PCB Board Selection
According to the predication of PCB industry, PCB substrate’s price accounts for about 10% of total material cost (components, shell, etc.). Many factors can affect the price, so in this article, we will discuss from the aspect of PCB substrate selection.
Copper Clad Laminate (core)
Copper clad laminate (CCL) is the most important material during the PCB production process, accounting for about 45% of the total PCB. The most common substrate is FR4, woven glass, epoxy. There are many types of CCL, the most common is classified based on the Tg (heat), common palte Tg is above 130 ℃, the middle one is above 150 ℃, and high Tg plate is above 170 ℃. As the Tg increases, the price increases accordingly.
With the rapid development of the electronics industry, especially the electronic products like smart phones and ipads, the high heat resistance of the PCB substrate material is an important guarantee as the fast development of high functionality and high multi-layer technology. The Tg of the substrate is improved, so does the heat resistance, moisture resistance, chemical resistance, and stability characteristic of the printed circuit board. The higher the Tg value, the better the heat resistance of the sheet, especially in the lead-free process, high Tg are applied more.
Prepreg is used in laminating the core plate and copper foil. When choosing, three main factors like thickness, dielectric coefficient, and price are considered in sequence by factories. Its model is 106,1080-7628, as the model number increases, the thickness of the prepreg increases, but the cost is reduced. Although the laminate thickness and finished product meet the requirements for the impedance test, high-grade prepregs suffer from warpage and cracking under extreme environmental conditions due to their poor plasticity.