Imaging tomography by transmission electron microscopy (TEM) is a technique which has been growing in popularity in recent years, yet it has not been widely applied to semiconductor defect studies and root cause determination [1- 3]. In part this is due to the complex equipment, computing needs, and microscope time required to generate the various images which ultimately compose the data set. However, the latest generation of TEMs—with their high level of stability and automation—are greatly reducing the resource needs to create high quality and informative movies of defects rotating about a central axis. One significant advance is the reduction in time required to fabricate a sample and perform the data acquisition by TEM. Today’s microscopes allow for sample fabrication to take place in a few hours or less and can acquire more than 100 images in about an hour at different sample tilt conditions with minimal analyst intervention. This paper describes using automated TEM sample preparation with dual beam focused ion beams (previously reported [4]) in conjunction with automated tomography software on a state-of-the-art TEM. By using an advanced tomography holder ±70° of tilt can be obtained. This is a powerful way to view defects as the failure can be viewed through more than 90° of rotation. Consequently a more complete understanding of the failure site can be obtained over a typical single projection TEM image. This can greatly facilitate root cause determination in a timely manner.

Energy-dispersive X-ray spectrometry (EDS) is a key analytical tool aiding root cause determination in the failure analysis (FA) process. This paper looks at a number of analytical TEM microscopes currently in use in various facilities: microscope A, a STEM operated at 200kV; microscope B, a 300kV TEM; and microscopes C and D, both 200kV TEMs. EDS counts per unit time from multiple microscope platforms were examined. Microscope D demonstrated two orders of magnitude higher counts per unit time than the other three microscopes. Microscope D represents the state-of-the-art EDS analytical TEM configuration and has achieved this through a novel windowless EDS configuration which significantly increases the detector area (by about a factor of three) that receives X-rays generated from the sample.