failure modes and mechanisms unique. This paper presents a comprehensive review for industry and academic research on LED failure mechanisms and reliability to help LED developers and end-product manufacturers focus resources in an effective manner. The focus is on the reliability of LEDs at the die and package levels. The reliability information provided by the LED manufacturers is not at a mature enough stage to be useful to most consumers and end-product manufacturers. This paper provides the groundwork for an understanding of the reliability issues of LEDs across the supply chain. We provide an introduction to LEDs and present the key industries that use LEDs and LED applications. The construction details and fabrication steps of LEDs as they relate to failure mechanisms and reliability are discussed next. We then categorize LED failures into thirteen different groups related to semiconductor, interconnect, and package reliability issues. We then identify the relationships between failure causes and their associated mechanisms, issues in thermal standardization, and critical areas of investigation and development in LED technology and reliability.
Full text available from the publisher and to the CALCE Consortium Members.