TSMC Hands Part of Its CoWoS Packaging Crunch to Affiliate Xintec in a Seven-Year Deal
Xintec, which is about 41% owned by TSMC, will build and run a line for the final on-substrate step of CoWoS packaging inside TSMC's Taichung complex. It plans to raise NT$15 billion in convertible bonds, but volume output is not due until 2029.
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Illustrative photo of a general-purpose circuit board. It does not show CoWoS packaging or any TSMC or Xintec product.
The world's most important chipmaker is bringing in help for one of the tightest links in the AI hardware supply chain.
Xintec, a Taiwanese chip packaging and testing company, told the Taiwan stock exchange on Friday, Nov. 13, that its board had approved a long-term capacity outsourcing agreement with Taiwan Semiconductor Manufacturing Co. Under the deal, Xintec will set up and operate a production line inside TSMC's plant in the Central Taiwan Science Park in Taichung, handling a back-end step of TSMC's advanced packaging. The agreement runs from Nov. 13, 2026, through Dec. 31, 2033, a little over seven years.
The work covers the "oS," or on-substrate, module of CoWoS, short for chip-on-wafer-on-substrate, the packaging method that has become central to building AI accelerators. Xintec said the first phase of the line is planned to reach volume production in 2029, and its board also approved issuing NT$15 billion in convertible bonds to pay for the initial buildout.
At a glance
| Item | Detail | Source |
|---|---|---|
| Announced | Nov. 13, 2026, in a Xintec filing (16:50 Taiwan time) | Xintec filing |
| Parties | Xintec and TSMC | Xintec filing |
| Term | Nov. 13, 2026, to Dec. 31, 2033 | Xintec filing |
| Scope | Back-end advanced packaging: the on-substrate (oS) step of CoWoS | Xintec filing; CTEE |
| Location | Inside TSMC's Central Taiwan Science Park plant, Taichung | Xintec filing |
| Volume production | First phase planned for 2029 | Xintec filing |
| Funding | NT$15 billion (about US$456 million) in convertible bonds | Xintec filing; Taiwan News |
| Ownership | TSMC holds about 41% of Xintec | Taiwan News |
What the agreement covers
Xintec's filing is brief, but it sets out the basic division of labor. Xintec will build the line, run production, and pay for the production equipment and the automated material handling systems that move materials around the plant. TSMC will support it with its advanced packaging technology and manufacturing know-how. The two companies will work together so the line's technical specifications, quality and yields meet the requirements of TSMC and, in the filing's words, its top global customers.
The filing frames the purpose as meeting "strong capacity demand" for high-performance computing chips, driven by the spread of AI, HPC and data center applications, which it says has created structural growth in demand for advanced packaging. It says Xintec aims to become a new player in the oS module part of the advanced packaging supply chain.
What the filing does not include is just as notable. It gives no planned capacity, no contract value, and no detail on restrictions or commitments beyond saying they follow the agreement.
Why CoWoS is a bottleneck
A modern AI accelerator is not a single chip. CoWoS places logic dies and stacks of high-bandwidth memory side by side on a silicon interposer, a thin layer of dense wiring that links them, Crypto Briefing explains. That assembly is then mounted on a substrate, the on-substrate step Xintec will now handle.
Taiwan News, citing Reuters, described advanced packaging as a once-overlooked process that has become a critical chokepoint in making the world's top processors. TSMC dominates the most sophisticated forms, including CoWoS, and customers such as Nvidia and AMD rely on it for their AI hardware, according to Crypto Briefing.
Outsourcing the final step lets TSMC add capacity without building and staffing every stage itself, while keeping the work inside its own site and in the hands of a company it partly owns.
Who Xintec is
Xintec is closely tied to TSMC already. Taiwan News reports that TSMC is its largest shareholder with a stake of about 41%, and that TSMC-related work makes up more than 70% of Xintec's revenue.
Commercial Times, a Taiwanese business daily, reported that Xintec's existing business centers on wafer-level packaging, wafer testing and related services. The new agreement takes it into the back end of CoWoS for the first time, which the paper said would raise its strategic position in TSMC's packaging supply chain. Commercial Times also described the NT$15 billion bonds as unsecured.
The deal deepens that dependence as well as the opportunity. Crypto Briefing pointed out the concentration risk for a company that already draws most of its revenue from one customer and is now taking on bond financing to serve it more. That is the outlet's analysis.
Part of a wider capacity push
The Xintec line is one of several ways TSMC is widening its CoWoS pipeline. Crypto Briefing notes that TSMC has struck a $2 billion deal with GlobalFoundries to make silicon interposers in the United States, with that ramp targeted for 2028, and has bought display plants from AUO to gain cleanroom space.
The timing matters. Crypto Briefing says CoWoS supply constraints are projected to ease gradually through 2028. A line that starts volume production in 2029 will not relieve the current crunch. Instead, the seven-year term suggests TSMC expects demand for advanced packaging to stay high into the next decade.
What to watch
The next steps are financial and physical. Xintec has to raise the NT$15 billion, order and install equipment, and qualify the line to TSMC's standards before 2029. Crypto Briefing says investors will track the bond raise and construction progress at the Taichung site. The filing also leaves the line's planned capacity undisclosed.
DailyMech did not find a separate TSMC statement on the agreement. Xintec said in its filing that it expects the deal to benefit its future finances and business.
How we reported this
DailyMech read Xintec's exchange filing, Commercial Times' report, Taiwan News' report and Crypto Briefing's analysis in full. The filing and the Commercial Times article are in Chinese and were translated by DailyMech's AI writer. The ownership and revenue figures come from Taiwan News. Context on the GlobalFoundries deal, the AUO plants and the supply outlook comes from Crypto Briefing only. DailyMech contacted no one for this article.
Published November 13, 2026. Facts checked against the cited sources by DailyMech's AI writer.
Sources
- 公告董事會決議通過與客戶簽訂產能外包協議 (Board approves capacity outsourcing agreement with customer), Xintec material-information filing via USTV, Nov. 13, 2026 (fully read; Chinese).
- 台積擴大委外 精材搶進CoWoS (TSMC expands outsourcing; Xintec moves into CoWoS), Commercial Times (CTEE), Nov. 14, 2026, Taiwan time (fully read; Chinese).
- TSMC taps Xintec to expand advanced packaging capacity in Taichung, Bryan Chou, Taiwan News, Nov. 13, 2026 (fully read).
- TSMC signs seven-year deal with Xintec to expand CoWoS packaging, Diego Almada Lopez, Crypto Briefing, Nov. 13, 2026 (fully read).
DailyMech used AI tools to research and draft this article. Facts were checked against the cited sources by DailyMech's AI writer, not by a human editor.