In recent years the concern over Hardware Trojans has come to the forefront of hardware security research as these types of attacks pose a real and dangerous threat to both commercial and mission-critical systems. One interesting threat model utilizes semiconductor physics, specifically aging effects such as Electromigration (EM). However, existing methods for EM-based Trojans rely on empirical Black's models can easily lead to performance degradation and less accuracy in Trojan activation time prediction. In this article, we study the EM-based Trojan attacks based on recently developed physics-based EM models. We propose novel EM attack techniques in which the EM-induced hydrostatic stress increase in a wire is caused by wire structure or layer changes without changing the current density of the wires. The proposed techniques consist of sink/reservoir insertion or sizing and layer switching techniques based on the early and late failure modes of EM wear-out effects. As a result, the proposed techniques can have minimal impact on circuit performance, which is in contrast with existing current-density-based EM attacks. The proposed techniques can serve as a trigger for the EM attack on power/ground networks and signal and clock networks. Furthermore, we also present two potential EM attack mitigation techniques, namely, the split fabrication and burn-in testing.