Nanoscale Nondestructive Metrology of Nanoelectronics using Picosecond Ultrasonic Near-Field Optical Microscopy

Recent advances in plasmonics have enabled unprecedented control of light matter interaction, making it possible to concentrate optical energy within spatial regions with dimensions as small as a few nanometers. On the other hand, rapid progress in picosecond ultrasonics techniques opens a new gateway to study hypersonic acoustic wave propagation in nanostructures with ultrahigh temporal resolution. The objective of this work is to leverage these two advances by incorporating a plasmonic nanofocusing optical probe into picosecond ultrasonic techniques for detection of ultrafast laser generated bulk and surface acoustic waves with frequency components exceeding 100GHz, corresponding to acoustic wavelengths well below 100nm, with nanoscale spatial resolution and picosecond time resolution. This work is aimed at addressing the critical need for reliable nondestructive techniques capable of dimensional metrology of nanostructured thin films such as copper interconnects, monitoring of semiconductor manufacturing processes and components, and identifying integrated circuit defects that lead to device failure. This project would, (1) develop a new photoacoustic technique: Picosecond Ultrasonic Near-Field Optical Microscopy, for nanoelectronics defect and dimensional metrology, and (2) explore this technique for nanomechanical characterization of individual nanostructured samples. Furthermore, this work will potentially provide a framework for future development of ultrafast photoacoustic transducers and acousto-plasmonic modulators.