Lingling Wei, The Wall Street Journal’s chief China correspondent, reported Tuesday that Huawei Technologies Co. this week unveiled a “Tau Law” it claims can succeed Moore’s Law as the industry’s organizing principle for chip advancement. The company’s semiconductor chief, He Tingbo, known as Huawei’s “chip queen,” announced the development at a conference in Shanghai.
But a careful reading of the technical paper Huawei released alongside the announcement reveals the company acknowledges a binding constraint, according to independent semiconductor analyst Jimmy Goodrich, who reviewed the document. The paper opens by stating that for companies whose “access to the most advanced lithography is constrained, the constraint became binding earlier and bears down more severely.” A few pages later it notes: “Assuming that another node would resolve the problem was no longer tenable.”
The lithography in question is extreme ultraviolet lithography (EUV), the manufacturing process that has powered the biggest chip advances of the past decade. EUV machines are produced almost exclusively by the Dutch company ASML, and U.S.-led export controls have barred their sale to China since 2019. The analysis Goodrich provided to the Journal concluded that Huawei’s own writing constitutes a tacit admission that it cannot overcome that barrier in any meaningful near-term timeframe.
Huawei’s technical approach is genuine engineering, analysts said. Instead of shrinking circuitry on a single layer — the traditional method — the company proposes stacking two layers of circuitry on top of each other so that signals travel shorter distances. The company said the method would make its next chip 55% denser than its predecessor and could deliver cutting-edge performance by 2031.
The stacking technique, several analysts noted, is not new. TSMC, Intel, AMD, and Samsung are all developing similar approaches. The difference, Goodrich said, is that their stacked designs sit atop chips manufactured with EUV. Huawei is pitching stacking as a substitute for conventional advances rather than a complement because the key technology that would make it a complement is unavailable to the company.
Goodrich estimated that TSMC will reach the performance level Huawei targets for 2031 by 2028 — and will be a full generation beyond it by 2031, applying the same stacking techniques on advanced chips. “The realistic gap in 2031 is six to eight years,” he told the Journal, “not the three years” implied by Huawei’s announcement.
A practical manufacturing obstacle compounds the gap. Goodrich said Huawei’s factories are estimated to produce usable chips only about 20% of the time, meaning four out of every five come out defective. Stacking requires bonding two chips with extreme precision, a process that becomes substantially more difficult when single-chip yields are already shaky.
Wei’s account described the Tau Law announcement as likely aimed at two audiences at once. To Washington, it signals that export controls are not working — providing cover for anyone seeking to ease them. To Beijing, it justifies turning down licenses for higher-quality Nvidia chips that President Trump recently authorized but China has not yet purchased, by claiming a domestic path.
Neither argument holds up against the paper’s contents, the Journal reported. The export controls have worked, but loopholes persist. On Sunday, the Bureau of Industry and Security, the agency overseeing export restrictions, issued guidance clarifying that a license requirement had always applied to offshore operations of Chinese companies — an implicit acknowledgment that the rule had been circumvented by China-headquartered companies smuggling advanced chips through overseas operations.
Goodrich told the Journal: “The engineering is genuinely impressive. The breakthrough framing is not.”