Tesna Inc. (Doosan Tesna) — AI supply-chain exposure

Tesna, owned by Korea's Doosan Group, is a wafer-test specialist that screens system ICs — SoCs, image sensors and automotive chips — primarily for customers of Samsung's foundry. It occupies the test step of the back end, confirming that fabricated silicon functions before it moves on to packaging. Its structural hook is tight coupling to the Samsung foundry ecosystem, which gives it a steady captive pipeline but also concentrates its fortunes on one customer base. The model places it peripherally: a focused test house exposed to the general chip cycle rather than the AI packaging bottleneck.