Glass substrate roadmaps examined — Absolics in final qualification and a first product that keeps slipping
Glass-core substrates, the replacement for organic chip packaging that Intel promised in September 2023 with more than $1 billion behind it, are now in final qualification. However, the product is still not in a single commercial product. SKC, a material manufacturer and chemical affiliate of the SK Group, said on its July 27 earnings call that embedded glass substrate samples from its Absolics plant in Covington, Georgia, are undergoing package-level reliability evaluation in Taiwan, with results possible before year-end.
Samsung Electro-Mechanics formalized a 482.1 billion won ($310 million) glass-core joint venture with Sumitomo Chemical’s Dongwoo Fine-Chem on July 2, targeting first production in the second half of 2027. Intel, which started the race, has shifted to licensing its patents and showing demo vehicles, with its own deployment now pointed at around 2030. However, and rather predictably, every timeline in the segment has slipped. Absolics originally planned mass production for the first half of 2024, and reported claims that AMD would adopt glass substrates for CPUs between 2025 and 2026 have come and gone unfulfilled.
Why glass?
The technical case for glass core substrates leans heavily on numbers Intel published a while back, such as 10 times the interconnect density of organic substrates and a 50% reduction in pattern distortion. Glass cores can be tuned to a thermal expansion coefficient of roughly 3 to 10 ppm per degree Celsius against silicon’s 2.6, which cuts warpage by about half compared with organic cores, and rectangular panels in the emerging 510mm x 515mm format use more than 75% of their area for large die against roughly 50% for round 300mm wafers. Through-glass vias have been demonstrated at six microns in diameter with aspect ratios beyond 15:1 at ECTC 2025, and Georgia Tech has shown stacked glass running at 220 GHz with 0.3 dB of loss.
Glass also chips and cracks at the edges during drilling and dicing, and MIT Technology Review reported in March that early Absolics production runs broke hundreds of panels every couple of days during early testing days. Edge-coating work has cut measured edge stress from 95 MPa to 49 MPa, and low-temperature dielectrics that cure below 180°C have been developed to reduce thermal stress during build-up, but metallizing vias below 10 microns and holding nanometer-scale flatness across half-meter panels remain open manufacturing problems.
Intel’s program
Intel demonstrated a working system booting Windows on a glass-core substrate in early 2025, and Rahul Manepalli, Intel’s VP of module engineering, told MIT Technology Review that the benefits of glass cores are “undeniable” and that Intel wants “to be one of the first ones who do it.” The commercial plan around that engineering has changed shape, however. DigiTimes reported in late July that Intel is in early-stage talks with Chinese cover-glass maker Lens Technology about a packaging partnership, but there has been no solid agreement made to date.
At NEPCON Japan in January, Intel Foundry showed its first thick-core glass substrate with two EMIB bridge dies embedded directly in the glass: a 78mm x 77mm package with two 800-micron-class glass layers, 10 redistribution layers on each side, and around 1,716 mm2 of silicon on top, roughly two full reticles, with no micro-cracking reported in testing.
There’s currently no production time to this, however, with TrendForce placing Intel’s commercialization somewhere around 2030, alongside co-packaged optics prototypes built on glass at its Rio Rancho, New Mexico site. Meanwhile, Amkor, Intel’s packaging partner on the optics work, put commercialization within three years at an industry event in Seoul in April.
Korea aiming for 2027
Samsung Electro-Mechanics moved its glass program from advanced R&D into a business-execution unit in February and has been sampling from a pilot line at its Sejong plant since late 2024. The GLASEM joint venture announced on July 2 splits ownership: 66% to Samsung Electro-Mechanics and 34% to Dongwoo Fine-Chem, with site production in Pyeongtaek, and targets an operating plant in the second half of 2027, with the joint venture making the drilled and metallized glass core that feeds Samsung’s substrate line. Korean industry reporting says samples have gone to AMD and Broadcom, and also puts Samsung’s overall glass maturity at 40 out of 100, a gap between marketing dates and process readiness worth keeping in mind.
Absolics’ $600 million plant in Covington, Georgia, backed by $75 million in CHIPS Act funding plus a further $100 million through the government’s advanced packaging R&D program with Georgia Tech, has a Phase 1 capacity of 12,000 m2 of substrate per year, enough for roughly two to three million H100-sized packages. The company produced mass-production samples in the first quarter, began customer qualification that reportedly includes AMD and AWS, and is targeting mass production by the end of 2026. LG Innotek runs a third Korean program from its Gumi plant, with prototypes delivered in 2024 and production targeted for 2027 to 2028.
TSMC and Japan
TSMC’s CoPoS line in Chiayi, built around 310mm x 310mm rectangular panels, received tools in February, completed its pilot line around June, and is aiming for pilot production in 2027, with mass production in the second half of 2028. Equipment supplier SCHMID has described glass integration in that platform as under review, not committed, and TrendForce puts TSMC’s commercial-scale glass-core production after 2030, meaning that the industry’s biggest packaging operation is going panel-level first and glass later, if at all. TSMC revived glass substrate research a couple of years ago after earlier deprioritizing it, reportedly under pressure from Nvidia, whose accelerator packages are the main thing outgrowing current packaging.
Japan’s Dai Nippon Printing began phased operation of a TGV glass-core pilot line at its Kuki plant in Saitama in December 2025 on 510mm x 515mm panels, with sample shipments from early 2026 and full mass production targeted for fiscal 2028. Toppan’s pilot line for glass cores and interposers at its Ishikawa plant was scheduled for commissioning in July, and Nippon Electric Glass has scaled its ceramic-reinforced GC Core panel to 515mm x 510mm at 1mm thickness. Rapidus is studying panel-level packaging on 600mm x 600mm glass as part of its 2nm program, with viability put at the late 2020s. China has its own entrants, led by display maker BOE, whose pilot line is sampling.
TrendForce estimates Nvidia’s Rubin Ultra package at roughly 7,470 mm2, about nine reticles’ worth of silicon and memory, against around 2,739 mm2 for Blackwell, and CoWoS interposer wafers cost on the order of $10,000 each, comparable to a processed 7nm wafer.
Organic substrates warp and lose dimensional stability at those sizes, and round interposer wafers waste a growing share of their area, which is what glass panels are meant to fix. SEMI’s first dedicated market report on glass cores, published in May with Global Net, projects initial production around 2028 in select high-performance applications and a 67.2% compound annual growth rate from 2028 to 2040, while Yole puts the advanced IC substrate market at $31 billion by 2030 with glass cores among the drivers.
At the moment, no production design exists, and all customers that have been named or otherwise attached to the tech, including AMD, Broadcom, AWS, and Nvidia, come from wider industry reporting. Nothing has been confirmed officially. As for whether we might see more substantial progress next year, Absolics will need to publish some solid package-level reliability results by the end of this year, or a first officially named customer at any of the Korean manufacturers. We also need to hear from TSMC on whether glass cores will go into CoPoS or remain under review into the 2030s.
