In failure analysis (FA), seeing the symptom is just the start—understanding the cause is what actually prevents future failures.
Tools like CSAM (C-mode Scanning Acoustic Microscopy) are excellent at identifying internal anomalies—like voids, delamination, or cracked die attach—but they don’t always reveal the full picture. That’s where mechanical cross sectioning comes in.
If you’re stopping your FA process after CSAM or X-ray, you’re missing out on the conclusive evidence and dimensional data that only cross sectioning provides.
Cross Sectioning: The Key to Going from Symptom to Root Cause
CSAM is often the first step in identifying internal defects in packaged ICs, BGA solder joints, or PCBs. But once you’ve detected something suspicious—like a large void or delamination—what’s next?
That’s where mechanical cross sectioning bridges the gap:
| Tool | What It Shows | What’s Missing |
|---|---|---|
| CSAM | Internal anomalies, air gaps, delam, cracks | No material composition, layer interface, or visual context |
| X-ray | Voids in solder, missing balls | Limited resolution and 2D compression |
| Cross Sectioning | Physical structure, material condition, bonding interfaces | Destructive but detailed |
Cross sectioning lets you cut directly into the region of concern, allowing failure analysts to confirm not only what went wrong—but also why.
Example: CSAM Reveals Delamination — Now What?
You run CSAM on a molded IC and see signs of delamination between the mold compound and die surface. That’s your symptom.
Now, cross sectioning can answer:
- Was there contamination at the interface?
- Was the die attach voided or improperly cured?
- Was there thermal stress damage to nearby materials?
- Is the delamination isolated or systemic across the die?
Using cross sectioning, our lab can analyze the actual material interfaces, grain structures, and mechanical separation zones that CSAM alone cannot show.
Cross Sectioning Turns Suspicion into Actionable Insight
Here’s what mechanical cross sectioning uniquely offers:
- Confirms CSAM findings by visually correlating voids or delam with physical damage
- Measures key dimensions like copper plating thickness, solder height, or die attach layer
- Identifies root cause like poor adhesion, voiding, corrosion, or thermal cycling fatigue
- Provides lab-grade documentation for customer reporting or regulatory compliance
When to Add Cross Sectioning to Your Workflow
We recommend cross sectioning as a follow-up to CSAM or X-ray in these scenarios:
- Delamination suspected in IC packages, BGAs, or PCBs
- Voids seen in solder joints or die attach areas
- Cracks or fractures detected acoustically or visually
- Thermal damage suspected in high-power devices
- Unexplained failures from in-field or HALT/HASS testing
Advice: Use CSAM to Locate. Use Cross Sectioning to Understand.
Together, CSAM and cross sectioning form a powerful duo:
- CSAM identifies the defect without damaging the part
- Cross sectioning investigates the root cause with precision detail
- You act confidently on what’s discovered—whether it’s a material issue, process defect, or design flaw
Why Engineers Trust Cross Section Lab
At Cross Section Lab, we specialize in failure analysis workflows that combine CSAM findings with expert cross sectioning. Our lab provides:
- Fast turnaround on urgent FA projects
- Clean, polished microsections with high-res imaging
- Expert-level interpretation of both symptoms and root causes
- Reports that support engineering, QA, and supplier decisions