```
CoWoS stands for Chip on Wafer on Substrate. It is a high-density packaging technology for high-performance chips. TSMC developed CoWoS in 2012.
In CoWoS, multiple silicon dies are placed on a silicon interposer, which is an intermediate layer on the package board.
The interposer acts as a communication layer for the active die on top. CoWoS is a 2.5D packaging technology. It is widely used in high performance computing.
```