Particle-Impact Noise Detection

For hermetically sealed microcircuits several screen tests should be performed before delidding the package. A particle impact noise detection test (FIND [MIL-STD-883 Method 2020 or MEL STD-750D, Method 2052-2]) is recommended. This shake test combines a series of shocks and vibrations and, through an attached transponder, acoustically detects any loose particles (for example, chips of cured adhesive, solder, wire, ceramic, or loose plating) that have detached and can cause shorted or open circuits and damage or breakage of thin wires and connections. 

Particle Impact Noise Detection Test, MIL-STD-883, Method 2020.7. 

Particle impact noise detection (PIND) tests, where each hybrid part or IC with a cavity where the die was unglassivated (insulated with a glass coating. Fig. 7.160 shows an IC with cracks in this coating), was vibrated and transducers, mounted on the part would detect if there were any particles rattling around. Parts with loose pieces in them were rejected from the shipment. 

Particle impact noise detection testing (PIND) A test where cavity devices are vibrated and monitored for the presence of loose particles inside the device package via the noise the material makes. These loose particles may be conductive (such as gold flake particles from gold eutectic die attachment operations) and could result in short circuits. This is not required on a 100% basis for military class B devices. It is required for aU class S, or devices generally required for spacecraft application use. 

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