What is PCB copper plating?

PCB copper plating refers to filling areas without wiring or idle spaces on PCBs with solid copper foil.

Advantages and disadvantages of copper plating

Advantages

  1. Placing copper on large-area PCBs can serve as a shield or isolation function. It can also effectively suppress EMC (electromagnetic compatibility).
  2. Since the general material of PCB is FR-4, which is a glass fiber reinforced epoxy laminate, it will deform or bend when subjected to pressure. Placing copper in the area without wiring on the PCB can effectively reduce the bending or deformation of the PCB.
  3. There are many high-speed signals involved in PCB. In order to ensure the integrity of the signal, we need to reduce the integrity of the signal and reduce the signal return path. We need to lay copper around the PCB wiring to reduce the return path.

Disadvantages

  1. The entire PCB is copper-plated. When we perform PCB sample welding or repair, the heat dissipation is too fast, which makes it difficult to replace the device, especially some larger devices. Sometimes we use different copper-plating connection methods according to the device type, using a cross connection .
  2. In the RF circuit, the antenna is a very important part. When there is copper near our PCB antenna, the impedance of the antenna will change suddenly, which will affect our signal transmission. Therefore, we generally do not lay copper near the antenna.

The shape of PCB copper plating

There are two ways to plating copper on PCB, one is called solid copper plating and the other is called grid copper plating. Their respective characteristics and scopes are different.

  1. Solid copper plating has the dual functions of increasing current and shielding. However, if solid copper plating is subjected to wave soldering, there is a certain amount of thermal expansion and contraction tension, and the board may warp up or even bubble. Therefore, solid copper plating generally opens several grooves to relieve the tension that causes copper foil blistering.
  2. Grid copper plating mainly plays a shielding role, and the effect of increasing the current will be reduced. From the perspective of heat dissipation, grid copper plating not only reduces the heating surface of copper, but also plays a certain electromagnetic shielding role. However, the production process has certain requirements for the grid shape copper plating. If the grid is too small, it will affect the quality yield.

Precautions for PCB copper plating

When designing PCB, we must pay attention to the copper plating on each surface. The main reason for copper plating is to prevent the bending and deformation of PCB and the interference and crosstalk of various signals. Therefore, when we are plating copper for routing, due to the large number of peripheral devices, it is difficult to ensure that there is a complete area for copper plating on one layer after routing. A large copper plating is divided into small isolated copper by routing. In order to ensure the continuity between copper plating, we need to plating copper on each layer, and then connect the isolated copper between different layers through vias to ensure the stability of the potential between the grounds. Of course, we will also encounter some unnecessary isolated copper, which needs to be removed, otherwise it is easy to cause poor EMC, or act as an antenna in some high-frequency signals, producing an antenna effect. If it is too large, it can be connected through vias, and if it is relatively small, it can be directly deleted.