Failure analysis process

MtronPTI’s FA process discovers electrical and physical evidence to clearly identify the cause of failure through straightforward but sophisticated analytical measurement systems, bench top equipment, and a range of other techniques. Using appropriate equipment and work processes, the location of the failure cause is determined, isolated, and physically characterized. The FA team then collaborates with other engineering disciplines (product, test, design, assembly and process) to move analysis forward. Progress, results and conclusions are communicated to internal and external contacts supporting the processes, to implement changes that limit and/or eliminate the cause of failure.

Information review, failure confirmation

Customer reported failure documentation is crucial for efficient FA, and must go through the  MtronPTI customer return process, which helps provide a clear and detailed description of device history, usage, characteristics of the failure, and any analytical findings prior to returning the device. This information will help the investigation and ensure resolution in a more timely matter.

The minimum set of background information that a customer should include when reporting a failure includes:

• 1). Component handling prior or receipt at MtronPTI. Precautions should be taken when removing and handling components to ensure that electrical or physical damage does not occur package testability is maintained.
• 2). Failure history and failure rate at the customer site. Is this a new product or have any changes occurred in this time frame?
• 3). Application conditions under which the failure occurred. Can a customer schematic be sent to MtronPTI?
• 4). The application’s failure mode and how it relates to the returned component.

The FA team reviews MtronPTI’s historical databases to provide additional perspective and guidance. After a review of all information, an initial analysis strategy is formed. Confirmation of the reported failure mode should occur prior to further analysis steps. Good correlation to reported failure modes insures confidence in any subsequent findings. Bench test equipment, such as network analyzers or application-based bench testing, and production-level automatic test equipment (‘ATE’) may be used for electrical characterization.

Non-destructive testing

FA in itself is reverse engineering and can be destructive to the returned product. Since the package will be at least partially destroyed to expose the contents, non–destructive techniques are carried out first to observe package or assembly-related failure mechanisms. The most common techniques MtronPTI uses are PIND (Particle Impact Noise Detection) and radiographic (XRAY) inspections to look for internal assembly anomalies.

Internal Inspection

MtronPTI carries out an internal optical inspection to check for any obvious assembly anomalies. Re–testing is also recommended to determine if the failure mode has changed.

Isolation

In many cases, MtronPTI’s internal inspection will not reveal an obvious failure mechanism. Depending on the technology and level of testability, the FA lab will utilize one or more techniques to isolate the failure site.

Analysis of failure site

Once a potential site has been determined or revealed, documentation and analysis is conducted. Further analytical techniques are employed depending on whether the morphology or material composition is required.

Report conclusion

Once analysis is complete, work is documented in a written report stating the relationship of the physical anomaly to the failure mode, and including sufficient documentation for root cause analysis.