Organic acid super roughening process for pretreatment of printed circuit board resistance welding film layer

Abstract

The invention provides an organic acid super roughening process for pretreatment of a printed circuit board resistance welding film layer. The organic acid super roughening process comprises the following steps that after a working solution of a printed circuit board resistance welding film layer pretreatment slot is completely discharged, the pretreatment slot is washed with tap water completely; circulating washing is performed with deionized water; an organic acid super roughening water solution is added and heated to 25-35 DEG C; a circulating filtering pump is started; a circuit board to be subjected to resistance welding film layer silk-screen printing is placed into the organic acid super roughening water solution to be soaked; the circuit board is taken out and is washed with the tap water; the circuit board is dried at the temperature of 70-80 DEG C; and the dried circuit board is transferred to the resistance welding film layer silk-screen printing process. According to the resistance welding film layer pretreatment organic acid super roughening process, through the manner of organic acid chemical super roughening, a copper surface of ultra high micro-roughness is formed, the quality defect that the resistance welding film layer falls in the subsequent surface treatment process of the circuit board is prevented, the production process is free of pollution, and the organic acid super roughening process is suitable for industrialized production.

Description

technical field [0001] The invention relates to an organic acid super-roughening process for the pretreatment of the solder resist film layer of a printed circuit board, which makes the copper surface of the circuit board undergo chemical super-roughening with an organic acid to form a super microscopic roughness (Ra≥0.5 microns) to strengthen The bonding force between the copper surface of the line and the solder mask layer ensures that the solder mask layer will avoid the solder mask layer from falling off in the subsequent surface treatment (including high temperature and strong chemical attack) and ensure product quality. Background technique [0002] With the development of high integration and high density of printed circuit boards, the requirements for solder mask are getting higher and higher, which makes the surface treatment of circuit boards more and more complicated. Such as electroless nickel-plated gold (including selective secondary nickel-plated gold), electr...

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Problems solved by technology

Such as electroless nickel-plated gold (including selective secondary nickel-plated gold), electroless nickel-palladium-gold, chemical silver-plated, chemical tin-plated, etc., due to the high temperature of the chemical plating solution, various chemical solutions have a strong impact on the solder mask layer. There are more or less attacks. It is difficult to achieve the roughness of the copper surface of the circuit required by the solder mask layer in the previous mechanical brushing or sulfuric acid / hydrogen peroxide chemical roughening (mechanical brushing roughness Ra: 0.1-0.2 microns, chemical Medium coarsening Ra: 0.3-0.4 microns, organic acid ultra-coarsening Ra≥0.5 microns), it is easy to cause the solder mask layer to fall off in the subsequent surface treatment process, resulting in scrapping, and the scrapping rate is as high as 0.96%, so it solves the problem of solder masking The pre-treatment of the film layer makes the line copper mask ultra-high micro-roughness (Ra≥0.5 microns), which is imminent

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