Causes of blistering on PCB surface
Author:Zhou Zhipeng Time:2021-06-10 15:44 Browse(197)
Causes of blistering on PCB surface, touch screen and OLED Forum
Today, I'd like to talk about the causes of blistering on PCB surface. Blistering on PCB surface is the problem of poor adhesion, that is, the surface quality of PCB surface, including the following reasons: 3p-p, y (W: W7 [8q]                                                                         .' l9 c" t   \ 1 J 2 K 1 x $V 3 ~ 1;2 W/ P6 B' D, @$ H; L 2. Surface micro roughness (or surface energy)    y; M8 {" w.
E: j    I/ qAll the board surface blistering problems can be summarized as the above reasons.

Causes of blistering on PCB surface

- [1} 3 F. H4 | 4 {7 d + A: ZThe adhesion between the coatings is poor or too low.
it is difficult to resist the coating stress, mechanical stress and thermal stress in the subsequent production and assembly process, resulting in different degrees of separation between the coatings.
/ y6 o; y3 P1 a: RSome factors that may cause poor surface quality in the production process of coating line are summarized as follows: 4 E7 o:] * K7 E.
\ "U & A1. Problems of substrate processing: - S{* Z. ]) J) s$ HEspecially for some thinner substrates (generally less than 0.8mm), it is not suitable to use the brush machine to brush the substrate because of the poor rigidity of the substrate2 ~& V0 u; D) s8 e    W: R. J in this way, it may not be able to effectively remove the protective layer specially treated to prevent the copper foil from oxidation during the production and processing of the substrate.
although the layer is thin and easy to remove, it is difficult to use chemical treatment, so it is important to pay attention to control in the production and processing, So as to avoid blistering caused by poor adhesion between copper foil and chemical copper; When the thin inner layer is blackened, there are also some problems, such as poor blackening and browning, uneven color and poor local blackening and browning1 L. Z$ j4 u0 Q- ? 2 u 2. Poor surface treatment caused by oil or other liquid contaminated with dust during machining (drilling, laminating, milling, etc.)9 O* E8 i! \ 6 T. T9 M $M. Q 3/ t! l- L! l- H" z0 c( s    The pressure of F4 w'p grinding plate before copper deposition is too high.
it causes the deformation of orifice, brush out the fillet of copper foil at orifice, and even leak the base material at orifice, which will cause bubble phenomenon at orifice in the process of copper deposition, electroplating and tin spraying welding; Even if the brush plate does not cause the leakage of the substrate, the heavy brush plate will increase the roughness of the copper at the orifice, so in the process of micro etching coarsening, the copper foil at the orifice is easy to coarsen excessively, and there will be a certain quality risk; Therefore, we should pay attention to strengthen the control of the brushing process, and adjust the brushing process parameters to the best through the abrasion test and water film test;, b+ X- w4 H% q3 }4. Washing problem:0 D) B" j4 y; f( X( \    G9 u because the copper plating process needs a lot of chemical treatment,There are many kinds of acid-base organic solvents, and the washing of the board surface is not clean, especially the adjustment of the degreaser by copper precipitation, which will not only cause cross contamination, but also cause the defects of poor treatment or poor treatment effect and uneven treatment of the board surface, resulting in some problems in the binding force; Therefore, we should pay attention to strengthen the control of water washing, mainly including the control of water flow, water quality, washing time, and dripping time of plate; Especially when the temperature is low in winter, the washing effect will be greatly reduced, and more attention should be paid to the control of washing; More information about PCB can be shared on jiepei's official website. Welcome to join us!! w2 t4 X! c$ x8 A& K3 I9 q' Q: U; w4 _* U.
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