Low-cost and TSV-free monolithic 3D-IC with heterogeneous integration of logic, memory and sensor analogy circuitry for Internet of Things

Abstract

For the first time, a CO2 far-infrared laser annealing (CO2-FIR-LA) technology was developed as the activation solution to enable highly heterogeneous integration without causing device degradation for TSV-free monolithic 3DIC. This process is capable to implement small-area-small-load vertical connectors, gate-first high-k/metal gate MOSFETs and non-Al metal inter-connects. Such a far-infrared laser annealing exhibits excellent selective activation capability that enables performance-enhanced stacked sub-40nm UTB-MOSFETs (Ion-enhanced over 50 %). Unlike TSV-based 3D-IC, this 3D Monolithic IC enables ultra-wide-IO connections between layers to achieve high bandwidth with less power consumption. A test chip with logic circuits, 6T SRAM, ReRAM, sense amplifiers, analog amplifiers and gas sensors was integrated to confirm the superiority in heterogeneous integration of proposed CO2-FIR-LA technology. This chip demonstrates the most variable functions above reported 3D Monolithic ICs. This CO2-FIR-LA based TSV-free 3D Monolithic IC can realize low cost, small footprint, and highly heterogeneous integration for Internet of Things.