Tech war: China experts at odds over role of ‘chiplets’

Chinese semiconductor experts are debating the viability of “chiplet” technology as a shortcut to achieving chip self-sufficiency, an issue that could have far-reaching implications for the country’s hi-tech supply chain and semiconductor development.

Chiplets, pre-developed silicon dies that can be packaged into a more complex processor, have gained popularity because they reduce design costs and may even offer a solution to extending Moore’s Law, which refers to the doubling in the number of transistors on an integrated circuit (IC) every two years.

For China, chiplet technology is particularly appealing because it opens up the possibility of incorporating a series of 14-nanometre node chips – which the country can produce – with other chips it cannot produce, to create a more powerful semiconductor that is equivalent to an advanced 7nm or even 3nm node chip, which could help reduce the impact of US trade sanctions.

HiSilicon, the in-house chip design unit of telecoms giant Huawei Technologies Co, is one of the first companies in China to research chiplets, while Shanghai-listed semiconductor IP company VeriSilicon Holdings is also pursuing the technology, which has been described by some analysts as the Lego approach to making microprocessors.

VeriSilicon CEO Wayne Dai told an online conference last week that chiplet technology would enable China to build up a “strategic stock” of advanced central processing units (CPUs) and graphic processing units (GPUs), the core chips used in computers and electronics devices.

“Chiplet has significant meaning to China for solving choke points [in the supply chain],” Dai said, referring to the country’s need to import advanced chips like CPUs and GPUs.

Dai said the technology provided an opportunity for China to hoard chiplets that might be in a technology area sanctioned by the US, so that they can be used at a later stage to produce more powerful processors when needed.

Dai said the technology provided an opportunity for China to hoard chiplets that can be used at a later stage to produce more powerful processors when needed. Although China is lagging the West when it comes to wafer fabrication of semiconductors, it has a well-established infrastructure for chip packaging and assembly, the process of assembling chiplet modules into a larger package.

Wei Shaojun, a professor at Tsinghua University and a leading expert on microelectronics, said chiplet technology was “complementary” to advanced chipmaking processes, not a replacement for it.

Nonetheless, chiplets have attracted a great deal of attention from Chinese companies, academia, and experts, after US trade sanctions blocked China’s top foundry Semiconductor Manufacturing International Corp (SMIC) from developing advanced process nodes below 10 nm, and crippled Huawei’s ability to operate as a global smartphone player.

Wu Huaqiang, dean at the School of Integrated Circuits at Tsinghua University, said at the same online conference that chiplets are not replacements for advanced chipmaking, but they may help China build up a “strategic buffer” and improve the performance and computing power of locally made chips used in the country’s data centres.

Wu said it would be very difficult for China to develop advanced chipmaking technology below 5nm due to lack of engineering expertise and access to specialised equipment, meaning China will lag behind leading fabs such as Taiwan Semiconductor Manufacturing Co (TSMC) for the foreseeable future.

TSMC, the world’s most advanced chip maker, has already achieved 5nm mass production for clients like Apple.

Meanwhile, international tech giants are embracing the technology as it is deemed a cost-efficient way to increase chip performance. Apple adopted the chiplet model to interconnect two M1 Max chips to create the M1 Ultra to power its high-end Mac studio computers.

China’s development of chiplets is still at a preliminary stage and the country relies on foreign vendors for key development tools, including electronic design automation (EDA) software. In the case of HiSilicon, the US is investigating allegations that US EDA vendor Synopsys provided the Huawei unit with banned technology, Bloomberg reported on Wednesday.

Meanwhile, China is a follower, not a leader, when it comes to key standards and interfaces for the technology. The Universal Chiplet Interconnect Express (UCIe), an international consortium tasked with developing industry specifications related to chiplet technologies, was established in March with 10 founding members, including Advanced Micro Devices, Arm, Advanced Semiconductor Engineering, Google Cloud, Intel, Meta, Microsoft, Qualcomm, Samsung Electronics and TSMC.

Wang Qidong, vice-director of the Institute of Microelectronics at the Chinese Academy of Sciences, said there are technical hurdles to overcome as well. For instance, packaging 14nm node chips to perform 7nm chip functions could increase power consumption by 40 per cent, making it impractical to use more mature technology to make cutting-edge chips.

“Even if we can find a technical solution, the other challenge is how to control costs. I don’t think anyone is very clear about this now,” Wang added. South China Morning Post