At present, the PCB carrier board used in SMD LED products is a special PCB type, which is the simplest IC carrier board. The BT base board on the market mainly uses BT resin developed by Mitsubishi Gas Company in Japan. It is mainly composed of B (Bismaleimide) and T (Triazine). The substrate made of BT resin has the advantages of high Tg(255~330℃), heat resistance (160~230℃), moisture resistance, low dielectric constant (Dk) and low loss factor (Df).