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SAM

What Is SAM (Scanning Acoustic Microscopy)?

SAM (Scanning Acoustic Microscopy)—often called C-SAM (C-mode Scanning Acoustic Microscopy)—is a non-destructive inspection technique that uses high-frequency ultrasound to image internal features in materials and assemblies. By analyzing reflected acoustic signals, SAM can reveal delaminations, voids, cracks, poor bonding, trapped air, and internal defects—especially in layered structures where optical methods cannot see beneath the surface.

SAM is widely used when you need to answer: “Is there a hidden delamination or void?” “Where is the interface defect?” “How large is it and how deep?”

What SAM Is Used For

SAM is commonly used to evaluate:

  • Delamination at interfaces (coatings, laminates, die attach, underfill, encapsulants)

  • Voids / porosity in adhesives, potting, and molded compounds

  • Cracks and internal damage (impact, thermal cycling, handling damage—project-dependent)

  • Bond quality (incomplete wetting, weak adhesion zones)

  • Package integrity in electronics (project-dependent):

    • underfill voiding, die attach voids

    • mold compound separation

    • substrate or interposer interface issues

  • Moisture/“popcorn” damage screening (package delamination after reflow—project-dependent)

Why SAM (vs. X-ray or Cross-Sectioning)?

Compared with X-ray

  • X-ray is great for density/metal features, but it can miss thin delaminations at interfaces where acoustic contrast is stronger.

  • SAM often provides clearer contrast for interface separation and planar delamination area (project-dependent).

Compared with destructive cross-sectioning

  • Cross-sections are definitive but can miss the defect if you cut the wrong location.

  • SAM helps you locate the defect first, then target cross-sections (or FIB) precisely.

Signals & Output Modes (What You Get From SAM)

Depending on your goal and sample geometry, SAM can provide:

  • C-scan (plan-view) maps: defect area at a selected depth/interface

  • B-scan (cross-sectional slice): acoustic cross-section along a line

  • A-scan (signal vs time): interface timing and reflection strength at a point

  • Optional measurements (project-dependent): defect area %, estimated depth, relative severity

Sample Types We Support

SAM works best on samples that couple well to ultrasound and have interpretable interfaces (project-dependent), including:

  • Electronics packaging (project-dependent): IC packages, modules, substrates, underfill/encapsulants

  • Adhesive bonds: bonded coupons, laminates, composite joints

  • Coatings & multilayers: stacked materials where interface integrity is critical

  • Plastics and composites: voids, impact damage, bondline issues (project-dependent)

  • Medical devices (project-dependent): bonded housings, sealed assemblies, polymer components

  • Batteries (project-dependent): layered components and adhesive interfaces (case-dependent)

Best practice: include a reference/control sample (known-good) for “what changed?” comparisons.

Typical Workflows

Screening / Incoming Inspection

Best for: fast go/no-go and lot comparison

  • Scan defined regions and interfaces

  • Flag delamination/voiding presence and relative severity

  • Provide pass/fail vs your criteria (if provided)

Failure Localization (Where is the defect?)

Best for: intermittent failures, leakage, poor adhesion, reliability drift

  • Identify defect location and approximate depth/interface

  • Mark ROI for targeted cross-section or follow-on analysis

Before/After Stress Testing (Reliability Support)

Best for: thermal cycling, reflow, humidity exposure (project-dependent)

  • Compare scans before vs after stress

  • Quantify growth of delamination/voiding area and location shift

What You Receive

  • SAM images/maps (C-scan; optionally B-scan/A-scan) with ROI labeling

  • Defect summary: location, interface depth (relative), size/area metrics (project-dependent)

  • Clear interpretation: what is likely delamination/voiding vs benign features, and recommended next steps

  • If needed: guidance for targeted cross-sectioning or complementary methods

FAQs

Generally yes—SAM is widely used as a non-destructive inspection method. The sample is coupled to a medium (often water) and scanned; special handling may be needed for moisture-sensitive samples (project-dependent).

SAM can infer depth/interface location using time-of-flight information, but precision depends on material acoustic properties and geometry (project-dependent).

SAM is excellent for finding and sizing defects, but cross-sections are often used for final confirmation and to identify the physical mechanism at the interface.

Tell us your constraints. There are approaches to minimize exposure depending on the system and project, but feasibility is sample-dependent.

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