Solder ball breakage
Virtual soldering is another common problem, mainly manifested in the failure of the soldering point to form a good metal connection. The main causes of virtual soldering include poor wettability of the solder, the soldering temperature is lower than the melting point of the solder paste, or the solder is contaminated during the soldering process.
soldering virtual soldering
Virtual soldering is another common problem, mainly manifested in the failure of the soldering point to form a good metal connection. The main causes of virtual soldering include poor wettability of the solder, the soldering temperature is lower than the melting point of the solder paste, or the solder is contaminated during the soldering process.
Solder ball offset
During the soldering process, due to thermal expansion, uneven surface tension, etc., the solder ball may shift, resulting in a decrease in the quality of the connection. Especially in high-density BGA packages, small shifts in the solder balls can cause serious performance issues.
Bridging
If there is too much solder or excessive flow of solder, bridging may form, that is, an electrical connection is formed between two or more solder joint that should not be present. The appearance of bridge connection not only affects the normal operation of the circuit, but also may cause a short circuit and cause damage to the equipment.
Post-soldering cracks
Post-soldering cracks refer to cracks that appear during or after soldering, which are caused by soldering stress, thermal cycling stress, or mechanical vibration. This crack can cause circuit breaks, affecting the reliability of the equipment.
Appearance defects
During the BGA soldering process, appearance defects such as uneven solder surface and darkening of solder color may occur. These defects are generally caused by improper soldering process parameters, poor ambient temperature and humidity control, or solder quality problems. While these defects do not necessarily directly affect the functionality of the board, they may affect the life and reliability of the board.
Internal defects
Using X-rays or other non-destructive testing techniques, internal defects of BGA soldering, such as holes and cracks inside the solder ball, may be found. These internal defects can be caused by gas generation and trapping during the soldering process, or due to uneven shrinkage during the solder cooling process. These internal defects may affect the electrical properties of the circuit and reduce its resistance to fatigue and vibration.
Poor electrical properties after soldering
Some defects may not be detected directly by visual or X-ray inspection, and can only be found in electrical performance tests. For example, poor weld quality can lead to problems such as increased resistance, current disturbances, and signal delays. These issues can seriously affect the performance of the board and even cause the board to not function properly.