There are many types of substrates used for PCB processing, but they are roughly divided into two categories, namely, the most commonly used boards for smt, which are inorganic substrate materials and organic substrate materials.

Inorganic substrates are mainly ceramic PCB boards, and the ceramic circuit substrate material is 96% alumina. In the case of high substrate strength, 99% pure alumina material can be used. However, the processing of high-purity alumina is difficult and the yield is low, so the price of using pure alumina is high. Oxide is also a material for ceramic substrates. It is a metal oxide with good electrical insulation properties and excellent thermal conductivity. It can be used as a substrate for high power density circuits.

Organic substrate materials refer to reinforced materials such as glass fiber cloth (fiber paper, glass, etc.), impregnated with resin binder, and made into blanks, then covered with copper foil, and made by high temperature and high pressure. This type of substrate is called copper clad laminate (CCL), commonly known as copper clad laminate, and is the main material for manufacturing pcb. A few days ago, circuit board quick proofing is widely used to make double-sided SMT is epoxy fiberglass circuit board, which combines the advantages of good glass fiber strength and epoxy resin, and has good strength and ductility.

Type and thickness of copper foil

Copper foil has a certain influence on the electrical performance of the product. Copper foil is generally divided into two categories: rolled copper foil and electrolytic copper foil according to the manufacturing method. Rolled copper foil requires high copper purity (generally ≥999%) and good elasticity. It is suitable for the manufacture of high-performance circuit boards such as flexible boards and high-frequency signal boards. It is indicated by the letter "W" in the product manual. Electrolytic copper foil is used in the manufacture of ordinary circuit boards. The purity of copper is slightly lower than that of rolled copper foil (generally 99.8%), and is represented by the letter "E".

The common thickness of rigid PCB is 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm, etc. The common thickness of flexible PCB is 0.2mm. The thinner the copper sheet, the worse the temperature resistance, and the leaching will make the copper foil penetrate; if the copper is too thick, it will easily fall off.