X-ray inspection of solder is the non-destructive imaging method used to evaluate hidden solder joints and internal defects in assembled packages - it is indispensable for BGA, QFN, and other packages with limited optical visibility.

What Is X-ray inspection of solder?

• Definition: Uses X-ray attenuation contrast to reveal joint shape, voids, bridges, and opens.
• Coverage: Provides visibility for hidden joints under array and leadless package bodies.
• Modes: Includes 2D X-ray and computed tomography for higher-detail analysis.
• Limitations: Image interpretation can be sensitive to overlap, resolution, and setup parameters.

Why X-ray inspection of solder Matters

• Hidden-Joint Control: Essential for defect detection where AOI cannot see solder interfaces.
• Reliability Link: Void and joint-geometry analysis helps predict thermal and mechanical risk.
• Process Optimization: X-ray trends directly inform paste and reflow tuning.
• Failure Analysis: Supports rapid diagnosis of field-return and production-yield anomalies.
• Cost Efficiency: Early detection reduces expensive downstream debug and rework.

How It Is Used in Practice

• Program Setup: Define package-specific algorithms and threshold criteria for automated analysis.
• Sampling Strategy: Balance inline throughput with risk-based sampling for critical packages.
• Correlation: Validate X-ray findings against cross-section and electrical test outcomes.

X-ray inspection of solder is a primary inspection technology for hidden-solder-joint quality assurance - x-ray inspection of solder should be integrated with process feedback loops to maximize yield and reliability impact.