Glass PCBs

Why Glass as a Core Material?

Near-Zero Coefficient of Thermal Expansion(CTE)

Matches silicon and other semiconductor materials,eliminating stress in packaged systems and during temperature cycling.

Ultra-Smooth Surface

Enables fabrication of extremely fine lines and spaces and reduces conductor loss at millimeter-wave frequencies.

Inherently Low Dielectric Loss

Excellent and stable electrical properties(Dk,Df)from RF through THz frequencies.

Thermal&Mechanical Rigidity

High thermal conductivity for a dielectric and exceptional flatness for large-panel processing.

Key Properties & Comparison to Conventional Materials

Performance Comparison Table:

Property	Standard FR-4	High-Frequency Laminate	Glass Core Substrate	Advantage for Design
Dimensional Stability (CTE)	14-17 ppm/°C	10-15 ppm/°C	~3.2 ppm/°C (matches Si)	Eliminates warpage, enables reliable large-size packages and chiplet interposers.
Dielectric Constant (Dk)	4.2-4.5 (varies)	2.2-3.5 (stable)	~5.3 (very stable with freq./temp)	Enables compact RF designs with predictable performance.
Dissipation Factor (Df) @ 10 GHz	~0.020	0.001-0.005	< 0.004	Ultra-low signal loss for millimeter-wave and high-speed digital.
Thermal Conductivity	0.3 W/mK	0.4-0.6 W/mK	~1.1 W/mK	Better heat spreading than polymers, improving device reliability.
Surface Roughness (Ra)	> 2 µm	~0.5 µm	< 0.1 µm	Minimizes skin effect losses, critical for >30 GHz frequencies.
Moisture Absorption	~0.1%	< 0.02%	~0%	Eliminates performance drift due to humidity, ideal for hermetic packages.

Primary Applications & Industries Served

Glass Core PCB technology is enabling innovation in several high-growth sectors:

RF&Millimeter-Wave Communications

● 5G/6G Infrastructure: Antenna-in-Package(AiP), beamforming modules, and mmWave front-end modules.

● Automotive Radar: 77/79 GHz radar sensors for ADAS, where stable performance across temperature is critical.

● Satellite&Defense: Phased array antennas, secure comms, and radar systems.

Advanced Semiconductor Packaging & Heterogeneous Integration

● Silicon/Glass Interposers: Providing ultra-fine RDL(Redistribution Layer)routing with superior electrical and thermal performance compared to organic interposers.

● Chiplet Integration: The ideal substrate for 2.5D/3D chiplet architectures due to CTE matching and high planarity.

● MEMS&Sensor Packaging: Provides a hermetic seal and stable platform for sensitive MEMS devices.

High-Performance Computing&Photonics

● Co-packaged Optics(CPO): Excellent substrate for integrating optical waveguides and electrical traces.

● Data Center Switches/Routers: Interposers and substrates for next-gen ASICs and FPGAs requiring massive I/O density.

"Design for Glass" Guide: Critical Rules for Success

Designing with glass substrates requires a paradigm shift from traditional PCB design, focusing on the material's brittleness and unique properties.

Our Recommended Glass PCB Design Practices:

Design Parameter	Recommended Practice(For High Reliability)	Common Pitfall to Avoid
Mechanical Layout&Corners	Use rounded corners and avoid sharp angles in the substrate outline to prevent stress concentration and cracking.	Designing with 90-degree corners, creating fracture initiation points.
Trace-to-Edge Clearance	Maintain a generous clearance(e. g. , >1. 0 mm)between any copper feature and the glass edge.	Routing traces too close to the edge, making the board susceptible to edge chipping.
Via Design&Pitch	For Through-Glass Vias(TGVs), use a conservative pitch≥3x the via diameter. Follow manufacturer guidelines for aspect ratios.	Overpopulating TGVs, compromising the mechanical integrity of the glass.
Thermal Management	Actively manage heat dissipation. While glass is thermally stable, it is a thermal insulator. Use thermal vias(if applicable)or direct thermal paths to a heatsink.	Assuming the glass substrate itself will effectively dissipate heat from power components.
Handling&Mounting	Design for uniform mechanical support. Specify mounting points that apply even pressure and avoid point loads.	Using point-to-point mounting or clips that induce bending stress.
Impedance Control	The highly stable Dk of glass allows for extremely precise impedance control. Provide clear targets for our thin-film process engineers.	Applying design rules meant for fibrous, anisotropic materials like FR-4.

Pro Tip: Engage Early in the Design Phase!Glass PCB fabrication is highly specialized. Contact our engineering team during the conceptual stage for guidance on material selection, stack-up feasibility, and design rule optimization tailored to our manufacturing processes.

Our Glass PCB Manufacturing Capabilities

We possess the specialized equipment and cleanroom environment required for high-precision glass substrate processing.

Technical Specifications:

● Substrate Materials: Borosilicate Glass, Fused Silica/Quartz.

● Standard Thickness: 100µm to 1.1 mm.

● Metallization: Thin-Film(Ti/Cu, Cr/Cu seed layers)with Electrolytic/Electroless Plating.

● Minimum Trace/Space: 8µm/8µm(standard), down to 5µm(advanced).

● Through-Glass Via(TGV)Diameter: 30µm-100µm.

● Surface Finishes: ENIG, Electrolytic Gold, Immersion Silver.

Quality&Assurance:

● Standards: Fabricated and inspected to relevant MIL-PRF and IPC standards for hybrid circuits.

● Testing: 100%Electrical Testing.High-Frequency Network Analysis for RF performance.Microscopic inspection for trace integrity.

● Inspection: White Light Interferometry for surface planarity measurement.Cross-sectioning for TGV and metallization quality.