After the price of one layer of "cloth" has risen by 270%, investment institutions have voted with hundreds of millions of yuan for the glass substrate sector, and Xunlin Technology has completed a Series B financing of nearly 200 million yuan.
Introduction: At present, the price of electronic-grade fiberglass cloth has doubled compared to the low point in 2025, the price of FR-4 copper clad laminate has risen by over 270%, the delivery period of some AI packaging substrates has been extended to more than 6 months, and the supply crisis of organic substrates continues to deepen. Against this backdrop, domestic leading glass substrate manufacturer Xunlin Technology announced the completion of a Series B financing of nearly 200 million yuan — this is the third round of financing completed by the company within half a year. This round of financing is invested by new shareholders including Inno Fund, Qiancheng Capital, Hymson, Guangpu Co., Ltd., Tongxin Capital, and old shareholders including Jinyumaowu, Haitong Kaiyuan, Beishan Industrial Investment continue to increase their holdings. The raised funds will be mainly used for glass substrate capacity expansion, packaging production line construction and operation, process precision upgrading R&D, and cutting-edge optical communication application layout.
Shareholding Structure: Market-oriented Capital, Industrial Capital and Regional State-owned Capital Participate Together, Old Shareholders Increase Their Investment Again
The shareholder lineup of this round presents a distinct "triple play": market-oriented hard technology funds represented by Inno Fund, Qiancheng Capital and Tongxin Capital, which have long been deeply engaged in the semiconductor and advanced manufacturing sectors; industrial capital represented by Hymson and Guangpu Co., Ltd., which come from the laser equipment and optical communication industries respectively, the upstream and downstream sectors closely related to glass substrates; market-oriented funds, regional state-owned capital and securities firm-backed capital represented by Jinyumaowu, Beishan Industrial Investment and Haitong Kaiyuan, continue to increase their investment in this round. The continuous investment of diversified shareholders provides solid support for the company's industrialization process, and is also the most direct confirmation of its mass production progress.
Industry Background: Overlapping of Substrate Shortage and Price Surge, Glass Substrate Usher in a Definite Window Period
Essentially, this round of financing is a strategic positioning for the time window. With the rapid surge of AI computing power, packaging substrates continue to be in short supply, ABF substrates are in short supply and the delivery period has been extended again and again; as chip packaging sizes continue to break through and the speed of optical modules continues to rise, organic substrates are approaching the physical limits in terms of thermal expansion matching, high-frequency loss and wiring density. The choices of industry giants have given the answer: Intel announced that Glass Core Substrate (GCS) has entered large-scale mass production, TSMC's CoPoS trial production line will be put into operation within the year, and Samsung and SKC Absolics are accelerating sample delivery and mass production preparation. Glass substrates are moving from the laboratories of giants to the center of the industry.
Core Logic of Substitution: One Layer of "Cloth" Restricts Organic Substrates, Three Major Applications Move Towards Full-scale Glass-based Development
What is more noteworthy than the trends of industry giants is that the cost foundation of organic substrates is loosening. Since the second half of 2025, the PCB industry chain has experienced a rare round of price increases: the price of copper clad laminates has risen sharply, and all PCB manufacturers have adjusted their prices. The real source of the price increase is not copper foil or resin, but a layer of "cloth" — electronic-grade fiberglass cloth. Its price has doubled compared to the low point in 2025, the industry inventory has dropped to an extremely low level in history, high-end low-dielectric products are highly monopolized by overseas manufacturers, and capacity expansion takes years to complete. The shortage of this layer of "cloth" has no solution in the short term.
The reason why fiberglass cloth is indispensable is that it is the "skeleton" of organic substrates, and one of its core missions is thermal stress matching: as the number of layers of AI server PCBs continues to rise, in order to make the thermal expansion coefficient of organic substrates close to that of silicon chips, the industry has to use a large amount of expensive low-CTE special fiberglass cloth. In other words, organic substrates are using more and more expensive "cloth" to imitate the inherent properties of glass — glass has a natural CTE matching silicon, its dielectric loss is far lower than that of organic materials, and it does not need this layer of "cloth" at all. When the cost of the "patch" crosses the cost inflection point of material substitution, glass-based development changes from an optional item to an inevitable item. However, "glass-based development" is not a single matter, but three distinct matters — the demand logic, technical indicators and industrial rhythm of the three major applications are completely different:
The first category, PCB substitution — an economically driven stock substitution with the fastest rhythm. Targeting AI server backplanes, high-frequency communication boards and new display substrates, the substitution objects are FR-4 and traditional PCBs. The logic is simple and sharp: better performance and lower cost. The signal loss is significantly reduced, and the comprehensive cost in scenarios of display and HDI substrates is far better than that of PCB substrates. This category competes for large-scale manufacturing and cost control capabilities, and is the main battlefield of current volume growth — 2026 will be the first year of glass-based PCB substitution.
Schematic Diagram of Glass Substrate Replacing Traditional PCB
The second category, ABF substrate substitution — driven by reliability and supply security, with a moderate rhythm. Targeting ultra-large-size FC-BGA packaging, Chiplet and HBM high-bandwidth memory, it replaces substrates that are monopolized by overseas players and continue to be in short supply. This is a duel of hard indicators: warpage, line width and line spacing, aperture and aspect ratio are all strictly controlled, testing the deep-water capabilities of precision process and reliability verification. Related products will be gradually launched to the market in 2027.
The third category, Interposer substitution — a long-term substitution driven by cost revolution, with the largest market space. Targeting CoWoS advanced packaging and CPO optoelectronic co-packaging, it replaces expensive silicon TSV interposers: glass has significantly better dielectric properties than silicon, higher panel-level processing utilization, and its comprehensive cost is expected to be much lower than that of silicon TSV; more critically, in CPO scenarios, glass can directly carry optical waveguides to realize optoelectronic integration. This industrial chain will gradually mature from 2027 to 2030 — whoever seizes the position in advance will hold the admission ticket to the next generation of packaging.
Schematic Diagram of Application of Glass Core Substrate and Glass Interposer
It is worth noting that when the industry generally focuses on GCS (Glass Core Substrate) and GI (Glass Interposer), the glass-based development of PCB will also inevitably be implemented rapidly, but Glass PCB has a harsh premise: the substitution indicator is extremely high, and very few enterprises can truly meet the requirements. To replace organic PCB, glass substrates must cross three thresholds at the same time — cost framework: the TGV substrate cost model of most enterprises cannot be closed at all; high copper thickness to line width ratio: under fine circuits, high current driving for server power supply and display also requires thick copper, while thick copper is exactly the common short board of glass copper plating in the industry; full-process direct yield, which is the recognized economic lifeline of the industry, and the domestic mass production level is uneven. Xunlin Technology is one of the very few enterprises in the world that have passed all three indicators and have the possibility of mass production: its comprehensive cost is expected to be significantly lower than that of similar PCBs, it has both thick copper capacity and fine circuit capabilities, its direct yield leads the industry, and its copper plating bonding strength is several times higher than the industry average, which guarantees the long-term reliability of mounting and rework. In the window period of continuous price increase, the cost-performance balance between glass substrates and organic PCBs is reversing — and the enterprises that can meet the demand after the reversal must pass these three thresholds first.
Mass Production Progress: The Last Kilometer Has Been Opened Up
The industry never lacks concepts and samples, what it lacks is real production capacity that can be stably delivered in batches. In the view of Xunlin Technology, only when the factory is put into operation, the yield is optimized, and the cost model is closed, can the demand change from sample orders to sustainable bulk orders. To this end, Xunlin has built a full-process glass substrate factory in Tianjin, covering the whole process from cutting, thinning, TGV pore forming, to PVD metallization, electroplating, patterning, and solder masking, with an annual production capacity of 300,000 square meters. Relying on the self-developed PVD copper plating technology and Cu-ABX quaternary alloy seed layer derived from the aero-engine thermal barrier coating system, the company's copper plating bonding strength is several times higher than the industry level, the mass production aperture and depth-to-diameter ratio of TGV cover mainstream demands, and the continuous VCP electroplating capacity is several times higher than that of traditional lines. At present, the company's Mini LED backlight, COB direct display and MIP display module substrates have entered the stage of batch shipment, and have been verified by leading domestic customers through its own module packaging line — the "last kilometer" for glass substrate PCBs to move from the laboratory to the production line has been opened up.
Application of Glass Substrate in MicroLED
Processing Path: Three Sets of Process Platforms Progressively Interact, Six Levels of Precision Realize Stepwise Leap
The capacity expansion logic of Xunlin is not simple replication of production capacity, but to build three progressive and interactive process platforms around the underlying capabilities such as TGV pore forming, PVD metallization, electroplating and patterning, to gradually tighten the five dimensions of aperture, pore density, structure, number of layers, line width and line spacing, and gradually open up the market — six levels of products move up step by step along three main process lines.
The starting point of this path is the first platform — large-size glass-based PCB process with subtractive method as the core: the display backlight and COB glass-based PCB that have entered mass production have double-sided copper plating plus TGV vertical conduction, large panel size and high yield, which is not only the basic disk of cash flow, but also the reliability base of all levels; by tightening the patterning precision on the same platform, it extends to glass-based HDI, introduces micropores and buried vias, realizes multi-layer TGV fine wiring, and enters the high-speed PCB and optical module substrate market. The second platform is high-order interconnection process with semi-additive fine circuit and multi-layer bonding as the core: high-order HDI realizes multi-layer stacking through unit bonding, avoiding the cumulative alignment error of layer-by-layer lamination, which is Xunlin's differentiated method for multi-layer development; when this fine circuit capability is further extended to substrates, GCS glass core substrates are opened up — shifting to the fine process of "through hole — hole filling — RDL — multi-layer stacking", directly targeting the ABF stock substitution market worth tens of billions of US dollars, which is also the main R&D direction of this round of financing. The third platform is oriented to the integration of packaging and optics: high-precision TGV and Glass Interposer (GI) continue to make efforts towards smaller aperture, higher aspect ratio and higher through-hole density, the cost is expected to be much lower than silicon TSV, targeting the long-term market of 2.5D/3D packaging and HBM; on the same platform, optical processing capabilities are further added, ion exchange optical waveguides, laser direct writing modification, optical fiber through holes and precision cavities are processed on the same board, and finally the co-construction of "circuit + optical path" on the same board is realized. The three platforms are not isolated from each other: the copper plating reliability and mass production yield verified by the subtractive platform are the common base of fine circuit and packaging processes; and the precision capabilities accumulated in hole filling, RDL and optical processing continuously feed back the precision improvement of the first two platforms — they support each other in the progressive process.
This six-level path is not a leapfrog bet, but a linear evolution of precision iteration — which is completely isomorphic with the climbing logic of large domestic PCB manufacturers from "single/double panel — multi-layer board — HDI — high-order HDI — IC substrate": the aperture is continuously tightened, the circuit is continuously refined, and the number of layers expands from double-sided to dozens of layers, which is essentially continuous narrowing and stepwise superposition on the basis of shared underlying process capabilities. This model fundamentally avoids the biggest hidden risk in the industry — production line obsolescence and investment failure: core processes such as TGV, PVD, electroplating, exposure and etching are widely reused among the three platforms, and platform upgrading relies on process package iteration and modular process superposition, rather than total reconstruction; the mass production revenue of each level of product in turn feeds back the R&D of the next generation. The production capacity formed by this round of financing will not depreciate with product iteration, but will continue to appreciate as precision improves.
Logic of Industrial Upgrading and Iteration of Glass Substrates
Views of Investors and Founders
The investor of this round, Inno Fund, said: "Glass substrates are at a critical window period from technical verification to large-scale mass production. We value Xunlin Technology's original breakthroughs in underlying processes such as PVD copper plating, and more value its implementation capability of having built a full-process production line and realized batch shipment — in hard technology investment, teams that can deliver products are the most scarce."
Dr. Zhen Zhen, Founder and CEO of Xunlin Technology, said: "This round of financing is the dual confirmation of the mass production route of glass substrates by industrial partners and market capital. The price increase of fiberglass cloth has made the whole industry see the cost ceiling of organic substrates clearly, and also makes the substitution value of glass substrates have economic certainty for the first time. Next, the funds will be concentrated on capacity ramp-up, packaging implementation and precision upgrading — from display substrates to high-order HDI, from glass core substrates to optical waveguides, we use three sets of progressive and interactive process platforms and continuous precision leap to make real batch delivery the final solution for industry demands."
About Xunlin Technology
Xunlin Technology was founded in September 2023, focusing on the R&D and industrialization of full-process glass substrate technology, covering core processes such as TGV through hole, PVD composite coating, continuous electroplating and fine circuits. Its products are applied in fields including Mini LED backlight, COB/Micro LED direct display, glass-based HDI, advanced packaging substrate and optoelectronic co-packaging. The company has realized the mass production of Micro LED level circuit precision and high-density TGV substrates, and is accelerating the expansion of its industrial territory from substrates to modules, from display to packaging, and from electricity to optics.