Failure analysis

Failure analysis is the process of collecting and analyzing data to determine the cause of a failure and how to prevent it from recurring. 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.

Forensic investigation
The main principle of failure analysis is a forensic inquiry into the process or product upon the failure. Such inquiry can be conducted using scientific analytical methods such as electrical and mechanical measurements, or through speculative approach when the data is not available but an action has to be taken. A good example of a speculative approach is analysis of an aircraft crashes where the evidence has been mostly destroyed but all parties are expecting corrective action. In such cases, one or more of the most viable theories are being implemented until an additional data is available. Of course even in the speculative approach the principles of scientific analysis are being applied to the extent possible by the existing clues and pieces of information, and only the missing information is supplemented by speculative approach in order to form a working model or hypothesis.

Another interesting 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.

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

Microscopes

 * Optical microscope
 * Liquid crystal
 * Scanning acoustic microscope (SAM)
 * Scanning Acoustic Tomography (SCAT)
 * Atomic Force Microscope (AFM)
 * Stereomicroscope
 * Photo emission microscope (PEM)
 * X-ray microscope
 * Infra-red microscope
 * Scanning SQUID microscope

Sample Preparation

 * Jet-etcher
 * Plasma etcher
 * 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

Scanning 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)

Laser Signal Injection Microscopy (LSIM)

 * Photo carrier stimulation
 * Optical Beam Induced Current (OBIC)
 * Light Induced Voltage Alteration (LIVA)
 * Thermal Laser Stimulation (TLS)
 * Optical Beam Induced Resistance Change (OBIRCH)
 * Thermally Induced Voltage Alteration (TIVA)
 * External Induced Voltage Alteration (XIVA)
 * Seebeck Effect Imaging (SEI)
 * Laser Assisted Device Alteration (LADA)

Semiconductor Probing

 * Mechanical Probe Station
 * Electron Beam Prober
 * Laser Voltage Prober
 * Time-Resolved Photon Emission Prober (TRPE)

Software Based Fault Location Techniques

 * CAD Navigation
 * Automatic Test Pattern Generation (ATPG)