Assessing Copper High Density-TSVs for Reliable Performance in Cryogenic Systems

This study evaluates copper High Density-Through Silicon Vias (HD-TSVs) in cryogenic environments, crucial for applications like quantum computing and astrophysics. The use of HD-TSVs notably allows for increased signal density, enabling device scaling. 1980 thermal cycles between 344 K and 77 K were conducted to assess the mechanical and electrical robustness of HD-TSVs to cryogenic conditions. Additionally, one thermal cycle was carried in a cryostat down to 2 K. In situ and ex situ electrical measurements show remarkable stability in the electrical resistances of the tested structures with a variation of less than ±3 %, even after 1980 of thermal cycles. These results confirm the robustness and electrical performance of copper HD-TSV at low temperatures, opening promises for their integration within cryogenic systems.