The copper wire of the impedance circuit board falls off. The manufacturer always says that it is a problem with the laminate. In order to avoid the problem as much as possible, I have summarized some reasons for your reference.
1. Copper foil is over-etched. The electrolytic copper foil used in the market is generally single-sided galvanized (commonly known as ashing foil) and single-sided copper-plated (commonly known as red foil). Commonly thrown copper is generally galvanized copper above 70um. Foil, red foil, and ash foil below 18um basically have no batch copper rejection.
2. There is also a situation where the etching parameters of the impedance circuit board are not problematic, but after etching, the copper wire is also surrounded by the residual etching solution on the PCB surface, and the copper wire will also be produced if it is not processed for a long time. Excessive undercutting and dumping of copper. This situation is generally manifested as concentrated on thin lines, or during periods of wet weather, similar defects will appear on the entire PCB. Strip the copper wire to see that the color of the contact surface with the base layer (the so-called roughened surface) has changed. The color of the copper foil is different from the normal copper foil. The original copper color of the bottom layer is seen, and the peeling strength of the copper foil at the thick line is also normal.
3. The design of the circuit is unreasonable. Using thick copper foil to design a circuit that is too thin will also cause excessive etching of the circuit and dumping of copper.
4. As mentioned above, ordinary electrolytic copper foils are all products that have been galvanized or copper-plated. If the peaks are abnormal during the production of the wool foil, or during galvanizing/copper plating, the plating crystal branches are bad, causing the copper foil itself The peeling strength is not enough. After the bad foil-pressed sheet material is made into a PCB, the copper wire will fall off when it is impacted by an external force when it is plugged in in the electronics factory. This type of copper rejection is not good. If you peel off the copper wire and see the rough surface of the copper foil (that is, the surface in contact with the substrate), there will be no obvious side erosion, but the peel strength of the entire copper foil will be very poor.
5. When there is no problem with the potion, the operation and the etching parameters are not problematic, it may also be the reason for the poor etching of the potion, which causes the surface to be etched not clean.
Therefore, if you want to completely avoid the cause of the copper wire falling off when choosing a manufacturer, the customer should also avoid looking for a manufacturer with low process capability and poor sheet metal, otherwise, it will be difficult to control the quality of the finished product. XPCB Limited is a circuit board manufacturer specializing in the production of high-precision double-sided PCB boards, multilayer PCBs and impedance PCB boards, blind buried via PCB boards, immersion gold PCB boards, and copper circuit boards.
XPCB Limited is a premium PCB & PCBA manufacturer based in China.
We specialize in multilayer flexible circuits, rigid-flex PCB, HDI PCB, and Rogers PCB.
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