Question

What are the reasons for the lack of copper in circuit board holes?

Answer 1

The reasons for lack of copper in circuit board holes are as follows:

1. Missing copper in the inner layer: During the manufacturing process of multi-layer circuit boards, unnecessary copper foil is removed through chemical corrosion or mechanical scraping to form inner circuits. If errors or improper operations are made during this process, the copper in some holes may be accidentally deleted or missing.

2. Drilling without coating: In circuit board manufacturing, holes are usually formed through drilling operations. Before drilling, the circuit board should be coated and charged to form a copper film on the hole wall for the subsequent copper plating process. If the coating charge is incomplete or not carried out, those holes will appear copper-free.

3. Poor copper plating: During the copper plating process of circuit board manufacturing, copper is electrochemically deposited on the surface and in the holes to form a conductive layer. If there are problems during the copper plating process, such as unstable current, contamination of the plating solution, or incorrect plating solution, some holes may be free of copper.

Answer 2

The reasons why there is no copper in the circuit board holes are analyzed as follows:
1. Poor drilling. Poor drilling may result in residual copper shavings in the hole or insufficient hole diameter, resulting in no copper in the circuit board hole.
2. Poor chemical copper plating. Electroless copper plating is a commonly used surface treatment method for circuit boards. If the electroless copper plating is poor, it may result in the inability to plate copper in the holes.
3. High temperature during welding. During the soldering process of circuit boards, high temperatures may cause the copper in the holes to be burned or evaporated, resulting in no copper in the circuit board holes.
4. PCB design issues. If the size or location of the holes in the PCB design is inappropriate, there may be no copper in the circuit board holes.

Answer 3

The reasons why there is no copper in the PCB board holes are as follows:

1. Cracks in the hole wall or splitting between the inner layers after drilling.

2. Insufficient neutralization treatment after removing the slag, resulting in residual basic Stannate compounds in the pores.

3. The concentration of the activation solution is low, which affects the adsorption of Pd.

4. Chemical copper potion potion has poor activity.