Investigation of TSV induced thermo-mechanical stress: Implementation of piezoresistive sensors and correlation with simulation

Abstract : This work deals with a methodology to evaluate residual stresses within microelectronic devices by using MOS (Metal Oxide Semiconductor) rosette stress sensors. The stress tensor was evaluated by carrying out electrical measurements on test vehicle: the bridge from electrical to stress values was ensured by the piezoresistive relations and, prior to further in-house calibration, coefficients from literature were employed. For correlation purpose, numerical simulations were performed in order to evaluate stresses induced by TSV (Through Silicon Via). In this paper, the whole framework is described, and stress fields evaluated from in-situ electrical measurements on CMOS65 rosette sensor are compared to simulated ones. Some of the ultimate targets of this work are to develop a validated framework to deeply understand TSV induced thermo-mechanical stresses and to allow design rules definitions for products reliability and transistor performances.