High Tg PCBs

At high temperatures, standard PCB materials may soften, warp, or lose electrical stability. High Tg PCBs provide better heat resistance and dimensional stability.
High Tg PCBs provide better heat resistance and dimensional stability than standard PCB materials.

What Is a High Tg PCB?

Tg is the temperature at which the resin in a PCB begins to lose rigidity. A higher Tg helps the board remain stable during lead-free soldering and high-temperature operation.

PCB materials are commonly classified as:

Standard Tg: 130°C–140°C
Mid Tg: above 150°C
High Tg: 170°C or higher

High Tg PCBs provide better thermal stability, mechanical strength, and resistance to moisture and chemicals. Material selection should consider the operating temperature, assembly process, board structure, and application environment. The final Tg value should be confirmed in the laminate datasheet.

High Tg Rigid PCBs

High Tg rigid PCBs use heat-resistant laminate materials to improve thermal stability and mechanical strength. Their solid structure maintains its shape and supports reliable operation in high-temperature environments.

High Tg Rigid PCB Applications

High Tg rigid PCBs are used in applications exposed to high temperatures, vibration, mechanical stress, or demanding operating conditions.

Common applications include:

Telecommunications — Supporting high-speed signal transmission and compact communication equipment designs
Aerospace — Providing reliable PCB structures for demanding environments and mission-critical electronics
Medical Devices — Enabling complex PCB layouts with improved reliability and space efficiency
Automotive Electronics — Supporting advanced vehicle systems with durable and high-performance circuit designs
Consumer Electronics — Helping achieve smaller form factors while maintaining electrical performance
Industrial Equipment — Improving PCB reliability for control systems and automation applications
Energy Systems — Supporting power electronics and complex circuits requiring stable performance

High Tg Rigid PCB Capabilities

Topline Circuit supports high Tg rigid PCB fabrication and assembly using materials selected for the project’s thermal, electrical, and mechanical requirements.

Engineering & Testing

2 mil trace width, 3 mil air gap, IPC Class 2 and IPC Class 3, flying probe netlist testing, differential impedance, TDR testing, and automated optical inspection (AOI)

Drilling & Routing

Countersinks and counterbores, scoring, rout-and-retain, laser routing, blind and buried vias, and stacked vias

Lamination

1–30 layers, vacuum lamination, and sequential lamination

Plating & Surface Finishes

Conductive and non-conductive via fill, plated edges, castellated holes, plated milling cutouts, hard gold, soft bondable gold, ENIG, immersion silver, lead-free HASL, and OSP

PCB Materials

Flex and rigid-flex materials, adhesive and adhesiveless polyimide, RF and high-speed laminates, mixed FR-4/PTFE constructions, metal-backed boards, and heavy copper rigid and rigid-flex boards

Topline Circuit Fabrication Capabilities

Key Design Considerations for High Tg Rigid PCBs

High Tg PCB design should consider the operating temperature, thermal cycling, vibration, mechanical stress, and assembly process.

Key factors include:

Tg value and laminate properties
Operating and peak temperatures
Thermal expansion and dimensional stability
PCB stack-up and finished thickness
Lead-free soldering requirements
Vibration and mechanical load
Moisture and chemical exposure

High Tg Flex PCBs

High Tg flex PCBs use flexible materials that support bending while maintaining thermal and mechanical stability. Common structures include:

Single-sided flex PCBs
Double-sided flex PCBs
Multilayer flex PCBs
Rigid-flex PCBs

HDI is not a separate type of flexible circuit. However, HDI features may be combined with flex or rigid-flex designs when higher routing density is required.

High Tg Flex PCB Applications

High Tg flex PCBs are used when a design requires flexibility, compact routing, and reliable performance under heat or repeated movement.