GlaSSEM, a joint venture between Samsung Electro-Mechanics and Doosan D&T, has had its mass production schedule for glass substrates delayed at least three times. According to The Elec, since equipment suppliers were first notified to prepare inventory in November 2025, the mass production timeline has been pushed from December last year to March this year, then to June, and is currently still undetermined. The direct reason for the delay is that the prototype submitted to a global communication chip client failed reliability tests, requiring re-development and certification. This could push back the construction of the production line to the second half of 2027, further delaying mass production to 2028 or even later. Meanwhile, Japanese manufacturers such as Shinko Electric Industries and DNP are accelerating their glass substrate technology and production line layouts, with DNP also targeting mass production in 2028. This narrows Samsung Electro-Mechanics' competitive window in the AI advanced packaging market.