This award is for research supporting the development of a new material system for micro/nanoelectronic interconnects. The material system under study is expected to overcome several issues associated with copper interconnects. This material system will make it possible to fabricate nanoscale interconnects that possess low electrical resistance and high mechanical strength to provide a robust next generation of nano-interconnects. Utilizing advanced micro/nanofabrication processes, carbon nanotubes (CNTs) will be grown inside through-silicon vias (TSVs) and a copper matrix will be added to enhance the density, strength and conductivity of the CNTs. Electrical resistance of individual vias and daisy-chained vias will be measured and an analytical approach will be used to determine the preferred path of current and obtain insights on interface resistance of copper and CNT bundles. Mechanical strength will be investigated through bend tests and thermal expansion of wafers containing TSVs while the electrical resistance of TSVs will be monitored for resistance variation for failure detection. Finite element simulation will be used to verify and calibrate the experiments. Mechanical and thermo-mechanical fatigue durability will be examined.
Interconnects are an essential component of any electronic system. In particular, TSVs are key interconnects necessary for fabrication of three-dimensional integrated circuits (3D-ICs). Therefore, advancements in the area of interconnects will enhance three dimensional (3D) integration of complex electronic devices. If successful, this research will result in a new material system that is capable of resolving several performance and reliability issues that exist with copper interconnects today, such as high resistivity at very small dimensions and electromigration. The research conducted in this study will lead to new directions taken in the manufacturing and fabrication of micro/nanoelectronic devices and systems by facilitating miniaturization of sub-systems and providing a path for a high-yield, high-volume manufacturing process. Outreach activities include a college workshop for K-12 students, the recruitment of women and minorities into the research program in collaboration with the University of Alabama's LSAMP Program, and participation in an REU Site.
