Chinese firms make headway in producing high bandwidth memory for AI chipsets

Two Chinese chipmakers are in the early stages of producing high bandwidth memory (HBM) semiconductors used in artificial intelligence (AI) chipsets, according to sources and documents.

The progress in HBM, even if only in older versions of HBM, represents a major step forward in China's efforts to reduce its reliance on foreign suppliers amid tensions with Washington that have led to restrictions on US. exports of advanced chipsets to Chinese firms.

CXMT, China's top manufacturer of Dram chips, has developed sample HBM chips in partnership with chip packaging and testing company Tongfu Microelectronics, according to three people briefed about the matter. The chips are being shown to clients, two said.

Tongfu Microelectronics' shares surged 8% in Wednesday trade.

In another example, Wuhan Xinxin is building a factory that will be able to produce 3,000 12-inch HBM wafers a month with construction slated to have started in February this year, documents from corporate database Qichacha show.

CXMT and other Chinese chip firms have also been holding regular meetings with South Korean and Japanese semiconductor equipment firms to buy tools to develop HBM, said two of the sources.

The sources were not authorised to speak on the matter and declined to be identified. Hefei-based CXMT or ChangXin Memory Technologies and Tongfu Microelectronics did not respond to requests for comment.

Wuhan Xinxin, which has flagged to regulators that it is interested in going public, and its parent company did not respond to requests for comment. The parent company is also the parent of Nand memory specialist YMTC, or Yangtze Memory Technologies. YMTC said it did not have the capability to mass produce HBM.

CXMT and Wuhan Xinxin are private companies which have received local government funding to advance technologies as China pours capital into developing its chip sector.

Wuhan's local government also did not respond to requests for comment.

Separately, Chinese tech behemoth Huawei, which the US has deemed a national security threat and is subject to sanctions, is aiming to produce HBM2 chips in partnership with other domestic companies by 2026, according to one of the sources and a separate person with knowledge of the matter.

The Information reported in April that a Huawei-led group of companies aiming to make HBM includes Fujian Jinhua Integrated Circuit, a memory chip maker also under US sanctions.

Huawei, which has seen demand soar for its Ascend AI chips, declined to comment. It is not clear where Huawei procures HBM. Fujian Jinhua did not respond to a request for comment.

HBM — a type of Dram standard first produced in 2013 in which chips are vertically stacked to save space and reduce power consumption — is ideal for processing massive amounts of data produced by complex AI applications, and demand has soared amid the AI boom.

The market for HBM is dominated by South Korea's SK Hynix — until recently the sole HBM supplier to AI chip giant Nvidia according to analysts — and as Samsung, and to a lesser extent US firm Micron Technology. All three manufacture the latest standard HBM3 chips and are working to bring fifth-generation HBM or HMB3E to customers this year.

China's efforts are focused on HBM2, according to two of the sources and a separate person with direct knowledge of the matter.

The US. has not put restrictions on exports of HBM chips per se but HBM3 chips are made using American technology that many Chinese firms including Huawei are barred from accessing as part of the curbs.

Nori Chiou, an investment director at White Oak Capital and former analyst who looked at the IT sector, estimated Chinese chipmakers lag their global rivals by a decade in HBM.

"China faces a considerable journey ahead as it lacks the competitive edge to rival its Korean counterparts even in the realm of traditional memory markets," he said.

"Nonetheless, (CXMT's) collaboration with Tongfu represents a significant opportunity for China to advance its capabilities in both memory and advanced packaging technologies within the HBM market."

Patents filed by CXMT, Tongfu and Huawei indicate plans to develop HBM domestically date back at least three years when China's chip industry increasingly became the target of US export controls.

CXMT has filed almost 130 patents in the US, China, and Taiwan for different technical issues related to the manufacturing and functionalities of HBM chips, according to Anaqua's AcclaimIP database. Of those, 14 were published in 2022, 46 in 2023 and 69 in 2024.

One Chinese patent, published last month, shows the company is looking at advanced packaging techniques like hybrid bonding to create a more powerful HBM product. A separate filing shows CXMT is also investing in developing technology needed to create HBM3.

Reuters