Interfacial chemistry control to enhance advanced microelectronic fabrication and IC packaging reliability

Transistor miniaturization has enabled the digital revolution by dramatically and continually increasing the computing power that can be packed into computer chips but also imposed great challenges in nano-fabrication processes and integration control. In this talk, our recent efforts in interfacial chemistry control to facilitate back-end-of-line microelectronic fabrication and improve IC packaging reliability will be presented. Fabrication of 3nm chip will require extremely precise critical dimension control down to just a few atoms in length. At such minute dimensions, the exact control of chemical bonding breaking and forming is key to modern microfabrication. In close collaboration with Intel, our team successfully identified, for the first time, the chemical bonding structure of 2-nanometer fluorocarbon post-etch residues that covered the fragile porous low-k dielectrics trench nano-structure. We developed a highly sensitive optical probe (U.S. Patent 9,366,601) to track chemical bonding modifications across fluorocarbon etch residues and low-k dielectric nanostructure throughout the fabrication process. The insights we obtained led to an effective UV-induced removal process of these chemically-inert, hydrophobic, and Teflon-like fluorocarbon post-etch residues and minimize low-k dielectric damages. In the IC packaging area, we are working with TI and NXP to eradicate the corrosion defects in order to meet the stringent safety and reliability requirements of self-driving cars and wearable electronics. The corrosion mechanism of copper bonding wire and aluminum bond pad in low ppm levels of chloride contamination was established. A novel passivation coating was developed to control the Cu/Al interface to achieve an effective corrosion protection for automotive semiconductor devices.