Research
Xuejun Fan, Ph.D.
Professor
View Dr. Fan's laboratory equipment
Dr. Fan's research primarily focuses on the characterization, modeling and reliability of materials, components, and systems in micro-/nano- electronics manufacturing and packaging. Areas include:
- Multi-physics/multi-scale modeling and characterization for advanced interconnect materials
- Moisture-related reliability in electronic packaging and manufacturing
- Design and reliability in 3D integration, wafer-level packaging, and heterogeneous system
- Solder joint reliability
- LED packaging, system integration, and reliability
- Wide bandgap power electronics packaging and thermal management
His research has been supported by National Science Foundation (NSF), Department of Energy (DOE), Semiconductor Research Corporation (SRC), and many industrial partners such as Texas Instruments (TI), Intel, Nvidia, Robert Bosch GmbH, Infineon Technologies, Philips, etc.
Tailoring Material Properties for 3D Microfabrication: In-Situ Experimentation and Multi-Scale Modelling
The effects of nanoscale conformal coatings of amorphous silicon carbide on the mechanical properties of carbon nanotube pillars are investigated. Several interesting mechanical failure modes such as bamboo and brittle-like composite rupture are observed as coating thickness increases (see Advanced Functional Materials, 24 (36), 5737–5744. 2014).
Moisture Sensitivity of Plastic Packages of IC Devices
For the past two decades, Dr. Fan has worked on moisture related issues in microelectronics packaging. This book provides the state-of-the-art development related to moisture issues in plastic packages. The book has been downloaded more than 30,000 times since its publication. He received IEEE CPMT Exceptional Technical Achievement Award for the contributions in the area of modeling and characterization in moisture related reliability in IC packaging (see Moisture Sensitivity of Plastic Packages of IC Devices. Springer, New York, 2010).
A Convection-Diffusion Model for Moisture Transport
A convection-diffusion porous model is derived to characterize moisture transport in polymeric composites. The coupling of convection and diffusion is achieved by combining the law of conservation of mass, Darcy's law, the relation for liquid-vapor chemical equilibrium, and the ideal gas law. The convection-diffusion model is able to interpret moisture desorption data collected in a rapid heating process. Vapor pressure evolution can also be predicted (see Journal of Polymer Science Part B: Polymer Physics. 53, 1440–1449. 2015).
Solder Joint Reliability Under Thermal Cycling and/or Impact Loading
The reliability under impact loading and thermal cycling for three different package structures: ball on I/O wafer level package (WLP), copper post WLP, and chip-scale ball grid array (BGA) package, were studied (see Microelectronics Reliability, 50, 536–546, 2010; IEEE Transactions on Components, Packaging and Manufacturing Technology. 3(1), 52-60. 2013).
Three scenarios of the secondary component attachment for solder ball reliability under impact loading were considered (see IEEE Transactions on Components, Packaging and Manufacturing Technology. 2(11), 1802-1810, 2012).
Achieving Warpage-Free Packaging: A Capped-Die Flip Chip Package Design
In the capped-die flip chip package, a metal cap tightly covers and bonds with the die through an adhesive material, leading to a capped-die with a higher effective CTE. By adjusting the thickness of metal cap, the effective CTE of the capped-die may match with that of substrate, theoretically achieving zero-warpage or warpage-free (see IEEE Transactions on Components, Packaging and Manufacturing Technology. 6(9), 1308 – 1316. 2016).
2000-Hour Accelerated Luminous Flux Depreciation Test for LED Luminaires and Lamps
An accelerated test method for luminous flux depreciation has been developed to reduce the test time within 2000 hours at an elevated temperature. The method is based on lumen maintenance boundary curve, obtained from a collection of LED source lumen depreciation data, known as LM-80 data. The exponential decay model and Arrhenius acceleration relationship are used to determine the new threshold of lumen maintenance and acceleration factor (see Reliability Engineering & System Safety. 147, 84–92. 2016).
Wrinkling Analysis of Stretchable Electronics
Wrinkling analysis in a film bonded to a compressible compliant substrate in large deformation, and the dynamic stability of flexible electronic structures under step loads were studied (see European Journal of Mechanics A: Solids 58, 247-255. 2016; Science China Physics, Mechanics & Astronomy. 59:624601. 2016; Computers, Materials & Continua, 44 (3), pp.205-221, 2014).
Lock-in Thermography (LiT) in Semiconductor Packages
Resilient Coastal Infrastructure Integrity Research
Research into the resilient coastal infrastructure for Southeast Texas region is vital, given the region’s unique environmental severity. Southeast Texas homes one of the most complex infrastructure systems in the United States (pipelines, railways, port and plant facilities, bridges and highways etc.). The deleterious effects of marine tropical environments, including temperature extremes, humidity, moisture, dust, mud, oil and solvents, corrosive effects of chemicals, and the destructive effects of tropical storms and hurricanes, all require special technical expertise.