Solution to the problem of seepage plating when PCB dry Film is used

                      Solution to the problem of seepage plating when PCB dry Film is used

       The reason why percolation plating shows that dry film and copper clad foil are not firmly bonded, so that the bath depth, and cause "negative phase" part of the coating thickened, most PCB manufacturers are due to the following points:

      1.Exposure energy is high or low

      Under ultraviolet light irradiation, photoinitiators absorbing light energy are decomposed into free radical initiators for photopolymerization to form somatotype molecules insoluble in dilute alkali solution. In the process of development, the swelling of the film becomes soft, which leads to unclear lines and even the falling off of the film layer, which results in poor combination of the film and copper. If the exposure is over-exposed, it will cause difficulties in development, and will also lead to exfoliation in the process of electroplating, so it is very important to control the exposure energy.

      2.High or low temperature of film

      If the temperature of the film is too low, due to the corrosion resistance film can not be fully softened and appropriate flow, resulting in the dry film and copper foil laminate surface adhesion is poor; If the temperature is too high because of the rapid volatilization of the solvent and other volatile substances in the corrosion inhibitor, bubbles are produced, and the dry film becomes brittle, which causes the percolation and exfoliation during electroplating electric shock.

      3.High or low pressure of film 

      When the pressure on the film is too low, it may lead to the uneven surface of the film or the gap between the dry film and the copper plate, which can not meet the requirement of binding force. If the film pressure is too high, the solvent and volatile components of the anti-corrosion layer become too volatile, causing the dry film to become brittle.