Three reasons why PCB copper wires fall off

Three reasons why PCB copper wires fall off

Reasons for the raw materials of printed circuit board printed circuit board laminates:

1. As mentioned above, the general electrolytic copper foil is a product processed by electroplating or copper plating on wool foil. Assuming that the peak value of the wool foil production process is abnormal, perhaps the plating crystal branch is bad during the galvanizing/copper plating process, and the peeling strength of the copper foil itself is not good. When the bad foil is pressed into a thin sheet to form a printed circuit board, the copper wire will fall under the impact of external force when it pierces into the electronics factory. When the rough surface of the copper foil (that is, the touch surface with the substrate) is peeled off, such poor copper extrusion will not cause significant side corrosion, but the peel strength of the entire copper foil will be very poor.

2. Copper foil has poor adaptability to resin: Due to different resin systems, the curing agent used in some special functional laminates (such as HTg sheets) is generally PN resin. The molecular chain structure of the resin is simple, and the degree of cross-linking during curing is low. Therefore, it is inevitable to use copper foil with a special peak to match it. When the laminate is produced, the copper foil used does not match the resin system, resulting in the lack of peel strength of the metal foil covered by the metal sheet, and the poor peeling of the copper wire during penetration.

2. Reasons for the production of printed circuit board printed circuit board laminates:

Under normal circumstances, only the hot-pressed high-temperature part of the laminate is required to last for more than 30 minutes, and the copper foil and the prepreg are basically completely bonded, so the adhesion between the copper foil and the substrate in the laminate is generally not affected. However, in the process of stacking and lamination, assuming that the polypropylene is contaminated or the copper foil surface is damaged, the bonding force between the laminated copper foil and the substrate will be lacking, resulting in positioning (only for large boards) or scattered The copper wire fell. However, there is no abnormality in the peel strength of the copper foil in the vicinity of the offline measurement.