Circuit board plate blister is actually a bad board adhesion problem, and then extended is the surface quality of the board, which contains two aspects:
- Board cleanliness problem;
- Surface roughness (or surface energy) problem.
All boards on the board surface foam problems can be summarized as the above reasons.
The adhesion between the coating is poor or too low, in the follow-up production process and assembly process is difficult to resist the production process of the coating stress, mechanical stress and thermal stress, and so on, resulting in different levels of separation between the coating phenomenon.
It is possible to summarize some of the factors that may cause poor quality in the process of production and processing.
- Substrate processing problems:
Especially for some thin substrate (generally 0.8mm below), because the substrate stiffness is poor, not with the brush board brush plate.
This may not be able to effectively remove the substrate during the production process to prevent the plate copper foil oxidation and special treatment of the protective layer, although the layer is thin, easy to remove the brush, but the use of chemical treatment there is a big difficulty, Processing important attention control, so as not to cause the board substrate copper foil and chemical copper between the poor adhesion caused by the plate surface foaming problem; this problem in the thin inner layer of black, there will be blackening Bad, uneven color, local black brown is not on the issue.
- The surface of the board in the machining (drilling, laminating, milling, etc.) caused by the process of oil or other liquid contamination of dust pollution caused by poor surface treatment.
- Shen copper brush bad:
Shen copper front plate pressure is too large, resulting in deformation of the orifice of the mouth of the mouth of the copper foil corners even hole leakage substrate, so that in the copper plating electroplating tin welding process will cause the phenomenon of hole blistering; The board does not cause leakage of the substrate, but the heavy brush will increase the orifice of copper roughness, and thus in the micro-euthanization process where the copper is easy to produce over-rough phenomenon, there will be a certain quality Hidden dangers; Therefore, we should pay attention to strengthen the control of the brush plate process, through the wear test and water film test brush plate process parameters transferred to the best;
- Washing problems:
Because the copper plating treatment to go through a large number of chemical treatment, all kinds of acid and alkali and other organic solvents and more solvent, the board is not washed, especially the copper adjustment of oil, not only will cause cross-contamination, but also cause Poor handling of the board or poor handling, uneven defects, resulting in a number of binding problems; so pay attention to strengthen the control of the washing, including cleaning water flow, water quality, washing time, and board drip Time and other aspects of control; especially winter temperatures are low, washing effect will be greatly reduced, but also pay attention to the strong control of the washing;
- Pretreatment of copper and micro-corrosion in pre-treatment of pattern plating:
The micro-erosion will lead to the lack of adhesion, causing the bubble phenomenon; therefore, to strengthen the control of micro-erosion; general copper pretreatment of the micro- Corrosion depth of 1.5 — 2 microns, pre-treated micro-corrosion of 0.3 — 1 micron, the best conditions through the chemical analysis and simple test weighing method to control the micro-etching thickness or erosion rate; under normal circumstances micro After the erosion of the board surface bright color, for the uniform pink, no reflection; if the color is not uniform, or reflective description of the process before the existence of quality hazards; attention to strengthen the inspection; another micro-corrosion copper content, bath temperature, , Micro-agent content and so are to pay attention to the project;
- Heavy copper rework bad:
Some sunken copper or graphics after the rework of the rework board in the rework process because of poor melting, rework method or rework process micro-erosion time control improper or other reasons will cause the board blistering; Shen copper rework if found online Shen copper bad can be washed directly from the line after the acid pickling without corrosive direct rework; it is best not to re-oil, micro-erosion; for the plate has been thickening of the plate, Pay attention to time control, you can first use one or two panels to measure the melting time, to ensure that the effect of faded; faded after the completion of the application of a group of soft brush after brushing brush and then according to the normal production process Shen copper, but the micro The time to halve or make the necessary adjustments;
- Plate in the production process of oxidation:
Such as copper plate in the air oxidation, not only may cause the hole without copper, rough surface, may also cause the board blister; Shen copper plate in the acid storage time is too long, the board will be oxidized, and This oxide film is difficult to remove; so in the production process Shen copper plate to be timely thickening treatment, should not be stored for too long, generally at least 12 hours to thicken the copper finish;
- Shen copper liquid activity is too strong:
In addition, the copper content is too high, which causes the bath activity to be too strong, the chemical copper deposition is rough, the hydrogen, the cuprous oxide and so on are mixed in the chemical copper layer (Including the addition of pure water to the bath), including the three components, the appropriate increase in complexing agent and stabilizer (such as the use of water), the use of the following methods can be: Content, appropriate to reduce the temperature of the bath;
- After the development of the graphics transfer after the lack of water, the development of the time is too long or the workshop too much dust, etc., will cause poor board cleanliness, fiber treatment effect is slightly worse, it may cause potential quality problems;
- Organic pollution in the plating tank, especially oil, is more likely to appear for automatic lines;
- Before the copper plating dip tank should pay attention to timely replacement, too much pollution in the bath, or copper content is too high, not only will cause board cleanliness problems, but also cause rough surface defects;
- In addition, some factories in the winter production of the bath is not heating the case, but also pay special attention to the production process of the board into the slot, especially the air mixing of the plating tank, such as copper and nickel; In the nickel before adding a heating water tank, (water temperature of 30-40 degrees or so), to ensure the early deposition of nickel layer of dense and good;
In the actual production process, causing a lot of reasons for the plate blistering, I can only do a brief analysis of the different manufacturers of equipment, technical level may be caused by different causes of blistering, the specific circumstances to be specific analysis, not general terms, ; Analysis of the above reasons, regardless of primary and secondary, the basic production process in accordance with the brief analysis, in this series, just to provide a solution to the direction and a broader perspective, we hope that the process of production and problems Solution, you can play a role!