Study of $2 \times 4 \mu\mathrm{m}$ Pitch Capsule Shaped TSVs and $2 \mu \mathrm{m}$ Pitch Tsvs in WoWoW Integration

We have successfully developed the via last TSVs integration technology which consists of $2 \times 4 \mu ~\mathrm{m}$ pitch capsule shaped TSVs and $2 \mu ~\mathrm{m}$ pitch circular TSVs for the first time. The capsule shaped TSVs has higher conductance per area by 55 % than $2 \mu ~\mathrm{m}$ pitch circular TSVs. Circular TSVs are advantageous for fine pitch layout. Capsule-shaped TSVs are advantageous in terms of conductive performance and TDDB reliability. The integration of circular TSVs and capsule-shaped TSVs takes all these advantages. This integration technology is expected to increase current capacity and improve signal transmission efficiency in 3D stacked circuits.