Copper-based metal surface tin immersion liquid and application thereof

Abstract

The invention provides a copper-based metal surface tin immersion liquid and application thereof. The copper-based metal surface tin immersion liquid comprises the following components by mass concentration: 10-200g / L of tin salt, 50-300g / L of a complexing agent, 10-400g / L of organic acid, 1-100g / L of a surfactant, 10-100g / L of an antioxidant and 1-100ppm of precious metal, wherein the complexingagent is a combination of citric acid, thiourea, isothiourea and mercaptan. The copper-based metal surface tin immersion liquid provided by the invention is simple in formula, applicable to horizontalor vertical production processes, easy to control and simple to operate; and the obtained tin surface is uniform and compact and has good multiple weldability.

Description

technical field [0001] The invention belongs to the field of electroless tin plating, and in particular relates to a copper-based metal surface immersion tin solution and an application thereof. Background technique [0002] Tin is a metal with good solderability and corrosion resistance, which is widely used in the electronics industry. With the miniaturization of electronic development, the lines and BGA points on the printed circuit board (PCB) are getting smaller and smaller, tin has been widely used as a solderable coating, and the traditional hot air leveling process can no longer meet the existing process requirements . The chemical immersion tin process has the advantages of excellent multiple solderability, dense coating, simple process flow, and environmental protection, and is widely used. But because the hydrogen evolution potential of tin is high and the catalytic activity is low, if sodium hypophosphite, borohydride, Ti 3+ Reductants such as tin can’t realiz...

AI Technical Summary

Problems solved by technology

At this time, the Giavani effect of chemical immersion tin will have a certain impact on signal transmission and stability

[0004] CN101705482A discloses an alkylsulfonic acid chemical tin plating solution, which includes the following components: organic sulfonic acid tin salt 1-40g / L, organic acid 5-250g / L, complexing agent 5-300g / L, Reducing agent 20-150g / L, surfactant 0.5-50g / L, antioxidant 0.1-25g / L, noble metal salt 1-500mg / L and brightener 0.5-3g / L, the alkylsulfonic acid chemical tin plating solution Add a large amount of reducing agent and brightener, so the organic content of the prepared coating is high, the coating is brittle, and cannot meet the needs of electronic devices for the flexibility of the coating, so it is suitable for high dielectric constant, high frequency materials or small pads Chemical immersion tin is not applicable

[0005] CN107365986A discloses a chemical tin treatment agent and a tin plating process using the chemical tin treatment agent. The chemical tin treatment agent includes the following raw materials: organic tin salt 100-150g / L, organic acid 30-50mL / L, Mixture 50-100g / L, reducing agent 50-100g / L, chelating agent 1-10g / L, surfactant 5-30g / L, antioxidant 1-10g / L, organic acid silver 1-10g / L, Gloss agent 1-5g / L and corrosion inhibitor 5-50g / L, this chemical tin treatment agent is prone to tin migration during the tin plating process, resulting in longer tin whiskers, which affects the processing and use of circuit boards

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