1. As mentioned above, generally electrolytic copper foil is a product processed by wool foil electroplating or copper plating. If the peak value during the wool foil production process is abnormal, perhaps the crystallization branching of the coating during the galvanizing/copper plating process is poor, and the peeling strength of the copper foil itself is insufficient. When bad foil is pressed into a thin sheet to form a Printed Circuit Board, copper wires can fall under the impact of external forces as they penetrate the electronics factory. When the rough surface of the copper foil (that is, the contact surface with the substrate) is peeled off, this poor copper extrusion will not cause significant side corrosion, but the peeling 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 the curing process is low. Therefore, it is inevitable to use copper foil with special peaks to match it. When producing laminates, the copper foil used does not match the resin system, resulting in a lack of peel strength of the metal foil covered by the metal sheet, and poor peeling of the copper wire when inserted.
Under normal circumstances, as long as the hot pressed high temperature part of the laminate lasts for more than 30 minutes, the copper foil and prepreg are basically completely bonded, so the adhesion between the copper foil and the substrate in the laminate is generally not affected. However, during the lamination process of stacking, if the polypropylene is contaminated or the surface of the copper foil is damaged, the bonding force between the laminated copper foil and the base material will be lacking, resulting in positioning (only applicable to large boards) or scattered Copper wire falls. However, near the offline measurement, there was no abnormality in the peel strength of the copper foil.
