ACCM Launches Celeritas Negative-CTE PCB Material to Solve AI Chip Warpage and Signal Loss

What Happened

Advanced Chip and Circuit Materials (ACCM) on June 15, 2026 announced commercial availability of two new PCB laminate materials:

• Celeritas HM50: Negative CTE (-8 ppm/C) material for power plane layers
• Celeritas HM001: Near-zero CTE material with Tier 9 electrical loss performance for signal layers

Together in a single stackup, they bring board CTE below 10 ppm/C while simultaneously supporting 100+ Gbps data rates — solving two problems that previously required separate (and often conflicting) solutions.

Why This Matters for PCB Engineers

The Problem Being Solved

Every hyperscaler building AI accelerator infrastructure confronts two converging constraints:

1. Thermomechanical warpage: Silicon CTE (2-4 ppm/C) vs standard PCB material CTE (~18 ppm/C) creates catastrophic reflow warpage in large-format packages. As AI chips scale beyond reticle limits, the mismatch literally tears solder joints apart.

2. Signal loss at extreme data rates: HBM, UCIe, and chip-to-chip interconnects running at 100+ Gbps push signal integrity requirements beyond what standard dielectrics can deliver.

These problems have historically been treated separately — thermal engineers optimizing CTE with one set of materials while signal integrity engineers demanded low-Dk/Df from another. The two goals often conflict.

What ACCM Claims

The key innovation: HM50 has negative CTE (-8 ppm/C), meaning it actively contracts when heated — counterbalancing the expansion of other board materials. By tuning the ratio of HM50 layers to standard layers, engineers can dial board CTE to any target between 8-15 ppm/C.

HIGH-LAYER-COUNT CAPABILITY

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How It Fits into a Stackup

ACCM proposes a layer-by-layer material assignment:

• Signal layers: Celeritas HM001 (near-zero CTE + Tier 9 loss performance)
• Power plane layers: Celeritas HM50 (negative CTE, drives board-level CTE down)
• Combined effect: Total board CTE tunable from 8-15 ppm/C depending on layer ratio

This approach means engineers do not need to pick between thermal performance and electrical performance — each layer gets the material optimized for its function.

Implications for Current AI Board Designs

For engineers currently designing 16-30 layer boards for AI inference/training cards:

1. Warpage management becomes material-driven rather than mechanical (no more expensive stiffening frames or mechanical constraints during reflow)
2. Signal layer loss improves without changing trace geometry or stackup height
3. BGA reliability improves dramatically — reduced CTE mismatch means less solder joint fatigue over thermal cycling

vs. Glass Substrate Approach

The industry has been watching glass substrate technology (from companies like Absolics, SKC) as a potential solution to CTE mismatch. ACCM explicitly positions against glass:

ADVANCED MATERIALS

Low-Loss Laminates for High-Speed Design

We work with Rogers, Isola, Panasonic Megtron, and other advanced laminates for demanding signal integrity applications. Talk to our materials engineering team.

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Industry Context

This announcement comes amid broader supply chain pressures in AI PCB materials:

• T-glass fiber cloth shortage constraining high-end laminate production (Digitimes, June 11)
• Lead times for advanced PCB materials stretching past 20 weeks (Digitimes, June 5)
• Nvidia driving HVLP4 copper foil demand upstream (Digitimes, June 11)

ACCM’s Celeritas entering commercial production potentially adds another high-demand material to an already-constrained supply chain. Early adopters will likely be hyperscaler programs (Google, Meta, Microsoft, Amazon) where the performance gains justify premium pricing and dedicated supply agreements.

What to Watch

• Pricing: ACCM has not disclosed material cost. Expect significant premium over standard high-speed laminates initially.
• Processing compatibility: Claim of compatibility with existing PCB processes needs validation across multiple fabs.
• Qualification data: Full JEDEC qualification data and multi-fab consistency data will determine adoption speed.
• Supply availability: A new material from a newer company always carries supply continuity risk for volume programs.

MATERIAL EXPERTISE

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Whether you are evaluating new laminates for thermal performance or choosing between Rogers, Megtron, and Tachyon for signal integrity — our engineers can advise based on your specific design constraints.

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Practical Takeaway

For engineers designing AI accelerator boards today: Celeritas is worth evaluating if your current stackup fails JEDEC warpage qualification or if you are struggling to meet loss budgets at 56+ Gbps per lane. The material is commercially available now, but expect to work directly with ACCM for supply allocation and processing guidance during this early phase.

For most standard high-speed designs (servers, networking, telecom) below the hyperscaler tier, existing materials like Megtron 6/7 and Tachyon 100G remain proven, available, and cost-effective choices.

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Related Reading:

• AI Accelerator PCB Thermal Management Design Guide
• High-Tg PCB Material Selection Guide
• AI Server PCB Material Supply Chain Analysis 2026
• RO4350B vs Megtron 6: High-Frequency Laminate Comparison