A technology race between South Korea and Japan is intensifying over the market for glass substrates used in artificial intelligence chips. As Samsung Electro-Mechanics (009150.KS) accelerates its push into the business by setting up a joint venture with Dongwoo Fine-Chem, Japan's Shinko Electric Industries has built a high-layer-count glass substrate that resists cracking even under high temperatures. Who can first mass-produce a glass substrate with high thermal reliability is emerging as the decisive battleground for capturing the market.
According to industry sources on the 15th, Shinko Electric Industries, a Japanese semiconductor package substrate maker, has built a 22-layer structure by stacking 11 copper wiring layers on each side of a glass substrate. The achievement solves the so-called "seware" problem, in which cracks or delamination occur inside the glass.
Behind the effort to curb glass from breaking easily lies a materials innovation. Shinko applied a polymer-based protective material to the edges of the glass substrate to disperse the stress that concentrates on specific areas when heat is applied. Through this, it succeeded in suppressing seware even after thermal loads.
AI chips are evolving toward integrating multiple processing chips and memory chips into a single package to boost computing performance. As a result, package sizes are growing, and the limits of conventional organic (polymer) substrates — which warp as their area widens — are becoming more apparent.
Glass substrates, by contrast, have high rigidity and little thermal deformation, making them well suited to stably supporting large AI chips. Because of this, major substrate makers, including Samsung Electro-Mechanics, are cultivating glass substrates as a next-generation growth business.
Samsung Electro-Mechanics has also picked glass substrates as its next revenue driver and is continuing advance development. Last month, the company signed a definitive agreement to establish "GlaSSEM," a joint venture for the glass substrate business, with Dongwoo Fine-Chem, the domestic subsidiary of Japan's Sumitomo Chemical. The joint venture is capitalized at 482.1 billion won ($346 million), with Samsung Electro-Mechanics holding a 66% stake and Dongwoo Fine-Chem 34%.
GlaSSEM will handle everything from the development of glass cores to manufacturing and sales. Dongwoo Fine-Chem will provide large-area glass processing and production technology, while Samsung Electro-Mechanics will provide high-layer-count, high-density package substrate design and mass-production technology.
Product validation with customers is already under way. At a second-quarter earnings conference call held on the 30th of last month, Samsung Electro-Mechanics said it is jointly developing large-area, high-layer-count glass substrates for data centers with global big tech firms, and is conducting technology approval and sample evaluation with some customers.
Trillion-Won Next-Generation Substrate Market: Japan Leads, Korea Chases
Behind Samsung Electro-Mechanics' focus on glass substrates is the flip-chip ball grid array (FC-BGA), which has established itself as a high-margin business. The company already mass-produces FC-BGA, a package substrate for AI chips. As the package area of AI chips has recently grown, demand from big tech firms for glass substrates — which can minimize warpage even over large areas — is expanding.
The related market is also expected to grow rapidly. According to market research firm Persistence Market Research, the global glass core substrate market is projected to grow roughly eightfold, from $128.1 million (about 181.2 billion won) this year to $1.036 billion (about 1.4657 trillion won) in 2033. The compound annual growth rate reaches 34.8%.
The industry assesses that, based on the technology results disclosed so far, Japanese firms are a step ahead. Shinko has developed process technology for Through Glass Via (TGV) — the fine holes that pass vertically through the glass substrate — and technology for stacking multiple layers of insulation and copper wiring on top of it. Another Japanese company, Dai Nippon Printing (DNP), built a TGV glass substrate pilot production line in Saitama Prefecture last December and has been supplying samples to customers since early this year. It plans to begin full mass production in 2028.
Samsung Electro-Mechanics is also conducting sample evaluation with customers, targeting mass production two years from now. As a result, which company first completes customer quality certification and secures stable yields around 2028 is expected to decide the shape of the market. Samsung Electro-Mechanics is currently preparing to order equipment to build GlaSSEM's glass substrate production line, but a specific schedule reportedly has not yet been finalized.
An industry official said, "For glass substrates, the key now is securing reliability — maintaining performance without cracks even after chips are mounted and heat is applied — rather than simply the technology of drilling fine holes," adding, "Samsung Electro-Mechanics already has an FC-BGA customer base to which it can apply glass substrates, putting it in a favorable position to pursue advance research and development."
