As the electronic technology continues to develop, there has been a high demand for high Tg boards. PCB Tg is a very important property of all epoxies. This can be described as a region of temperature whereby the base material, which could be glass as well as polymer, changes from its glassy, rigid, and solid state, to a rubbery state.
All printed circuit boards have a unique Tg value, which is based on the substrate. PCB will begin to alter its state which could cause a bad effect during PCB fabrication once the temperature surpasses the Tg value.
Furthermore, the high Tg boards usually feature better stability when at a high temperature. This is because its substrate provides a better chemical stability, mechanical stability, and heat resistance for the circuit board.
Therefore, Tg value has to be around 20 to 25 degrees centigrade more than the standard operating temperature of that device where you are using the board to choose a printed circuit board. Take for instance, you have a circuit board having a Tg value of around 130 degrees centigrade then the device’s working temperature must be below 110 degrees centigrade.
What does a High Tg PCB Mean?
As explained earlier, the glass or polymer base materials shifts from the rigid, solid, and glassy state to its rubbery state whenever there is a rise in temperature to a specific area, so this temperature is termed glass transition temperature (Tg).
Furthermore, this means that Tg is clearly a mechanical property, which designates glass transition temperature. This is the highest temperature whereby this substrate stays rigid. Explaining further, the usual PCB substrate isn’t just melting, deformation, softening and phenomena at different high temperatures. However, there is a very sharp decline in both the mechanical and electrical properties that will have a great effect on a specific product’s life.
As expected, the normal PCB FR4-Tg is around 130 to 140 degrees, while the medium Tg is higher than 150 to 160 degrees, while high Tg is more than 170 degrees. In addition, high FR4-Tg usually has a better chemical and mechanical resistance to moisture and heat than the standard FR4. When the Tg value is higher, the material’s temperature resistance becomes better. Therefore high Tg PCB material is much more popular, especially in the lead-free process.
What are the Properties of the High Tg PCB?
Due to the quick development of the electronics industry, the wide use of the high tg material can be seen in communication equipment, computer, instrument, precise apparatus, and more. As a result of high multilayer development and high functionality, the PCB substrate material requires higher heat resistance as a prerequisite.
Furthermore, the boards become more inseparable. This is due to the substrate’s high heat resistance in cases of fine wiring, small aperture, and thinning. Also, this is happening as a result of the emergence, as well as the development of the high density mounting technology which CMT and SMT represents.
Therefore, the main difference between the high FR4-Tg and the general FR-4, is the adhesion, mechanical strength, dimensional stability, water absorption, thermal decomposition while in its hit state, most especially after the absorption of water, which are differences present in different conditions like thermal expansion. Also, it is clear that the high Tg PCB is much better compared to the usual PCB substrate materials. Therefore, recently, there has been a high demand for high Tg PCB. However, they are more expensive than the usual printed circuit boards.
Furthermore, a high Tg material is well known in the LED lighting industry. This is because LED heat dissipation is much higher compared to the usual electronic components. However, the FR-4 board’s same structure is far less expensive than the metal core PCB like aluminum PCB.
The high Tg materials possess these properties:
- Resisting high temperatures
- Great PTH reliability
- Lengthy delamination durability (the aging of materials for safety reasons
- Great mechanical properties
- Thermal expansion is low
- High thermal stress resistance value
- Temperature durability is high
What are the Benefits of High Tg PCBs?
The high Tg PCBs come with these benefits
Higher stability: A high Tg pcb will improve its heat resistance, device stability, moisture resistance, and chemical resistance automatically if you increase the PCB substrate’s Tg.
It bears high power density designs: A high Tg PCB offers a great solution for good heat management. However, this only holds when the device features a high power density as well as a high rate of heat generation. High Tg PCBs do this by utilizing a bigger printed circuit board to change a device’s power and design requirements
Great for HDI and multilayer PCBs
There will be high heat dissipation levels. This is because both HDI and multilayer PCBs usually feature dense circuits and are more compact. This is why the high Tg PCBs are useful here.
When a High Tg PCB Becomes Necessary
You will require a high Tg PCB when your printed circuit board can’t handle a thermal load higher than 25 degrees centigrade less than the glass transition temperature. Furthermore, when operating within a centigrade range of 130 degrees or more, then using high Tg PCBs ensures safety.
One good reason behind the high Tg PCB is due to its movement to the RoHS PCB.
Applications of High Tg PCB?
High Tg PCBs are the best solution for high power density present in electronic products, whereby heat generation seems to disturb the heat sink as well as other parts of the product. In addition, you can apply high Tg PCBs in electronic industries that can function in very high temperatures as high Tg PCBs have become more popular recently
We at Hillman serve customers with high Tg PCBs which meets the specifications and demands of the customer and within a fast lead time. Below are the applications of the high Tg PCB:
- Rfid
- Gateway
- Antenna
- Inverter
- Embedded computer systems
- Contract manufacturing services
- Wifi Booster
- Embedded Systems Development
- Ac Power Supplies
Conclusion
High Tg PCBs have different applications. They also enhance the entire lifespan of a printed circuit board and are useful in high Tg PCB manufacturing. Although, using a high Tg PCB is great, there’s a need to ensure that you work with the best quality printed circuit boards.
