In a previous study, the authors introduced a novel technique of using low-beam energy Gallium Focused Ion Beam to expose a large area of Shallow Trench Isolation (STI) over a Dynamic Ring Oscillator (DRO) incurring virtually no change of its operating frequency. In this paper, the authors further investigate the influence of extended dose delivery of 5 kV Ga+ after the initial exposure of the STI over a DRO on modern 7 nm process. The motivation of this study is to understand the dynamics between the Ga+ ion interaction at lower beam energies on live and functional devices and the failure mechanism of the device from such interaction. The frequency of the DROs after the initial STI exposure at 5 kV exhibits <1% increase. Additional dosage of lowkV exposure was performed over the exposed STI and its effects on the DRO frequency was monitored. Finally TEM analysis of the irradiated DROs will be analyzed to understand the failure mechanism of transistors.

The result of applying normal xenon ion beam milling combined with patented DX chemistry to delayer state-of-theart commercial-grade 14nm finFETs has been demonstrated in a Helios Plasma FIB DualBeam™. AFM, Conductive-AFM and nano-probing with the Hyperion Atomic Force nanoProber™ were used to confirm the capability of the Helios PFIB DualBeam to delayer samples from metal-6 down to metal-0/local interconnect layer and in under two hours produce a sample that is compatible with the fault isolation, redetection, and characterization capabilities of the AFP. IV (current-voltage) curves were obtained from representative metal-0 contacts exposed by the PFIB+DX delayering process and no degradation to device parameters was uncovered in the experiments that were run. Compared to mechanically delayering samples, the many benefits of using the PFIB+DX process to delayer samples for nano-probing were conclusively demonstrated. Such benefits, include sitespecificity, precise control over the amount of material removed, >100μm square DUT (device under test) area, nm-scale flatness over the DUT area, nm-scale topography between contacts and the surrounding ILD, uniform conductivity across the DUT area, all with no obvious detrimental effects on typical DC device parameters measured by nano-probing.

Good control over beam and chemistry conditions are required to enable uniform delayering of advanced process technologies in the FIB. The introduction of newer, thinner and more beam sensitive materials have made delayering more complicated. We shall introduce a new chemistry for device delayering and present results from both Ga and Xe ion beams showing its improvement over existing chemistries.