Optoelectronic imaging of integrated-circuits has revolutionized device design debug, failure analysis and electrical fault isolation; however modern probing techniques like laser-assisted device alteration (LADA) have failed to keep pace with the semiconductor industry's aggressive device scaling, meaning that previously satisfactory techniques no longer exhibit a sufficient ability to localize electrical faults, instead casting suspicion upon dozens of potential root-cause transistors. Here, we introduce a new high-resolution probing technique, two-photon laser-assisted device alteration (2pLADA), which exploits two-photon absorption (TPA) to provide precise three-dimensional localization of the photo-carriers injected by the TPA process, enabling us to implicate individual transistors separated by 100 nm. Furthermore, we illustrate the technique's capability to reveal speed-limiting transistor switching evolution with an unprecedented timing resolution approaching <10 ps. Together, the exceptional spatial and temporal resolutions demonstrated here now make it possible to extend optical fault localization to sub-14 nm technology nodes.
Time-resolved photon emission has been shown to be useful in analyzing clock skews and timing-related defects in flip-chip devices. In practice, time-resolved photon emission using the S-25 Quantar detector cannot be used at long loop lengths (typically >10 μs). This paper discusses a near-infrared (NIR) optimized time-resolved emission system to demonstrate that even with long loop lengths time-resolved photon emission can be extremely useful for defect localization. Specifically, it describes time-resolved photon emission system, and shows how time-resolved photon emission was used to solve two different issues that caused scan fails on silicon-on-insulator devices, and briefly discusses the interpretation of optical waveforms. The two issues are presented as case studies.
We describe a technique that is used to obtain timing information from laser assisted device alteration (LADA). The technique uses a non-pulsed laser scanning microscope to obtain timing information with a temporal resolution on the order of microseconds. Custom software is used to extract the timing information from the LADA images.
The rapidly developing semiconductor industry demands constant innovations in optoelectronic imaging of semiconductor integrated circuits to keep up with continuing device scaling. It was recently shown that two-photon laser-assisted device alteration (2pLADA) can deliver precision fault isolation. Here we describe an investigation into the influence of the incident light polarization on the 2pLADA spatial resolution. Linear polarization provides a highly confined but elliptical focal spot, while circular polarization diminishes the lateral resolution but benefits from a symmetrical focal spot. Radially polarized light potentially provides the highest lateral imaging resolution in all directions at the expense of the longitudinal resolution. By comparing 2pLADA results obtained using linear, circular and radial polarizations we show that certain polarizations have advantages in particular applications. Therefore a polarization optimized 2pLADA tool can achieve a sufficiently high performance to isolate faults of transistors separated by as little as 100 nm and maybe smaller.
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