Printed circuit board surface processing method and printed circuit board

Abstract

The invention discloses a printed circuit board surface processing method and a printed circuit board. According to the surface processing method, tin immersion is carried out after the carbon oil printing and the printed circuit board is baked before the tin immersion to enable the surface of carbon oil to be heated to shrink, then moisture in the carbon oil is removed, gaps on the surface of the carbon oil are decreased, and potion is prevented from entering the carbon oil during the tin immersion; at the same time, the time from the baking to the tin immersion is controlled to ensure that the carbon oil is prevented from absorbing the moisture to cause the spreading of the surface gaps; the surface processing process is short in flow; the reliability of the printed circuit board is relatively high, the carbon oil combination is favorable, no copper falls, the tin surface is glossy and no blackening phenomenon happens; and the tin immersion process can be directly carried out on carbon oil tin immersion surface processing type plates, so that the method can be used for production in a batch way and has a relatively good market prospect.

Description

technical field [0001] The invention relates to the technical field of surface treatment of printed circuit boards, in particular to a method for surface treatment of printed circuit boards and the printed circuit board. Background technique [0002] There are many surface treatment methods for PCB (printed circuit board), such as tin spraying, immersion gold, immersion tin, etc. The reliability, corrosion resistance and wear resistance of the PCB are guaranteed. [0003] Due to its good electrical conductivity, high hardness, abrasion resistance, and low cost, carbon oil is generally used for PCB boards with key-type structures. The carbon oil process and other surface treatment methods can be mass-produced, but the carbon oil + immersion tin process cannot be mass-produced due to the problems of carbon oil loss and tin surface pollution. For the carbon oil + immersion tin process, the current production time in the industry Generally, the following two methods are used t...

AI Technical Summary

Problems solved by technology

[0006] However, there are certain deficiencies in the above two methods;

[0007] like figure 1 As shown, using the scheme 1 to immerse tin and then print carbon oil, it is easy to cause tin surface 10 pollution, which affects the reliability of PCB: tin surface 10 is very easy to oxidize and pollute, and copper surface 20 needs to be printed during carbon oil printing after tin immersion. Carbon oil screen printing, and needs to be baked, during the printing and high-temperature baking process, the tin surface 10 will be oxidized, and blackened parts 30 will appear, which will affect the solderability of the PCB;

[0008] However, the operation of plan 2 is complicated, the production efficiency and cost are high, and the operation process and production cost of printing blue glue and tearing blue glue need to be increased, and the blue glue is easy to seep oil on the PAD, resulting in sinking tin and dew copper

And with the existing operation method in the industry, if the oil is used to sink tin directly, the potion will attack the carbon oil, causing the carbon oil to fall off

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