A Novel Multi-Scale Method for Thermo-Mechanical Simulation of Power Integrated Circuits

Abstract

During development of power IntegratedCircuits (IC), several iterations between the design and test/ measurement steps are performed. Computer-aided engineering significantly shortens the product development process because the numerical simulations can identify and remediate most deficiencies during the design stage. The recent IC manufacturing technologies lead to ca. 10 4 -order scale separation between transistor cell details and the device active area, resulting in very complex IC models. For the IC complexity to be overcome, advanced multi-scale analysis methods are required to perform accurate simulations in a decent time (order of hours). This paper proposes an advanced and enhanced multi-scale simulation method for the thermo-mechanical analysis of power ICs. The computational IC structure is automatically generated from a Cadence layout and partitioned into far-field and homogenized regions -the macro-model. Detailed localized micro-scale sub-models are assigned to limited portions of the homogenized region. The two-way simulated data transfer between the homogenized macro-model and the micro sub-models is one multi-scale approach novelty proposed in this paper. The method is validated on a real test chip structure presented in literature. The proposed multi-scale approach in conjunction with the two-way macro-micro data transfer lead to similar accuracy in the prediction of defect location, yet with significant simulation time -and computational resource reduction (CPU time and RAM usage reduced by almost 80% and 60% respectively) compared to the method used as reference.

Test Structure Design for Defect Detection during Active Thermal Cycling

“…In conclusion, the width, the length, the density, and the grouping of the thin metal lines used as IMD cracking sensors can be conveniently adjusted in order to detect the desired failure mechanism while preserving a reasonable amount of the device metallization reliability. In order to make an assessment regarding an adequate placement of the sensors, the results of the thermo-mechanical simulations presented in [ 10 , 27 ] were taken into consideration. The simulations were carried out on almost identical metallization structures and the simulated stress and strain distributions suggested that the maximum plastic strain accumulation takes place in TTML, right underneath the PM bottom edge (along the XX’ axis in Figure 2 a).…”