Glass Substrates Are Progressing Faster Than Ever Lately, it's SEMCO that's been pushing commercialization forward SEMCO has just completed initial reliability testing of its 100 × 100 mm glass substrates and moved to package-level testing using actual customer chips The company is working with several major global customers SEMCO targets an operational production line by late 2027 and full-scale manufacturing in 2028 Previous TGV reliability issues delayed equipment orders, making successful package-level validation a critical milestone It's strongly rumored that $LPK played a key role in resolving these issues, with improvements coming primarily from the development of thicker glass substrates

Glass substrates will likely become a big investment theme in 2027, especially if we remain in a bull cycle, where themes tend to get fast-tracked I’ve already done some coverage, including an interview with LPK’s CEO In case anyone wants to check it out

Glass substrates are arriving sooner than planned. NVIDIA is pressing its substrate makers to speed up development, which could bring adoption to before 2028. BOE has 24 layer substrates over 100 by 100 mm already validated in house and being tested with real server CPUs and GPUs, with a mass production investment decision by 1H27. Samsung Electro Mechanics and LG Innotek are targeting 2027 to 2028. Glass replaces the conventional core inside the package with a much flatter and more stable material, so AI chips can be packed denser and run cooler. Packaging is turning into the next capex fight after CoWoS. -TrendForce

$LPK CEO on glass substrates adoption: "The first players are positioning themselves and placing ramp-up orders. The timeline has slipped compared with our original 2026 expectations, but we're talking about delays of a few months, not a year."

As interposers and substrates approach their scaling limits, 2.5D packaging is moving toward 3.5D, with tighter D2D pitch, higher bandwidth density, and lower energy per bit to overcome reticle-driven constraints on lateral scaling. Higher integration density makes yield increasingly critical to economics. Final yield compounds across process steps, so losses at any stage directly affect overall yield. More HBM stacks, chiplets, substrates, and bonding interfaces increase integration complexity, while some defects are detected only late in the process flow. This tightens process-control requirements across the integration flow and increases the importance of advanced inspection.

$NVDA IS PUSHING GLASS SUBSTRATES TO EXTREME THICKNESSES According to Korean semiconductor publication KIPOST, NVIDIA is requesting glass substrates with a thickness of 2,000 µm (2 mm), potentially driving the adoption of new metallization technologies, including atomic layer deposition (ALD). As AI packages grow larger to accommodate more GPUs and HBM, substrate rigidity becomes increasingly important. Thicker glass improves mechanical stability and reduces warpage, but makes through-glass vias (TGVs) harder to manufacture. For perspective, a 2 mm substrate with 50 µm vias would have an aspect ratio of 40:1. Conventional sputtering struggles to deposit uniform conductive seed layers inside such deep, narrow holes. ALD's superior conformality could provide a solution. However, ALD isn't the only competing technology. In September, TRUMPF announced its HiPIMS technology for coating deep TGV structures, using highly ionized plasma to improve coverage. Meanwhile, MKS Atotech introduced a wet metallization process combining electroless copper seeding with advanced electroplating. Progress is also being made in drilling. Korean equipment manufacturer Philoptics demonstrated TGV processing on 2 mm-thick, 510 × 515 mm glass panels, claiming zero defective holes in its demonstration.

Rosenblatt: "We believe each $1mn of InP substrates can support ~$30mn of transceiver sales, so the $194.4mn 2027 contract could underpin ~$5.8bn of annual transceiver revenue, or roughly 12mn modules at the ~$500 blended ASP implied by AAOI's 2027 revenue and capacity targets. Over the full five-year agreement, that implies ~$29bn of transceiver revenue at constant pricing." $AAOI

TRUMPF is presenting on glass-core substrates at SEMICON TRUMPF is a core supplier to $ASML and is allied with $SHMD to bring glass-core substrates to reality They’re betting heavily on this, and they’re highly credible Big implications for $LPK (if anyone still cares about the name)

Prices of Indium Phosphide (InP) substrates and epi-wafers are set to jump over 10% in the 4th quarter – the biggest price hike in history – as the AI-driven optical communications boom causes severe shortages, media report. One supplier reportedly said inventory is so tight that “even with cash, you might not get anything.” InP substrate prices have risen for three consecutive quarters and are heading into a fourth, while epi-wafers are entering their third consecutive increase. Valued for high-frequency, high-speed data transmission, InP is a critical material as AI data centers shift from copper to optical interconnects (optics in, copper out.) $AXTI $SMTOF #SumitomoElectric# 5802 $LITE $COHR $AAOI