How circuit board is made

It is very complicate of the production of PCB（circuit board）.Taking a four-layer printed board as an example, the production process mainly includes:

1.PCB layout

2.core board production

3.inner-layer PCB layout transfer

4.core board drilling and inspection

5.lamination, drilling

6.hole wall copper chemical precipitation

7.outer layer PCB layout transfer

8.outer layer PCB etching and other steps.

But first, let’s learn about the classification of circuit boards.

Usually, we can divide it into single-sided circuit board PCB, double-sided circuit board PCB, four-layer circuit board PCB, six-layer circuit board PCB and other multi-layer circuit board PCB according to the number of layers.

1.Single-sided circuit board PCB:

On the most basic circuit PCB board, we usually concentrate these parts on one side, and concentrate the wires on the other side. Because the wires only appear on one side, this kind of circuit board PCB is called a single-sided circuit board (Single-sided). Because the single-sided circuit board has many strict restrictions on the design of the circuit. (For there is only one side, the wiring cannot cross and must be routed around a separate path), so only early circuits or circuits with very simple wiring are used.

2.Double-sided circuit board PCB:

This type of circuit board has wiring on both sides, but to have wires on both sides, there must be a proper circuit connection between the two sides. Such “bridges” between circuits that we call it vias. A via hole is a small hole filled or coated with metal on the circuit board PCB, which can connecte it to wires on both sides. Because the area of the double-sided circuit board is twice as large as that of the single-sided circuit board, the same buried double-sided circuit board solves the difficulty of wiring staggered in the single-sided circuit board. (We can connecte it to the other side through the via hole) .It is more suitable for use on more complex circuits than single-sided boards.

3.Multilayer circuit board PCB:

In order to increase the wires in many areas, more single- or double-sided wiring boards, we use them for multi-layer circuit boards. Use one double-sided board as the inner layer, two single-sided as the outer layer or two double-sided as the inner layer, two single-sided as the outer layer of the circuit board PCB, through the positioning system and insulating adhesive materials alternately together and conductive patterns.

The circuit board PCB that is interconnecte according to the design requirements becomes a four-layer and six-layer circuit board PCB, also known as a multi-layer circuit board PCB. The number of layers of the board does not mean that there are several independent wiring layers. In special cases, we will add an empty layer to control the thickness of the board.

Usually, the number of layers is even and includes the outermost two layers. Most motherboards are 4 to 8 layers of structure, but technically it can achieve nearly 100 layers of PCB.

Most of the large supercomputers use fairly multi-layer motherboards, but because clusters of many ordinary computers can replace these such computers. Also due to super-multilayer circuit boards have gradually fallen out of use. Because the layers in the PCB are tightly combined, it is generally not easy to see the actual number, but if you look closely at the motherboard, you can still see that it is several layers.

Next, let’s learn about the production process of the circuit board.

As a component of important electronic components, pcb board is not only a support for electronic components, but also a carrier for electrical connections. Different types of pcb boards have different manufacturing processes. Now the common single-sided and double-sided tin-sprayed boards are used. , Double-sided nickel-gold plating, multi-layer nickel-gold plating, multi-layer immersion nickel-gold plate, etc. These five pcb board process flows will be explained in detail.