Section 14: PWB Vias, X-Sections
September 1, 2010 |Estimated reading time: 2 minutes
These images of SMT defects and attributes were compiled by consultant Tom Clifford. Section 14 includes images of partially filled vias, plugged vias, wide open vias, non-uniform via covers, annular ring defects, voids, top-side dimples 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: How is this possible? Via on left is not parallel to the other two vias. Off-angle drill?Figure 2: Via plug has pushed up several mils above the plane of the shoulder.Figure 3: Plugged (not filled) via, both sides. Lumps are borderline excessive.Figure 4: Examples of badly filled/plugged vias. Likely source or cause of contamination.Figure 5: Wide-open via. Tent or plug didn't work. Open to contamination.Figure 6: Plating cap or viain-pad didn't work, leaving dimple and likely pin-hole.Figure 7: Non-uniform via covers; open, dimpled, pin-hole. Also, possible annular ring defect.Figure 8: Marginal via cover: Likely pin-hole condition.
Figure 9: Nice via-fill and cover. Only very slight (acceptable) lump.Figure 10: Extreme via-ill lump. Caused the SMR to stand off 20-25 mils.Figure 11: Perfect via cover. Could be considered a "buried" via.Figure 12: External view of another via from the 14-10 board, causing a towering stand-off. This via lump erupted leaving a pinhole as well.Figure 13: Partially-filled via, showing trapped contaminant.Figure 14: Partially-filled via, showing trapped contaminant.Figure 15: Not filled. Unknown contaminant.Figure 16: One end plugged/covered, wide open source of contamination. Possible annular ring defect.Figure 17: Voids and top-side dimples. Possible annular ring violation.Figure 18: Badly filled/covered via. Voids, open, contamination.Figure 19: Nice via cover, but fill void condition may be unacceptable.Figure 20: Nice via-cover, but lots of voids.
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
Section 10: BGAs Re-Balled Section 11: SMT Assembly DefectsSection 12: SMT Assemblies, T-Cycled CracksSection 13: SMT PWB Pads
(Upcoming)Section 15: Wrap-UpDo 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.