Solder Joint Inspection
Very different means to inspect solder joints are available today. Visual inspection with optical aids (magnifying glass, microscope, video system, etc.) and the direct assessment by the person inspecting is used for sporadic and case-specific controls. Systematic and in-line controls of the assemblies are performed by automated systems. AOI (automated optical inspection) systems optically judge the general appearance of the joint, while the inner structure of joints is evaluated by X-Ray analysis. If metallurgical characteristics need to be assessed, destructive testing methods are required. The joint(s) to be inspected needs to be sectioned and polished, following which the analysis is performed by an optical light microscope or by a scanning electron microscope (SEM). With the SEM, elements themselves can also be analyzed.