The exact position of the BGA component on the circuit board depends entirely on the accuracy of the chip placement machine. Most placement machines have a specific positioning system that helps achieve precise placement of the BGA component. Some chip mounters can also check the coplanarity of BGA solder balls and identify defects, like missing solder balls, which improves soldering reliability.
Additional measures can further improve the accuracy of BGA component installation. For instance, a local fiducial mark can be set outside the BGA pad or multiple fold lines can serve as fiducial marks for manual inspection post-assembly. Both methods have proven effective in actual manufacturing.
BGA components exhibit self-centering effects during soldering due to solder surface tension. Some designers intentionally add pads at the four corners of the BGA pad design to enhance this effect, ensuring BGA components automatically reset after shifting installation positions.
The welding temperature profile directly impacts soldering quality, typically consisting of preheating, soaking, reflux, and cooling stages. Each stage undergoes different physical/chemical changes. The temperature curve, crucial in determining solder joint formation, is closely tied to joint reliability. Establishing a satisfactory temperature profile for BGA packages is challenging, requiring measurement of package temperature, circuit board surface temperature, and internal solder joint temperature of the BGA component.
Since all BGA solder joints are beneath the package post-soldering, traditional inspection methods like flying probe tests or visual inspections are inadequate. Leading methods for scanning BGA solder joints for welding defects are AOI (Automatic Optical Inspection) and AXI (Automatic X-ray Inspection) testing. Due to the BGA structure’s characteristics, inspecting a single solder joint of a BGA component is nearly impossible; the entire package may need repackaging.
Other considerations during the BGA assembly process include electrostatic protection and BGA component baking. BGA components typically demand special packaging with electrostatic protection measures. Rigorous electrostatic protection during PCB assembly requires equipment grounding, personnel management, and environmental controls.
Additional measures can further improve the accuracy of BGA component installation. For instance, a local fiducial mark can be set outside the BGA pad or multiple fold lines can serve as fiducial marks for manual inspection post-assembly. Both methods have proven effective in actual manufacturing.
BGA components exhibit self-centering effects during soldering due to solder surface tension. Some designers intentionally add pads at the four corners of the BGA pad design to enhance this effect, ensuring BGA components automatically reset after shifting installation positions.
The welding temperature profile directly impacts soldering quality, typically consisting of preheating, soaking, reflux, and cooling stages. Each stage undergoes different physical/chemical changes. The temperature curve, crucial in determining solder joint formation, is closely tied to joint reliability. Establishing a satisfactory temperature profile for BGA packages is challenging, requiring measurement of package temperature, circuit board surface temperature, and internal solder joint temperature of the BGA component.
Since all BGA solder joints are beneath the package post-soldering, traditional inspection methods like flying probe tests or visual inspections are inadequate. Leading methods for scanning BGA solder joints for welding defects are AOI (Automatic Optical Inspection) and AXI (Automatic X-ray Inspection) testing. Due to the BGA structure’s characteristics, inspecting a single solder joint of a BGA component is nearly impossible; the entire package may need repackaging.
Other considerations during the BGA assembly process include electrostatic protection and BGA component baking. BGA components typically demand special packaging with electrostatic protection measures. Rigorous electrostatic protection during PCB assembly requires equipment grounding, personnel management, and environmental controls.
