Analysis of Integrated Circuits on the Scanning Electron Microscope
The SEM plays an important role in the performance of failure analyses of Integrated Circuits. As the complexity and density of electrical functions increases on the silicon chip, the more it is nescessary to analyze the detailed characteristics of the failed device. The types of failures of interest are those that have marginal or catastrophic performance characteristics and show no obvious visual defects.Three aspects of the SEM capabilities will be discussed.Standard high power magnification operationVoltage Contrast mode of operationEmission X-ray analysis operationVarious physical characteristics of an Integrated Circuit can be viewed on the SEM. These characteristics are difficult to view on a high power optical microscope due to the depth of field limitations. These characteristics include the following.Oxide stepsMetalization profile over oxide stepsWire bond analysisEtched metalization characteristicsThe Voltage Contrast mode of operation allows direct visual observation of electrical activity on the surface of the silicon chip.