Failure analysis

Failure analysis is the process of collecting and analyzing data to determine the cause of a failure, often with the goal of determining corrective actions or liability. According to Bloch and Geitner, ”machinery failures reveal a reaction chain of cause and effect… usually a deficiency commonly referred to as the symptom…”. Failure analysis can save money, lives, and resources if done correctly and acted upon. 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. Nondestructive testing (NDT) methods (such as industrial computed tomography scanning) are valuable because the failed products are unaffected by analysis, so inspection sometimes starts using these methods.

Failure analysis is the process of collecting and analyzing data to determine the cause of a failure, often with the goal of determining corrective actions or liability. According to Bloch and Geitner, ”machinery failures reveal a reaction chain of cause and effect… usually a deficiency commonly referred to as the symptom…”. Failure analysis can save money, lives, and resources if done correctly and acted upon. 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. Nondestructive testing (NDT) methods (such as industrial computed tomography scanning) are valuable because the failed products are unaffected by analysis, so inspection sometimes starts using these methods.

Forensic investigation

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 analyzing 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 analyze failures before a product is marketed. Several of the techniques used in failure analysis are also used in the analysis of no fault found (NFF) which is a term used in the field of maintenance 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. A 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. Structural Engineers and Mechanical Engineers are very common for the job. More specific majors can also get into the position such as materials engineers. Specializing in metallurgy and chemistry is always useful along with properties and strengths of materials. Someone could be hired for different reasons, whether it be to further prevent or liability issues. The median salary of a failure analysis engineer, an engineer with experience in the field, is $81,647. A failure analysis engineer requires a good amount of communication and ability to work with others. Usually, the person hired has a bachelor's degree in engineering, but there are certifications that can be acquired.

Methods of analysis

The failure analysis of many different products involves the use of the following tools and techniques:

Microscopes

Optical microscope Scanning acoustic microscope (SAM) Scanning electron microscope (SEM) Atomic force microscope (AFM) Stereomicroscope Photon emission microscopy (PEM) X-ray microscope Infra-red microscope Scanning SQUID microscope USB microscope

Sample preparation

Jet-etcher Plasma etcher Metallography Back side thinning tools Mechanical back-side thinning Laser chemical back-side etching

Spectroscopic analysis

Transmission line pulse spectroscopy (TLPS) Auger electron spectroscopy Deep-level transient spectroscopy (DLTS)

Device modification

Focused ion beam etching (FIB)

Surface analysis

Dye penetrant inspection Other Surface analysis tools

Electron microscopy

Scanning electron microscope (SEM) Electron beam induced current (EBIC) in SEM Charge-induced voltage alteration (CIVA) in SEM Voltage contrast in SEM Electron backscatter diffraction (EBSD) in SEM Energy-dispersive X-ray spectroscopy (EDS) in SEM Transmission electron microscope (TEM) Computer-controlled scanning electron microscope (CCSEM)

Laser signal injection microscopy (LSIM)

Photo carrier stimulation Static Optical beam induced current (OBIC) Light-induced voltage alteration (LIVA) Dynamic Laser-assisted device alteration (LADA) Thermal laser stimulation (TLS) Static Optical-beam-induced resistance change (OBIRCH) Thermally induced voltage alteration (TIVA) External induced voltage alteration (XIVA) Seebeck effect imaging (SEI) Dynamic Soft defect localization (SDL)

Semiconductor probing

Mechanical probe station Electron beam prober Laser voltage prober Time-resolved photon emission prober (TRPE) Nanoprobing

Software-based fault location techniques

CAD Navigation Automatic test pattern generation (ATPG) [ Chip bonder]

See also

Metallurgical failure analysis Failure cause 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 Microscope 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

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