CoWoS Technology Analysis: Why TSMC’s advanced packaging has become an AI chip production capacity bottleneck?

In 2026, the global semiconductor industry is undergoing a profound structural transformation. The World Semiconductor Trade Statistics (WSTS) predicts that the global semiconductor market size in 2026 will grow 89.9% year-on-year to reach $1.5112 trillion. The core engine driving this explosive growth is, without a doubt, the continued expansion of demand for AI compute capacity. However, beyond wafer-fabrication capacity, a link that had previously been little known to the general public—advanced packaging—is quietly becoming a “new bottleneck” restricting the delivery of AI chips. The core of this bottleneck is a technology called CoWoS.

CoWoS: A packaging technology that defines the AI chip era

CoWoS stands for Chip-on-Wafer-on-Substrate, a 2.5D advanced packaging technology developed by TSMC. To understand its value, it’s necessary to go back to a fundamental question: why do AI chips need “advanced packaging”?

Conventional chip packaging directly bonds compute chips and memory onto a PCB substrate, but PCB traces are too wide and signal transmission distances too long, making it impossible to meet the bandwidth requirements of AI training, which demands tens of terabytes per second per step. CoWoS’s solution is to place compute chips such as GPUs or ASICs side-by-side with high-bandwidth memory chips (HBM) on a silicon interposer layer, using high-density TSVs (through-silicon vias) and micro-bump points. Dense, fine circuitry within the interposer layer enables high-speed interconnects between chips, and the whole assembly is then packaged onto the substrate.

This architecture delivers three key advantages: bandwidth can reach dozens of times that of traditional DDR, fully addressing the “memory wall” problem in AI training; signal transmission distances are significantly shortened, reducing the power consumption of data movement; multiple Chiplets and multiple HBM stacks can work together within a single package, breaking through area limitations of a single chip.

TSMC officially introduced CoWoS in 2011, after multiple iterations, and it has now formed three types of solutions:

CoWoS-S: Uses a full-silicon interposer layer, with the highest performance and the most mature technology. The silicon interposer value in a single-wafer CoWoS-S is approximately $10k.

CoWoS-R: Uses an interposer layer based on an RDL (redistribution layer), balancing cost and interconnect performance.

CoWoS-L: The current mainstream solution, replacing an ultra-large full-silicon interposer layer with “local silicon bridges.” This reduces warpage and cost while supporting larger package area and more HBM stacking. The interposer value for CoWoS-L increases to about $15k, up nearly 50% versus CoWoS-S.

From NVIDIA’s Hopper and Blackwell to the latest Rubin architecture, each generation of flagship GPU is deeply tied to TSMC’s CoWoS-L process. It can be said that without CoWoS, there would be no AI training chips for today’s large models with billions to hundreds of billions of parameters.

Why advanced packaging has become the new bottleneck for AI chips

The production capacity bottleneck for AI chips is shifting from front-end wafer manufacturing to back-end advanced packaging.

First, the rapid expansion of chip size directly consumes effective capacity.

As large-model parameters surge from tens of billions to trillions, AI chip sizes continue to grow. Li Xiao, Chief Marketing Officer at Chengdu YiCheng Technology, said the core reason for the CoWoS capacity constraint isn’t simply slow ramp-up of capacity, but the sharp increase in chip size—when chip size expands beyond a certain point, the number of chips that can be produced from a full wafer drops sharply, while effective capacity actually shrinks. Taking NVIDIA’s Rubin-series chips (with Interposer having a 5.5x reticle size) as an example, on a 300mm wafer only 7 can be placed, with area utilization of just 45%.

Second, the outbreak speed of demand far exceeds the pace of supply-side capacity expansion.

According to Morgan Stanley’s forecast, global CoWoS demand will rise from 689k wafers in 2025 to 15.11k in 2026, and further to 10k in 2027—nearly tripling within two years. In 2023 and 2024, these figures were only 117k and 372k wafers, respectively.

Even though supply-side capacity expansion is aggressive, it always fails to catch up. Based on information released by TSMC, CoWoS monthly capacity in 2024 is about over 30k wafers; in 2025, it reaches 70k wafers; by the end of 2026 the original plan was 110k wafers, but it ultimately exceeded 130k wafers. The expansion target for 2027 is around 200k wafers. Morgan Stanley estimates 120k wafers by the end of 2026 and 200k by the end of 2027. Mizuho Asia further raised it to 140k wafers for 2026 and 190k to 200k wafers for 2027.

The huge gap between capacity and demand forms the most direct mathematical basis of the “bottleneck.”

Third, advanced packaging has become a core manufacturing step that determines a chip’s compute performance, bandwidth, and yield.

In the post-Moore era, the marginal benefits of planar transistor scaling keep narrowing, and the cost of setting up and R&D for advanced wafer production lines at 3 nanometers and below is rising exponentially. The industry’s main development line is gradually shifting toward Chiplet partitioning and heterogeneous integration, directly pushing packaging from a traditional back-end assembly process to a core stage that determines the chip’s final performance.

Is the bottleneck easing—or shifting?

In 2026, there are two seemingly contradictory but actually complementary views on whether the CoWoS bottleneck is easing.

On one hand, the supply-demand gap is indeed narrowing.

Supply-chain data show that as TSMC and its partners actively expand advanced packaging capacity, the CoWoS supply-demand gap is expected to narrow from about 20% at the beginning of 2026 to about 10% by year-end. TSMC’s CoWoS monthly capacity may reach 120k to 140k wafers in 2026. With an additional 50k to 60k wafers of capacity from OSAT partners, the industry’s monthly capacity could approach 200k wafers.

Wedbush analysts also support this trend: “If the CoWoS gap narrows from 20% to about 10% by the end of 2026, it suggests that the most tightly constrained stage of supply-demand for the current generation of AI chips’ advanced packaging may see marginal easing.”

On the other hand, ‘bottleneck easing’ doesn’t mean ‘bottleneck elimination.’

In a report dated July 1, 2026, Nomura warned that the AI semiconductor cycle is far from peaking, and that in the second half of 2026 the industry may face “epic” supply-chain mismatches. The real supply bottleneck is shifting from CoWoS itself to a broader set of component areas such as wafer-level substrates, PCBs, and copper-clad laminates. The report notes that many component suppliers underestimate the growth of AI-driven orders when planning capacity expansions.

JPMorgan Chase’s supply-chain checks reached a more cautious conclusion: in its model, the advanced packaging supply-demand gap in 2027 to 2028 may still remain around 20%.

What deserves even more attention is the change in demand structure. Morgan Stanley expects that CoWoS demand globally will reach 15k in 2027, with NVIDIA remaining the largest customer (689k, 45%). However, AMD demand will surge by 308% (from 130k to 530k). NVIDIA’s share of total demand will decline from about 56% in 2026 to about 45% in 2027—absolute demand is growing, but the share is diluted. Google TPU share is expected to rise from 23% in 2026 to 27% in 2027. The share of packaging related to server CPUs will increase from 11% in 2025 to 24% in 2027, becoming the second-largest source of demand after NVIDIA GPUs.

Demand evolves from “single GPU-driven” to “four-wheel drive” from GPU + CPU + TPU + in-house ASIC. That means even if CoWoS capacity continues to expand, new demand increments may still keep absorbing the newly added supply.

Capacity expansion race: TSMC’s “ultimate sprint”

Facing persistently full orders, TSMC is expanding CoWoS capacity at an unprecedented speed.

On capital expenditures, Morgan Stanley’s report shows that TSMC will increase capex to $56 billion in 2026 and $75 billion in 2027. At a corporate briefing, TSMC disclosed that total capex for 2026 is locked at $1.39M to $56 billion, with 10% to 20% of resources being allocated toward advanced packaging processes such as CoWoS.

In its capacity expansion strategy, TSMC adopts a two-track parallel model: refurbishing older 8-inch fabs and building new dedicated facilities. Two major core bases—Chiayi AP7 and Southern Taiwan Science Park AP8—continue to invest in dedicated packaging production lines. The capacity target for the fourth quarter of 2026 is raised to 130k to 140k wafers. The supply chain notes that TSMC’s new-fab construction projects are essentially staffed with 24-hour shift rotations, accelerating construction progress.

For overseas expansion, TSMC’s Arizona project in the United States has a cumulative planned total investment of $165 billion, including 8 wafer fabs and 4 advanced packaging facilities. The first packaging production line is expected to achieve mass production around 2028.

In terms of technical evolution, TSMC plans to introduce a transition version of CoWoS with a 5.5x reticle size in 2026, and achieve large-scale mass production of CoWoS with a 9.5x reticle size in 2027. The effective area of a single package approaches 8,000 square millimeters, enabling systems with 4 3D-stacked chips. Meanwhile, TSMC is also pushing next-generation panel-level CoPoS packaging technology, and its subsidiary, Tsaiyu Longtan plant area, has built pilot CoPoS production lines.

However, expanding capacity also comes with concerns. TSMC has not yet finalized equipment vendors’ order allocations, leaving the supply chain uneasy and worried about forming a price-cut and order-chasing atmosphere. From placing an order to producing and shipping equipment takes at least 7 to 9 months, and suppliers worry they may not be able to deliver equipment on schedule.

How the “packaging war” for AI chips affects the crypto industry?

The tight advanced packaging capacity situation is transmitting to the crypto asset market through multiple channels.

From the underlying logic of compute infrastructure, the supply of AI chips directly affects the construction pace of global data centers and cloud computing infrastructure. Morgan Stanley expects that the top 14 global cloud service providers will invest nearly $1.3 trillion in cloud capex before 2027. These infrastructures are not only the physical foundation for AI training and inference, but also key carriers for blockchain network nodes to run and Web3 applications to be deployed. If the advanced packaging capacity bottleneck persists, it will to some extent affect the expansion pace of global compute infrastructure.

From market sentiment and asset price correlation, on July 27, 2026 (Beijing time), the US semiconductor sector saw significant volatility. The Philadelphia Semiconductor Index fell 4.25%, TSMC dropped nearly 3%, AMD fell 3.29%, and NVIDIA slid 0.92%. At the same time, Bitcoin on the Binance exchange was quoted at $65,387, up 1.64% over 24 hours; the Gate platform shows Bitcoin trading at about $65,150. Ethereum also strengthened, rising from the 1,836 low to around 1,953.

The linkage between the semiconductor sector and crypto assets is becoming increasingly complex. On one hand, an AI chip supply bottleneck could delay the expansion of compute infrastructure, potentially constraining blockchain networks that rely on high-performance computing. On the other hand, as an alternative asset, crypto assets may attract some capital seeking to hedge when traditional tech stocks see greater volatility. This “seesaw effect” has shown early signs in the market performance on July 27, 2026—while the semiconductor sector plunged, Bitcoin held the crucial support around $65,000.

From a more long-term industrial perspective, the integration of AI and the crypto industry is deepening. Compute-intensive cryptography applications such as zero-knowledge proofs and fully homomorphic encryption are increasingly dependent on high-performance chips. Emerging tracks such as decentralized AI compute markets and AI-agent-driven DeFi protocols also require support from underlying chip production capacity. Advanced packaging, as the “throat” of AI chip supply, means changes in its capacity will profoundly affect the intersection area of these two trillion-dollar industries.

Conclusion

CoWoS has evolved from an internal TSMC technical code name into a “critical bottleneck” across the global AI industry chain. This process reflects deeper shifts in power structures within the semiconductor industry. In the post-Moore era, whoever controls advanced packaging controls the delivery pace of AI chips.

In 2026, CoWoS monthly capacity is sprinting from 30k wafers toward 200k wafers, and the supply-demand gap is narrowing from 20% to 10%—but “bottleneck easing” doesn’t mean “bottleneck elimination.” The growth engine on the demand side is expanding from a single NVIDIA GPU driver to a broad set of new customers including AMD, Google, and Amazon, as well as entirely new categories such as server CPUs and in-house ASICs. The capacity race surrounding advanced packaging has only just entered the mid-game.

For the crypto industry, changes in the AI chip supply chain are both a challenge and an opportunity. The expansion pace of compute infrastructure, the correlation between tech stocks and crypto assets, and the increasingly deep technical convergence between the two industries all make the seemingly distant semiconductor topic of “advanced packaging” materially connected to the long-term trajectory of crypto asset markets. Understanding CoWoS means understanding the underlying logic of AI chip supply; and understanding AI chips means understanding the underlying pulse of productivity evolution in the digital age.

FAQ

Q1: What is the fundamental difference between CoWoS and traditional packaging?

Traditional packaging bonds chips and memory directly onto a PCB substrate. With wide wiring and long signal transmission distances, it cannot meet the high-bandwidth needs of AI chips. CoWoS enables high-density interconnects between chips through a silicon interposer layer, delivering bandwidth that reaches dozens of times that of traditional solutions while significantly reducing power consumption.

Q2: Why is CoWoS capacity expansion so slow?

There are three reasons for the slow expansion: first, equipment delivery cycles are long, taking 7 to 9 months from ordering to shipping; second, chip sizes keep expanding, reducing the number of effective chips produced per wafer; third, advanced packaging involves precise processes, so time is needed for new production line construction and yield ramp-up.

Q3: When will the CoWoS capacity bottleneck truly ease?

The market expects the supply-demand gap to narrow from 20% to 10% by the end of 2026. But both Nomura and JPMorgan Chase believe the real bottleneck may shift to other stages such as substrates and PCBs, and the gap in 2027 to 2028 could still remain around 20%.

Q4: What impact will CoWoS supply-demand changes have on the crypto industry?

AI chip supply affects the construction pace of global compute infrastructure, which in turn affects blockchain network operation and Web3 application deployment. At the same time, there is some seesaw effect between the semiconductor sector and crypto assets; when tech stocks are volatile, it may influence crypto market sentiment.

Q5: Besides CoWoS, what other advanced packaging technologies are worth watching?

TSMC is advancing next-generation CoPoS (panel-level packaging) technology. NVIDIA’s next-generation Feynman-architecture GPUs are also expected to become among the first products to be deployed. In addition, new technological routes such as glass substrates and CPO (co-packaged optics) are also accelerating.