Rapid technology scaling results in ever shrinking device size. As such, sharper nanotips are required for application in nanoprobing systems. In this work, we present a two-step methodology of fabricating tungsten nanotips with radius of curvature down to 20 nm by using and optimized AC electrochemical etching of tungsten in KOH followed by laser irradiation in KOH. Finally we show the application of the fabricated nanotips with different radius of curvature (ROC) for nanoprobing.

This article presents two cases to demonstrate the application of focused ion beam (FIB) circuit edit in analysis of memory failure of silicon on insulator (SOI) devices using XTEM and EDX analyses. The first case was a single bit failure of SRAM units manufactured with 90 nm technology in SOI wafer. The second case was the whole column failure with a single bit pass for a SRAM unit. From the results, it was concluded that FIB circuit edit and electrical characterization is a good methodology for further narrowing down the defective location of memory failure, especially for SOI technology, where contact-level passive voltage contrast is not suitable.

New process will introduce new failure mechanisms during microelectronic device manufacturing. Even if the same defect, its root causes can be different for different processes. For aluminum(Al)-tungsten(W) metallization, the root cause of metal bridging is quite simple and mostly it is blocked etch or under-etch. But, for copper damascene process, the root causes of metal bridging are complicated. This paper has discussed the various root causes of metal bridging for copper damascene process, such as those related to litho-etch issue, copper CMP issue, copper corrosion issue and so on.

Bond-pad is an important structure of a microelectronic device because it plays the role of enabling the device to communicate with other external devices. Its integrity directly affects the performance of the microelectronic device. This paper presents our investigation on bond-pad Inter-Metal Dielectric (IMD) crack issue. Our investigation has considered the following factors: top via pattern (sea of vias/without vias) for bond-pad, top metal thickness (8 kÅ /9 kÅ /10 kÅ) and probe overdrive force (30 um/50 um/70 um). The bond-pad IMD cracks were exposed and decorated by chemicals (Aqua Regia and Hydrochloric acid), and inspected by an optical microscope. A scoring system was designed to assess the dependence of the bond-pad IMD crack severity on the above-mentioned factors. The investigation results showed that the IMD crack severity is strongly dependent on the probe overdrive force, top via pattern, and only slightly on top metal thickness.

Process development usually has an indispensable period of yield-learning. The length of the period is highly dependent on identification of the root causes of yield-limiting defects and thus failure analysis plays an important role in the yield improvement process. This paper presents the failure analysis of yield-limiting defects in 0.15µm process development. The failure analysis involves failure mode categorization by MOSAID tester, defective contact identification by contact-level Passive Voltage Contrast (PVC) technique and subsequent Focus Ion Beam (FIB) cross-section followed by Transmission Electron Microscopy (TEM) analysis. Finally, the root causes for the yield-limiting defects were identified.