High Tg PCB Manufacturer With RF4 PCBs of Any Tg Available

High-Tg PCB Overview

Tg, or glass transition temperature, is a measure of the heat resistance of FR4 PCBs. It is 30℃ higher than the maximum working temperature of FR4 PCB and 40℃ higher than that of the electronic device.

A high-Tg PCB is an FR4 PCB whose Tg is 170℃ and above. Middle Tg falls in the range between 150℃ to 170℃. General FR4 PCBs have a Tg value between 130℃ to 150℃.

FR4 stands for flame retardant level 4, which means the epoxy glass can extinguish itself after being burned. FR4 material at temperatures below the Tg value is in a glassy state.

When the temperature reaches the Tg value, the material changes from the glassy state to the rubbery state, in short, it becomes soft.

The higher the PCB Tg, the higher laminating and working temperatures the FR4 PCB can withstand. Besides of better heat resistance, high-Tg PCBs have better moisture and chemical resistance.

High-Tg PCB Manufacturing and Assembly

If you want high-Tg FR4 PCB, keep in mind that high-Tg FR4 materials can't be laminated with low or middle-Tg FR4 materials. Hybrid lamination of FR4 materials with different Tg causes the board popcorns or overflow of epoxy.

The fabrication of high-Tg PCBs requires the lamination temperatures to be higher because the prepreg needs to melt to bond the layers.

After lamination, the PCB is harder than general Tg PCBs, so in the mechanical drilling step, the drill bit has to use a larger drilling force.

In the PCB assembly process, high-Tg PCBs can withstand higher reflow soldering temperatures.

Lead-free solder needs high reflow temperatures to melt to bond PCB pads and component pins. So lead-free PCBs are generally high-Tg PCBs.

At PCBONLINE, you can have high-Tg PCB manufactured and assembled at one-stop. By working with PCBONLINE, you can choose laminates of any Tg for pCB fabrication, including FR408HR, FR408, Isola FR4, etc.

Considerations of Choosing High Tg PCB Materials

There are many options for high-Tg FR4 laminates, such as Shengyi S1000-2 and S1000-2M of Tg 180℃, Ventec VT-47 of Tg 180℃, and ITEQ IT-180ITC of Tg 175℃, etc.

You can check out the datasheets of FR4 PCB laminates from PCBONLINE's PCB laminate page.

Besides Tg, another main consideration of PCB laminates is CTE-z, which measures the thermal expansion and contraction of the PCB material.

If a laminate has a low CTE-z and a high Tg, it is a high-performance PCB material.