Improvement method:

　　1, the copper clad plate in the warehouse before IQC must be random inspection, check whether the surface of the board scratches the substrate phenomenon, if there should be timely contact with the supplier, according to the actual situation, make appropriate treatment.

　　2, the copper clad plate is scratched during the opening process, the main reason is that there are hard objects on the surface of the opening machine, and the friction between the copper clad plate and the objects causes the copper foil scratch to form the phenomenon of exposing the substrate, so the table must be carefully cleaned before the opening of the material to ensure that the table is smooth and there is no hard objects.

　　3, the copper clad plate is scratched by the drill when drilling, the main reason is that the spindle clip is worn, or the debris in the clip is not clean, the drill is not firmly grasped, the drill does not go to the top, the length of the drill is slightly longer than the set, the height of the drilling is not enough, the drill tip scratches the copper foil to form the phenomenon of exposing the substrate when the machine tool moves.

　　a, the clip can be replaced by the number of times recorded by the knife or according to the wear degree of the clip;

　　b. Clean the clip regularly according to the operating rules to ensure that there is no debris in the clip.