I believe that many engineers really want to know what are the undesirable phenomena in BGA soldering, and how to distinguish and identify them? The following is the experience we want to share with you.
- Connecting tin: Connecting tin is often called “short”, that is, the solder ball and the solder ball are connected together during the soldering process, which leads to the short circuit
- False soldering: False soldering is usually called the “pillow effect”. There are many reasons for false soldering. BGA false soldering has always been a headache for engineers in the SMT industry: BGA false soldering is “concealed”. Not only there are a certain percentage of defects, but they are also not easy to find and difficult to identify.
- Bubbles: Bubbles are not falses, but if the bubbles are too large, there will be hidden quality problems, and the acceptance of bubbles has IPC standards. The air bubbles are mainly caused by the air in the blind hole without being discharged in time during the soldering process.
- Cold soldering: For cold soldering, many people may think that it is the same as fake soldering. Although they are the same, they are not completed. Cold soldering is caused by abnormal reflow soldering temperature and the solder paste is not completely melted. It may be that the temperature did not reached the melting point of the solder paste or insufficient reflow time .
- Dirty: The pad is dirty. It may be due to the poor environmental protection during the production process or there is foreign matter on the pad resulting in poor soldering.