Copper pouring process for automotive PCBA processing

In the production and processing of automotive PCBA, some circuit boards need to be coated with copper. Copper coating can effectively reduce the impact of SMT patch processing products on improving the anti-interference ability and reducing the loop area. Its positive effect can be fully utilized in SMT patch processing. However, there are many things to pay attention to during the copper pouring process. Let me introduce to you the details of the PCBA processing copper pouring process.

一. Copper pouring process

1. Pretreatment part: Before the formal copper pouring, the PCB board needs to be pretreated, including cleaning, rust removal, cleaning and other steps to ensure the cleanliness and smoothness of the board surface and lay a good foundation for the formal copper pouring.

2. Electroless copper plating: Coating a layer of electroless copper plating liquid on the surface of the circuit board to chemically combine with the copper foil to form a copper film is one of the most common methods of copper plating. The advantage is that the thickness and uniformity of the copper film can be well controlled.

3. Mechanical copper plating: The surface of the circuit board is covered with a layer of copper foil through mechanical processing. It is also one of the copper plating methods, but the production cost is higher than chemical copper plating, so you can choose to use it yourself.

4. Copper coating and lamination: It is the last step of the entire copper coating process. After copper plating is completed, the copper foil needs to be pressed onto the surface of the circuit board to ensure complete integration, thereby ensuring the conductivity and reliability of the product.

二. The role of copper coating

1. Reduce the impedance of the ground wire and improve the anti-interference ability;

2. Reduce voltage drop and improve power efficiency;

3. Connect to the ground wire to reduce the loop area;

三. Precautions for copper pouring

1. Do not pour copper in the open area of the wiring in the middle layer of the multilayer board.

2. For single-point connections to different grounds, the method is to connect through 0 ohm resistors or magnetic beads or inductors.

3. When starting the wiring design, the ground wire should be routed well. You cannot rely on adding vias after pouring copper to eliminate unconnected ground pins.

4. Pour copper near the crystal oscillator. The crystal oscillator in the circuit is a high-frequency emission source. The method is to pour copper around the crystal oscillator, and then ground the shell of the crystal oscillator separately.

5. Ensure the thickness and uniformity of the copper clad layer. Typically, the thickness of the copper clad layer is between 1-2oz. A copper layer that is too thick or too thin will affect the conductive performance and signal transmission quality of the PCB. If the copper layer is uneven, it will cause interference and loss of circuit signals on the circuit board, affecting the performance and reliability of the PCB.