1、 Dry film mask with perforation

Many customers believe that after a hole is broken, the film temperature and pressure should be increased to enhance its adhesion. However, this view is not correct because the solvent in the corrosion resistant layer evaporates excessively when the temperature and pressure are too high, making the dry film brittle and thin, making it easy to break through during development. We always need to maintain the toughness of the dry film. Therefore, after a hole is broken, we can improve it from the following points:

1. Reduce film temperature and pressure

2. Improve drilling edge

3. Increase exposure energy

4. Reduce development pressure

5. After applying the film, the parking time should not be too long to avoid causing the semi fluid like drug film at the corner to diffuse and thin under pressure

6. During the film application process, do not tension the dry film too tightly

2、 Penetration occurs during dry film electroplating

The reason for infiltration plating is that the adhesion between the dry film and the copper foil is not strong, causing the plating solution to penetrate deeply and causing the "negative phase" part of the coating to become thicker. Most PCB manufacturers experience infiltration plating due to the following reasons:

1. Exposure energy is too high or too low

Under UV irradiation, the photoinitiator that has absorbed light energy decomposes into free radicals to initiate monomer photopolymerization reactions, forming body shaped molecules that are insoluble in dilute alkali solutions. When the exposure is insufficient, due to incomplete polymerization, the adhesive film swells and becomes soft during the development process, resulting in unclear lines and even film layer detachment, resulting in poor adhesion between the film and copper; If the exposure is excessive, it will cause difficulties in development and also cause warping and peeling during the electroplating process, resulting in infiltration plating. So it is important to control the exposure energy well.

2. The film temperature is too high or too low

If the film temperature is too low, due to insufficient softening and appropriate flow of the anti-corrosion film, the adhesion between the dry film and the surface of the copper foil laminated plate is poor; If the temperature is too high, bubbles will be generated due to the rapid volatilization of solvents and other volatile substances in the corrosion inhibitor, and the dry film will become brittle, causing warping and peeling during electroplating electric shock, resulting in infiltration plating.