PCB News - Four reasons causing the PCB board to dump copper

Four reasons causing the PCB board to dump copper

Printed circuit boards {Printed circuit boards}, also known as printed circuit boards, are providers of electrical connections for electronic components.

Printed circuit boards are often represented by "PCB", but cannot be called "PCB boards".

Its development has a history of more than 100 years; its design is mainly layout design; the main advantage of using circuit boards is to greatly reduce wiring and assembly errors, and improve the level of automation and production labor.

PCB is one of the indispensable parts of electronic equipment. It basically appears in every kind of electronic equipment. In addition to fixed various large and small parts, the main function of PCB is to make various parts perform electrical connect. Since the raw material of the PCB board is a copper clad laminate, there will be a phenomenon of copper dumping in the process of making the PCB. So what are the reasons for the copper dumping of the PCB board?

1. The PCB circuit design is not appropriate. Using thick copper foil to design a circuit that is too thin will also lead to excessive etching of the circuit and the phenomenon of copper rejection.

2. The copper foil is over-etched. The electrolytic copper foil used in the market is usually single-sided galvanized (commonly known as ashing foil) and single-sided copper plating (commonly known as red foil). The more common copper foil is usually more than 70um galvanized. Copper foil, red foil and ash foil below 18um hardly have batch copper rejection.

3. A local collision occurred in the PCB process, and the copper wire was subjected to external mechanical force to separate from the substrate. This undesirable phenomenon is manifested in poor positioning or orientation, and obvious twisting of the dropped copper wire, or scratches/impact marks in the same direction. Check the rough surface of the copper foil at the place where the peeling is not good, you can see that the color of the rough surface of the copper foil is normal, there will be no side erosion, and the peeling strength of the copper foil is normal.

4. Under normal circumstances, the copper foil and the prepreg are basically completely combined after the laminate passes through the high temperature section of hot pressing for more than 30 minutes, so the pressing usually does not affect the bonding force of the copper foil and the substrate in the laminate. However, in the process of stacking and stacking laminates, if the PP is contaminated or the matte surface of the copper foil is damaged, it will also cause insufficient bonding between the copper foil and the substrate after lamination, resulting in positioning (only for large As far as the board is concerned) or the sporadic copper wire drops, but the peeling strength of the copper foil near the disconnection line will not be abnormal.

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