Failure analysis is the process of collecting and analyzing data to determine the cause of a failure. It is an important discipline in many branches of manufacturing industry, such as the electronics industry, where it is a vital tool used in the development of new products and for the improvement of existing products. The failure analysis process relies on collecting failed components for subsequent examination of the cause or causes of failure using a wide array of methods, especially microscopy and spectroscopy. The NDT or nondestructive testing methods (such as Industrial computed tomography scanning) are valuable because the failed products are unaffected by analysis, so inspection always starts using these methods.
- 1 Forensic investigation
- 2 Failure analysis engineers
- 3 Methods of analysis
- 4 See also
- 5 References
- 6 Further reading
- 7 External links
Forensic inquiry into the failed process or product is the starting point of failure analysis. Such inquiry is conducted using scientific analytical methods such as electrical and mechanical measurements, or by analysing failure data such as product reject reports or examples of previous failures of the same kind. The methods of forensic engineering are especially valuable in tracing product defects and flaws. They may include fatigue cracks, brittle cracks produced by stress corrosion cracking or environmental stress cracking for example. Witness statements can be valuable for reconstructing the likely sequence of events and hence the chain of cause and effect. Human factors can also be assessed when the cause of the failure is determined. There are several useful methods to prevent product failures occurring in the first place, including failure mode and effects analysis (FMEA) and fault tree analysis (FTA), methods which can be used during prototyping to analyse failures before a product is marketed.
Failure theories can only be constructed on such data, but when corrective action is needed quickly, the precautionary principle demands that measures be put in place. In aircraft accidents for example, all planes of the type involved can be grounded immediately pending the outcome of the inquiry.
Another aspect of failure analysis is associated with No Fault Found (NFF) which is a term used in the field of failure analysis to describe a situation where an originally reported mode of failure can't be duplicated by the evaluating technician and therefore the potential defect can't be fixed.
NFF can be attributed to oxidation, defective connections of electrical components, temporary shorts or opens in the circuits, software bugs, temporary environmental factors, but also to the operator error. Large number of devices that are reported as NFF during the first troubleshooting session often return to the failure analysis lab with the same NFF symptoms or a permanent mode of failure.
The term failure analysis also applies to other fields such as business management and military strategy.
Failure analysis engineers
A failure analysis engineer often plays a lead role in the analysis of failures, whether a component or product fails in service or if failure occurs in manufacturing or during production processing. In any case, one must determine the cause of failure to prevent future occurrence, and/or to improve the performance of the device, component or structure.
Methods of analysis
The failure analysis of many different products involves the use of the following tools and techniques:
- Optical microscope
- Scanning acoustic microscope (SAM)
- Scanning acoustic tomography (SCAT)
- Atomic force microscope (AFM)
- Photoemission electron microscope (PEM)
- X-ray microscope
- Infra-red microscope
- Scanning SQUID microscope
- USB microscope
- Plasma etcher
- Back side thinning tools
- Mechanical back-side thinning
- Laser chemical back-side etching
- Transmission line pulse spectroscopy (TLPS)
- Auger electron spectroscopy
- Deep-level transient spectroscopy (DLTS)
- Focused ion beam etching (FIB)
Scanning electron microscopy
- Scanning electron microscope (SEM)
- Transmission electron microscope (TEM)
- Computer-controlled scanning electron microscope (CCSEM)
Laser signal injection microscopy (LSIM)
- Photo carrier stimulation
- Thermal laser stimulation (TLS)
- Mechanical probe station
- Electron beam prober
- Laser voltage prober
- Time-resolved photon emission prober (TRPE)
Software-based fault location techniques
- Metallurgical failure analysis
- Acronyms in microscopy
- List of materials analysis methods
- List of materials-testing resources
- Failure mode and effects analysis (FMEA)
- Failure rate
- Forensic electrical engineering
- Forensic engineering
- Forensic materials engineering
- Forensic polymer engineering
- Forensic science
- Material science
- Sample preparation equipment
- Accident analysis
- Characterization (materials science)
- Failure reporting, analysis and corrective action systems (failure data collection)
- Article on the subject at IEEE archive
- Finite Element Implementation of Advanced Failure Criteria for Composites
- Martin, Perry L., Electronic Failure Analysis Handbook, McGraw-Hill Professional; 1st edition (February 28, 1999) ISBN 978-0-07-041044-2.
- Microelectronics Failure Analysis, ASM International; Fifth Edition (2004) ISBN 978-0-87170-804-5