Surface Masking
Material application on an integrated circuit package covers physical evidence of mechanical sanding during component remarking. Component refurbishers apply a thin layer of epoxy or polymer resin over the top surface of an encapsulated device to hide original part numbers. This process of blacktopping creates a uniform surface texture that conceals original markings and ghost images.
Verification relies on solvent testing using acetone or mineral spirits to dissolve the non-factory coating. The material boundary stops at the plastic package resin, as legitimate ceramic or metal packages do not receive polymer coatings during secondary operations.
Detection Procedure
Chemical swabbing with a mixture of acetone and alcohol strips the secondary polymer coating to expose underlying grind marks. Visual inspection under high magnification reveals differences in surface texture between the factory molding compound and the secondary resin layer. When secondary coatings are present, blacktopping alters the thermal expansion characteristics of the package surface, which can cause cracking during reflow soldering.
Acetone wipe testing following IDEA-STD-1010 standards provides immediate confirmation of surface manipulation. Solvent exposure dissolves non-cured epoxy coatings within two minutes.
Acceptance Limit
Visual standard AS6081 mandates zero tolerance for non-factory surface coatings on military and commercial active components. Incoming inspection lots showing evidence of blacktopping face immediate quarantine and full batch rejection. Receiving inspection personnel document package dimensions and surface consistency against original manufacturer datasheets.
Authenticated components display factory-molded indentations without resin pooling. Package integrity dictates long-term reliability in high-reliability assembly applications.
