Study on High Temperature Resistance and Process of Tin Coating

Abstract

Aiming at the problems such as high temperature shrinkage and discoloration of tin plating on copper-based lead frames, as well as poor resistance to salt water corrosion at room temperature, different electroplating processes were used to analyse the microstructure, phase structure, electrochemical corrosion resistance, and mechanical properties of the coating. Results showed that the sufficient deoxidation and coarsening of copper surface before tin-plating could significantly improve the bonding strength of tin-plating and effectively prevent the tin-shrinkage phenomenon at high temperature. After tin plating, soaking the coating in anti-high-temperature oxidant solution could effectively prevent yellowing at high temperature and improve the corrosion resistance in salt-water.

Keywords

• power semiconductor device|copper-based lead frame|tin plating|electrochemical corrosion