PhD - Leuven | More than two weeks ago
Solving a head-breaking reliability problem
Recent developments in advanced on-chip and 3D-TSV interconnects lead to the introduction of thermal gradients during chip operation and reliability testing. Also, metal or Si-heaters for Si photonics applications require high currents leading to thermal gradients.
Interconnects reliability is classically tested using constant current stresses at elevated temperatures. The interconnect failure mechanism triggered by these tests is called electromigration and the lifetime model used in this case is the classical Black's law. Unfortunately, this model is only valid if the Joule heating induced by the stress current in the metal line is limited. If this condition is not fulfilled, the parameters extracted with this model are meaningless.
While electromigration tests on nowadays interconnects fulfill the absence of Joule heating requirement, this is not the case in advanced on-chip and 3D-TSV interconnects (see figure). Obviously, for metal or Si-heaters for Si photonics thermal gradients need to be properly considered during reliability testing as well. As a result, a new approach to electromigration testing is needed.
The following activities are foreseen:
Required background: Physics or Electrical engineering
Type of work: 10% Literature. 30% Modeling, 10% Test structure, 50% Experimental
Supervisor: Ingrid De Wolf
Daily advisor: Kristof Croes
The reference code for this position is 2020-031. Mention this reference code on your application form.
Chinese nationals who wish to apply for the CSC scholarship, should use the following code when applying for this topic: CSC2020-15.