A hole in the dry membrane mask
Many clients think, after a broken hole, should increase film temperature and pressure, and to enhance their binding force, actually this kind of view is incorrect, because after high temperature and pressure, corrosion resistant layer of excessive solvent volatilization, make the dry film brittle thin and vulnerable to break through the hole when developing, we always want to keep dry film toughness, so, after a broken hole, we can do it from the following points to improve:
1. Reduce the temperature and pressure of the lamination
2. Improve the drilling of the top
3. Improve exposure energy
4. Reduce the development pressure
5. The post time cannot be long after the lamination, so as to avoid the spreading of the semi - fluid film at the corner
6. The dry film should not be too tight during the film
2. Electroplating on dry film plating
The reason of the plating is that the dry film and the coated copper foil are not fastened, so that the liquid is deeply deposited, while the "negative phase" part of the coating is thickened, and most PCB manufacturers are caused by the following points:
1. Exposure energy is high or low
Under uv irradiation, the photoinitiator of light energy is absorbed into free radicals to induce the photopolymerization of the monomers, forming molecules that are not soluble in dilute alkaline solutions.In the case of insufficient exposure, due to the incomplete polymerization, during the development of the film, the swelling of the film is soft, resulting in the unclear line and even the peeling of the film layer, resulting in the poor combination of the membrane and copper.If overexposed, it can cause the development difficulty, also in the plating process to produce the uplift, the formation of the plating.So it's important to control the exposure.
2. The coating temperature is high or low
If the coating temperature is too low, due to the lack of adequate softening and proper flow of the anti-corrosion film, the combined net force of the dry film and the coated copper foil laminate is poor.If the temperature is too high due to the rapid volatilization of solvent and other volatile substances in the anticorrosive agent, the dry film becomes brittle, and the electroplating is formed when the electroplating shock is formed.
3. The membrane pressure is high or low
When the lamination pressure is too low, it may result in the uneven surface of the lamination surface or the gap between the dry film and the copper plate.If the lamination pressure is too high, the solvent and volatile components of the corrosion resistant layer are too volatile, causing the dry film to become brittle and the electroplating electric shock will be spun off.