Advanced failure analysis of memory devices

Throughout the computer era, the need for faster and denser memory devices has put constant pressure on memory manufacturers. The push to maximize memory capabilities has resulted in ever-changing technology. As a result, the failure analysis on advanced memory devices becomes increasingly challenging. In this paper, the author will first provide an overview of semiconductor memory devices based on their formation, functionality and applications. Then the main focus will be put on common failure analysis techniques and toolsets used for analyzing memory devices, particularly for Flash memory, SRAM and DRAM devices. More detailed discussion of Flash memory including its operation basics, specific failure modes and analysis results for these failures modes will be provided to demonstrate the daily usage of the tools and techniques. With current trends of making more complex memory devices in combination with other logic applications, memory devices are evolving from memory heavy to logic heavy devices. The difference in failure analysis requirements between memory and logic devices is getting smaller. Therefore, having good awareness of new developments in tools and techniques for both memory and logic devices will help the analysts stay ahead of the curve for the coming challenges in the foreseeable future.