In the blink of an eye, modern electronics systems can sample sensors, perform countless computations, and drive dazzling displays. The sheer amount of data a single system can generate and process is staggering. All this microcomputing muscle would be for naught, however, without a way to store data. Memory is one of the core components of almost any system, from a simple RFID tag to the most powerful processing behemoth. While electronic memories can certainly store and accurately recall more detail than the notoriously malleable human mind, they are by no means immune to failure. Since many modern memories have upwards of 4 billion “bits” of potential data that may be malfunctioning, it is often necessary to enlist outside help in the form of failure analysis services to get to the root of a case of silicon paramnesia.
One of the first steps in providing failure analysis services for a client with a defective memory device is to ascertain exactly how the device is failing. An inability to read any data from the device may steer an analyst in a completely different direction than a device which reads out garbled data; therefore, this step is vital in setting the pace of the analysis. This initial evaluation is often performed with a dedicated memory tester that can read, write, and compare large sets of data; by using these tools, an analyst can generate a test program that will identify how much of the memory device is affected by the failure, and in many cases even generate a list of improperly functioning memory addresses. By working closely with the manufacturer, an analyst can take these addresses and translate them into physical locations on the device – thereby identifying potential sites for further analysis.
In other cases, a client may call upon the help of external failure analysis services for the retrieval of vital data. As an example of how a FA team can be useful in these situations, consider the hypothetical case of an embedded system that was designed and put into service in the field over ten years ago. The system reaches the end of its useful lifespan, and the end user needs a replacement; unfortunately, the program code for the embedded device has long since been lost to the annals of time, and the engineers associated with the initial design have scattered to the winds. Thanks in large part to their experience of experimenting on devices with the intent of modulating a failure condition, an FA team can take the failing system and subject it to a wide variety of different test conditions, until the right combination of stresses restore some limited degree of functionality to the device and allow the memory to be dumped for analysis by the customer.
While memory testing is certainly not one of the first things that spring to mind when one considers failure analysis services, in cases where a detail-oriented approach is necessary, the experience of a FA team is often invaluable when compared with the results obtained from more production-focused testing. From that perspective, the ability to test memories is not a failure analyst’s focus, but rather another one of the myriad tools in a well-rounded FA engineer’s toolbox.
Derek Snider is a failure analyst at Insight Analytical Labs, where he has worked since 2004. He is currently an undergraduate student at the University of Colorado, Colorado Springs, where he is pursuing a Bachelors of Science degree in Electrical Engineering.