Amkor is one of the world's largest outsourced semiconductor assembly and test (OSAT) providers. After chips are fabricated at a foundry, they must be packaged—encased in a protective substrate, connected to external contacts, and tested before delivery. Amkor performs this across a range of packaging types, from standard flip chip to advanced 2.5D configurations that integrate multiple chips on a shared substrate.

AI chips have made advanced packaging a critical bottleneck in the semiconductor supply chain. Architectures like Nvidia Blackwell and AMD MI300 require 2.5D packaging that bonds high-bandwidth memory directly to the GPU die using a silicon interposer. TSMC performs much of this in-house through its CoWoS process, but CoWoS capacity has remained fully booked as AI chip demand has outpaced TSMC's ability to expand. This has created overflow demand for OSATs like Amkor, which offer alternative advanced packaging for customers and chip designs that cannot be served within TSMC's own lines.

Amkor is expanding its 2.5D packaging capacity and investing in process development to serve AI chip customers. Advanced packaging revenue grew approximately 15% YoY in 2025. The company's opportunity is tied to both the volume of AI chips being produced and the structural shift toward chiplet-based chip architectures, which require more sophisticated and higher-value packaging than monolithic designs. As AI accelerators continue integrating more chiplets and larger HBM stacks, the assembly complexity—and Amkor's value-add—grows with each generation.