IC substrate is the key packaging material in semiconductor packaging, among which ABF substrate is mainly used in GPU, CPU, ASIC, FPGA and other high-computing power chips, with the launch of NVIDIA H100, GH200 and other GPU products, its performance requirements for the substrate area, data transmission and power consumption are gradually improving. We believe that benefiting from the rapid development trend of AI, the importance and market size of IC substrates, especially ABF substrates, are expected to usher in rapid growth.
summary
The IC substrate is the key packaging material, and the ABF substrate assumes the function of "computing power base". The IC substrate is between the chip and the PCB to realize the signal transmission connection, among which the ABF substrate has the advantages of multi-layer and fine lines due to its unique multi-layer structure, and is more suitable for scenarios with a large number of I/O ports in more advanced processes, with the growing demand for computing power and the development of TSMC's CoWoS process, the requirements of downstream enterprises for ABF substrates are gradually increasing, mainly reflected in: 1) a larger area (currently to 110mm* 110 mm or more), 2) finer line width and line spacing (L/S to 5/5 μm or less), 3) Higher number of layers (20 layers and 9/2/9 structure or more).
We believe that with the recovery of the traditional PC market and the demand for AI PCs and AI server GPUs spawned by AI, the market size of IC substrates, especially ABF substrates, is expected to grow rapidly, and the market size is expected to increase to $28.96 billion by 2028, with a CAGR of 11% from 2022 to 2028 The ABF carrier board market size was $4.81 billion in 2022, and Yole expects the market size to grow to $10.65 billion by 2028.
At present, the global ABF substrate market is monopolized by Japanese and Taiwanese companies, and the localization rate is still low: according to Yole statistics, in 2022, IBIDEN occupies the first place with a share of 21% among the global ABF substrate suppliers, and Xinxing Electronics ranks second with a share of 18.9%, in addition to other suppliers including Nanya Circuit (13.3%), Shinko (12.2%), AT&S (10.8%), and Jingshuo (8.8%). At present, the IC substrate industry in Chinese mainland started late and is currently in the stage of accelerated catch-up. We are optimistic that the localization rate of ABF carrier board is expected to gradually increase in the future.
risk
The localization process of IC substrates has slowed down, the recovery of downstream demand has slowed down, and the development of AI large models has not been as expected.
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IC substrate: the core material of packaging, the base of computing power chips
IC substrate is the core material of packaging, and ABF substrate is mainly used in high-computing power chips
In the packaging process, the IC substrate is between the chip and the PCB to realize the signal transmission connection, and at the same time provide protection and support for the chip and form a heat dissipation channel, so that the packaged chip can reach the required size, which is the key material in the package.
Figure 1: Schematic diagram and development trend of the substrate
Source: Yole, CICC Research
IC substrates are mainly divided into two types: BT/ABF substrates, and the main differences are the different media used and their performance.
► BT substrate is based on BT resin, which is based on bismaleimide and triazine as the main resin components, and adds epoxy resin, polyphenylene ether resin or allyl compounds as modified components to form a thermosetting resin, which has high glass transition temperature, excellent dielectric properties, low thermal expansion rate, good mechanical characteristics and other properties, so it is widely used in memory, radio frequency, mobile phone AP and other fields, but because it has a hard glass fiber sand layer, although it can stabilize the size and prevent thermal expansion and contraction from affecting the yield,
► The core structure of ABF substrate still retains the glass fiber cloth prepreg resin (FR-5 or BT resin) as the core layer, and at the same time, the upper and lower layer structure is adopted, and the ABF laminated dielectric film is added, and the copper foil substrate of prepreg glass fiber cloth laminated copper foil used in BT carrier board is discarded, and replaced with electroplated copper. The ABF carrier board made by this has the advantages of multiple layers and thin lines
From the perspective of packaging types, the two most common ones are BGA (Ball Grid Array) and CSP (Chip Scale Package), of which BGA is a ball grid array package, which has the advantages of large I/O spacing, high reliability, and good heat dissipation performance, and is widely used in high-power and high-integration chips, while CSP is a chip-size package, which has the advantages of miniaturization and high assembly density, and is the mainstream packaging form in the storage field.
FCBGA substrates are characterized by three aspects: large size, high stack, and fine circuits. As the size of the data processing chip increases to 70 mm × 70 mm, the companion FCBGA substrate transitions from 80 mm × 80 mm to larger sizes of 110 mm × 110 mm. Second, the number of additional layers on the substrate will be increased from 10 layers (4/2/4) to 20 layers (9/2/9) or more to meet the needs of high-density interconnects, and the line width/line spacing will be reduced to 5 μm or less for high-density wiring.
Figure 2: FC-BGA/FC-CSP package comparison
Source: Yole, CICC Research
With the rapid development of advanced packaging, TSMC's CoWoS process has gradually increased the demand for ABF substrates
AI/HPC accelerates the requirements for computing performance and drives the development of advanced packaging. The requirements for chips such as low latency, low power consumption, multi-function, large memory and high integration have stimulated the development of advanced packaging. TSMC believes that packaging is no longer limited to Moore's Law, and that advanced packaging will help AI/HPC maintain the pace of performance growth over the next decade. Yole expects the advanced packaging market to grow from $44.3 billion to $78.6 billion from 2022 to 2028, at a CAGR of 10%.
Figure 3: 2022-2028 Advanced Packaging Market Size Development Forecast
Source: Yole, CICC Research
The 2.5/3D package is represented by TSMC CoWoS. The UCIe Alliance has specified a variety of advanced packaging technologies for chiplets, including Intel EMIB, TSMC CoWoS, ASE FoCoS-B, etc., and CoWoS (Chips on Wafer on Substrate) technology first passes the chip on The Wafer (CoW) packaging process is connected to the silicon wafer, and then the CoW chip is connected to the substrate to integrate into CoWoS, the core of which is to stack different chips on the same silicon interposer to realize the interconnection of multiple chips. According to different interposers, CoWoS packages are divided into three types: CoWoS-S/R/L.
According to NVIDIA's official website, its A100 chip adopts TSMC's 7nm process, and the packaging mode adopts TSMC's CoWoS packaging technology, integrating 1 A100 GPU chip and 6 HBM2 on a 55mm*55mm 12-layer FCBGA substrate, while Nvidia H100 uses 4nm process, and the package form is 1 H100 GPU chip and 6 HBM 2E integrated in a 55mm* 58mm on a 12-layer FCBGA carrier board.
Figure 4: NVIDIA GPU package structure
Source: Nvidia website, CICC Research
Figure 5: NVIDIA GPUs use 12-layer FCBGA carrier boards
Source: Nvidia website, CICC Research
In addition, the EMIB (Embedded Multi-die Interconnect Bridge) technology released by Intel in 2014 has an I/O count of up to 250~1000 to improve the chip interconnection density, and the silicon interposer is embedded in the ABF substrate to save a large area of the silicon interposer. Although the cost is reduced, the area, number of layers and production difficulty of ABF are increased, and the requirements for ABF and production capacity consumption are further improved.
Figure 6: Sapphire is available in an Intel EMIB package
Source: Intel, YOLE, CICC Research
The localization rate of IC substrates is low, and the demand side benefits from the rapid improvement of AI
Demand side: Downstream demand is still dominated by traditional PCs, and it is expected to benefit from the rapid growth of HPC demand in the future
ABF carrier board is mainly used with high-end computing chips such as GPU, CPU, ASIC, etc., and the downstream application scenarios are mainly PC, server, AI chip, base station, etc., taking Xinxing Electronics, a leading carrier board company in Taiwan, China as an example, according to Xinxing Electronics' 4Q23 performance meeting, about 55% of the terminal applications of its IC carrier boards will be used in computers, about 26% in the communication field, 13% in consumer electronics and 6% in automobiles. We believe that with the rapid growth of GPU shipments in the future, the demand for ABF carrier board area and number of layers is expected to continue to increase, which is expected to drive the rapid growth of ABF carrier board demand.
Since PCs occupy a large share in the downstream applications of ABF carrier boards, the recovery of the PC market has a great impact on the demand for ABF carrier boards. According to Canalys, global PC (excluding tablet) shipments in 4Q23 rose 3% year-on-year to 65.3 million units, ending a seven-quarter losing streak. At the same time, Canalys predicts that global PC shipments are expected to increase by 8% year-on-year to 267 million units in 2024, and IDC predicts that AIPC penetration is expected to reach 85% in 2027 as PC manufacturers such as Lenovo and Dell plan to launch AIPC products in 2024. We believe that with the rapid increase in the penetration rate of AI PCs, it is expected to accelerate the recovery of the PC market, and the demand for carrier boards is expected to increase simultaneously as PC CPU processors need to use ABF carrier boards.
Exhibit 7: Global PC shipments and growth rate
Source: Canalys, CICC Research
Exhibit 8: China's traditional PC and AIPC shipment forecasts
Source: IDC, CICC Research
In addition to traditional PC processors, ABF carrier boards are also used in high-computing power chips such as GPUs, FPGAs, and ASICs. We believe that the market size of GPUs for AI acceleration in the cloud is growing rapidly due to the continuous upgrading of AI applications and the demand for large-scale model computing. According to ARKInvest's predictions, the large model behind ChatGPT's application continues to iterate, and the newly put into use GPT-4 has a maximum of 1.5 trillion model parameters, far exceeding GPT-3, which has only 175 billion parameters. Since generative AI must be trained with massive amounts of data, combined with a large number of parameters exceeding 100 billion/trillion yuan of the model itself, the demand for computing power for large models has increased significantly, which in turn has driven the demand for GPU market. According to Nvidia's forecast, the total market size of AI chips and hardware systems is expected to reach $300 billion in the future, and according to AMD's forecast, the market size of AI accelerator chips in data centers will reach $400 billion in 2027. At present, NVIDIA has launched GPU products such as A100, H100, B100, and GH200 for the rapid growth of AI, and AMD has launched MI300 products, and compared with the 3/2/3 structure of the traditional ABF carrier board for PC, the GPU is generally 5/2/5 architecture and above, so we believe that the high-performance computing chip CPU (Intel Eagle Stream, AMD Genoa) and GPGPU (NVIDIA GH200, etc.) for ABF substrates has significantly increased the area and number of layers.
Therefore, based on the demand repair of traditional PCs and the rapid growth of HPC demand, we believe that the market size of ABF carrier board is expected to grow rapidly. At the same time, it is expected that the market size is expected to increase to $28.96 billion by 2028, with a CAGR of 11% from 2022 to 2028, of which ABF carrier boards are mainly used in the UHD FO/2.5&3D/FCBGA field, and the market size of ABF carrier boards in 2022 will be $4.81 billion, and Yole is expected to grow to $10.65 billion by 2028.
Exhibit 9: IC Substrate Market Size Forecast 2022-2028
Source: Yole, CICC Research
Supply side: The global market is monopolized by Japanese and Taiwanese companies, and the localization rate is still at a low level
The global IC substrate competition pattern is relatively fragmented, with Taiwan, China, Japan and South Korea all having a certain share. Due to the similar manufacturing process to PCB, the IC Substrate supply chain is similar to PCB, mainly concentrated in Taiwan and Japan. According to Yole statistics, in the global IC substrate market in 2022, Xinxing Electronics has a market share of 17%, making it the world's leading supplier of IC substrates, IBIDEN and Nanya Circuit are tied for second place with a market share of 10%, and the rest of the suppliers are mainly Japanese, South Korean, and Taiwanese companies such as Samsung, Kyocera, Jingshuo, etc., according to Yole statistics, IBIDEN will occupy the first place with a share of 21% and Xinxing Electronics will occupy 18.9% among ABF substrate suppliers in 2022 In addition, other suppliers include Nanya Circuit (13.3%), Shinko (12.2%), AT&S (10.8%), and Jingshuo (8.8%). Among them, Taiwanese companies such as Xinxing Electronics, Nanya Circuit, and Jingshuo Technology occupy an important share in the field of ABFIC substrates, and have increased their ABF substrate production capacity. The IC substrate industry in Chinese mainland started late and is currently in the accelerated catch-up stage. According to Prismark's estimates, in 2022, the market share of the four major mainland substrate manufacturers of Shennan Circuit, AKM Meadville, Zhuhai Yueya, and Xingsen Technology will only be about 6%, and they are still dominated by BT substrates, and the localization rate is still low in the field of high-end products such as ABF substrates.
Figure 10: IC Substrate Market Landscape in 2022
Source: Yole, CICC Research
Exhibit 11: ABF Carrier Board Market Landscape in 2022
Source: Yole, CICC Research
At present, the localization rate of IC substrates of Chinese mainland manufacturers is still low, and BT substrates are the mainstay. At present, Chinese mainland is realizing the rapid catch-up of IC substrates, and has a certain scale in the BT field, such as the Shenzhen IC substrate factory has achieved 300,000 square meters / annual production capacity, mainly for MEMS, fingerprint modules, RF modules and other IC substrate products, Wuxi IC substrate factory 600,000 square meters / The annual production capacity is mainly for IC substrate products of memory products, and the second phase of Wuxi factory is continuing to promote capacity improvement and mass production climbing; Guangzhou FC-BGAIC substrate project has been completed and put into operation in the fourth quarter of 2023; according to the investor relations record of Xingsen Technology, it has achieved the construction of 35,000 square meters/month BT substrate production capacity, mainly for memory chips, fingerprint identification chips, RF chips, application processor chips, The company is expected to enter the stage of small batch production in the first quarter of 2024, with a production capacity of about 2 million pieces/month, and in 2023, the second phase of the FCBGA packaging substrate manufacturing project with a total investment of 2.15 billion yuan will start, with a production capacity of 480,000 pieces/year, and the Zhuhai factory with an investment of 3.5 billion yuan at the end of 2021 will have an estimated production capacity of Via 120,000 pieces per month for Post copper pillar method substrates, 20,000 pieces per month for embedded packaging substrates, and 60,000 pieces per month for FCBGA packaging substrates.
Dismantling of IC substrate production process and industrial chain links
SAP and mSAP are the main production processes for IC substrates
Subtractive is the main production process of traditional PCB, in which a layer of copper is plated on the copper clad laminate to protect the circuit and vias while etching the unwanted copper skin, leaving the copper in the circuit and via. The process has high side etching, and the copper layer will also etch the side in the process of downward etching, which limits the fineness of the subtractive method.
The key difference between SAP (Semi-Additive Process) and mSAP is that SAP does not have base copper. The seed layer in SAP is chemically deposited copper (thickness 0.5~1 μm), while the seed layer in mSAP is pressed ultra-thin copper foil (thickness 2~3 μm). Due to the etching selectivity of the flash etching solution, the ultra-thin and loose copper layer is easier to remove, but if the bond between the seed layer and the medium is weak, the wire drop phenomenon will be very serious for long-distance fine lines on large-size substrates.
mSAP (Modified Semi-Additive Process) is mostly used for BT substrates without ABF materials, and the minimum linewidth spacing is 15/15μm. The mSAP process uses extremely thin base copper (2~3μm) as the base copper, and makes corrosion resistance patterns on the substrate (BT-like carrier boards), thickens the circuit through pattern plating, removes the corrosion resistance patterns, and then flashes the bottom copper, and the retained part forms a fine electronic circuit. Ordinary materials can be achieved with ultra-thin copper foil, and the matching equipment is highly compatible, and there is no need to update the equipment, so most of the industry preferentially chooses the mSAP process.
Figure 12: MSAP vs. SAP processes
Source: Huang Yong, Wu Huilan, Chen Zhengqing, et al.Research on semi-addition method[J].Printed Circuit Information,2013(08):9-13,Research Department of CICC
Core materials and key equipment in the production process
The core process of ABF production can be divided into core board production and inner and outer layer production. Taking a 10-layer FCBGA carrier board as an example, the inner core board is fabricated through cutting, drilling, route etching and AOI inspection. After that, ABF lamination and laser drilling are carried out on the ultra-roughened inner core board, and a series of film drying, exposure, development and graphic plating are carried out after metallization in the hole, and finally the fine circuit is made through thin film and flash etching, and there will be curing, cleaning, baking and AOI testing in the process to ensure the yield of the carrier board.
Figure 13: Production process of a 10-layer FCBGA carrier board
Source: Wang Ligang, Zou Donghui, Tao Jinbin. Research on Key Technologies for Fabrication of 10-Layer FCBGA Substrate[J]. Printed Circuit Information, 2023, 31 (S2): 1-8
The main raw materials in the production process of ABF substrates can be divided into structural materials and chemical materials. Structural materials include resins, ABF films, copper foils and insulating materials, while chemical materials include dry films, wet films, photoresists, etchants, contrast agents, etchants, etchings, etchants, etchings, etchings, etching ABF film is a kind of epoxy resin added glass powder pressed to make of sheet semi-cured material, which does not contain glass fiber, with this material to manufacture the insulation layer of the outer circuit can be a good realization of SAP, in the manufacture of high-end substrate manufacturing is widely used. However, ABF is a patented product of Ajinomoto Fine Chemical Co., Ltd., and according to the statistics of Crystallization Technology, the global ABF film market size reached US$460 million in 2021, of which Ajinomoto accounted for 96.8%.
The thickness of the copper foil affects the fineness of the line. The determining factor affecting the amount of etching bite in the mSAP process is the thickness of the base copper, the thinner the base copper, the less the corresponding etching amount, the smaller the side erosion of the line, the more conducive to the fine line operation, especially the 10μm/10μm fine line needs ultra-thin copper foil to reduce the over-corrosion and side erosion during etching. However, there are still great difficulties in the preparation process of ultra-thin copper foil, because the thickness of ultra-thin copper foil is too small, and the coating is easy to produce pinholes and holes, which affects the quality of copper foil. In 2020, Mitsui Kinzoku began mass production of 1.5~5 μm ultra-thin electrolytic copper foil, MicroThin™, which is characterized by ultra-thinness and low signal transmission loss.
The core production equipment of ABF carrier board includes LDI, AOI, PTH, etc. Compared with traditional exposure (film first, then projection by parallel light, and finally transcription), LDI (Laser Direct Imaging) equipment directly engraves the laser on the photosensitive material, and the accuracy is higher than that of traditional exposure. AOI (Automatic Optic Inspection) line inspection equipment can detect the line width and spacing of the line and the opening and short circuit of the line during the manufacturing process. PTH (Plating Through Hole) equipment and VCP (Vertical conveyor plating) equipment are used for plating fine routes. In addition, there are testing machines, film machines, laser drilling machines, etc.
Figure 14: Key steps in the production of FCBGA carrier boards
Source: Wang Ligang, Zou Donghui, Tao Jinbin. Research on Key Technologies for Fabrication of 10-Layer FCBGA Substrate[J]. Printed Circuit Information, 2023, 31 (S2): 1-8
Multi-layer, fine circuits and large size are the development trends of advanced IC substrates. At present, the number of mainstream layers of ABF carrier boards will be increased from 10 to 12-14 layers. At the technical level, Xinxing can achieve 32 layers, Jingshuo 14 layers, Nandian 8-16 layers, and Yueya Semiconductor can achieve product breakthroughs of more than 14-20 layers. In terms of line density, BT carrier board lines are above 12 microns, ABF lines are 8 microns, and Yole expects to officially enter the 5 micron competition in 2025. In terms of carrier board area, ABF carrier boards commonly include 35mmX35mm, 100mmX100mm, and even 200X200mm integrated chips, which are mostly used for AI and high-performance computing. Chinese mainland has the ability of Shennan, Yueya, Xingsen, Huajin, etc. with small batch production line width/line spacing 12/12-15/15μm FCBGAIC carrier boards.
Exhibit 15: FCBGA Technology Roadmap
Source: Yole, CICC Research
Future technology evolution: focus on new applications of glass substrates
The glass IC substrate is led by Intel and is suitable for the next generation of advanced packaging materials. In order to solve the warpage problem of organic substrates used in chip packaging, Intel is actively introducing the industry's first next-generation advanced packaging glass substrate, which will be used in applications that require larger packages, such as commercial aspects involving data centers and artificial intelligence, according to Intel's estimates, it is expected to start providing complete glass substrate solutions after 2025 and achieve 1 trillion transistor packages by 2030. Glass substrates have superior performance. Compared to today's organic substrates, glass has unique properties such as the ability to withstand higher temperatures, a 50% reduction in pattern distortion through enhanced flatness, improved focusing depth for lithography, and the dimensional stability required for extremely tight interlayer interconnect coverage. Thanks to these features, the interconnect density on the glass substrate can be increased by a factor of 10, while increasing the designer's flexibility in power transmission and signal line placement. In addition, the improved mechanical properties of the glass substrate enable ultra-large packages with very high assembly yields.
Figure 16: Intel's advanced packaging technology roadmap
Source: Intel, CICC Research
TGV (Through Glass Via) is a vertical electrical interconnection through a glass substrate, corresponding to TSV (Through Silicon Via), which has the possibility of replacing silicon interposers, and is considered a key technology for next-generation 3D integration. TGV uses high-quality borosilicate glass and quartz glass as the substrate, and realizes 3D interconnection through seed layer sputtering, electroplating filling, chemical mechanical planarization, RDL rewiring, and bump process. TGVs are microvias typically 10 μm-100 μm in diameter. For a variety of applications in advanced packaging, tens of thousands of TGV vias are typically applied and metallized per wafer to achieve the required conductivity. Compared with silicon substrates, TGV technology has the advantages of excellent high-frequency electrical characteristics, low cost of large-size ultra-thin glass substrates, simple process flow, and strong mechanical stability.
In terms of process, the glass substrate adopts the same SAP process as the ABF carrier board in the processing process. In addition, the glass substrate needs to be laminated with seed layer and wire plating, PVD, CMP and other processes, and then laminated on both sides of the glass core board, but because TGV technology does not need to make an insulating layer, the process complexity and processing cost are reduced.
Risk Warning
IC substrate localization process slowdown: due to Chinese mainland's late start in the field of IC substrates, especially ABF substrates, there is still a large gap with overseas leading products in manufacturing process, production cost and technology, although we believe that the localization of the supply chain is the development trend of domestic GPU and CPU, but if the domestic ABF carrier board and overseas cannot shorten the technical gap, it will have a certain negative impact on the localization process of the carrier board industry chain and delay the progress of IC substrate localization.
Downstream demand recovery slowdown: ABF carrier board downstream applications mainly include PC, consumer electronics, communications, etc., as soon as possible we believe that benefiting from the rapid development of AI, the demand for ABF carrier board is expected to usher in rapid growth, but at present, its main demand is still PC processors, general-purpose server processors and other consumer terminals, if the overall demand for consumer electronics slows down, it will still have a negative impact on the demand for ABF carrier board.
The development of AI large models is less than expected: With the continuous digitalization and intelligent transformation of society, the implementation of AI large model scenarios has accelerated to empower hundreds of industries. We believe that the vigorous development of artificial intelligence has driven the increase in the demand for computing power in society, including upstream hardware infrastructure such as servers and network communication equipment, which may benefit from the increase in computing power demand driven by artificial intelligence.
Article source:
This article is excerpted from: "Intelligent Computing Future Series III: Accelerating the Carrier Board Industry and Upgrading the Computing Chip Base" released on March 29, 2024
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