Mass Production Delayed to 2028! Samsung Electro-Mechanics’ Glass Substrate Certification Fails, Re-testing to Take at Least One Year

According to recent foreign media reports, GlaSSEM—a glass substrate joint venture between Samsung Electro-Mechanics and Dongyou Fine Chemical, a subsidiary of Japan’s Sumitomo Chemical—has encountered setbacks in its R&D efforts. The TGV (Through-Glass Via) samples it submitted to leading global communications semiconductor manufacturers failed reliability certification, delaying the originally planned mass production target from the second half of 2027 to 2028 or beyond. Equipment procurement schedules have already been postponed multiple times, and production line construction has come to a complete halt.

South Korean media outlet The Elec recently reported that the root cause lies in material composition and manufacturing processes. During temperature cycling and humidity aging tests, the samples exhibited deformation and unstable micro-via conductivity, failing to meet the reliability thresholds required for AI computing chips and CPO (Co-Packaged Optics) optical module packaging. Samsung Electro-Mechanics must now recalibrate its glass formulation and TGV drilling parameters, remake samples, and undergo full requalification through customer validation processes. Industry insiders estimate this cycle will take at least one year.

TGV technology is a strategic battleground for next-generation advanced packaging. TSMC, Intel, and South Korea’s SKC (Absolics) all aim to begin volume supply around 2027. With Samsung Electro-Mechanics—the leader in South Korea’s materials sector—facing delays, the short-term supply gap for high-end substrates is expected to widen significantly.

Meanwhile, in contrast to Samsung’s certification failure, BOE (Beijing Oriental) successfully completed its panel-level pilot line automation in the first half of this year. Its 9-2-9/20-layer samples passed six reliability tests and have been sent to OSAT (Outsourced Semiconductor Assembly and Test) providers. Kaisheng Technology has shipped 8-inch pilot-line samples to JCET and Tongfu Microelectronics. Changxin Technology has launched its via formation and metallization pilot lines. Wogoo Photonics is already supplying small batches of 1.6T CPO glass carriers and conducting multiple rounds of verification with Enflame Technology and Xianfeng’s CoPoS solutions.

Analysts point out that as overseas giants delay mass production, Chinese downstream CPO and AI packaging manufacturers will accelerate the adoption of domestically produced substrates. With an integrated supply chain spanning raw materials, laser drilling, thin-film deposition, and testing, Chinese suppliers offer significant advantages in both delivery time and cost.

However, glass substrate qualification cycles are long, and challenges such as brittleness and CTE (Coefficient of Thermal Expansion) control remain difficult. Samsung’s failure serves as a warning. Domestic Chinese manufacturers must build robust long-term reliability databases and steadily advance through customer mass qualification processes to fully capture this window of production capacity shortage and close the critical gap in advanced packaging.