3D integration technologies provide feasible and cost effective approaches for integrating architectures composed of heterogeneous technologies to realize future microprocessors targeted at the ”More than Moore” technology projected by ITRS. 3D integration supports heterogeneous stacking because different types of components can be fabricated separately,and layers can be implemented with different technologies.It is also possible to stack optical device layers or non-volatile memories (such as magnetic RAM (MRAM) or phase-change memory (PCRAM)) on top of microprocessors to enable cost effective heterogeneous integration [5] [6]. The addition of new stacking layers composed of new device technology will provide greater flexibility in meeting the often conflicting design constraints (such as performance, cost, power, and reliability),and enable innovative designs in future microprocessors.