High-temperature PCBs are designed to operate reliably in environments where temperatures exceed the limits of standard PCBs, typically withstanding sustained temperatures of 150°C to 300°C or more. These boards are essential for applications like automotive under-the-hood systems, industrial ovens, power electronics, and aerospace engines, where heat generated by components or external conditions can degrade standard materials.

The key to their performance is the substrate material. Instead of standard FR-4 (which begins to decompose above 130°C), high-temperature PCBs use materials like polyimide (PI), which maintains stability up to 260°C, or ceramic (alumina, aluminum nitride), capable of withstanding 300°C+ and offering excellent thermal conductivity. For extreme temperatures (500°C+), metal-core PCBs (MCPCBs) with aluminum or copper cores dissipate heat efficiently, preventing component overheating.

Copper traces on high-temperature PCBs are often plated with nickel or gold to resist oxidation at elevated temperatures, while solder masks are made from silicone or polyimide, which remain flexible and insulating under heat. Vias (holes connecting layers) are plated with thick copper to maintain conductivity and prevent thermal fatigue.

Manufacturing processes are adapted to handle these materials: laser drilling for precise vias in ceramic substrates, and high-temperature lamination to bond layers without delamination. Testing includes prolonged exposure to target temperatures to verify resistance to warping, trace degradation, or solder joint failure. By combining heat-resistant materials with specialized design, high-temperature PCBs ensure reliable operation in the most thermally challenging environments.