With the flourishing development of technologies such as AI, cloud computing, big data analytics, and mobile computing, modern society has an increasingly high demand for computing power.

Moreover, with the advancement beyond 3 nanometers, wafer sizes have encountered scaling limitations and manufacturing costs have increased. Therefore, besides continuing to develop advanced processes, the semiconductor industry is also exploring other ways to maintain chip size while ensuring high efficiency.

The concept of “heterogeneous integration” has become a contemporary focus, leading to the transition of chips from single-layer to advanced packaging with multiple layers stacked together.

The term “CoWoS” can be broken down into the following definitions: “Cow” stands for “Chip-on-Wafer,” referring to the stacking of chips, while “WoS” stands for “Wafer-on-Substrate,” which involves stacking chips on a substrate.

Therefore, “CoWoS” collectively refers to stacking chips and packaging them onto a substrate. This approach reduces the space required for chips and offers benefits in reducing power consumption and costs.

Among these, CoWoS can be further divided into 2.5D horizontal stacking (most famously exemplified by TSMC’s CoWoS) and 3D vertical stacking versions. In these configurations, various processor and memory modules are stacked layer by layer to create chiplets. Because its primary application lies in advanced processes, it is also referred to as advanced packaging.

According to TrendForce’s data, it has provided insights into the heat of the AI chip market. In 2023, shipments of AI servers (including those equipped with GPU, FPGA, ASIC, etc.) reached nearly 1.2 million units, a 38.4% increase from 2022, accounting for nearly 9% of the overall server shipments.

Looking ahead to 2026, the proportion is expected to reach 15%, with a compound annual growth rate (CAGR) of AI server shipments from 2022 to 2026 reaching 22%.

Due to the advanced packaging requirements of AI chips, TSMC’s 2.5D advanced packaging CoWoS technology is currently the primary technology used for AI chips.

GPUs, in particular, utilize higher specifications of HBM, which require the integration of core dies using 2.5D advanced packaging technology. The initial stage of chip stacking in CoWoS packaging, known as Chip on Wafer (CoW), primarily undergoes manufacturing at the fab using a 65-nanometer process. Following this, through-silicon via (TSV) is carried out, and the finalized products are stacked and packaged onto the substrate, known as Wafer on Substrate (WoS).

As a result, the production capacity of CoWoS packaging technology has become a significant bottleneck in AI chip output over the past year, and it remains a key factor in whether AI chip demand can be met in 2024. Foreign analysts have previously pointed out that NVIDIA is currently the largest customer of TSMC’s 2.5D advanced packaging CoWoS technology.

This includes NVIDIA’s H100 GPU, which utilizes TSMC’s 4-nanometer advanced process, as well as the A100 GPU, which uses TSMC’s 7-nanometer process, both of which are packaged using CoWoS technology. As a result, NVIDIA’s chips account for 40% to 50% of TSMC’s CoWoS packaging capacity. This is also why the high demand for NVIDIA chips has led to tight capacity for TSMC’s CoWoS packaging.

TSMC’s Expansion Plans Expected to Ease Tight Supply Situation in 2024

During the earnings call held in July 2023, TSMC announced its plans to double the CoWoS capacity, indicating that the supply-demand imbalance in the market could be alleviated by the end of 2024.

Subsequently, in late July 2023, TSMC announced an investment of nearly NTD 90 billion (roughly USD 2.87 billion) to establish an advanced packaging fab in the Tongluo Science Park, with the construction expected to be completed by the end of 2026 and mass production scheduled for the second or third quarter of 2027.

In addition, during the earnings call on January 18, 2024, TSMC’s CFO, Wendell Huang, emphasized that TSMC would continue its expansion of advanced processes in 2024. Therefore, it is estimated that 10% of the total capital expenditure for the year will be allocated towards expanding capacity in advanced packaging, testing, photomasks, and other areas.

In fact, NVIDIA’s CFO, Colette Kress, stated during an investor conference that the key process of CoWoS advanced packaging has been developed and certified with other suppliers. Kress further anticipated that supply would gradually increase over the coming quarters.

Regarding this, J.P. Morgan, an investment firm, pointed out that the bottleneck in CoWoS capacity is primarily due to the supply-demand gap in the interposer. This is because the TSV process is complex, and expanding capacity requires more high-precision equipment. However, the long lead time for high-precision equipment, coupled with the need for regular cleaning and inspection of existing equipment, has resulted in supply shortages.

Apart from TSMC’s dominance in the CoWoS advanced packaging market, other Taiwanese companies such as UMC, ASE Technology Holding, and Powertek Technology are also gradually entering the CoWoS advanced packaging market.

Among them, UMC expressed during an investor conference in late July 2023 that it is accelerating the deployment of silicon interposer technology and capacity to meet customer needs in the 2.5D advanced packaging sector.

UMC Expands Interposer Capacity; ASE Pushes Forward with VIPack Advanced Packaging Platform

UMC emphasizes that it is the world’s first foundry to offer an open system solution for silicon interposer manufacturing. Through this open system collaboration (UMC+OSAT), UMC can provide a fully validated supply chain for rapid mass production implementation.

On the other hand, in terms of shipment volume, ASE Group currently holds approximately a 32% market share in the global Outsourced Semiconductor Assembly and Test (OSAT) industry and accounts for over 50% of the OSAT shipment volume in Taiwan. Its subsidiary, ASE Semiconductor, also notes the recent focus on CoWoS packaging technology. ASE Group has been strategically positioning itself in advanced packaging, working closely with TSMC as a key partner.

ASE underscores the significance of its VIPack advanced packaging platform, designed to provide vertical interconnect integration solutions. VIPack represents the next generation of 3D heterogeneous integration architecture.

Leveraging advanced redistribution layer (RDL) processes, embedded integration, and 2.5D/3D packaging technologies, VIPack enables customers to integrate multiple chips into a single package, unlocking unprecedented innovation in various applications.

Powertech Technology Seeks Collaboration with Foundries; Winbond Electronics Offers Heterogeneous Integration Packaging Technology

In addition, the OSAT player Powertech Technology is actively expanding its presence in advanced packaging for logic chips and AI applications.

The collaboration between Powertech and Winbond is expected to offer customers various options for CoWoS advanced packaging, indicating that CoWoS-related advanced packaging products could be available as early as the second half of 2024.

Winbond Electronics emphasizes that the collaboration project will involve Winbond Electronics providing CUBE (Customized Ultra-High Bandwidth Element) DRAM, as well as customized silicon interposers and integrated decoupling capacitors, among other advanced technologies. These will be complemented by Powertech Technology’s 2.5D and 3D packaging services.

Read more

• [News] AMD Eyes CoWoS-like Supply for AI Chips with TSMC Full Capacity
• [News] Samsung Boosts 2.5D Packaging Equipment to Compete for TSMC’s CoWoS Orders

(Photo credit: TSMC)

Taiwanese Semiconductor testing and packaging giant ASE announced today that its subsidiary, ASE Semiconductor, will lease the plant in Nanzih, Kaohsiung, owned by Taiwan’s ASE Test Inc., to expand its packaging capacity.

In the announcement, ASE Holdings revealed that ASE Semiconductor would lease a plant in Nanzih District, Kaohsiung, from its subsidiary ASE Test Inc. The total floor area of the building is approximately 15,600 square meters, with an estimated total usage rights asset value of NTD 742 million (approximately USD 23.8 million).

ASE Holdings stated that the primary purpose of this move is to optimize the overall planning and efficient utilization of plant space within the group, as well as to expand ASE’s packaging capacity.

According to CNA’s report, industry sources believe that ASE’s primary objective with this expansion is to enhance its production capacity for advanced packaging of Artificial Intelligence (AI) chips, but it is not directly related to CoWoS packaging.

Market insiders point out that ASE Holdings has been collaborating with foundry on technologies related to advanced packaging interposers and has CoWoS solutions. The earliest expected time for mass production is by the end of this year or early next year.

Reportedly, according to data, ASE’s Kaohsiung plant contributes to approximately 20% of ASE Holding’s overall revenue. The plant primarily provides services such as packaging, wafer bumping and probing, materials, and final testing.

The Kaohsiung plant is also establishing several smart plants, focusing on high-end processes, including Fan-Out packaging, System-in-Package (SiP), wafer bumping, and FlipChip packaging. These technologies find applications in various fields, including automotive, medical, IoT, high-speed computing, artificial intelligence, and application processors.

ASE actively positions itself in various advanced packaging technologies. Notably, the Fan-Out Chip on Substrate with Bridge (FOCoS-Bridge) packaging technology integrates multiple Application-Specific Integrated Circuits (ASICs) and High Bandwidth Memory (HBM), targeting the customized AI chip advanced packaging market.

In addition, ASE Semiconductor has introduced a cross-platform integrated design tool that combines several advanced packaging technologies, addressing the demands of advanced packaging for AI chips.

Read more

• [News] Chinese Semiconductor Design Industry Diverts to Malaysia to Evade U.S. Controls; Potential Advanced Packaging Orders Surge for ASE
• [News] Strong Demand for AI Testing Boosts Revenue Outlook for OSAT like ASE Holdings, KYEC and Sigurd

(Photo credit: ASE)

ASE Holdings conducted an earning conference on October 26th to unveil its Q3 financial results and offer insights into future business prospects. All eyes are on ASE’s progress in CoWoS advanced packaging. Joseph Tung, the Chief Financial Officer (CFO) of ASE, expressed confidence in AI and ongoing investments in advanced packaging, expecting a twofold increase in revenue share for advanced packaging in the coming year.

The market’s attention is keenly focused on wafer bank (a storage system used in semiconductor manufacturing to keep semiconductor wafers on hand for production, helping to streamline the manufacturing process) levels and inventory management. Tung mentioned that wafer bank levels are consistently declining and will further reduce Q4. With consumer electronics and computer clients gearing up to launch new products, inventory levels are expected to be maintained at a certain level. Overall, inventory reduction is nearing completion.

Tung emphasized that the real challenge lies not in inventory reduction but in the timing of the recovery in consumer demands and the impact of inflation. ASE remains cautious in its outlook for the upcoming year.

As for AI-related developments, Tung is optimistic about the expansion of CoWoS advanced packaging capacity through TSMC. ASE is also set to boost its production capacity for advanced packaging to cater to urgent customer demands. Next year, it is expected that revenue in advanced packaging will double. Tung emphasized that the AI era has already arrived and expects AI to extend to more terminal devices over the next few years. ASE has also invested in the development of Co-Packaged Optics (CPO) technology, ready to meet customer demands when the market is prepared.

To seize opportunities in advanced packaging, ASE previously introduced an Integrated Design Ecosystem (IDE) to optimize collaborative design tools through a platform, systematically enhancing advanced packaging architecture. This initiative has the potential to reduce design cycles by approximately 50%.

Tung pointed out that there are signs of a recovery in PC-related chip testing and packaging, and this year’s performance in automotive chip testing and packaging is expected to outperform other segments.

Looking ahead to future market conditions, Tung believes that the global semiconductor industry’s environment in the coming year will be more favorable than the current year.

(Image: ASE)

According to a report by Taiwan’s Commercial Times, JPMorgan’s latest analysis reveals that AI demand will remain robust in the second half of the year. Encouragingly, TSMC’s CoWoS capacity expansion progress is set to exceed expectations, with production capacity projected to reach 28,000 to 30,000 wafers per month by the end of next year.

The trajectory of CoWoS capacity expansion is anticipated to accelerate notably in the latter half of 2024. This trend isn’t limited to TSMC alone; other players outside the TSMC are also actively expanding their CoWoS-like production capabilities to meet the soaring demands of AI applications.

Gokul Hariharan, Head of Research for JPMorgan Taiwan, highlighted that industry surveys indicate strong and unabated AI demand in the latter half of the year. Shortages amounting to 20% to 30% are observed with CoWoS capacity being a key bottleneck and high-bandwidth memory (HBM) also facing supply shortages.

JPMorgan’s estimates indicate that Nvidia will account for 60% of the overall CoWoS demand in 2023. TSMC is expected to produce around 1.8 to 1.9 million sets of H100 chips, followed by significant demand from Broadcom, AWS’ Inferentia chips, and Xilinx. Looking ahead to 2024, TSMC’s continuous capacity expansion is projected to supply Nvidia with approximately 4.1 to 4.2 million sets of H100 chips.

Apart from TSMC’s proactive expansion of CoWoS capacity, Hariharan predicts that other assembly and test facilities are also accelerating their expansion of CoWoS-like capacities.

For instance, UMC is preparing to have a monthly capacity of 5,000 to 6,000 wafers for the interposer layer by the latter half of 2024. Amkor is expected to provide a certain capacity for chip-on-wafer stacking technology, and ASE Group will offer chip-on-substrate bonding capacity. However, these additional capacities might face challenges in ramping up production for the latest products like H100, potentially focusing more on older-generation products like A100 and A800.

(Photo credit: TSMC)