South Korean equipment makers are gaining a larger role in SK Hynix's supply chain for high-bandwidth memory (HBM) wafer test equipment. Digital Frontier and UniTest have secured additional orders, signaling a diversification of a supply structure that had been centered on Japanese suppliers.
According to industry sources on Aug. 24, Digital Frontier and UniTest have won a combined 283.94 billion KRW in orders from SK Hynix this year for equipment related to HBM4 wafer testing.
Digital Frontier, a subsidiary of DI, has accumulated 232.1 billion KRW in HBM4 wafer tester orders, while UniTest has secured 51.84 billion KRW. Both companies have traditionally focused on testers for conventional DRAM and NAND flash memory, but are expanding their supply of equipment designed for HBM.
The addition of Korean suppliers to an HBM test-equipment supply chain previously dominated by Japanese semiconductor-test specialist Advantest points to a broader supplier base. Korean vendors are expanding their presence by taking on and complementing specific testing functions.
Digital Frontier has supplied wafer testers to SK Hynix since the HBM3 generation, while UniTest entered the supply chain with HBM4. UniTest said it completed mass-production qualification testing for an HBM4 burn-in tester for SK Hynix earlier this year.
Wafer testing is the process of checking a semiconductor's electrical performance and identifying defective chips while they remain on the wafer, before the wafer is cut into individual dies. Because HBM stacks multiple DRAM dies, screening out defective dies before stacking is critical to final package yield.
Demand for dedicated wafer testers is rising as HBM generations become more advanced. Earlier HBM products could use DRAM wafer testers adapted for HBM applications. However, as the number of test items and required test time have increased, purpose-built HBM test equipment has become more necessary.
“Each new HBM generation requires more test items and longer testing time, so demand for test equipment could grow faster than output volumes,” an industry official said. “Starting with HBM4, the push to secure dedicated test equipment from multiple suppliers is likely to become more pronounced.”
Demand for related equipment is expected to continue. SK Hynix began mass shipments of HBM4 in the second quarter and plans to ramp up production in the second half of the year.
