Defect localization has become more complicated in the FinFET era. As with planar devices, it is still generally possible to electrically isolate a failure down to a single transistor. However, the complexity of certain FinFET devices can lead to ambiguity as to the exact physical location of the defect. The default technique for isolating the defect location for this type of device is to start with a plan view S/TEM lamellae. Once the defect is located in plan view, the lamellae can be converted to cross-section (if necessary) for further characterization. However, if the defect is not detectable in plan view S/TEM analysis, an alternative approach is to examine the device in cross-section along either the x- or y- axis. Once the defect is located in the initial cross-sectional lamellae, it can be converted to the orthogonal axis if the initial cross-sectional lamellae did not provide adequate information for characterization. However, in converting a cross-sectional lamellae to the orthogonal axis, the initial lamellae must be exceedingly thin due to the dimensions of devices on 1x nm FinFET technologies, else other structures on the sample can obscure the view in the S/TEM. This can lead to structural integrity (warping) issues for the converted lamellae. In this paper, a novel solution to the warping issue is presented.

A key capability of focused ion beam (FIB) tools is the ability to deposit conductive materials by introducing organometallic precursors such as tungsten hexacarbonyl [W(CO)6] or (methylcyclopentadienl) trimethyl platinum [C9H17Pt]. The FIB deposited metal is often used in applications such as the modification of integrated circuits (ICs) by creating new electrical connection on the device. The electrical properties of the FIB material are of particular concern to high speed digital and radio frequency (RF) circuit designers because the resistivity of the FIB deposited metal is orders of magnitude higher in value than the near bulk resistivity value of the metals used in IC manufacturing. In this paper, we developed a correlation between the chemical composition of the FIB deposited metal and the electrical resistivity using an effective media theory (EMT) model. Analysis shows that gallium from the ion beam is the dominant contributor to lowering the resistivity of the jumper. The results of this work and model allow us to understand the role the chemical elements play in the electrical resistance of the FIB electrical jumper and to estimate the FIB metal resistance from energy dispersive spectroscopy (EDS) analysis and the geometry.

The modern scanning transmission electron microscope (S/TEM) has become a key technology and is heavily utilized in advanced failure analysis (FA) labs. It is well equipped to analyze semiconductor device failures, even for the latest process technology nodes (20nm or less). However, the typical sample preparation process flow utilizes a dual beam focused ion beam (FIB) microscope for sample preparation, with the final sample end-pointing monitored using the scanning electron microscope (SEM) column. At the latest technology nodes, defect sizes can be on the order of the resolution limit for the SEM column. Passive voltage contrast (PVC) is an established FA technique for integrated circuit (IC) FA which can compensate for this resolution deficiency in some cases. In this paper, PVC is applied to end-pointing cross-sectional S/TEM samples on the structure or defect of interest to address the SEM resolution limitation.

Focused ion beam (FIB) systems use a gallium liquid metal ion source as the source of the ions, providing a typical beam current range of 1 pA to 20-60 nA. Using a reactive gas in addition to the FIB usually enhances the etch rate from 1 to 15 times, but with the combination of xenon difluoride gas and a silicon substrate the enhancement can be over 1000 times. Such an enhancement makes the removal of large volumes of Si more practical, even with the typical upper end of FIB currents of 20-60 nA. This paper discusses the application of full-thickness silicon trenching to the process development of WtW bonding. With the increase in 3DIC, it is expected that fresh process characterization and failure analysis techniques will be required. The work presented shows the feasibility of extending FIB techniques to the process development of wafer-to-wafer bonded samples even on full-thickness wafers.

Cross-sectional style transmission electron microscopy (TEM) sample preparation techniques by DualBeam (SEM/FIB) systems are widely used in both laboratory and manufacturing lines with either in-situ or ex-situ lift out methods. By contrast, however, the plan view TEM sample has only been prepared in the laboratory environment, and only after breaking the wafer. This paper introduces a novel methodology for in-line, plan view TEM sample preparation at the 300mm wafer level that does not require breaking the wafer. It also presents the benefit of the technique on electrically short defects. The methodology of thin lamella TEM sample preparation for plan view work in two different tool configurations is also presented. The detailed procedure of thin lamella sample preparation is also described. In-line, full wafer plan view (S)TEM provides a quick turn around solution for defect analysis in the manufacturing line.