Optimizing Reflow Profiles to Control Initial Intermetallic Compound Thickness
Optimizing reflow profiles keeps initial intermetallic compound thickness between 1.5 and 2.5 micrometers, preventing brittle joint fracture.
Micro-Section Analysis
Meaning
Destructive testing technique provides a high-resolution view of the internal structure of electronic assemblies. A micro-section analysis involves embedding a sample in resin before cutting and polishing the surface for examination under a microscope. It provides a two-dimensional view of hidden features such as solder joint wetting and internal cracks.
This method is the definitive way to verify compliance with IPC standards for printed circuit boards.
Structural Inspection
Physical cross-sectioning reveals flaws that x-ray or visual checks cannot detect. Detailed micro-section analysis allows practitioners to measure the thickness of individual plating layers with sub-micron precision. This data is used to identify the root cause of failures during environmental stress testing.
Quality Assurance
Laboratory verification proves that the manufacturing process is under control. Performing a micro-section analysis is a mandatory step in the first article inspection process for high-reliability hardware. It documents the presence of intermetallic layers and the absence of voids in the internal copper traces.
Precise measurement of the knee area in a plated through-hole confirms the integrity of the vertical interconnects.
Failure Diagnosis
Forensic investigation provides the evidence needed to settle disputes with suppliers. The results of a micro-section analysis show whether a defect was caused by poor material quality or incorrect assembly parameters.