Surface bubbling is one of the most common quality defects in circuit board production. Because of the complexity of circuit board production process and process maintenance, especially in chemical wet treatment, it is difficult to prevent surface bubbling defects. Based on many years of practical experience in production and service, this paper briefly analyzes the cause of bubbling on the surface of copper immersed electroplate of circuit board.
Surface bubbling is one of the most common quality defects in circuit board production. Because of the complexity of circuit board production process and process maintenance, especially in chemical wet treatment, it is difficult to prevent surface bubbling defects. Based on many years of practical experience in production and service, this paper briefly analyzes the cause of bubbling on the surface of copper immersed electroplate of circuit board.
Circuit board surface bubbler is actually the problem of bad surface binding force, and then extended is the surface quality of the board, which contains two aspects: 1. The cleanliness of the board; 2. Surface micro roughness (or surface energy); All board bubbling problems on the circuit board can be summarized as the above causes. The binding force between the coatings is poor or too low, and it is difficult to resist the coating stress, mechanical stress and thermal stress generated in the production and processing process in the subsequent production and assembly process, and finally cause the separation phenomenon of different degrees between the coatings.
Keyou circuit specializes in the production of rapid proofing and batch, with high precision single/double/multi-layer PCB (1-26 layer), thermoelectric separation copper substrate, multi-layer industrial control PCB, medical PCB, security PCB, communication PCB, automotive PCB, composite bus copper substrate, foldable metal substrate and so on.
Some factors that may cause bad quality of board surface in the process of production and processing are summarized as follows:
1. Problems of substrate processing; Especially for some thinner substrates (generally below 0.8 mm), because the substrate rigidity is poorer, unfavorable use brush brush plate machine, it may be unable to effectively remove the substrate in order to prevent the surface oxidation of copper foil in the process of production and processing and special processing layer, while the layer is thinner, brush plate is easy to remove, but the chemical processing is difficult, So in the production and processing of important attention to control, so as not to cause the surface of the substrate copper foil and chemical copper bonding force between the bad caused by the surface of the bubbling problem; This problem in the thin inner layer of black, there will be bad black brown, uneven color, local black brown is not first-class problems.
2. The surface of the board in machining (drilling, laminating, milling, etc.) caused by the process of oil pollution or other liquid dust pollution surface treatment phenomenon,
3. Bad copper plating brush plate: the pressure of the grinding plate before copper plating is too large, resulting in deformation of the orifice, and the copper foil rounded corners and even the orifice leaking base material, so that the orifice foaming phenomenon will be caused in the process of copper plating and tin spraying welding; Even if the brush plate does not cause substrate leakage, the excessive brush plate will increase the roughness of copper at the mouth, so in the process of micro-etching and coarsening, the copper foil is easy to produce excessive coarsening phenomenon, and there will be a certain quality hidden trouble; Therefore, attention should be paid to strengthen the control of brush plate process, brush plate process parameters can be adjusted to the best through wear mark test and water film test.
In the actual production process, there are many reasons for causing surface bubbling, the author can only do a brief analysis, for different circuit board factory equipment technical level may appear different reasons caused by the bubbling phenomenon, the specific situation to specific analysis, not generalize, mechanically mechanically; Above reason analysis does not distinguish primary and secondary and importance, basically according to the production process process to do a brief analysis, in this series, just to provide you with a direction to solve the problem and a broader vision, I hope to everyone's process production and problem solving, can play a role!
