cowos

CoWoS, short for Chip-on-Wafer-on-Substrate, is TSMC's advanced-packaging family for placing large logic dies beside high-bandwidth memory and connecting them through extremely dense package wiring. **The classic form is 2.5D integration.** Logic and HBM stacks attach to a silicon interposer with fine redistribution wiring; through-silicon vias carry signals and power down to an organic package substrate. The interposer provides far denser connections than a conventional substrate can. **CoWoS is a family rather than one fixed stack.** Different variants use a full silicon interposer, local silicon bridges, or redistribution structures to balance reticle size, cost, yield, and package area. The common goal is enormous die-to-die bandwidth within one package. **AI made capacity strategic.** Modern accelerators need a large logic die, multiple HBM stacks, known-good assembly, and difficult thermal management. A shortage at any packaging step can strand otherwise functional GPU wafers.