This presentation introduces the practice of focused ion beam (FIB) chip editing and its power and versatility as a problem-solving tool. It begins with a review of the features and functions of FIB systems, the role of gas chemistry in milling, etching, and deposition, and the use of IR imaging for navigation and targeting. It goes on to identify challenges due to packaging materials, chip-package interactions, and other factors, and in each case, provide alternate approaches and procedures to circumvent potential problems. It also covers advanced practices and methods and assesses potential future advancements.

This presentation covers ion beam analytical tools, their capabilities, and uses. It provides an overview of ion sources, examines emerging trends in surface analysis, and assesses the potential of ultrafast lasers for panoscopic patterning, athermal ablation, and elemental analysis. It compares and contrasts liquid metal, gas field, and plasma sources and presents examples highlighting the capabilities of FIB-SIMS and FIB-SEM Auger/XPS surface analysis techniques. It also introduces computationally guided microspectroscopy (CGM) and assesses its potential impact on multi-variant analysis, point spread deconvolution, and compressed sensing.

The characterization of back side illumination (BSI) image sensors is challenging because of the unique construction of such sensors with silicon on top. A novel method for BSI image sensor characterization is presented in this paper. The proposed approach is based on backside circuit editing using ion beam and optical imaging techniques. This provides access to buried conductors and creates probe points for measurements that can be made using an optical, electron beam, or mechanical micro/nano prober.

The automation of TEM imaging and lamella preparation using focused ion beam (FIB) technology has gained significant momentum, particularly in the development of microprocessors. A key requirement of automating TEM sample preparation is ensuring consistent thickness control and accurate targeting of features of interest in the ultra-thin lamella. This work examines the factors that impact both metrics. It explains how FIB pattern calibration requires milling to be divided into steps to minimize the effects of drift, how the height of the protective cap on the ion-beam tip influences sample thickness, and how FIB aperture erosion has little impact on lamella thickness until it reaches a certain point where the lamella profile cannot be reliably maintained. It was also found that the tail of the ion beam remains invariant during aperture degradation in the operable range and that it plays a prominent role in determining the cross-sectional thickness of the TEM lamella.

This paper describes an accurate and controllable delayering process to target defects in new materials and device structures. The workflow is a three-step process consisting of bulk device delayering by broad Ar ion beam milling, followed by plan view specimen preparation using a focused ion beam, then site-specific delayering via concentrated Ar ion beam milling. The end result is a precisely delayered device without sample preparation-induced artifacts suitable for identifying defects during physical failure analysis.

This paper evaluates the use of plasma etching for preparing TEM specimens to analyze high aspect ratio 3D NAND integrated circuits. By controlling plasma etching parameters, a relatively high material removal rate could be obtained. Moreover, through the control of etch time, the top region of the test specimens could be completely removed down through the expected number of layers, making it possible to resolve details throughout the entire sample, particularly in the middle region of the 3D NAND, using TEM cross-section analysis.

This paper evaluates the use of nanomilling and STEM imaging to analyze failure mechanisms in sub-50 nm InP HEMTS. The devices were life tested at elevated temperatures and biases and their electrical characteristics were measured at each stress interval. Devices that were damaged were investigated further to assess the underlying failure mechanism. Advanced microscopy with sub-nm resolution was employed to examine the physical characteristics of the failed HEMT devices at the atomic scale. As the paper explains, the examination was conducted using a focused ion beam/scanning electron microscope (FIB/SEM), an Ar gas ion nanomill, and STEM imaging.

This paper demonstrates a novel defect localization approach based on EBIRCH isolation conducted from the backside of flip chips. It discusses sample preparation and probing considerations and presents a case study that shows how the technique makes it possible to determine the root cause of subtle defects, such as bridging, in flip chip failures.

Convention hand polishing, which is widely used for delayering, is becoming increasingly difficult as metal lines and stacks in semiconductor devices get thinner. For one thing, endpointing at the exact targeted layer and region of interest is a major challenge. The presence of cobalt and its propensity to oxidize, thus complicating electrical measurements, is another challenge. In this study, the authors demonstrate an alternative delayering method based on plasma focused ion beam (PFIB) milling aided by DX gas. The workflow associated with the new method is more efficient than that of conventional hand polishing and can help prevent cobalt oxidation.

This paper presents a large-volume workflow for fast failure analysis of microelectronic devices. The workflow incorporates a stand-alone ps-laser ablation tool and a FIB-SEM system. As implemented, the picosecond laser is used to quickly remove large volumes of bulk material while the Xe plasma FIB provides precise end-pointing to the feature of interest and fine surface polishing after laser ablation. The paper presents several application examples, including a full workflow to prepare artefact-free, delamination-free cross-sections in an AMOLED mobile display and the preparation of devices and packages (including flip chips) of varying size. It also covers related issues such as CAD navigation, data correlation, and the use of bitmap overlays for end-pointing.

With manufacturers now capable of creating transistors in the 5-7 nm node range, the ability to isolate, inspect, and probe individual metal and via layers is of the utmost importance for defect inspection and design validation. These isolated layers can be inspected for defects via SEM, provide design validation, or tested with electrical probing for failure analysis. The work herein describes a functional workflow that enables manufacturers to perform this kind of sample preparation in an automated fashion using plasma focused ion beam (FIB) technology. The workflow is scalable and can be used in both lab and fabrication environments.

This paper presents a method for determining positional variation and offsets in high aspect ratio etches used in the production of 3D NAND devices. The method uses a 3D fiducial as a positional reference in the field-of-view, which not only allows for high precision tracking of features through the depth of the device, but also aids in the alignment of images when performing 3D reconstructions. The workflow is based on plasma dual beam diagonal milling, which allows users to characterize structures through the device stack at a much higher throughput/slice than conventional methods, enabling enhanced process monitoring and control.

This paper discusses the development of an automated cell layer counting process for preparing 3D NAND flash memory samples for TEM analysis. In an initial proof-of-concept, several line markings were inscribed on the test device in evenly spaced intervals in order to evaluate its helpfulness for a human operator. A more automated procedure was then developed in which cell layers were counted to a desired target layer starting from a reference layer set by the operator. At that point, the operator could begin preparing the TEM sample.

An image sensor module failed in the field and was returned showing functional issues and a supply-to-ground short. After the hard lens mounted over the imaging chip was removed, the short disappeared along with the functional issues. This paper explains how the authors were able to restore the failure mode and discover the underlying defect, via backside focused ion beam cross-sectioning, with minimal intrusion into the top-side package and silicon.

For unique single failures, which tend to be the case in customer return and reliability failures, selecting another sample or performing root cause deconvolution is not an option, and if diagnostic tests are not conclusive, it becomes necessary to extend the effectiveness of automatic test pattern generator (ATPG) diagnosis in order to determine the failure mechanism. This paper proposes a way to improve resolution using single-shot logic and high-resolution targeted patterns. Two cases are presented to demonstrate the approach and show how it performed on actual failing units.

This paper presents a development in semiconductor device delayering by broad ion beam milling that offers a uniform delayering area on a millimeter scale. A milling area of this size is made possible by the user's ability to position ion beams individually to cover the desired area. This flexibility in ion beam positioning also enables more precise targeting of an area of interest.

Integrated circuit (IC) delayering workflows are highly reliant on operator experience to determine processing end points. The current method of end point detection during IC delayering uses qualitative correlations between the thickness and color of dielectric films observed via optical microscopy. The goal of this work is to quantify this relationship using computer vision. As explained in the paper, the authors trained a convolutional neural network to estimate the thickness of dielectric films based on images and measurements recorded during processing. The trained vision model explained 39% of the variance in dielectric film thickness with a mean absolute error of approximately 47 nm. The paper describes the entire workflow, including verification testing, and addresses the primary sources of error.

Global thinning is a technique that enables backside failure analysis and radiation testing. In some devices, it can also lead to increased thresholds for single-event latchup and upset. In this study, we examine the impacts of global thinning on 28 nm node FPGAs. Test devices are thinned to 50, 10, and 3 μm via CNC milling. Lattice damage, in the form of dislocations, extends about 1 μm below the surface, but is removed by polishing with colloidal SiO2. As shown by finite-element modeling, thinning increases compressive global stress in the Si while solder bumps (in flip-chip packages) increase stress locally. The results are confirmed by stress measurements obtained through Raman spectroscopy, although more complex models are needed to account for nonlinear effects in devices thinned to 3 μm and heated to 125°C. Thermal imaging shows that increased local heating occurs with increased thinning, but the maximum temperature difference across the 3-μm die is less than 2°C. Ring oscillators throughout the FPGA fabric slow about 0.5% after thinning and another 0.5% when heated to 125°C, which is attributed to stress changes in the Si.

This presentation introduces the practice of focused ion beam (FIB) chip editing and its power and versatility as a problem-solving tool. It begins with a review of the features and functions of FIB systems, the role of gas chemistry in milling, etching, and deposition, and the use of IR imaging for navigation and targeting. It goes on to identify challenges due to packaging materials, chip-package interactions, and other factors, and in each case, provide alternate approaches and procedures to circumvent potential problems. It also covers advanced practices and methods and assesses potential future advancements.

This presentation covers ion beam analytical tools, their capabilities, and uses. It provides an overview of ion sources, examines emerging trends in surface analysis, and assesses the potential of ultrafast lasers for panoscopic patterning, athermal ablation, and elemental analysis. It compares and contrasts liquid metal, gas field, and plasma sources and presents examples highlighting the capabilities of FIB-SIMS and FIB-SEM Auger/XPS surface analysis techniques. It also introduces computationally guided microspectroscopy (CGM) and assesses its potential impact on multi-variant analysis, point spread deconvolution, and compressed sensing.