Section 10: BGAs Re-Balled
August 4, 2010 |Estimated reading time: 1 minute
These images of SMT defects and attributes were compiled by consultant Tom Clifford. Section 10 includes images of re-balled collapsing and non-collapsing C-BGAs, compromised fillets, mis-registered balls and more.
These images of SMT defects and attributes provide resources for training, quality control specs and standards and research. Other Sections, published and upcoming, are listed below the gallery. Descriptions, provided below each image, do not necessarily define causality or severity, but serve only as identification.Figure 1: Re-balled collapsing/melting P-BGA, by shop S. Note: Lumpy, irregular, worrisome fillet.Figure 2: Re-balled non-collapsing (non-melting) C-BGA, by shop S. Note: Porous, cracked fillet.
Figure 3: Re-balled C-BGA, by shop S. Porous, poorly-melted fillet. Might reflow in later assembly, might not.Figure 4: Properly re-balled CBGA. Note: Shiny, ample fillet.Figure 5: Re-balled non-melting balls on C-BGAs, by shop A. Long-term reliability is questionable.Figure 6: Ditto, for these reballed P-BGA balls. Fillets look compromised.Figure 7: Reballed by Shop A. Odd appearance--unknown cause and consequence.
Figure 8: New, as delivered, nominal, non-melting C-BGA.Figure 9: Reballed C-BGA. Note: Mis-registered balls, plus bad fillets.Figure 10: Re-balled C-BGA. Note: Porous fillet, apparently only partially reflowed paste.
Figure 11: Reballed CBGAs. Note: Cracks and separations within fillet or at fillet-package interface.Figure 12: Odd situation: Perfect fillet right next to porous, grainy fillet. Why?Section 1. BGA PCB Defects, Plating
Section 2. BGA PCB Defects, External Damage
Section 3: BGA PCB Defects, Via-in-Pad
Section 4: BGA PCB Defects, Dimensions, Poke-Thru
Section 5: BGA PCB Defects, Mask
Section 6: BGA PCB Defects, Metallic Contamination
Section 7: BGA Pads--Non-Metallic ContaminationSection 8: BGA PWB-Related Assembly DefectsSection 9: BGA Assembly X-Sections
(Upcoming)Section 11: SMT Assembly DefectsSection 12: SMT Assemblies, T-Cycled CracksSection 13: SMT PWB PadsSection 14: PWB Vias, X-Sections
Do you have images of solder-joint or other interconnect features or defects that you would want to share? Send them to Holly Collins at SMT, editorial@iconnect007.com. You must obtain permission to publish the photos and may not show proprietary or company-specific information on the images. We are particularly interested in images of advanced SMT assembly technologies and failure analyses.