Tin-plated copper foil is a composite material formed by depositing a tin coating on a copper foil substrate. It combines the high conductivity of copper with the protective properties of tin, holding an important position in the electronics manufacturing industry. Its substrate thickness is typically between 0.035 and 0.15 mm, and the surface tin coating thickness is no less than 0.3 μm, which can be adjusted to around 2.0 μm according to application requirements. The adhesion between the coating and the substrate reaches level 5B, effectively preventing delamination during processing.
In terms of performance, tin-plated copper foil exhibits multiple advantages. Regarding conductivity, the pure tin coating obtained through a non-soldering process maintains a surface resistance of 0.1~0.15Ω, and the contact resistance of double-sided tin-plated products can be controlled below 0.5mΩ, meeting the transmission requirements of precision circuits. In terms of corrosion resistance, the protective layer formed by the tin plating significantly slows down the oxidation process and greatly extends the material's failure time in humid environments. Even after 3000 temperature cycles from -40℃ to 125℃, the bright tin plating maintains stable solder joints. Mechanically, it combines good flexibility and fatigue strength, resisting breakage during bending and winding. The substrate performance degradation after electroplating is less than 10%, making it suitable for complex molding requirements.
In terms of applications, tin-plated copper foil has wide applicability. In consumer electronics, matte tin plating products can achieve stable soldering with a linewidth/spacing of 30μm and are commonly used in flexible circuit board manufacturing. In automotive electronics, its high-temperature cycling resistance meets the needs of components such as ECUs. Using double-sided tin plating in photovoltaic junction boxes can improve energy conversion efficiency by 0.3%. Furthermore, it can be used as an electromagnetic wave shielding layer in communication equipment or leverage etching precision advantages in high-density circuit board manufacturing.
In terms of process development, breakthroughs have been achieved in green tin plating technology. The cyanide-free plating solution system reduces the COD value of wastewater from 5000 mg/L to 50 mg/L, with a tin recovery rate exceeding 99.9%. The novel Sn-Bi-Ag ternary alloy coating has a melting point as low as 138℃ and a creep resistance life exceeding 10,000 hours at 125℃, further expanding its application space in fields such as flexible electronics.
