What Are Circuit Boards?
A board is a component that serves as the foundation for creating a circuit by connecting multiple electronic components with wires.
There is also a universal board, which can be connected simply by inserting jumper wires or components and can be used to create your own circuits in a simplified manner.
A printed circuit board (PCB) is an insulator with copper wiring patterns and pads for connecting electronic components on its surface, and electronic circuits are completed by connecting electronic components with solder. Similar to ICs, printed circuit boards can be designed using CAD and mass-produced by manufacturing equipment in the image of literally printing.
They are used in a wide variety of devices ranging from small electronic devices such as smartphones to servers, industrial equipment, and automobiles, making them indispensable components for modern society.
Circuit Board Materials
To accommodate a wide variety of products, printed circuit boards are available in a variety of materials.
1. FR-1,2 (Paper Phenol Substrate)
Used as single-sided boards for white goods, remote controls, etc.
2. FR-3 (Paper Epoxy Substrate)
Similar to paper phenolic substrates, FR-3 is used as a single-sided substrate, and is used for high-voltage circuits and circuits that require moisture resistance.
3. FR-4,5 (Glass Epoxy Substrate)
Most multilayer boards are made using this material. FR-5 has high heat resistance and is used for automotive applications.
4. CEM-3 (Glass Composite Substrate)
Although CEM-3 has inferior mechanical properties and stability to glass epoxy substrates, it can be manufactured at a lower cost and is used as a double-sided substrate for products that cannot be handled with a single-sided substrate. They are used in home appliances and audio/visual equipment.
5. Glass Polyimide Substrate
With its excellent flexibility and heat resistance, a glass polyimide substrate is used as a flexible substrate.
Circuit Board Classification
First, printed circuit boards are broadly classified into two categories according to material: rigid rigid substrates and soft flexible substrates. When simply referring to a board, rigid boards are generally referred to. Flexible substrates are thin and bendable, so they are widely used in thin products and moving parts such as robots. In addition, there are other classifications based on the number of layers and structure as shown below.
1. Single-Sided Substrate
Wiring and electronic components are mounted on one side of the board. Although complex circuits cannot be mounted, they can be manufactured at low cost.
2. Double-Sided Substrate
This is a board on which wiring and electronic components are mounted on both sides of the board. Compared to single-sided boards, more complex circuits can be mounted.
3. Multilayer Board
This is a board in which wiring is formed not only on both sides of the board but also inside the board. The boards are stacked using an adhesive sheet called prepreg to form a single board.
4. Build-Up Substrate
This is fabricated by repeating via processing and wiring formation for each layer. This is a multilayer substrate consisting of 4 to 10 layers, with 1 to 3 wiring layers formed on each of the front and back surfaces of 2 to 4 layers of a substrate called a core substrate.
5. Thick Copper Substrate
This type of substrate is used in equipment that handles large currents. To cope with high current, the thickness of copper used for the wiring pattern is increased. They are used in industrial machinery, machine tools, trains, automobiles, etc.