The Fiber Weave Skew Problem Is Over: ACCM Celeritas™ SF1600 Delivers Zero-Skew for PCIe 7, 224 Gbps and Beyond

SAN JOSE, Calif.--(BUSINESS WIRE)--Advanced Chip & Circuit Materials, Inc. (ACCM) today introduced Celeritas SF1600, a laminate and prepreg material that eliminates fiber weave skew at its root. Fiber weave skew is a materials problem, not a routing one. Woven glass creates a spatially periodic dielectric in which differential pairs travel alternately through resin-rich and glass-rich regions. In a differential pair, the two conductors traverse different paths, which produces a time delay (skew) that panel rotation, serpentine routing, or zig-zag compensation cannot address at 224 Gbps PAM4 and beyond. Celeritas SF1600 removes the cause entirely through ACCM’s proprietary resin and reinforcement technologies, delivering validated zero-skew performance and the lowest dielectric loss in its class – on standard FR-4 equipment with no special handling, storage, or infrastructure.

The industry has been looking to Quartz-based products to address the loss requirements for current and next-gen applications. Not only do these products fail to address the skew problem, they bring with them new problems. Their resin chemistries – heavily filler-loaded to achieve CTE and DF requirements – create a mismatch with quartz fiber (softening point ~1,665°C) that standard CO2 laser drilling cannot address cleanly, leaving fiber stubs in microvia walls that compromise plating quality and via reliability. The same filler-laden chemistries result in poor adhesion to copper: Tier 9 quartz-based systems deliver ~2 pli peel strength on HVLP4 copper and none of these systems perform reliably beyond HVLP3, closing off the conductor-loss headroom that 224 Gbps and 448 Gbps budgets depend on. By contrast, Celeritas SF1600 exceeds 5 pli on the same foil. Compounding this, suppressing fiber-weave resonance below the Nyquist frequency for 224 Gbps signaling requires panel rotation exceeding 15 degrees – a costly waste of real estate on a material that already commands a premium price and faces constrained supply.

Celeritas SF1600 delivers Dk = 2.80 and Df = 0.0007, stable over frequency to 110 GHz and over temperature and moisture. Measured insertion loss is ~1.05 dB/inch at 56 GHz on 7-mil differential pairs with HVLP4 copper; ~0.95 dB/inch is projected with HVLP5. Celeritas SF1600 drills cleanly with standard CO2 and UV laser tooling and supports mechanical drilling with no fiber pull-out or tool wear.

Key performance attributes include:

• Zero fiber weave skew (validated multiple times through measurement)
• ~1.05 dB/inch insertion loss at 56 GHz on 7-mil differential pairs with HVLP4 copper (~0.95 dB/inch projected with HVLP5)
• Dk = 2.80 and Df = 0.0007 across frequency
• Glass transition temperature (Tg) ~215°C
• Thermal decomposition temperature >400°C
• Passes 50× 260°C reflow simulation
• Excellent stacked µvia reliability (500 cycle OM testing)
• Available in thicknesses from 25 to 150 µm
• Compatible with standard FR-4 laminate processing—no special storage, handling, or chemistry required
• Smooth, consistent CO2 and UV laser drillability and mechanical drillability—no fiber stub residue, no special process window required
• Peel strength >5 lbs on HVLP4 copper (vs. ~2 pli for Tier 9 quartz-resin systems); compatible with HVLP5

Bit error rate failures leave no physical evidence – the board does not crack, does not delaminate, and passes visual inspection. The consequences are only seen at the deployment level, in the form of a link that won't come up, or a system that runs at 80% bandwidth and nobody knows why. This makes it easy to qualify in the lab a material that underperforms in the field, and for programs to stall before the root cause is understood. The financial exposure is real and large – it is just invisible until it isn't. Celeritas SF1600 and ACCM’s Celeritas materials portfolio are built on data validated under production-representative conditions. For design teams at 224 Gbps and beyond, the engineering case is unambiguous.

About Advanced Chip & Circuit Materials, Inc. (ACCM)

ACCM is a U.S.-based advanced materials company headquartered in San Jose, California, manufacturing PCB, substrate, and build-up dielectric materials at its Wisconsin facility. The company develops materials solutions for AI, ultra high-speed digital, and semiconductor packaging applications.