The foaming of the line board surface is actually a problem of poor binding force of the board surface, which is also the surface quality problem of the board surface.
The foaming of the line board surface is actually a problem of the poor binding force of the board surface, which is also the surface quality problem of the board surface, which includes two aspects:
1.Plate surface cleanliness problem; 2. Microscopic surface roughness (or surface energy) problem.
All the plate foaming problems on the circuit boards can be summarized as the above reasons.
The binding force between coatings is poor or too low, and it is difficult to resist the coating stress, mechanical stress and thermal stress and so on in the subsequent production process and assembly process, eventually resulting in different degrees of separation between coatings.
Some factors that may cause poor plate quality in the production and processing process are summarized as follows:
Problems of substrate process treatment:
Especially for some thinner substrate (generally below 0.8mm), because the substrate rigidity is poor, you should not use the brush plate machine brush plate.
1.It may not be effectively removed to prevent the oxidation of the copper foil during substrate production. Although the layer is thin and easy to remove, it is difficult to adopt chemical treatment, so it should pay attention to control the poor binding force between the copper foil and chemical copper of the substrate, uneven color and poor blackening in the thin inner layer.
2. Poor surface treatment of the plate surface caused by oil pollution or other liquid contamination in the machining process (drilling, lamination, milling edge, etc.).
3. Poor copper sinking brush plate: the pressure of copper sinking front grinding plate is too high, Cause hole deformation brush hole copper foil corner and even hole leakage substrate, In this way, copper electroplating welding and tin welding; Even if the brush plate did not leak the substrate, But the too heavy brush plate will increase the roughness of the orifice copper, Therefore, the copper foil is easy to occur in the process, There will also be certain quality risks; Therefore, attention should be paid to strengthening the control of the brush plate process, The process parameters of the brush plate can be adjusted to the best through the abrasion test and the water film test;
4. Water washing problem: because the copper sinking plating treatment should be treated through a large amount of chemical medicine, All kinds of acid and alkali inorganic organic and other drug solvents, The plate surface is not clean, In particular, copper sinking adjustment oil remover, Not only does cross-contamination, At the same time, it will also cause poor local treatment or poor treatment effect, Inuniform defects, Cause some problems in the binding force; Therefore, attention should be paid to strengthen the control of water washing, Mainly includes the cleaning water flow rate, water quality, Wash the water for the time, And the plate dripping time and other aspects of the control; Especially in winter, the temperatures are low, The water washing effect will be greatly reduced, More attention should be paid to the strong control of water washing;
5. Before copper sinking treatment and micro corrosion in graphic plating pretreatment: excessive micro corrosion will cause hole leakage substrate, Cause the foaming phenomenon around the hole mouth; Insufficient microcorrosion can also result in insufficient binding force, Cause the bubble phenomenon; Therefore, the control of microcorrosion should be strengthened; the depth of general copper deposition pretreatment is 1.5- -2 micron, Graphic plating before processing microablation at 0.3- -1 micron, If possible, it is best to control the microcorrosion thickness or corrosion rate by chemical analysis and simple test weighing method; In general, the plate surface after microerosion is bright, For a uniform pink color, No reflection is available; If the color is uneven, Or reflective instructions before the process of quality risks; Pay attention to strengthen the inspection; Additional copper content of the microcorrosion groove, Liquid tank temperature, capacity, Micro-corrosion agent content and other items should be paid attention to;
6. Poor rework of copper sinking: some rework plates of copper sinking or graph turning are due to poor fading in the rework process, The rework method is not correct or in the rework process of micro-corrosion time improper control or other reasons will cause the plate surface foaming; If the rework of copper sinking plate is found online, poor copper sinking can be washed directly from the line after washing and acid washing directly rework without corrosion; It is better not to remove the oil again, Microcorrosion; for already electrically thickened plates, The micromicrogroove shall be faded, Note the time control, You can roughly calculate the fading time, Ensure the plating fading effect; After fading, apply a set of soft grinding brush and then sink copper according to the normal production process, However, the corrosion time should be halved or make necessary adjustment;
7. Plate surface oxidation during production: such as copper sink plate oxidation in the air, Not only may it be copper-free in the hole, The plate is rough, It may also cause plate surface foaming; The copper sink plate is stored in the acid liquid for too long, The plate surface can also be oxidized, And this oxide membrane is very difficult to remove; Therefore, the copper sinking plate should be thickened in time, Should not be stored for too a long time, Generally, the copper plating should be thickened within 12 hours at the latest;
8. The activity of the copper sink is too strong: the content of the three components in the newly opened cylinder or tank is high, especially the copper content, Can cause the groove fluid activity is too strong, Chemical copper deposits are coarse, hydrogen, Copper oxide and other substances mixed in the chemical copper layer caused by excessive coating quality decline and poor binding force defects; The following methods can be taken appropriately: to reduce the copper content, (Fill pure water into the tank liquid) includes three components, Increase improve complexation and stabilizer content, Appropriate reduce the temperature of tank fluid, etc.;
9. Insufficient washing after development during graphic transfer, After display for too long time or excessive workshop dust, etc, Will cause poor plate surface cleanliness, The fiber treatment effect is slightly poor, It may cause potential quality problems;
10. Organic pollution occurs in the electroplating tank, In particular, the oil pollution, For automatic line is more likely;,
11. Copper plating acid tank should be replaced in time, Too much pollution in the tank fluid, Or too high in the content of copper, Not only will it cause the plate surface cleanliness problem, It can also cause defects such as rough plate surface;
12. In addition, In winter, some factories produce medium tank liquid without increasing temperature, More attention should be paid to the live slot of the production process, Especially for plated grooves with air stirring, Such as copper and nickel; For nickel cylinder in winter, it is best to add a warm washing tank before nickel plating, (Water temperature is around 30-40 degrees), Ensure the early deposition; in the actual production process, There are many reasons for plate surface foaming, I can only do a brief analysis, For different manufacturers of equipment technical level may appear the foaming phenomenon caused by different reasons, The specific situation should be analyzed specifically, Can not be generalized, apply mechanically; The above reason analysis is regardless of priority and importance, Brief analysis is made basically according to the production process flow, In this series comes out, Just to provide you with a direction to solve the problem and a broader vision, I hope to treat everyone's process production and problem-solving aspects, Can play a role of throwing bricks and attracting jade!
