Dual Focused Ion Beam Research Articles

Automated three-dimensional X-ray analysis using a dual-beam FIB

We present a fully automated method for three-dimensional (3D) elemental analysis demonstrated using a ceramic sample of chemistry (Ca)MgTiO x . The specimen is serially sectioned by a focused ion beam (FIB) microscope, and energy-dispersive X-ray spectrometry (EDXS) is used for elemental analysis of each cross-section created. A 3D elemental model is reconstructed from the stack of two-dimensional (2D) data. This work concentrates on issues arising from process automation, the large sample volume of approximately 17×17×10 μm 3, and the insulating nature of the specimen. A new routine for post-acquisition data correction of different drift effects is demonstrated. Furthermore, it is shown that EDXS data may be erroneous for specimens containing voids, and that back-scattered electron images have to be used to correct for these errors.

Characterization of metal-oxide nanosensors fabricated with focused ion beam (FIB)

A procedure to contact single metal-oxide nanowires and nanoparticles of different materials using a Dual Beam FIB has been developed. The quality of the electrical contacts has been evaluated and the possibility of extracting the electrical parameters of these nanowires and nanoparticles demonstrated. The response of some of them to different gases is presented, proving the feasibility of fabricating metal-oxide nanosensors.

3D reconstruction and characterization of polycrystalline microstructures using a FIB–SEM system

A novel methodology is described in this paper which is a step towards three-dimensional representation of grain structures for microstructure characterization and processing microstructural data for subsequent computational analysis. It facilitates evaluation of stereological parameters of grain structures from a series of two-dimensional (2D) electron backscatter diffraction (EBSD) maps. Crystallographic orientation maps of consecutive serial sections of a micron-size specimen are collected in an automated manner using a dual-beam focused ion beam–scanning electron microscope (FIB–SEM) outfitted with an EBSD system. Analysis of the serial-sectioning data is accomplished using a special purpose software program called “Micro-Imager”. Micro-Imager is able to output characterization parameters such as the distribution of grain size, number of neighboring grains, and grain orientation and misorientation for every 2D section. Some of these data can be compared with results from stereological exercises. Stacking the 2D statistical information obtained from the analysis of the serial-sectioning data provides a means to quantify the variability of grain structure in 3D.

Focused Ion Beam Techniques for Butterfly Wing Scales Analysis and 3-D Reconstruction

AbstractWe have developed and successfully demonstrated a protocol for mounting and electrical grounding of a butterfly wing scale using a series of localized electron- and ion-beam assisted Pt depositions in the dual-beam Focused Ion Beam (FIB)-SEM system. This method eliminates introduction of silver paint or other typical mounting materials, along with their chemistries, and produces a stable structure for FIB cross-sectioning, electron imaging, chemical analysis by Energy Dispersive Spectrometry (EDS) and/or Auger Electron Spectroscopy (AES), and FIB milling for 3-D reconstruction.

Fabrication of metallic contacts to nanometre-sized materials using a focused ion beam (FIB)

Nanometre-sized materials, like nanowires, nanoparticles or nanobelts, are gaining huge interest as building blocks of modern electronic nanodevices. Their fabrication feasibility has been demonstrated in the last years, and different routes are already well established in order to synthesize these materials. However, the assessment of their electrical properties is still a challenging issue, due to the difficulty to perform a precise nanolithography process allowing the access to such small structures. The fabrication of metallic contacts with precision in the nanometre range is necessary, as well as achieving a flexible system that allows to contact individual structures. Such a system could be a dual-beam Focused Ion Beam instrument, which combines Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB) in one machine, able to assist deposition of materials with nanometre precision. In this work, the methodology of fabrication of metallic nanocontacts to access different nanometre-sized materials inside a dual-beam FIB instrument is presented. Both electron and ion-beam assisted deposition are used and advantages of one or the other primary beams are discussed as a function of the material to be contacted and of the field in which such material will be further employed. The resulting electrical properties are presented and the influence of the contacting method is discussed. Finally, the complete fabrication process of nanodevices is illustrated in the case of metal-oxide nanowires showing gas sensing capabilities, which have been contacted using a dual-beam FIB machine. Their gas response is presented and the possibility of using this method in future technologies is briefly discussed.

Sculpting Needle-Shaped Atom Probe Specimens with a Dual Beam FIB

The goal of atom probe specimen preparation is to produce a needle-shaped specimen with an end radius of less than 50 nm on a smooth uniform shank with a taper angle of less than 5°. Neither the microstructure nor the solute distribution should be altered during fabrication. Traditionally, electropolishing has been the dominant method for producing these needles. Focused ion beam (FIB) instruments enable specimens to be fabricated from a wider range of materials and different forms [1].

New Electron Microscopy Techniques for the Study of Meteoritic Metal

Metallic Phases in extraterrestrial materials are composed of Fe-Ni with minor amounts of Co, P, Si, Cr, etc. Electron microscopy techniques (SEM, TEM, EPMA, AEM) have been used for almost 50 years to study micron and submicron microscopic features in the metal phases (Fig. 1) such as clear taenite, cloudy zone, plessite, etc [1,2]. However lack of instrumentation to prepare TEM thin foils in specific sample locations and to obtain micro-scale crystallographic data have limited these investigations. New techniques such as the focused ion beam (FIB) and the electron backscatter electron diffraction (EBSD) techniques have overcome these limitations. The application of the FIB instrument has allowed us to prepare {approx}10 um long by {approx} 5um deep TEM thin sections of metal phases from specific regions of metal particles, in chondrites, irons and stony iron meteorites, identified by optical and SEM observation. Using a FEI dual beam FIB we were able to study very small metal particles in samples of CH chondrites [3] and zoneless plessite (ZP) in ordinary chondrites. Fig. 2 shows a SEM photomicrograph of a {approx}40 um ZP particle in Kernouve, a H6 chondrite. Fig. 3a,b shows a TEM photograph of a section of the FIB prepared TEMmore » foil of the ZP particle and a Ni trace through a tetrataenite/kamacite region of the particle. It has been proposed that the Widmanstatten pattern in low P iron meteorites forms by martensite decomposition, via the reaction {gamma} {yields} {alpha}{sub 2} + {gamma} {yields} {alpha} + {gamma} in which {alpha}{sub 2}, martensite, decomposes to the equilibrium {alpha} and {gamma} phases during the cooling process [4]. In order to show if this mechanism for Widmanstatten pattern formation is correct, crystallographic information is needed from the {gamma} or taenite phases throughout a given meteorite. The EBSD technique was employed in this study to obtain the orientation of the taenite surrounding the initial martensite phase and the kamacite which forms as {alpha}{sub 2} or as Widmanstatten plates in a series of IVB irons. Fig. 4a,b shows EBSD orientation maps of taenite and kamacite from the Tawallah Valley IVB iron. We observe that the orientation of the taenite in the IVB meteorites is the same throughout the sample consistent with the orientation of the high temperature single phase taenite before formation of the Widmanstatten pattern.« less

The Total Release Method for FIB In-situ TEM Sample Preparation

T.M. Moore Omniprobe, Inc., Dallas, TX moore@omniprobe.com In 1965, Gordon Moore forecast that the microprocessor industry would continually scale to smaller feature sizes and the number of transistors would double every 18 months. Scaling below the 100nm node, combined with the implementation of copper and low dielectric constant insulators to increase the processor speed, has produced the situation in which SEM inspection no longer offers suitable resolution to image key artifacts and structures. The transmission electron microscope (TEM), once considered more of a development tool, is now in the forefront for process control and failure analysis, especially for measurements such as the thickness of semiconductor device non-planar barrier and seed layers. The use of focused ion beam (FIB) microscopes has become the method of choice for site-specific TEM sample preparation. Originally, the FIB was used as a final thinning step for mechanically prepared ribbons of semiconductor material adhered to modified TEM grids, known as the “H-Bar” method. More recently, the method for performing the entire TEM sample preparation process within the FIB is known as “in-situ lift-out” and is based on the use of a chamber-mounted nanomanipulator and beam-induced material deposition.[1-5] The use of the FIB offers advantages over conventional mechanical TEM sample preparation. The dual-beam FIB offers the ability to locate the lift-out site with SEM resolution and then use the ion beam to excise the sample without sacrificing the wafer, followed by thinning the extracted sample to the thickness required for TEM inspection. This is especially attractive for 300 mm processing where the value of each wafer in the flow can exceed $100,000. The risk to the quality and reliability of the process wafer due to gallium contamination from the ion beam is considered manageable.[6] In-situ lift-out also enables the return of the mostly abandoned practice of including informative test die on product wafers. The Total Release method for in-situ lift-out is designed to maximize throughput of a TEM sample preparation process.[4-5] The method can be simplified into three successive steps (see Figure 1). The first is the excision of the lift-out sample using FIB milling and extraction of the sample from its trench with two rapid ion milling steps, or “cuts”. The first cut is “U”-shaped and partially surrounds the target. The second is a straight cut that intersects the first cut beneath the target and produces a wedge-shaped sample. Then the probe is fixed to the released sample, typically with ionbeam metal deposition, and the sample is removed from the wafer by the nanomanipulator. The second step is the “holder-attach” step, during which the wedge is translated on the probe tip to the TEM sample holder (the lift-out grid). Then the sample is attached to the TEM holder (again, typically with ion beam-induced metal deposition) and later detached from the probe tip point using FIB milling. The third and final step is the thinning of the wedge into an electron-transparent thin section using FIB milling. The use of a simple probe tip for lift-out in the FIB has throughput and efficiency advantages over alternative methods. For example, lift-out can also be accomplished by a method referred to as ex-situ lift-out, in which ion beam-thinned samples, still attached to the wafer, are removed from the FIB and then detached from the wafer with a statically charged glass needle. These samples are then permanently deposited onto the suspended areas on a polymer membrane-coated TEM grid. Ex-situ lift-out can be faster than the in-situ method, and it requires less time in the FIB. However, in-situ lift-out offers a much higher overall throughput through

Direct observations of dislocation substructures formed by nano-indentation of the α-phase in an α/β titanium alloy

Nano-indentation has been used to assess the hardness of equiaxed grains of α-Ti as a function of orientation. Surface normals of these grains in metallographic sections were assessed using orientation imaging microscopy. Thin membranes of material from below a series of nano-indentations were excised by use of a dual-beam focused ion beam instrument. In this way, the dislocation substructures beneath individual indentations were characterized using transmission electron microscopy, permitting an identification of both statistically stored and geometrically necessary dislocations.

Location specific in situ TEM straining specimens made using FIB

A method has been devised and demonstrated for producing in situ straining specimens for the transmission electron microscope (TEM) from specific locations in a sample using a dual-beam focused ion beam (FIB) instrument. The specimen is removed from a polished surface in the FIB using normal methods and then attached to a pre-fabricated substrate in the form of a modified TEM tensile specimen. In this manner, specific features of the microstructure of a polished optical mount can be selected for in situ tensile straining. With the use of electron backscattered diffraction (EBSD), this technique could be extended to select specific orientations of the specimen as well.

Three-dimensional analysis of porous BaTiO3 ceramics using FIB nanotomography.

Three-dimensional (3D) data represent the basis for reliable quantification of complex microstructures. Therefore, the development of high-resolution tomography techniques is of major importance for many materials science disciplines. In this paper, we present a novel serial sectioning procedure for 3D analysis using a dual-beam FIB (focused ion beam). A very narrow and reproducible spacing between the individual imaging planes is achieved by using drift correction algorithms in the automated slicing procedure. The spacing between the planes is nearly of the same magnitude as the pixel resolution on scanning electron microscopy images. Consequently, the acquired stack of images can be transformed directly into a 3D data volume with a voxel resolution of 6 x 7 x 17 nm. To demonstrate the capabilities of FIB nanotomography, a BaTiO3 ceramic with a high volume fraction of fine porosity was investigated using the method as a basis for computational microstructure analysis and the results compared with conventional physical measurements. Significant differences between the particle size distributions as measured by nanotomography and laser granulometry indicate that the latter analysis is skewed by particle agglomeration/aggregation in the raw powder and by uncertainties related to calculation assumptions. Significant differences are also observed between the results from mercury intrusion porosimetry (MIP) and 3D pore space analysis. There is strong evidence that the ink-bottle effect leads to an overestimation of the frequency of small pores in MIP. FIB nanotomography thus reveals quantitative information of structural features smaller than 100 nm in size which cannot be acquired easily by other methods.

FIB failure analysis of memory arrays

Many modern microelectronic chips contain embedded memory arrays. A typical memory bit-cell contains several transistors. Failure of a single transistor or contact within a bit cell makes the entire bit cell inoperable. A dual-beam Focused Ion Beam (FIB) tool combines milling capability with in situ Scanning Electron Microscope (SEM) imaging, which is very useful for identifying the root cause when a physical defect is present. This paper describes the slice-and-view FIB technique for failure analysis (FA) in memory arrays. Several failure mechanisms have been identified, including missing patterns, killer particle defects, shorted and open stack vias. Transmission Electron Microscopy (TEM)/Scanning TEM (STEM) analysis was able to provide additional information when SEM resolution was not sufficient. Processes were adjusted appropriately leading to yield enhancement.

Anwendung der FIB für Materialwissenschaft und Fehleranalyse / Using FIB for Materials Science and Failure Analysis

The Focused Ion Beam (FIB) technology has become an indispensable tool in the development, manufacture, and failure analysis of microelectronic devices in recent years. Since the ion beam allows to manufacture, modify or etch conducting or insulating structures of about 20 nm to 100 μm in an efficient way, depending on the use of reaction gases, FIB's open up new prospects in materials science and, in particular, the target preparation of TEM lamellae which is indispensable in the micro- and nanotechnologies. In this context, FIB technology also makes it possible to prepare samples with phases of extremely different hardnesses without smearing or producing artifacts, but it has to be noted that the ion beam amorphizes some atomic layers at the surface. A combination of an electron column and an ion column within an advanced dual beam FIB will minimize possible defects. We first provide a description of the specific properties of the ion beam and the FIB set-up and will then report about a range of applications in materials- and bio-science as well as in micro- and nanoelectronics.

DualBeam focused ion beam technology.

ScanningVolume 25, Issue 4 p. 221-221 Scanning the IndustryFree Access Dualbeam focused ion beam technology Phaedra E. McGuinness, Phaedra E. McGuinness Managing EditorSearch for more papers by this author Phaedra E. McGuinness, Phaedra E. McGuinness Managing EditorSearch for more papers by this author First published: 06 December 2006 https://doi.org/10.1002/sca.4950250410Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume25, Issue4July/August 2003Pages 221-221 RelatedInformation

Application of FIB/SEM and TEM to Bit Failure Analyses in SRAM Arrays

ABSTRACTMany microelectronic chips contain embedded memory arrays. A single SRAM bit-cell contains several transistors. Failure of any of the transistors makes the entire bit-cell inoperable. Dual-beam Focused Ion Beam (FIB) combines the slicing capability of FIB with in-situ SEM imaging. The combination offers unparalleled precision in looking for root causes of failures in microelectronic devices. Once a failure site is located, an FIB lift-off method can be used to prepare a TEM sample containing the area of interest. Further structural, elemental information can then be acquired from the failure site. We report here analyses of single and multiple bit failures in SRAM arrays carried out using FIB/SEM, and in two cases TEM imaging and EDS/PEELS. Root causes of bit failures including remnant seed-layer metal between stacked vias have been identified.

Dual-beam Focused Ion Beam: A Multifunctional Tool for Nanotechnology

Dual-beam Focused Ion Beam: A Multifunctional Tool for Nanotechnology

Precision TEM Specimen Preparation for Integrated Circuits using Dual-Beam FIB Lift-Out Technique

Abstract Focused ion beam lift-out technique has become increasingly attractive to the TEM community due to its unique advantage of no mechanical grinding/polishing involved in the process [1-3]. The technique essentially consists of two parts: preparation of membrane using focused ion beam (FIB) and transfer of the membrane (lift-out) to a grid. Up to date, this technique has only been demonstrated on single beam FIB systems. From a practical standpoint, overall sample quality (thickness) and lack of end-point precision are two major issues associated with the conventional single beam FIB technique. These issues are primarily related to ion beam damage and endpoint control encountered during the final stages of specimen thinning. As a result, the widespread use of FIB lift-out technique for high precision TEM specimen preparation has been limited. Recent technological advances have made it possible to combine both an electron beam column and an ion beam column into an integrated dual beam-focused ion beam (DB-FIB) system.

Novel Preparation of Precision Planar TEM Specimens for Integrated Circuits Using Dual-Beam Focused Ion Beam

Abstract Preparation of precision planar TEM specimen for failure analysis in microelectronics industry has become increasingly difficult as the critical dimensions of integrated circuits (ICs) continue to shrink down to deep sub-micron regime. Accurate defect localization and endpoint control of specimen final thinning are critical steps leading to successful specimens and defect characterization. Conventional dimple and ion-mill method becomes inadequate for this class of specimen preparation due to poor optical imaging resolution, non-planar polishing, lack of flexible ion beam control and in situ process monitoring for endpoint control. These problems are exacerbated by the high density and a wide range of materials found in IC device structures. In this paper we present a novel method employing dual-beam focused ion beam (FIB) which significantly improves upon these difficulties.