High Tg PCB: The Glass Transition Temperature (Tg) means the glass transition temperature during continued heating. Circuit board material must own features of flame-resistant. and it can only be softened and can’t burn at a certain temperature. The temperature point is called the glass transition temperature (Tg).
The temperature point is called the glass transition temperature (Tg). Generally, Common FR4 Tg is 140 degrees, Middle Tg is around 150 degrees, and high Tg is higher than 170 degrees. Glass transition temperature (Tg) is one of the characteristic temperatures of high molecular polymers. Taking Tg as the line, the polymer shows different physical properties: below the Tg value, the polymer material is plastic; above the Tg value, the polymer material is rubber.
During the experience of applications, Tg is the peak temperature of plastics engineering and the bottom temperature of rubber engineering.
The higher the Tg value, the better the PCB thermal and moisture resistance performance. Once the working temperature reaches or exceeds the Tg value, the circuit board’s form will change from glassy to liquid form; as a result, PCB may not work. Additionally, this value also has a relationship to the dimension and structure of the board. Especially in the lead-free process, more application of high TG circuit boards. Engineers pursue high Tg PCBs in harsh telecom, satellite communication, and even military applications.
Characteristics such as moisture, chemical, and stability resistance are all enhanced and improved. The characteristics of high TG materials include:
Stability
PCBs with high Tg have better stability in heat resistance, chemical resistance, and moisture resistance.
Heat dissipation
A high Tg PCB has good heat dissipation if the device has high power density and fairly high heat generation.
Ideal for Multilayer and HDI PCB
Since Multilayer and HDI PCB are more compact and circuit dense, they will result in high heat dissipation. Therefore, high Tg PCBs are usually a choice for multilayer and HDI PCBs to ensure the reliability of PCB manufacturing.
High TG PCBs are commonly used on devices that generate extreme temperatures, contain highly reactive chemicals, and generate a lot of vibration and shock during operation:
Industrial control
PLC controllers control long-term manufacturing processes, such as metal cutting, grinding, welding, and melting equipment. High Tg can protect the working unit well.
Automotive electronics
An engine’s efficiency depends on its controller’s reliability. High TG PCBs are crucial to withstand the high temperatures created by high RPMs and long run times.
Telecom industry
Switching gateway for communication equipment that supports a large amount of information exchange generating immense heat, but high Tg PCB can guarantee stability.
Layers: 8 L Thickness: 2.0mm
Out Layer Copper Thickness: 1 OZ
Inner Layer Copper Thickness: 1 OZ
Min Hole Size: 0.2mm Min Line Width: 3mil
Surface Finish: HASL
Application: Base Station
Layers: 10 L Thickness: 2.0mm
Out Layer Copper Thickness: 1 OZ
Inner Layer Copper Thickness: 1 OZ
Min Hole Size: 0.3mm Min Line Width: 4mil
Surface Finish: ENIG
Application: Micro Base Station
Layers: 8 L Thickness: 1.6mm
Out Layer Copper Thickness: 1 OZ
Inner Layer Copper Thickness: 1 OZ
Min Hole Size: 0.25mm Min Line Width: 4mil
Surface Finish: ENIG
Application: Automotive
Feature | Capability |
Quality Grade | Standard IPC 2, IPC 3 |
Number of Layers | 2 – 40 layers |
Material | Tg140 FR-4,Tg150 FR-4,Tg170 FR-4, IT180, Rogers 4350B |
Max Board Size | Max 450mm x 900mm |
Final Board Thickness | 0.2mm – 6.5mm |
Copper Thickness | 0.5oz – 13oz |
Min Tracing/Spacing | 2mil/2mil |
Min Drilling Hole Diameter | 6mil |
Solder Mask Color | Green, Red, Yellow, Blue, White, Black, Purple, Matte Black, Matte green |
Silkscreen Color | White, Black |
Surface Treatment | HASL lead-free, Immersion gold, OSP, Hard Gold, Immersion Silver, Enepig |
Testing | Fly Probe Testing and A.O.I. test |
Lead Time | 2 – 28 days |
The materials used to manufacture high Tg PCB circuit boards are flame-retardant. Glass epoxy has flame-retardant properties. As a result, composites containing epoxy resins and polymers are the first choices for high Tg circuit board fabrication.
FR4: FR4 stands for Glass Fiber Reinforced Epoxy Laminate. It is the NEMA grade designation for epoxy fiberglass composites. FR stands for flame retardant. This FR4 material has been tested for flame retardant properties according to the UL94V-0 standard. The material provides resistance in dry and wet conditions, so the FR4 material resists heat dissipation caused by dielectrics and conductors.
IS410: IS410 is a laminate and prepreg material that can withstand 180°C Tg. It can sustain multiple thermal excursions and it has withstood the 6 times solder test under 288°C. It can also be applied to lead-free soldering in high-temperature PCB manufacturing.
IS420: IS420 is a high-performance multifunctional epoxy resin. It offers enhanced thermal performance and has low expansion rates as compared to regular FR4 materials. This material can block UV radiations, and it is collaborative with Automated Optical Inspections (AOI).
G200: is a combination material between epoxy resin and Bismaleimide/Triazine (BT). It owns high thermal resistance, high mechanical strength, and high electrical performance. It is applied to multi-layered Printed wiring boards.
However, besides these regularly used High-Tg materials, ARLON 85N, ITEQ IT-180A, and S1000, etc are other FR4 materials, that applied to High-Tg PCB manufacturing.