Counterfeit Part Investigation

The purpose of Counterfeit Part Investigation is to ensure that parts going into critical applications are of a known or traceable pedigree which have not been subjected to prior use. Counterfeit are parts that have been purposely altered to give a false indication of the parts function or pedigree. The steps of this plan are necessary to ensure complete verification of the parts from an unknown lot or if parts are bought outside of the manufacturers approved network of distributors.

Traceable Paperwork When at all possible, parts should have traceability back to the manufacturer. This insurance is the ultimate proof of pedigree. This being said, this paperwork can easily be modified and in most cases is not available through parts brokers who may supply the parts. In the absence of this paperwork it is the responsibility of the user to ensure that parts are genuine.
Electrical Test When electrical test is properly performed, parts can be screened to ensure functionality is within specifications over temperature. While this test does provide information about the functionality of the part it does not provide proof of pedigree. This may pose some issues if one part out of the suspect lot is from an original lot known to have issues. In addition, it may not identify parts that have been previously used or have dormant failures that would shorten the useful lifespan of the part.
External Visual Inspection External visual inspection is a non-destructive method used to identify evidence which indicates purposeful alterations of the parts. This investigation looks at every aspect of the external package and leads to ensure no evidence of remarking or prior use exist. While this step is considered non-destructive, some parts markings will be tested utilizing solvents appropriate to test the permanency and quality of the part markings. In addition solvent may be used to verify if blacktopping has occurred as a precursor for remarking parts. The following steps are utilized during this step to ensure full investigation of the parts in question.
1. Photo documentation of parts as received.
2. External Visual Inspection of all aspects of the part at a magnification of 10X minimum.
  1. Looking for Blacktopping
  2. Looking for scaring on the leads indicating prior use
  3. Looking for any damage to the package that would indicate prior use
  4. Looking for ACID etch of the surface of the part
  5. Looking for any evidence of sanding of the surfaces of the part
  6. Utilizing solvents to ensure marking permanency
    1. Acetone Swab
    2. MIL-STD-883 Method 2015 Resistance to Solvents
    3. Heated 1-Methyl 2-Pyrrolidinone (180C for 2-5 minutes)
3. Configuration measurements of parts based on manufacturer package outline.
Configuration Configuration measurement ensure the package conforms to the manufacturers package drawing requirements. This ensures package dimensions are within tolerance. Packages that are outside of the tolerances are suspect as modified parts.
X-Radiography X-Radiography can be used effectively to ensure parts are consistent and represent normal construction characteristics for the part being analyzed. When utilizing X-Radiography it is useful to have a known good sample. ASI does maintain a large database of parts being analyzed, no guarantee can be made that a known good part is on record. To ensure parts are valid, customers are asked to provide a known good part when available.
Acoustic Microscopy Acoustic Microscopy has been a valuable tool for identifying molding compound to lead frame or die on plastic parts is intact. This bonding interface is damaged slightly when parts are reflowed onto boards but become extensive when parts have been removed from boards for re-use. Many parts that have been removed from boards exhibit extreme de-lamination around the die and bond wire regions of the lead frame and may include de-lamination of the interface between the molding compound and the active surface of the die. This is a strong indication of prior use and parts should be considered counterfeit if this damage is present.
De-Encapsulation and Die Verification While this step has been used as a stand-alone verification of the validity of the part, it only gives one piece of information. To completely analyze the parts the previously mentioned tests should be performed. De-Encapsulation and Die verification is performed to verify the die in the parts being analyzed are valid for the part type in question. Die photos and die markings photos are utilized to make a judgment call about the validity of the parts. When a known good part is available, the die and die markings will be compared to ensure the correct die is being utilized in the part. Some challenge(s) still exist as mask sets change over time creating instances where the die do not match identically with known good parts from a different pedigree. While ASI does have a large database of information from previously analyzed parts, it is always good to have a known good part from the same generation to compare.
Conclusion While all of the steps mentioned above constitute a full analysis of the parts, the cost of such an analysis may preclude customers from having the ability to have the full workup performed. Traceability paperwork is normally the issue to begin with so customers need to find another means of determining part pedigree. Electrical test is invaluable but the NRE cost alone coupled with the amount of time it takes to develop test programs and design test fixtures prohibit many users from utilizing this step. It is ASI's opinion that the best means for analyzing parts to ensure pedigree and functionality is to follow all steps but in light of these cost and time constraints, at a minimum, ASI recommends performing External Visual Inspection, Configuration, X-Radiograph, Acoustic Microscopy and De-encapsulation and die verification on all Plastic encapsulated devices that are obtained through sources outside of the manufacturer's approved distribution network.