Japan earthquake tests automotive semiconductor supply chain resilience

While the Kumamoto earthquake disrupted several semiconductor facilities, automakers appear better prepared to manage the impact than during previous supply chain crises.

A magnitude 7.1 earthquake struck Japan's Kumamoto Prefecture on July 28, triggering safety inspections, temporary shutdowns and localized power outages across a region that plays an important role in automotive semiconductor production. While several chipmakers suspended operations for safety checks, initial assessments indicate limited facility damage and gradual resumption of production, easing immediate concerns across the automotive semiconductor supply chain.

Several companies reported temporary operational disruptions immediately following the quake. Sony Semiconductor Solutions evacuated personnel from its image sensor facilities in the Kikuyo/Koshi area, while Tokyo Electron Kyushu suspended operations at its local plants to conduct safety inspections. Mitsubishi Electric also temporarily halted operations at its Koshi and Kikuchi power semiconductor facilities as a precaution, though no damage was reported.

Among the facilities attracting significant attention is Taiwan Semiconductor Manufacturing Co.'s (TSMC) Kumamoto manufacturing complex, operated through its subsidiary Japan Advanced Semiconductor Manufacturing (JASM). The facility plays an important role within Japan's semiconductor ecosystem, supplying chips used in vehicles, industrial equipment and consumer electronics.

TSMC confirmed that all JASM personnel were evacuated safely following the earthquake and that subsequent structural inspections identified no damage affecting building safety. The company reported that water, power and workplace safety systems remain operational and that production is being restored in stages while engineers complete equipment inspections and calibration procedures. TSMC has not yet provided a timeline for full restoration of normal operations.

JASM's Kumamoto campus consists of two fabrication facilities. Fab 1 is currently operational and manufactures chips using 12/16nm and 22/28nm process technologies at a capacity of approximately 55,000 wafers per month. These products support automotive microcontrollers, image sensors and other automotive logic applications. Fab 2 remains under construction and is expected to manufacture 6/7nm and 3nm semiconductors beginning in the second half of 2028. TSMC stated that the construction site sustained no damage, although some work was temporarily suspended as a precaution.

Several strategic stakeholders and OEMs have exposure to the facility. Sony Semiconductor Solutions is a major shareholder in JASM and utilizes the site within its image sensor supply chain. Denso has secured manufacturing capacity at JASM for automotive semiconductor production, while Toyota invested in the venture to strengthen long-term supply security. Honda has also secured production allocations from the facility for future vehicle programs.

Despite the disruption, TSMC's Kumamoto operations account for less than 3% of the company's total manufacturing capacity, and the company expects only a minimal impact on third-quarter revenue.

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While TSMC reported no structural damage, Renesas Electronics experienced a more direct operational impact from the earthquake. The company temporarily suspended operations at its Kawashiri factory in Kumamoto City and its Nishiki factory in Kuma District, both of which supply automotive and other semiconductor products and are located near the affected area.

Renesas reported no injuries but identified minor structural damage at the facilities, including leaks within ultra-pure water systems used for wafer processing at the Kawashiri site and damage to some manufacturing equipment. Nishiki resumed production on July 29 and returned to full pre-earthquake capacity by July 31. Kawashiri remains under repair, with phased production scheduled to begin on Aug. 5 and full capacity expected approximately three weeks later.

Renesas is better insulated from disruption than many chipmakers because it manufactures automotive microcontrollers across multiple sites, reducing the risk of supply interruptions for OEMs that rely on its products. Front-end production can be sourced from multiple facilities, including Naka, Kawashiri, Saijo, Takasaki and Kofu, reducing dependence on any single site. This flexibility likely contributed to Nishiki's rapid return to full production through the use of existing wafer inventory and output from unaffected facilities.

Renesas is also not entirely dependent on TSMC for manufacturing within the 22-28nm range and maintains relationships with other foundry partners, including GlobalFoundries, providing an additional layer of supply flexibility.

While Renesas benefits from a diversified manufacturing footprint, the extent to which specific automotive semiconductor products remain uniquely dependent on Kawashiri has not been publicly disclosed. As a result, the share of single-sourced versus multi-sourced products remains an important variable when assessing any residual supply-chain risk and will likely be a key area to monitor as the company provides further operational updates.

Reflecting management's assessment of the situation, Renesas CEO Hidetoshi Shibata stated during the company's July 31 earnings call that the overall financial impact of the earthquake is expected to be limited.

Vehicle production impact likely to remain limited

For now, the earthquake is unlikely to have a meaningful impact on global light-vehicle production. Most affected facilities have reported either limited damage or precautionary shutdowns, with operations gradually resuming across the region. TSMC has restarted production in stages following successful inspections, while Renesas has already restored full operations at Nishiki and outlined a recovery plan for Kawashiri.

Even if temporary wafer-fabrication interruptions occur, semiconductor supply chains typically require months before disruptions begin affecting vehicle assembly due to the lengthy manufacturing, packaging, testing and integration cycle associated with automotive semiconductors.

Japanese automakers are generally better positioned than they were during previous industry disruptions, reflecting lessons learned from both the 2011 earthquake and the 2021 semiconductor shortage. Years of investment in inventory management, supplier visibility and business continuity planning have strengthened supply chain resilience across OEMs, Tier 1 suppliers and semiconductor manufacturers. It's still unclear where the biggest inventory buffers sit across the supply chain, making it difficult to identify exactly where manufacturers have the most protection from disruption.

Additionally, Renesas' use of multiple manufacturing sites and foundry partners, including GlobalFoundries for certain technology nodes, further reduces supply concentration risk.

The situation still bears close watching. Historical experience shows semiconductor disruptions caused by earthquakes can take anywhere from hours to weeks to resolve, particularly when equipment must be requalified and production lines recalibrated. Current assessments point to a limited long-term impact, but aftershocks, the pace of recovery at Kawashiri and any exposure to single-sourced components remain key risks for the automotive semiconductor supply chain.