Indium Through Si Via for Quantum Chiplet Integration

Chiplet integration is pivotal for Fault-Tolerant Quantum Computing systems, enabling heterogeneous device assembly via 2.5D interposer technology, improving density and reduced quantum signal loss. Indium (In) is a promising candidate for superconducting interconnect material for the integration. This study demonstrated In-ECD filling in TSVs structures and evaluated intermetallic compounds formation using Cu and Ru seed layers. Additionally, In overburden removal by CMP is also demonstrated using alkaline slurry, achieving smoother surfaces compared to acidic slurry.