In-depth electrical analysis to reveal the failure mechanisms with nanoprobing

This paper highlights the use of a localized probing technique, nanoprobing, to reveal some of the subtle defects affecting the yield of integrated circuits in the nanometer generation nodes. The tool is equipped with the capability to isolate and characterize the exact failing transistors of the malfunctioned devices. As a result, the identification process of the failure mechanisms, and hence the root cause, can be accelerated. The electrical characterization at the transistor level also offers an appropriate guide to the required physical analysis that has to be carried out in order to "visualize" the defects. Based on the in-depth diagnosis of the defective site, the three case studies covered in this paper demonstrate the importance of this advanced failure-analysis methodology. For the analysis, static random-access-memory test-chips were used. With that, marginal failures or degradations relating to the ultrathin gate oxides, variations in the resistance of the implanted layers in the substrate, and abnormal passive-voltage-contrast signature were determined.