High Tg PCB refers to a specialized circuit board engineered for superior heat resistance, utilizing base materials with an elevated glass transition temperature (Tg) to endure high-temperature operating environments.
According to the IPC-TM-650 2.4.25D standard, a PCB qualifies as High Tg when its laminate Tg value exceeds 170°C. The glass transition temperature (Tg)—a critical property of PCB substrates—marks the threshold where material transitions from rigid to flexible. Manufacturers like Weller PCB rigorously test materials to ensure compliance with high-reliability applications, as specified in technical datasheets, such as S1000-2, which is a base material with Tg>180.
In addition, the Glass Transition Temperature is also the temperature point at which the polymer material melting from hard. At the glass transition temperature, the polymer material experience transition from rigid status to more flexible status making the temperature at the border of the glass-like to a soft rubbery state material.
Essentially, that high Tg PCB material has the property of flame-resistant; so it should not be brittle to heat or at a specific temperature; it can only become to be soft. The temperature point of the PCB board is called the Glass Transition Temperature (Tg) therefore a high Tg PCB is one of which the printed circuit board is made to have the capable of withstanding extremely high temperatures.
Also, during the layer lamination of PCB fabrication process, the higher the glass transition temperature point means the higher the temperature requirement in the manufacturing process. High-temperature requirements during lamination process will enable the boards to be crisp and hard, which tends to affect the electrical properties of the circuit board’s hole.
Nevertheless, normal PCB materials at high temperatures operation process will be subject to some phe
