Tin plating solution and its preparation method and application

Abstract

The invention relates to a tin plating electrolyte which contains a solvent and the materials with following concentration: 10-20g / L of tin methane sulfonate, 30-60g / L of methanesulfonic acid, 0.4-5g / L of compound additive, and a proper amount of PH regulator; and the compound additive is formed by thiourea, hydroquinone, 2-mercapto benzimidazole and propylene glycol block polyether. For the tin plating electrolyte, by reasonably selecting types and use amount of additives, the problems of instable plating solution and high cost in the methanesulfonic acid system are solved, and by using the tin plating electrolyte, a high-mass plating layer is acquired beneficially.

Description

technical field [0001] The invention relates to the field of circuit boards, in particular to a tin plating solution and a preparation method and application thereof. Background technique [0002] Electroplated tin-lead alloy is the earliest tin alloy discovered with great application value, and it was quickly applied to electronic components. However, with the promotion of lead-free electronic components, it is becoming more and more important to seek an alternative solderable coating. more urgent. As one of the "hardware" - gold, silver, copper, iron, tin, tin is a soft, malleable silver-white metal with excellent solderability and corrosion resistance. Pure tin plating is usually used to prevent The surface of the material is oxidized to improve corrosion resistance and weldability. Electroplated tin is mainly used in microelectronics, printed circuit board (PCB), automobile, jewelry decoration, electrochemical energy storage battery and other fields. In addition, due ...

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Problems solved by technology

[0003] However, electroplating tin not only needs to precisely control the thickness of the tin layer, but also ensure the accurate application of the solder layer. The spontaneous growth of tin whiskers on the surface of the coating is an important technical problem in the field of electronic electroplating. The growth of tin whiskers will cause short circuits and electronic failures. The reliability of electronic products poses a potential threat

[0004] In addition, in the existing acidic tin plating solution, the main salt is Sn 2+ The form exists, and the plating solution is easily oxidized to Sn by dissolved oxygen in the air and water during storage and electroplating. 4+ , Sn 4+ Hydrolysis forms highly dispersed tin oxide particles, leading to the formation of tin sludge. The instability of the plating solution leads to the inability to obtain a bright and dense tin coating during electroplating, which adversely affects the corrosion resistance of the coating.

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