Identification and Characterization of Submicron Defects for Semiconductor Processing

Combining electron and focused ion beam techniques for failure analysis and design verification of integrated circuits

A novel analytical method applying combined electron beam induced current (EBIC) imaging based on scanning electron microscopy (SEM) and focused ion beam (FIB) cross sectioning in a SEM/FIB dualbeam system is presented. The method is demonstrated in several case studies for process characterization and failure analysis of thin film technology based Solar cells, including Silicon (CSG), Cadmium Telluride (CdTe) and Copper Indium Selenide (CIS) absorbers. While existing techniques such as electro-, photoluminescence spectroscopy and lock-in thermography are able to locate the larger, electrically active defects reasonably fast on a large area, the FIB-SEM EBIC system is uniquely capable of detecting sub-micron, sub-surface defects and of analysing these defects in the same system. In combination with a FIB, the localized region of interest can be easily cross sectioned and additional EBIC analysis can be applied for a three dimensional analysis of the p/n junction.

Ion beam-based techniques have contributed significantly towards the prerequisites of society. These techniques are proven to be vital in the synthesis of materials, device fabrication as well as the characterization of the materials. Apart from the synthesis and characterization of materials, the manipulation of the physical properties and device characteristics are other important aspects. Ion beam-based sputtering methods are being extensively used to grow thin films of different kinds of materials. Recently, the focused ion beam (FIB) technique is used to prepare samples for various experimental techniques like transmission electron microscopy, X-ray imaging, etc. This technique is being further extended to microsystem technology.Ion beam methods have shown the potential to utilize them for material synthesis. Silicon-based materials, graphene, nanowires, plasmonic nanostructures, and quantum dots are some of the examples. Additionally, by passing through the material, ion beam techniques play an important role in modifying the physical characteristics of the material. Ion beam irradiation and implantation are two common and well-known techniques that are proven to be assets for this purpose. These techniques have found immense importance in recent years especially in semiconductor-based electronics. This book briefly discusses the ion beam processes and the potential applications in oxide semiconductors.

Frontiers in NDE research nearing maturity for exploitation to ensure structural integrity of pressure retaining components

In this study, we propose a method for evaluating the dielectric property of a single fine particle using the focused ion beam technieque. Lead zirconate titanate (PZT) particles (Sakai Chemical Industry LQ) were sintered at 1473 K for 2 h to fabricate bulk PZT. The bulk PZT was milled to fabricate sample particles. The particles were dispersed on a Au surface substrate, and were shaped into a parallel-plate capacitor using the focused ion beam (FIB) technique. The FIB technique was used to deposite tungsten, W, with a square shape on top of the particle sample as an upper electrode, and the particles were shaved into a rectangular shape; the area of the electrode was 2×10-12 m2 and the thickness of the PZT segment was 2×10-6 m. The capacitance of the fabricated PZT particle sample was successfully measured by compensating the parasitic capacitance of the experimental setup. Consequently, the relative permittivity of the PZT particle sample was 1250 at 105 Hz. This value was comparably close to the 1750 of the bulk PZT. The issue of electric contact between the particles and the substrate should be overcome in order to discuss permittivity quantitatively.

Focused ion beam (FIB) techniques were applied to the fabrication of lateral-type thin-film edge field emitters (FE's). In the present paper, two different processes to fabricate lateral-type thin-film edge FE's have been demonstrated. One technique utilizes the FIB as an etching tool. The FIB with a diameter of 1 µm was used to cut a thin nickel film with a thickness of 150 nm deposited on a silicon substrate which had been thermally oxidized, in order to produce an emitter-collector gap. As a result, a diode structure with the gap of about 2 µm could be obtained. In the other technique, a tungsten oxide thin film was exposed with the FIB to form the electrodes, followed by development in sodium hydroxide solution and reduction in hydrogen ambient. The FIB with a diameter of 5 µm was used to expose the tungsten oxide, a negative resist against ion beam irradiation, with a thickness of 40 nm. A diode structure with the gap of also about 2 µm could be obtained. Current-voltage characteristics of these devices were measured and field emission currents were observed. Ejection of the electrons from the latter FE into vacuum was confirmed with luminescence of zinc sulfide phosphor.

In the 2xxx series alloys, intergranular corrosion is generally related to the strong reactivity of copper-rich intergranular precipitates leading to a copper enrichment of these particles. While the nature of the oxides formed inside the intergranular corrosion defects was assumed to strongly influence the intergranular corrosion propagation rate, it was not clearly identified due to the thickness of the oxide layer formed which required to use high resolution analytical techniques. The present work aims to characterize the intergranular corrosion defects formed for a 2024-T351 aluminum alloy after a 24 hours continuous immersion in a 1 M NaCl solution and compares the results to literature data concerning the oxide layers formed on copper-rich model alloys. A combination of focus ion beam (FIB) technique, transmission electron microscopy (TEM) observations and energy dispersive X-Ray spectroscopy (EDX) analyses was used to accurately characterize both the morphology and chemical composition of the intergranular corrosion defects. Results evidenced the dissolution of intergranular copper-rich particles, the formation of a 10-200 nm-thin metallic copper-rich layer at the oxide/metal interface and the incorporation of copper inside the amorphous alumina oxide film leading to the formation of structural defects of the oxide film.

Trimming the electrical properties on nanoscale YBa2Cu3O7−x constrictions by focus ion beam technique

Summary form only given, substantially as follows. Ultrasonic non-destructive inspection is today a routine method in industries for the detection, localization and sizing of surface and buried defects in engineering structures. However, the analysis of the huge amount of data obtained during an ultrasonic non-destructive inspection is not a simple task and is usually time consuming. This is why the data are displayed in the form of images in order to take advantage of the power of visual representation of information and image processing tools used so as to speed up the analysis problem. In ultrasonic non-destructive inspection the data are displayed in the form of mainly three types of images known as B-SCAN, C-SCAN and D-SCAN displays. Our work is concerned with the application of an image processing algorithm on B-SCAN displays in order to detect crack defects in thick engineering structures. This algorithm is based on the Hough transform in which a gradient analysis is performed during the computation of the Hough space. In order to decide whether a defect is present in the structure or not we need to set a threshold and analyze the Hough space. Any maximum in the Hough space which is greater than the threshold represents a defect in the structure. Due to the diversity of B-SCAN displays which may or may not contain defects, the threshold is not a fixed one and depends on the Hough space obtained.

Microfabrication of AFM tips using focused ion and electron beam techniques

There are growing demands for integrated study of isotopes, trace elements and crystallography of micron-sized grains observed on polished sections or scattered on surface of sample holders. However, transmission electron microscopy (TEM) observation is largely restricted by the challenges associated with the preparation of ultrathin sections from given micron-sized grains after chemical and isotopic analyses. Here, we report a new method of combining focused ion beam (FIB) and microtome techniques. This method is demonstrated by the successful preparation of several ultrathin slices from a presolar graphite grain. The presolar graphite grain was a spherule with a diameter of 5 μm. It was found by nanoscale secondary ion mass spectrometry (NanoSIMS) mapping of a carbonaceous acid residue from the Qingzhen enstatite chondrite (EH3), deposited on a gold foil mount. The spherule showed isotope anomalies in C and Si, with 12C/13C = 99 ± 2 and δ29Si/28Si = 172 ± 36‰, and likely originated in an asymptotic branch giant (AGB) star. After NanoSIMS analysis, this spherule was transported and fixed on a pre-cut top surface of an epoxy stub, using FIB. The fixed spherule was then embedded entirely in resin, and cut into ~ 70 nm slices with a microtome. TEM observation of these ultrathin sections revealed a turbostratic structure free of any subgrains. The morphology, Raman spectrum, C and Si isotopic compositions, internal texture and crystallography of this graphite spherule suggest that it condensed from a carbon-rich outflow of an AGB star.

In recent years, nanomachining has attracted increasing attention in advanced manufacturing science and technologies as a value-added processes to control material structures, components, devices, and nanoscale systems. To make sub-micro patterns on these products, micro/nanoscale single-crystal diamond cutting tools are essential. Popular non-contact methods for the macro/micro processing of diamond composites are pulsed laser ablation (PLA) and electric discharge machining (EDM). However, for manufacturing nanoscale diamond tools, these machining methods are not appropriate. Despite diamond’s extreme physical properties, diamond can be micro/nano machined relatively easily using a focused ion beam (FIB) technique. In the FIB milling process, the surface properties of the diamond cutting tool is affected by the amorphous damage layer caused by the FIB gallium ion collision and implantation and these influence the diamond cutting tool edge sharpness and increase the processing procedures. To protect the diamond substrate, a protection layer—platinum (Pt) coating is essential in diamond FIB milling. In this study, the depth of Pt coating layer which could decrease process-induced damage during FIB fabrication is investigated, along with methods for removing the Pt coating layer on diamond tools. The optimum Pt coating depth has been confirmed, which is very important for maintaining cutting tool edge sharpness and decreasing processing procedures. The ultra-precision grinding method and etching with aqua regia method have been investigated for removing the Pt coating layer. Experimental results show that when the diamond cutting tool width is bigger than 500 nm, ultra-precision grinding method is appropriate for removing Pt coating layer on diamond tool. However, the ultra-precision grinding method is not recommended for removing the Pt coating layer when the cutting tool width is smaller than 500 nm, because the possibility that the diamond cutting tool is damaged by the grinding process will be increased. Despite the etching method requiring more procedures to remove the Pt coating layer after FIB milling, it is a feasible method for diamond tools with under 500 nm width.

Optimization of FIB methods for phase shift mask defect repair

Study of cyclic strain localization and fatigue crack initiation using FIB technique

Nanoscale fabrication and characterization techniques critically underpin a vast range of fields, including nanoelectronics and nanobiotechnology. Focused ion beam (FIB) techniques are appealing due to their high spatial resolution and widespread use for processing of nanostructured materials. Here, we introduce FIB-induced fluorescence spectroscopy (FIB-FS) as a nanoscale technique for spectroscopic detection of atoms sputtered by an ion beam. We use semiconductor heterostructures to demonstrate nanoscale lateral and depth resolution and show that it is limited by ion-induced intermixing of nanostructured materials. Sensitivity is demonstrated qualitatively by depth profiling of 3.5, 5, and 8 nm quantum wells and quantitatively by detection of trace-level impurities present at parts-per-million levels. The utility of the FIB-FS technique is demonstrated by characterization of quantum wells and Li-ion batteries. Our work introduces FIB-FS as a high-resolution, high-sensitivity, 3D analysis and tomography technique that combines the versatility of FIB nanofabrication techniques with the power of diffraction-unlimited fluorescence spectroscopy.