CXMT Reportedly Plans HBM3E Output at 20% to 30% Yields

Why CXMT is pressing ahead

The reason is scarcity. Chinese AI chipmakers have struggled to obtain enough advanced memory to raise output, the sources said, and the US tightened export controls on certain advanced HBM products bound for China in December 2024. Reuters' sources say Chinese chipmakers have increasingly sought the memory through unofficial channels, where it can cost several times more.

For the supply chain, the consequence is cost. Low yields make production expensive because a large share of chips must be discarded or reworked, and one source expects CXMT's HBM3E to cost more than comparable overseas products. Reuters reported last month that Huawei, Cambricon, MetaX and Iluvatar CoreX had raised prices for current and next-generation AI chips by 20% to 50% as memory costs complicated their ramps.

How far behind it is

In testing, CXMT's HBM3E performed closer to SK hynix's previous-generation HBM3 than to its HBM3E, one of the sources said. CXMT has sent customers two versions, the other source said: a standard design and an updated one with changes meant to improve yields. Counterpoint Research put SK hynix at 50% of global HBM revenue in the second quarter, ahead of Samsung at 33% and Micron at 18%, with most revenue coming from HBM3E. CXMT held 10% of global DRAM revenue in the quarter, making it the fourth-largest supplier of conventional memory, Counterpoint said.

Reuters noted that Samsung said in July it had expanded HBM4 sales and shipped HBM4E samples to major customers, putting CXMT at least one generation behind in commercial HBM production. SK hynix said in its third-quarter results release that it expects HBM4 to surpass HBM3E in both shipment volume and revenue in the fourth quarter; that is company guidance, not a result. CXMT also faces an equipment limit. Reuters said US export controls restrict its access to some of the most advanced chipmaking equipment, which makes closing the gap harder. Voltgrid has also covered Micron's decision to reject CXMT-style 4F2 DRAM.

Why Low HBM Yields Raise Costs

High-bandwidth memory (HBM) is made by stacking memory chips vertically so they can exchange data rapidly with an AI processor, Reuters explains. Yield is the share of chips coming off the line that meet specification.

The sources put CXMT at about 20% to 30%, against around 70% at SK hynix, so far fewer of each production run are usable. Every good stack therefore costs more to make, which is why one source expects CXMT's HBM3E to cost more than overseas rivals' and why the first output is described as limited. For China's AI chipmakers, supply of the memory depends on how fast that yield rises.

What is not confirmed yet

CXMT has not confirmed the production plan, the yield range or the customers. The yield figures are estimates from unnamed sources, and the production timeline comes from one of the two. No volume or price has been reported.