关键词: 沉积氯, 烘烤时间, 湿气, 多焊点, 原电池腐蚀

Abstract: There is a potential difference between different metals, andit is easy to produce galvanic corrosion on the solder joints polluted by sulfur and chlorine, which will reduce the reliability of bonding products and shorten the life of products. Therefore, the corrosion of solder joints is highly valued by people.The ball grid array (BGA) products with palladiumplated copper wire were taken as the research object. By experimental means of energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) etc., the factors affecting the simultaneous corrosion of multiple solder joints by chlorine were firstly analyzed, and then the solder joint surface was divided into three regions: The upper surface, the side surface and the interface.The corrosion analysis and verification of each region were conducted, and the corrosion mechanism of chlorine corroded solder joints was finally obtained. The experimental results show that: (1) The main influencing indicators of difficulty of chlorine corrosion are the density of IMC and the exposed area of copper on the palladium plating layer. The smaller the density of IMC, and the larger the area of copper exposed on palladium plating layer, the more likely chlorine corrosion will be. (2) The corrosion path of solder joints show that chlorine migrates along the surface of copper sphere to the interface between copper sphere and IMC. (3) The shorter the baking time of the solder joints, andthe greater the palladium coverage on the surface layer of the solder joints, the lower the probability of the solder joints being corroded by chlorine will be.

Key words: deposition chlorine, baking time, moisture, multiple solder joints, galvanic corrosion