With the use of components in computer and communications equipment faster and faster, the main problem comes from the availability of PCB substrate materials and compatibility with products and processes. This includes the stress exposed to the base material for a long time during assembly and the thermal expansion coefficient of the desired substrate and assembly. However, two types of substrates have been explored, including new organic and inorganic materials, and the basic characteristics of these two substrates are briefly described as follows.
The Organic Substrate
The organic substrate has phenolic resin impregnated paper or epoxy resin, polyimide, cyanate ester, BT resin and other impregnated non-woven fabric or glass cloth layer. The use of these substrates depends on the physical properties required for the PCB application like operating temperature, frequency, or mechanical strength.
The Inorganic Substrate
Inorganic substrates include ceramics and metal materials such as aluminum, iron, and copper. The use of these substrates usually depends on the need for cooling, in addition to iron, the inorganic substrate provides a motor flux path for the floppy disk drive.