Surface treatment method of printed circuit board and application of surface treatment method

Abstract

The invention discloses a surface treatment method of a printed circuit board and application of the surface treatment method. When the gold finger area is electroplated with thick nickel gold, the chemical gold immersion area which does not need to be electroplated is protected by adopting an anti-gold-electroplating adhesive tape with the tensile strength of 1.4-1.8 kg / 10mm, the elongation of 120%-180% and the adhesive force of 0.08-0.12 kg / 25mm. The anti-gold-plating adhesive tape is tightly attached in the electroplating process, the problems of diffusion plating and ink falling of a chemical gold immersion area in the electroplating process are avoided, the anti-gold-plating adhesive tape has the characteristic of no degumming after being torn off, and the quality risk of adhesive residues is avoided. Meanwhile, the anti-gold plating adhesive tape is combined with the specific photosensitive ink, so that the surface treatment method can meet the high-precision requirement that the distance between the chemical gold immersion area and the golden finger area is larger than 6 mil, the production process is simplified, and the manufacturing cost is reduced.

Description

technical field [0001] The invention relates to the technical field of printed circuit board production, in particular to a surface treatment method of a printed circuit board and its application. Background technique [0002] With the ever-changing and multi-functional requirements of electronic products, the integration of IC (chip) and BGA (ball array package) in circuit board design is also getting higher and higher, and the pins of IC and BGA are getting denser, which gives SMT (chip and plug-in) placement and circuit board fabrication pose technical challenges. At the same time, in order to cope with technical improvement and functional flexibility and detachability, different areas of the circuit board have different surface treatment requirements. For example, for segmented card gold finger circuit boards such as information transmission and servers, in order to improve the wear resistance, electrical conductivity and oxidation resistance of the gold finger, it is u...

AI Technical Summary

Problems solved by technology

[0003] At present, in the process of circuit board production, the surface treatment methods of partial electroplating thick nickel gold and chemical precipitation nickel gold mainly use heat-cured chemical-resistant gold wet film and expensive selective dry film for surface protection. This method is not only difficult to achieve high precision Requirements, and cannot withstand the high temperature conditions of the chemical nickel-gold process (above 80 ° C), there are quality risks such as penetration, ink loss and residual glue

Moreover, for complex line layout, high precision requirements and design of segmented golden finger signal transmission and high-frequency, high-speed connector card board products for servers (such as figure 2 As shown), the distance between the electroplated nickel-gold area and the chemical nickel-gold area is less than 1mm (1mm=40mil), and the front end of the gold finger is designed with a segmented card connector (such as image 3 shown), at this time, heat-cured chemical-resistant gold wet film and electric-resistant gold blue glue will be difficult to meet product requirements

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