STIRRI-BGA-TF specialty no-clean universal tacky flux (ROL0) provides reliable soldering of BGA components, featuring BGA-balanced viscosity with an increased amount of solids. Specifically designed for BGA purposes, it addresses BGA slumping issues. However, despite its primary focus on BGAs, the flux can adequately perform also for any other soldering task, including leaded or unleaded hand-soldering with hot-air or machine soldering.

BGA solder sphere slumping is a defect that occurs during the reflow soldering process, where the solder spheres deform and spread out, resulting in poor solder joint formation. This can lead to various issues, including:

• Poor electrical connection: The spread-out solder spheres may not adequately contact the BGA pads, leading to increased resistance and potential electrical failures.
• Mechanical weakness: The reduced solder volume can weaken the joint, making it more susceptible to mechanical stress and vibration.
• Thermal fatigue: The non-ideal solder joint shape can accelerate thermal fatigue, reducing the component's lifespan.

Several factors can contribute to BGA solder sphere slumping:

• Excessive reflow temperature: High temperatures can cause the solder spheres to melt excessively, leading to deformation.
• Insufficient reflow time: If the solder spheres do not have enough time to solidify properly, they can slump as they cool.
• Poor solder flux/paste quality: Substandard solder paste can have inadequate viscosity, allowing the solder spheres to spread.
• Component placement accuracy: Inaccurate component placement can lead to uneven solder distribution and increased slumping.
• PCB design issues: Poor PCB design, such as inadequate thermal vias or insufficient copper thickness, can contribute to slumping.

To prevent BGA solder sphere slumping, it is essential to:

• Optimize the reflow profile: Carefully control the temperature and time parameters to ensure proper solder melting and solidification.
• Use high-quality solder flux/paste: Select a solder paste with appropriate viscosity and thermal properties.
• Ensure accurate component placement: Employ precise placement equipment and techniques to minimize misalignment.
• Design for manufacturability: Consider factors like thermal dissipation, component placement density, and solder joint geometry during PCB design.
• Implement quality control measures: Regularly inspect solder joints for defects and take corrective actions as needed.

By addressing these factors, manufacturers can minimize BGA solder sphere slumping and improve the reliability of their electronic products. 

While BGA-TF has low activity and is a safe bet, for higher activity BGA/rework consider Hydra-MA-TF resin-based synthetic REM1 tacky flux. Made for the OEM manufacturing, Hydra-MA-TF may surpass BGA-TF in assembly line industrial-grade performance.