# OSATs taking CoWoS back-end and overflow

Part ID: 1.11a · Layer 1 (Compute silicon & packaging) · child of 1.11

Outsourced assembly and test (OSAT) providers that take on back-end assembly and overflow packaging work when primary CoWoS capacity is full.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Amkor | manufacturer | inferred | public | AMKR |  |
| ASE Technology (ASE/SPIL) | manufacturer | inferred | public | 3711.TW |  |
| KYEC | manufacturer | inferred | public | 2449.TW | test |
| Powertech | manufacturer | inferred | public | 6239.TW |  |

Confidence tags: disclosed = company/filing statement; reported = trade press or partner list; inferred = taxonomy lead.