Samsung Electro-Mechanics' move into semiconductor glass substrates has slipped again after reliability bottlenecks in prototype customer testing delayed investment plans, with the company shifting its operating start to 2028 and the industry timetable moving from the second half of 2027 to the first half of 2028. Serenity said the setback points to at least another quarter of delay for the sector's mass-production push. TrendForce had previously reported that SKC subsidiary Absolics also pushed its schedule from the second half of 2026 to the first half of 2027 and aims to complete final verification by year-end, reinforcing the view that the glass substrate supply chain is resetting its timeline. The revised timetable could shape capacity ramp plans for LPK, Philoptics and E&R even as glass substrates remain a closely watched advanced packaging technology for AI and high-performance chips.