Electronic Materials Laboratory

Research Activities

Research on Reliability Failure Mechanisms in Cu and Al Interconnects

The success of current and future microelectronic technology hinges greatly on the integration of interconnect structure with desired materials, structure, dimension and reliability. But, continuing miniaturization makes the interconnects to be excessively prone to reliability failures induced by such as stress voiding and electromigration. Our research team investigates the fundamental mechanism behind such failures in both Al and Cu interconnects.

Research on Dielectric Layer Reliability

Dielectric layer is an essential part of interconnects used in microelectronics and it suffers from various types of failure with the use of less compact materials for the purpose of reducing its dielectric constant. One of the most notable examples of such material is the porous low-k, that is being implemented in industry. Future dielectrics are expected to contain even higher porosity than what is used now, and it is found to show various types of unexpected properties that negatively affect the reliability. Our team investigates the underlying mechanism behind such mechanisms including viscoplasticity as well as the influence of mobile ion migration.

Electromigration in Solder Interconnects and Wirebonds

The microstructure and its evolution in solder joint and wirebond interface is the revived research topic with major technology change in microelectronics industries, that is the use of microscale solder joint for advanced device packaging and the use of Cu wirebond rather than Au wire. Such changes spur various new metallurgical problems of scientific and technological importance. Our team is investigating the thermodynamics of voiding in solder joint as well as the mechanism of intermetallic layer growth induced by interdiffusion in various material combinations.

Study of Phase Equilibria in Cu-Al system

This research is motivated by our findings suggesting that Cu-rich side of Cu-Al binary system shows different microstructure from what is predicted by the known phase diagram. We are investigating the phase diagram itself, while thermodynamic simulation on the phase formation is conducted for substantiation of our findings. This research is related to more on the basic material science but its outcome is expected to impart sizable impacts to various applications.


  • Choong-Un Kim, Ph.D. Professor & Associate Chair
  • Post-doc: M-Y. Kim, PhD.
  • Visiting Scholar: S. Haghshenas

Graduate Students

  • P. Liu (Ph. D.)
  • Valery Ouvarov Bancalero (Ph.D)
  • Y. R. Kim (Ph.D.)
  • J. Miles (Ph.D.)
  • H. Khaled (Ph.D.)
  • H. Naik (MS)
  • K. Claunch (MS)

Facilities and Equipment

  • Reliability testing
    • Electromigration testing systems (400 DUTs)
    • Micro-bending and shear fatigue system for solder joint.
    • High resolution IV testing system
    • Voltammetry metrology setup.
    • General corrosion testing and galvanic corrosion testing.
  • Processing
    • Solder processing facility
    • PCB patterning facility
  • Characterization
    • Metallurgical microscope
    • Topometrix AFM
    • JEOL 6400 SEM with WDX for in-situ experiments.