Semiconductor Failure Analysis Techniques
Semiconductor failure analysis occupies a prominent position among high tech fabricators. Even the most sophisticated ICs fail, and when they do, it’s critical that engineers and fabricators discover the root causes of the failure, so as to avoid the same issues in subsequent designs. Semiconductor analysis can therefore enhance semiconductor reliability by addressing observed shortcomings in design and fabrication and then avoiding them in the future.
Semiconductor failure analysis initially involves pinpointing the nature of the failure. Semiconductor failures can be broadly grouped into two categories: functional failures and parametric failures. A functional failure means the device failed in its intended function, while parametric failures mean the device’s function lies outside the specifications for a measurable characteristic.
Parametric failures have nothing to do with the intended functionality of the device. The initial phase of semiconductor failure analysis then calls for failure verification in which the failure is identified and categorized.
The next phase of testing seeks to localize the exact origin and causes of the failure. To achieve that goal, semiconductor failure analysis will subject the device to various forms of testing, some non-destructive, and others destructive. Obviously, one must exercise caution in moving on to the destructive semiconductor failure analysis techniques, as they will render any other forms of testing impracticable. Some of the non-destructive semiconductor failure analysis techniques include: optical microscopy, X-ray radiography, curve tracing and hermeticity testing. Destructive techniques include: decapsulation, sectioning, microprobing, SIMS, LIMS and chromatography.
Together, these techniques will enable analysts to pinpoint the location and nature of the semiconductor failure. However, care must be taken to compare the results of various semiconductor failure analysis techniques to eliminate faulty conclusions based on conflicting results. Reliable semiconductor failure analysis requires careful examination by skillful engineers, and not just the latest equipment.