Semiconductor Atomic Force Microscopy (AFM)

Wafer metrology is a vital component of successful Pathfinding and Yield Ramp for the modern Semiconductor Fab. Critical dimensions of <5nm are now becoming common place on bleeding edge technologies, and Semiconductor companies need high repeatability and reproducibility of measurements to ensure proper feedback in the yield learning process flow. The Jupiter XR and Cypher S AFMs from Oxford Instruments Asylum Research offer NIST traceable, closed loop dimension measurements in X,Y, and Z. Patented ultra-low noise LVDT sensors (both Jupiter XR and Cypher S offer <1.5 Angstrom noise in X and Y) provide accurate and repeatable measurements of the smallest critical dimensions.

Ultra flat epitaxial layers are common in semiconductor fabrication. Both Cypher S and Jupiter XR offer <0.35 Angstrom resolution in Z for accurate, repeatable measurements on the flattest epitaxial layers. Read our White Paper "Measuring Surface Roughness with the Asylum Research Jupiter XR Atomic Force Microscope" for more information.

Automated inspection of epitaxial silicon grain structure
Non-uniform grain size can often be observed in epitaxial silicon layers, especially near the wafer edge where there can be greater variations in processing conditions. Here, an automated routine was used to inspect a series of points at different offsets from the wafer edge. The Jupiter software offers flexibility in defining these locations at any point on the 210 mm sample chuck. Roughness (Rq) of each image is only 80-85 pm.

Roughness measurements of a disk media substrate taken 1000 times over 15 hours on Jupiter XR. The Rq roughness remains stable within 1% demonstrating the extreme repeatabiity of Jupiter XR made possible by Asylum's exclusive blueDrive Tapping Mode.

Failure Analysis and Yield Learning

Failure Analysis (FA) and defect characterization in the semiconductor industry has evolved. No longer is it enough to simply analyze returned product. FA processes are being developed to proactively analyze device failure over their lifetime. Additionally, defects and failures that occur in various stages of the production process need to be addressed and looped back into the yield learning flow faster than ever before. An ultra-high resolution, repeatable AFM provides the most detailed and reliable look possible at your devices. AFM provides feedback for both electrical failure analysis and physical failure analysis, as well as tribological, mechanical, and interfacial analysis of devices. We'll look at some FA techniques for semiconductors that involve AFM below.

Nanoprobing, is a method by which nanosharp tungsten probes measure the electrical characteristics and localize defects of integrated circuits. This type of measurement-- typically performed with an AFM nanoprober or SEM nanoprober -- helps semiconductor researchers and engineers test integrated circuits (IC) and other materials during the Yield Ramp and Failure Analysis process. Many of the techniques traditionally performed on a dedicated nanoprobing system can be automated and more cost effectively run on a high speed, ultra-high resolution AFM such as the Jupiter XR or Cypher S. We'll take a look at a couple of the dedicated AFM techniques below:

Watch Webinar: "Making and Analysing Semiconductor Devices"

Learn more about the Jupiter XR large-sample AFM

Watch Webinar: "More Than Just Roughness: AFM Technique for Thin Film Analysis"