Microelectronics Failure Analysis - How we do it
The electronic systems we study in academia consist of basic components such as transistors, resistors, capacitors etc. These same components are also used in the complicated Integrated Circuits (ICs) which make up the internals of the computer on which you're reading this article. The difference lies in the fact that they're small - very small. So tiny in fact, that the term microelectronics is applied to them. The procedure for finding out how they malfunction is called microelectronics failure analysis.
Finding out where a malfunction has occurred is difficult enough when examining a normal circuit. But when analyzing a microchip, the complexity magnifies a thousand fold. Failure analysis of such systems requires a precise understanding of the chip along with an intimate knowledge of the manufacturing process and experience in the field.
Microelectronics Failure Analysis Procedures
Those experienced in the field are familiar with what sort of things can go wrong with a chip when certain conditions are applied. Therefore, the first step is to clarify the circumstances surrounding the error along with examining the manufacturing and transfer process. The field of "Forensic Engineering" gives us the tools to we need to narrow down the possibilities. For example, we have the "Failure mode and Effects" (FMEA) analysis as well as the "Fault Tree Analysis" (FTA) which structure the way we go about the examination.
Once we have a good idea of what the problem can be, we apply one of several techniques depending on the flaw we think is present. For example, if we determine that the problem is likely to be caused by impurities in the material, we can apply a number of emission spectroscopy tests. Auger electron spectroscopy and Deep level transient spectroscopy can detect minute impurities with great precision.
On the other hand, when we guess the problem is a malfunctioning circuit, we can use micro thermal imaging techniques such as liquid crystal imaging and floroscent microthermal imaging to isolate heat points which indicate the place where the error is occurring.
Of course, if we want to get a close look at the chip, we have electron microscopy. These days we can can even glimpse inside 3D structures using x ray imaging with a very high resolution. Generally we prefer such non invasive tests which keep the chip intact. Find out more about the various techniques in detail and how we use them to analyze complicated defects.