What are the common BGA welding defects and how to deal with them
2024-01-06
The welding of BGA is an important process of PCBA processing, but due to the difficulty of post-welding inspection and maintenance of BGA, X-ray fluoroscopy must be used to ensure the reliability of the welded connection. Therefore, it is important to diagnose BGA soldering defects during reflow soldering in PCBA processing.
The common BGA soldering defects are described as follows.
(1) Blowing holes: hole-like or circular pits appear on the surface of the solder ball.
Hole blowing diagnosis: During reflow soldering, there is gas leakage in the pores of the BGA solder ball.
Blowing hole treatment: X-Ray is used to check whether there are pores inside the raw material and adjust the temperature curve.
(2) Cold welding: the surface of the solder joint is dull and not completely welded.
Cold welding diagnosis: insufficient heat during welding, vibration causes bare solder joints.
Cold soldering: Adjust the temperature profile to reduce vibration during cooling.
Cold welding diagnosis: insufficient heat during welding, vibration causes bare solder joints.
Cold soldering: Adjust the temperature profile to reduce vibration during cooling.
(3) Crystal cracking: The surface of the solder joint is in a state of glass crack.
Crystal rupture diagnosis: When gold is used as a solder pad, crystals break when gold and tin/lead are fused.
Crystallization rupture treatment: The gold pad is pre-coated with tin and the temperature profile is adjusted.
Crystal rupture diagnosis: When gold is used as a solder pad, crystals break when gold and tin/lead are fused.
Crystallization rupture treatment: The gold pad is pre-coated with tin and the temperature profile is adjusted.
(4) Offset: BGA solder joints and PCB solder pads are misaligned.
Offset diagnosis: the patch is not accurate, and the conveying vibration.
Offset diagnosis: strengthen the maintenance and maintenance of the placement machine, improve the accuracy of the placement, and reduce the vibration error.
Offset diagnosis: the patch is not accurate, and the conveying vibration.
Offset diagnosis: strengthen the maintenance and maintenance of the placement machine, improve the accuracy of the placement, and reduce the vibration error.
(5) Bridging: Solder flows from the solder pad to another solder pad to form a bridge or short circuit.
Bridging diagnostics: solder paste, solder ball collapse, poor printing.
Bridging treatment: Adjust the temperature curve, reduce the reflow air pressure, and improve the printing quality.
Bridging diagnostics: solder paste, solder ball collapse, poor printing.
Bridging treatment: Adjust the temperature curve, reduce the reflow air pressure, and improve the printing quality.
(6) Solder sputtering: There are tiny solder balls on the surface of the PCB close to or between two solder joints.
Solder Splash Diagnosis: Solder paste is of poor quality and heats up too quickly.
Solder sputtering treatment: check the storage time and conditions of solder paste, select the appropriate solder paste as required, and adjust the temperature curve.
Solder Splash Diagnosis: Solder paste is of poor quality and heats up too quickly.
Solder sputtering treatment: check the storage time and conditions of solder paste, select the appropriate solder paste as required, and adjust the temperature curve.
In the process of PCBA machining, correctly diagnose the problems of BGA welding and deal with them in time. It can not only reduce the loss caused by improper operation, but also check the quality of the product from time to time.
Which parts of the industrial PCB are most prone to failure?
The importance and design requirements of PCBA prototype
SEND MESSAGE