Why are BGA solder joints prone to oxidation

In electronic packaging, BGA (Ball Grid Array) is undoubtedly one of the most frequently used electronic packaging methods and is widely used in various high-performance electronic devices. However, in the process of understanding, it is easy to encounter the problem of BGA solder joints being easily oxidized. So what is the reason for this?

1. Why are BGA solder joints prone to oxidation?
(1)Environmental factors: Oxygen and moisture in the air are the main factors that cause BGA solder joints to oxidize. If the solder joints are exposed to the air for too long, or the ambient humidity is too high during storage and transportation, the surface of the solder joints will oxidize.
(2)Material factors: Differences in the chemical properties of solder balls and substrate materials may also cause solder joint oxidation. For example, some materials are prone to react with oxygen in certain environments to form oxides.
Process factors: Improper settings of welding process parameters, such as excessively high welding temperatures and long welding times, may lead to excessive oxidation of the solder joint surface.

2. How to solve the problem of BGA solder joint oxidation?

(1)Cleaning with detergent: Use suitable detergents and cleaning methods to remove the oxide layer on the surface of BGA solder joints. When selecting a cleaning agent, the composition and applicability of the cleaning agent should be fully considered to avoid damage to the solder joints or other components. During the cleaning process, ensure sufficient rinsing and drying to prevent residues from causing secondary contamination or oxidation.

(2)Surface treatment agent: Use surface treatment agents, such as activators or deoxidizers, to remove the oxide layer and repair the surface of BGA solder joints. These chemicals can react with the oxide layer and convert it into a solderable metal surface. Before using a surface treatment agent, read the product instructions carefully and follow the recommended usage.

(3)Add flux: During the soldering process, an appropriate amount of flux can be added to help remove the oxide on the surface of the solder joint. The flux can reduce the surface tension of the solder joint and promote good bonding between the solder ball and the substrate. At the same time, the active ingredients in the flux can also react with the oxide to further reduce the degree of oxidation.