High-Throughput, Site-Specific Sample Prep of Ultra-Thin TEM Lamella for Process Metrology and Failure Analysis

摘要

Semiconductor devices with critical dimensions less than 20nm are now being manufactured in volume. A challenge facing the failure analysis and process-monitoring community is two-fold. The first challenge of TEM sample prep of such small devices is that the basic need to end-point on a feature-of-interest pushes the imaging limit of the instrument being used to prepare the lamella. The second challenge posed by advanced devices is to prepare an artifact-free lamella from non-planar devices such as finFETs as well as from structures incorporating 'non-traditional' materials. These challenges are presently overcome in many advanced logic and memory devices in the focused ion beam-based TEM sample preparation processes by inverting the specimen prior to thinning to electron transparency. This paper reports a high-throughput method for the routine preparation of artifact-free TEM lamella of 20nm thickness, or less.