Kristof Croes, Group Leader, imec

Kristof Croes received his BSc in physics from the Catholic University of Louvain (Belgium) and MSc in biostatistics from the Limburgs Universitair Centrum (LUC). After that, he obtained the Ph.D degree, concerning the development of statistical techniques for planning reliability experiments. Afterwards, he joined the reliability business unit of XPEQT, first as the software responsible and then as the manager of the R&D. From 2003 till the end of 2006, he was product and application manager of the package-level reliability products of the Singapore-based company, Chiron holdings. In early 2007, he went back to research, working as a BEOL reliability engineer at imec. Currently, he is a group leader of the Reliability, Electrical Test and Modeling group, working on test, characterization (electrical, thermal and (thermo)-mechanical) and reliability with main focus on advanced interconnects (2D, 3D, OIO). Kristof was an (invited/tutorial) speaker at several leading-edge semiconductor conferences, such as IRPS, IITC and IEDM. He also (co)-authored more than 100 papers in the field of reliability.

Evaluation of Constant Power Electromigration for Si Photonics Heaters Applications

To allow operation at constant temperatures, on-chip heaters are essential structures for Si Photonics devices. As these structures are operated by high currents, electromigration is a key reliability concern. Classical electromigration tests, where a constant current is send through the device and where the resistance is monitored as a function of time, might be an over-pessimistic methodology for this application: during operation, to maintain a constant temperature, the current is lowered once the device starts to degrade. For classical tests, this lowering is not considered and thus the devices as stressed too much once degradation is initiated. In this work, we evaluated the electromigration method where, instead of a constant current, a constant power is send through the device and the potential gain in lifetime is assessed. This work was done using imec test structures and the FormFactor’s 1164 reliability test system with electromigration modules.