Pretreatment liquid of organic weldable protective agent preparation method

Abstract

The invention relates to a pretreatment liquid of an organic weldable protective agent preparation method, which is suitable for antioxidant operation of finishing surface processing working procedurein the manufacture process of a printed-circuit board (PCB). The pretreatment liquid is prepared by no less than two benzimidazole derivatives, no less than two substituted carboxylic acid ammonium salts and deionized water, wherein the usage of the benzimidazole derivative is 0.005%-0.25% and the usage of substituted carboxylic acids ammonium salt is 0.05-0.5%. The pretreatment liquid can obviously improve the reaction activity of the copper surface, adjusts the deposition reaction of the follow-up OSP, improves the compactness and hydrophobicity of the final OSP coating; therefore, the pretreatment liquid can obviously increase the anti-oxidation capability of the printed circuit board in the storage process and the high temperature usage condition, meets the excellent weldable requirements of an electronic assembly plant on the printed circuit board.

Description

technical field [0001] The invention relates to the technical field of electronic chemicals, in particular to a pretreatment liquid used in an organic solderable preservative (OSP) process and a preparation method thereof. Background technique [0002] The organic solderable preservative process (OSP) has been used in the industry for many years. Its main function is to perform anti-corrosion and anti-oxidation treatment on the copper surface pads of PCB (Printed Circuit Board, that is, printed circuit boards), so that the copper surface pads can be used for a long time. It is not easy to oxidize during storage and under high temperature conditions, maintaining the excellent solderability of the pad. Foreign Japanese patents 5-186888, 7-24305, US patents 5376189, 5173130 and European patent EP0791671 have described the protection technology in detail. Their film-forming substances include benzotriazole, benzimidazole and arylphenylimidazole, etc. The advantages are water-so...

AI Technical Summary

Problems solved by technology

[0003] However, in the process of using the products of OSP suppliers at home and abroad, most of them have defects such as slow film formation speed, loose film structure, and poor oxidation resistance, which are prone to oxidative discoloration in the subsequent high-temperature assembly process and lead to poor soldering. Return incidents occur frequently, causing economic losses to many parties

Some suppliers increase the film forming speed by adjusting parameters, but the consequences of this are often due to the high activity of the OSP liquid, and the film components are not only deposited on the copper surface, but also on the row rollers, rollers and inner walls of the cylinder of the production line. Over time, a large number of hard-to-clean crystals have accumulated, which not only affects the appearance of the OSP board, but also has a great hidden danger to the performance of the OSP

If the situation is serious, it may even make it impossible to continue the production of PCB, which brings great troubles to PCB manufacturers.

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