Amkor, historical partner of AMD and HBM developer together with SK Hynix and AMD, is the responslible of Fiji GPUs packaging (TSV+GPU+HBM).
The Korea manufacturing facility K4, at Gwangju, is where the Fiji GPUs are tested and packaged. In Amkor site we can read:
K4 Product/Service Offering:
PBGA, ChipArray®, StackedCSP, System-in-Package (SiP), fcCSP, FC SCSP, WLCSP, FCBGA, FPFC BGA, FPFC CSP, FPFC SCSP, TMV® PoP, TSV, Wafer Bumping and Die Processings Services (DPS)
