edfas.org 23 ELECTRONIC DEVICE FAILURE ANALYSIS | VOLUME 27 NO. 1 This leads to reduced debugging time, improved reliability, and more effective root-cause analysis, particularly in complex circuits. The next step for the QDM’s application in EFA is to assess its ability to map current paths within more advanced multi-layered chips, particularly those involved in heterogeneous integration. By further enhancing depth sensitivity and improving spatial resolution, QDM technology is poised to become an indispensable tool in the analysis of complex semiconductor devices, providing critical insight into both lateral and vertical current flows. CONCLUSION AND OUTLOOK This article introduced quantum sensing with diamond through the QDM as an innovative, nondestructive EFA tool. Detailed operation from an FA engineer’s perspective shows how it integrates into standard workflows. Measurements on two integrated circuits demonstrated a lateral spatial resolution of 3.0 ± 0.5 µm, illustrating the type of data a QDM provides. Its performance was compared to established FA methods, highlighting its specific advantages. Although the QDM is still in its early development stages, akin to the adoption of lock-in thermography in the 2000s, initial results reveal strong application potential. There are several ways to improve the QDM; for example, transitioning to AC imaging could leverage NV sensors’ established sensitivities in the nT to pT (Hz)-0.5 range at MHz and GHz frequencies,[19] potentially accelerating measurements by several orders of magnitude and enabling assessments of ICs at their native clock frequencies. In conclusion, the QDM shows considerable promise as an FA tool, particularly as the field advances toward heterogeneous integration and wide band-gap materials. Future work will focus on over-the-package analysis with a QDM, aiming to establish its depth-sensing capabilities. ACKNOWLEDGMENTS The authors would like to thank the PHEMOS team of Hamamatsu Photonics for fruitful discussions and providing the copper wire sample shown in Fig. 2. They would also like to thank Prof. Dominik Bucher and Robin Allert for discussions on this subject. REFERENCES 1. IEEE International Roadmap for Devices and Systems, Metrology, Institute of Electrical and Electronics Engineers, 2023. Fig. 5 Magnetic field maps of CD4011B activity acquired using the QDM. A current of 8 mA was applied to power the chip. (a) The Bx component arises from currents flowing along the y-axis, where positive values indicate upward currents, and negative values represent downward currents. (b) The By component corresponds to currents along the x-axis, with positive values indicating right-to-left currents, and negative values indicating left-to-right currents. (c) The Bz component represents the out-of-plane magnetic field, encompassing contributions from currents along both the x- and y-axes. Fig. 6 Overlay of the current density for various input combinations of the controllable NAND gates with the IR image of the IC. (a) Current reconstructed from magnetic field measurements, with all input gates set to a low state. (b) Current reconstructed from magnetic field measurements, where both input gates, Pins 8 and 9 of the lower-right NAND gate were in a high state, resulting in an absence of current in the highlighted (dotted) area. (a) (b) (c) (a) (b)
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