Ingrid de Wolf

Already very early in the development history of microelectronics components, researchers ran into problems with ‘stress’. Actually, one could have expected this: When putting different materials together, with different thermal expansion coefficients or lattice distances, and subjecting them to high temperature steps, stress is bound to pop-up. And too high stress easily results in damage. However, mechanical stress is not always bad. It affects important material properties such as the mobility of charge carriers and helps MEMS to stay straight. As such, it can be turned into something positive. Indeed, also microelectronics devices, in some cases, work better under stress.
This lecture will present the never-ending story of stress in microelectronics and show how stress was measured and modeled, and, depending on the situation, solved, used or circumvented. It is a story of the good, the bad and the ugly.

Ingrid De Wolf received the PhD in Physics from the KU Leuven, Belgium, in 1989. In the same year she joined IMEC, where she worked on microelectronics reliability, with special attention for mechanical stress analysis using micro-Raman spectroscopy and failure analysis.  From 1999 to 2014, she headed the group REMO, where research is focused on reliability, test and modelling of 3D technology, interconnect, OIO, MEMS and packaging. She (co-)authored more than 550 publications. She is fellow at IMEC, IEEE senior member, professor at the Department of Materials Engineering of the KU Leuven and program director of the Master of Nanoscience, Nanotechnology and Nanoengineering at the Faculty of Engineering Science at the KU Leuven.