Samsung Electro-Mechanics has once again pushed back its glass substrate mass production schedule. The timeline for GlaSSEM, a joint venture with Dongwoo Fine-Chem, has now been delayed at least three times, with production potentially not starting until 2028, as prototype products failed to pass customer reliability certification.

According to The Elec's August 18 report, since GlaSSEM first notified equipment suppliers to prepare inventory in November 2025, the mass production milestone has been postponed from last December to March, then again to June, with no confirmed date currently. The report cites insiders who say the direct cause of the delay is that a glass substrate prototype submitted to a global communication chip customer failed reliability testing, requiring redevelopment and re-certification.

This means production line construction could be pushed to the second half of 2027 at the earliest, with mass production potentially delayed further to 2028 or even later. For equipment suppliers waiting on procurement schedules, the uncertainty surrounding project advancement is also increasing.

Reliability Certification Failure Disrupts Production Pace

The core obstacle for GlaSSEM lies in customer-side validation. After the prototype failed reliability testing, the company must redevelop a new version and complete the certification process again, which has simultaneously delayed equipment procurement and production line construction.

Samsung Electro-Mechanics' foray into glass substrates is primarily driven by demand from the scaling-up of AI chip packaging. As packaging sizes expand, traditional organic substrates face issues such as warping, whereas glass, with its higher rigidity and lower thermal deformation, is viewed as a potential solution for large-size, high-performance AI chip packaging.

However, a significant engineering hurdle remains between prototype validation and mass production. This certification failure also indicates that Samsung Electro-Mechanics still has some distance to cover before commercial implementation.

Japanese Manufacturers Accelerate, Competitive Window Narrows

Meanwhile, Japanese manufacturers are speeding up their glass substrate technology and production line initiatives.

According to the Seoul Economic Daily, Shinko Electric Industries showcased a 22-layer glass substrate at the Advanced Packaging Summit 2026 in July this year. The structure features 11 layers of copper wiring on each side of the glass and employs edge resin design to mitigate the risk of cracking and delamination caused by thermal stress.

Another Japanese company, DNP, launched a TGV glass substrate pilot production line in Saitama in December 2025, also targeting mass production by 2028.

For Samsung Electro-Mechanics, the glass substrate market is at a critical stage of transitioning from technical verification to industrialization. The consecutive delays in mass production plans not only slow its own commercialization progress but also further narrow the window for competing with Japanese rivals in the AI advanced packaging market.