Recent developments in FIB have included optics and automation improvements as well as technique development. in the past decade, ion beam optics have improved rapidly to the point where the beam size and profile does not dramatically limit its use in many applications ranging from failure analysis to manufacturing. Developments in FIB can therefore focus on techniques to increase removal rates, enhance selectivity and improve surface finish. in this work we present various efforts to improve FIB micromachining using chemical enhancement, where the incident ions initiate chemical reactions with surface adsorbates; and using geometrical optimization of milling patterns. Chemical enhanced FIB micromachining (CE-FIBM) techniques include the use of water vapor to improve FIB micromachining of various materials including polymers, integrated circuits and diamond as well as the use of various halogen based (F, Cl and I) precursors for machining of materials ranging from Si to Fe-Ni alloys. The machining of a free edge provides a geometrical yield enhancement of more than 5 and, when combined with simultaneous chemical enhancement, can increase total yield by as much as 30 times. The major applications of FIB for preparing cross sectional analysis samples for FIB or SEM imaging, or for TEM analysis benefit in may ways from the specialized gas chemistry assistance methods developed over the past 10 years. Integrated circuit and MEMS device editing techniques have also been enhanced through the use of unique materials specific gas assisted FIB solutions.

Segregation of elements to the grain boundaries in Ni-base alloys can have a large effect on the mechanical and corrosion properties of these materials. The extent of segregation, whether it is equilibrium or non-equilibrium segregation, is dependent upon the thermo-mechanical treatments applied to the alloy. in order to determine if a particular thermo-mechanical process delivers the desired microstructure, a complete microstructural analysis including an examination of grain boundary segregation must be performed.

In the past, TEM has been used to identify the various phases and precipitates in these materials through the use of bright- and dark-field imaging, electron diffraction, and EDS. However, one of the elements that can play a large role in determining the properties of these alloys is boron. in this group of alloys, boron is generally present in bulk analyses in only a few tens of ppm, and as a result it is difficult to detect using the aforementioned techniques. More commonly, boron segregation to the grain boundaries is usually studied by means of Auger analysis, whereby the sample is charged with hydrogen in order to promote brittle intergranular fracture in-situ in the Auger microprobe. Boron can then be detected at the surface of the clean grain boundary fracture surfaces.

Recent developments in transmission electron microscopy put high demands on specimen preparation. in general the imaging quality is not limited by the performance of the microscope but by the quality of the specimen. in order to achieve a spatial resolution of 0.1 nm in HRTEM undamaged samples with a thickness below 10 nm are required. in energy filtering analytical electron microscopy (EFTEM), a constant specimen thickness over large areas and very low contamination is needed.

Conventional ion-milling techniques for TEM specimen preparation are essentially blind. Thus, it is left to chance whether the specimen detail of interest is suitable for TEM-imaging (many specimen areas are too thick). Another problem is the reaction of the specimen with the atmosphere during the transfer from the preparation stage to the microscope, which makes it very difficult to obtain the clean specimen surfaces that are needed in analytical EFTEM. Especially in high-resolution electron microscopy and electron holography the formation of amorphous oxidation and contamination layers on otherwise crystalline materials may seriously reduce the quality of high resolution images of the crystal structure.

As the importance of nano-scaled structures in both science and engineering increases, techniques for reconstructing three-dimensional structural, crystallographic and chemical relationships become increasingly important. in this paper we described a technique which uses focused ion beam (FIB) sputtering to expose successive layers of a 3D sample, coupled with secondary electron imaging and secondary ion mass spectrometry of each sputtered surface. Computer interpolation of these different slice images then enables reconstruction of the 3D structure and chemistry of the sample. These techniques are applicable to almost any inorganic material, at a spatial resolution of tens of nanometers, and fields of view up to (tens of μm).

The FIB instrument used in this study is an FEI 200 with a minimum ion probe diameter < 10 nm, an ion current density ∼ 10 A/cm2, a maximum ion current of 11 nA, and a standard Ga+ ion energy of 30 keV. Our instrument is equipped with a continuous dynode electron multiplies (CDEM) for secondary electron imaging and a quadrupole mass spectrometer for secondary ion mass spectroscopy (SIMS) / element specific mapping. Gallium ions of this energy will ablate any material, with sputter yields typically of order ten, corresponding to a material removal rate of order 1 μm3nA−1s−1.

Techniques for the 3D analysis of materials at the sub-micron level are of major importance for understanding the structure and performance of new nanoengineered materials. Established techniques for determining 3D shapes of individual grains include X-ray tomography and light microscopy for grains ≫ 1μm, and 3D-atom probe for conducting grains < 50nm size. A new technique of TEM EELS tomography is being developed for particles 2-300nm in a chemically distinct matrix.

For the grain size range 200nm-20μm, we have applied a new technique of 3D analysis using focused ion beam (FIB) sectioning to the site-specific analysis of the shape of individual grains in a single phase matrix. in the 3D FIB technique, a sample surface may be serially sectioned using a highly focused beam of Ga+ ions (Fig. 1). A sequential set of 2D secondary electron images through the sample can be aligned in 3D by cross-correlation of the position of reference markers in the 2D images.

We have developed an FIB micro-sampling technique to prepare both plan view and cross-sectional TEM specimens from a specific site.

The instruments that were used in this study are the Hitachi FB-2000A FIB system equipped a with micromanipulator unit and an HF-2200 cold field emission 200kV analytical TEM equipped with a scanning attachment allowing both STEM and SEM imaging.

Figure 1 shows a procedure to prepare a micro-sample for either plan view or cross-sectional TEM observation of the specific site. First, the micro-sample for plan view TEM observation is trench milled by using an FIB(Figure 1a). Second, a tip of a micromanipulator W-probe is bonded to the micro-sample with the FIB assisted metal deposition. Then, the micro-sample is lifted out and transferred onto a micro-sample carrier(Figure 1b).

Advantages of the FIB lift-out technique over traditional H-bar TEM specimen preparation have been recognized. The ability to rapidly (< 1 hour) prepare a site specific TEM specimen without destroying the entire bulk specimen has led to a wide spread reliance on this method. The main disadvantage of this technique is an inability to accomplish additional membrane thinning if required. Traditional H-bar preparation allows additional thinning. However, mechanical polishing is time consuming and the bulk sample is destroyed. A method has been developed which combines the efficient, site specific advantages of the lift-out method with the H-bar's ability to accomplish additional thinning. in this procedure a lift-out specimen is removed from the bulk sample and mounted onto a half-grid in a configuration similar to that employed by the H-bar technique.

A 1.0-micron thick lift-out specimen was prepared using a FEI Strata DB-235 FIB dual-beam workstation by sputtering away bulk material leaving a thin membrane containing a desired feature (FIG 1).

The FIB lift-out (LO) technique has been applied to a sample that been pulled to failure by tensile testing. An aluminum alloy (5083) was cold deformed using DSI's Maxistrain technology [1]. The alloy was cut with a low speed diamond coated wafering blade such that the fracture surface would fit inside the focused ion beam (FIB) specimen chamber. The sample was then mounted and placed in an FEI 200TEM FIB instrument. An FIB image of the tip of the fracture surface is shown in figure 1. A region for TEM specimen preparation was chosen such that the specimen would be in the plane of the tensile axis. The area of interest was chosen to ensure that FIB undercutting of the specimen could be accomplished upon tilting inside the FIB, and to ensure that the micromanipulator needle would have access to the FIB prepared specimen. A region of interest was coated with Pt using the FIB. A TEM specimen was then prepared in the usual LO manner [2,3]. The location of the finished LO specimen is circled in figure 1. After FIB milling was completed, the sample was removed from the FIB and placed on a light optical microscope stage. The electron transparent membrane was removed from the deformed sample using a glass rod attached to a micromanipulator. While the successful LO was performed, it should be noted that the micromanipulation was non-trivial due to the rough fracture surface combined with the poor depth of field of the light optical microscope.

In this communication we present a method using Focused Ion Beam (FIB), Energy Filtered TEM (EFTEM) and STEM for semiconductor defects interception and high resolution observation. This method takes benefit of the specific imaging properties of respectively EFTEM and STEM techniques. A demonstration is presented for the observation of dislocations in a silicon integrated circuit.

Silicon defects such as dislocations are one of the major issues in Integrated Circuit fabrication. Due to their low distribution density these silicon defects are not easily observed using TEM cross section. in this paper we present a more appropriate technique using: FIB, EFTEM and STEM for such defects observation. First, in order to improve the probability of defects being present in the specimen, a very thick lamella is prepared using FIB. Then, using an energy filter for eliminating the inelastic electrons needed to allow thick specimen TEM imaging, direct defect localization and observation at medium resolution is carried out. After that, taking advantage of the beam broadening in the STEM, the defect position inside the specimen is more accurately evaluated. For that purpose two STEM observations are carried out from the two opposite specimen surfaces. The comparison of image contrast is used for further FIB specimen thinning. The process can be continued down to a thickness compatible with an acceptable spatial resolution TEM imaging.

Recently, several studies have been conducted to investigate the behavior of polymer based composites reinforced with clay particles, which can remarkably improve the properties of the polymers. Studies using transmission electron microscopy (TEM) are necessary to understand the role of clay minerals/particles in the reinforcing effect in the polymer based materials. TEM sample preparation of polymer/clay nanocomposites using conventional techniques has been difficult and tedious. Nevertheless, the focused ion beam (FIB) technique for preparing metal and ceramic samples provides another method for preparing polymer nanocomposite samples. This paper presents a new approach for preparing TEM specimens of the polymer nanocomposites using the FIB technique.

Two types of epoxy (Dow Chemical Company, DER 331) nanocomposite samples were investigated: one containing 7.5 wt.% organomontmorillonite clay (Southern Clay Products Inc., Cloisite 30B) and the other (carbon fiber reinforced plastics; CFRP) containing carbon fibers (Hexel Fibers, AS4) in addition to 5 wt. % clay. Details of preparing the epoxy based clay nanocomposites will be published elsewhere. Procedures for preparing TEM thin sections using FIB were based on techniques developed by Ramirez de Arellano et al.

In recent years, the availability of focused ion beam (FIB) milling systems has given a much-needed boost for transmission electron microscopy (TEM) as a technique for site-specific analysis. Much progress has been made in the area of site-specific cross-sectional and planar TEM sample preparation techniques. However, a continuing need exists to reduce the sample preparation time, in order to improve TEM cycle time for better support of process development, yield improvement and production in a high-volume industrial environment. Thus, a faster TEM sample preparation technique is always desirable to meet this demand. A new approach to TEM sample preparation is described in this paper.

Following the new approach developed in the present work, one can prepare on a single TEM grid at least two different cross-sectional samples of site-specific device structures or up to four different cross-sectional samples of blanket films. Two different samples, each containing an area of interest near the center, are cleaved or cut to a width of about 1.25 mm; these samples may be from two separate locations of a wafer, or from two different wafers where TEM analyses are required.

The ability to acquire TEM specimens from micrometer sized particles using an innovative FIB LO technique has been previously demonstrated [1-3]. This technique allowed for the preparation of a TEM LO specimen from regions which were smaller than the conventional dimensions of the LO specimen (∼5 μm × 20 μm). This paper shows how the LO technique previously developed for the preparation of micrometer sized particles [3] may be extended and utilized for the preparation of submicrometer sized particles for TEM analysis.

In this study, TiO2 particles on the order of 200 nm in width were investigated. A small portion of the TiO2 particles was dusted onto double stick carbon tape adhered to a sample stud and then sputtered coated with Au-Pd to protect the outer surface from FIB imaging. The sample stud containing the TiO2 particles was placed in an FEI 200TEM FIB workstation. Figure 1 is a FIB image of the Ti02 particles of interest. Gaps around these particles were deposited with Pt using the FIB assisted CVD process as shown in Figure 2. in this procedure, the Pt acts as a “weld” to hold the particles together, and to allow for a larger region to be milled (e.g., >10 μm) for subsequent specimen preparation.

The Small Angle Cleavage Technique (SACT) can produce samples from brittle and cleavable materials very quickly. It is possible for a skilled person to produce about 10 XTEM specimens in an hour. However, there are materials related limitations to the technique. These include 1) the ductile/brittle nature of the substrate, i.e. the fracture mechanics of the materials, 2) the strength of the interfaces between multi-layers, 3) the thickness of any ductile layers, and 4) the strength of the layer materials. in most of the cases where SACT fails, the sample is near electron transparency at the apex of the sample. Where there is a weak interface as in some multi-layer systems, or where the material itself is weak such as when an evaporated Ge layer is used, some of the film near the substrate is sufficiently thin, but there is a jog in the film stack and further back from the apex it is not transparent. If such a SACT sample is viewed from the surface in an SEM, this apparent delaminating of the top layers is evident and usually within 1 μm of the apex.

The purpose of this paper is to show that the geometry of a SACT-prepared sample is well suited for applying FIB milling for further thinning of the sample to electron transparency. in addition, the FIB can be easily applied to SACT specimens that fail to produce usable samples for the reasons cited above. The SACT method allows two main options for mounting the samples that are illustrated in Fig 1.

In recent years, the use of the focused-ion beam (FIB) microscope has become widespread in the areas of materials processing and materials characterizaation. Although initial commercialization of FIB instruments was driven by applications in the semiconductor industry, recently the FIB has emerged as a broad characterization tool capable of imaging, material removal and material deposition. This combination makes it a useful instrument for applications ranging from site-specific sample preparation for transmission electron microscopy1 to thin-film head manufacturing. However, since the interaction of a high-energy ion beam (e.g., 30 keV Ga) with a solid inevitably produces implantation damage and the possibility of other effects such as grain growth, dislocation motion or degradation of magnetic properties , it is important to quantify to what extent the material under examination has been modified. Simple TRIM simulations may provide an estimation of the implantation level and depth to which ions will travel into a solid, but these results may not be accurate because FIB milling is not a static situation.

In order to investigate Ga implantation depth, concentration and possible grain growth effects, three circular regions on a 500 nm thick electroplated Ni-80 at.% Fe film were milled using 30 keV Ga ions at three different beam currents, Fig. 1.

The technique for the preparation of specimens for transmission electron microscopy (TEM) using the focused ion beam (FIB) miller typically consists of a series of milling steps performed over both sides of an area of interest until an electron transparent membrane is achieved [1]. This process is often accompanied by the formation of damage layers on the surfaces of the specimen. The origins of any damage layer are still not clear. On one hand the process of amorphisation of the target material by the highly energetic ion beam is well known. Alternatively, other workers have reported that this damage layer can be connected with redeposition of milled material. [2,3]. in this paper we have studied redeposition effects during FIB milling of silicon TEM specimens.

A FEI xP200 FIB system with a Ga+ ion source operating at 30 kV was used in this work. to study redeposition effects a row of trenches on a silicon specimen was milled under different beam currents ranging from 1000 to 6600 pA. The size of such trenches was 15x10 μm wide and 1 μm deep. The specimen was then removed from the FIB and sputter coated with a ∼50-100 nm thick Au film to preserve the trench surfaces from further damage during subsequent milling. The specimen was then placed back in the FIB system and a second set of trenches 5×8 μm wide and 0.6 μm deep was milled on the bottom of first set of trenches (Fig. 1a). The specimens were sputter coated with Au again and were placed back in the FIB system and the trenches were then covered with 1 μ thick Pt strips using the metal deposition facility of the FIB. The presence of these protection layers (Au and Pt) ensures that the final TEM specimen have unmodified original damage layers resulting from the initial milling steps. Cross-sectional TEM specimens of the trench walls were then prepared using normal FIB procedures (Fig. 1b) [2].

The focused ion beam (FIB) miller allows preparation of site-specific transmission electron microscopy (TEM) specimens from a wide range of materials in both cross-sectional and planar configurations [1,2]. However, radiation damage during exposure to the high-energy gallium beam may result in the formation of amorphous regions on thin film specimens. The thickness of such damage layers, on both sides of a TEM specimen, is comparable with the thickness required for lattice imaging. For example, the thickness of an amorphous layer in Si after 30 kV Ga+ FIB processing has been reported in the range from 15 [3] to 28 nm [4]. This problem limits the capabilities of FIB sample fabrication.

The aim of this study was to investigate, in detail, the structure, composition and the thickness of the damage layers in Si specimens after milling with a gallium ion beam. Using a FEI xP200 FIB system, with 30 kV Ga+ ions, a row of trenches on a silicon sample was milled under different beam currents ranging from 150 to 6600 pA. The average size of such trenches was 15×10 μm wide and 1 μm deep. The trenches were then removed from the FIB and sputter coated with a thick Au film to preserve the trench surfaces from further damage during subsequent TEM specimen preparation steps. Cross-sectional TEM specimens of the trench walls were then prepared using standard FIB procedures [5]. Observations were made using a Philips CM 200 Field Emission Gun TEM operating at an accelerating voltage of 200 kV.

Critical dimensions in advanced semiconductor devices are now such that a significant fraction of some structures is contained within the thickness of a TEM foil. An important example is the vias used in multilevel metallization to interconnect transistors and other structures. Current generation vias have a diameter of 300 nm, and vias in devices under development are targeted at 180 nm. These dimensions are to be compared to the thickness of a TEM foil, which may be ∼50 nm. Vias are typically fabricated by etching holes in a dielectric layer, then depositing into these holes a barrier metal, such as Ta, followed by a Cu seed layer and finally Cu fill. Critical to via processing reliability are the thicknesses of barrier and seed layers. A TEM cross section of such a via will contain sharply curved layers which, when seen in projection, will lead to inaccurate measurement of layer thicknesses. Ordinary plan view preparation of these vias avoids this projection problem, but uncertainty is introduced in the height at which the via is sectioned.

We have developed an angled plan view (APV) FIB preparation technique that allows accurate measurement of barrier and seed thicknesses at discrete heights from bottom to top of a via.

The considerable improvements in computational power and the increased sophistication of programming techniques now make it possible to automate many aspects of electron microscopy [1]. Automation offers several important advantages over manual operation. Automation of microscope operation permits novice microscopists to obtain data relatively easily thus increasing instrument utilization. The experienced microscopist should be able to acquire data more rapidly and with greater ease compared to manual operation, resulting in increased efficiency. Alignment of energyfilters and proposed Cs correctors are difficult and time consuming even for experienced microscopist and stable alignment algorithms are critical for practical use. Automation is essential for extensive statistical sampling of microstructures and can permit experiments to be performed that were previously impractical. For example, spectrum imaging involves acquisition of thousands of spectra from a predefined area. The acquisition and processing of such large volumes of data cannot be accomplished without the aid of automation. The future prospects for automation are exciting, although it is important to carefully consider the relationship between the computer controlled microscope and the operator. Here I give a personal perspective on approaches to automation which increase the power and efficiency of modern transmission electron microscopes.

The degree of automation is an important consideration that is related to the complexity of the analysis strategy. Some analysis situations call for repetitive sampling of a well-defined quantity such as layer thickness or particle size. These simple repetitive operations are ideal candidates for total automation. For many applications of automation it is necessary not only to acquire the data but also to process the data and extract the quantity of interest.

Tissue heterogeneity and three-dimensionality are generally neglected by most traditional analytical microscopy methods in Biology. These often disregard contextual information important for understanding most biological systems. in breast cancer, which is a tissue level disease, heterogeneity and three dimensionality are at the very base of cancer initiation and clonal progression. Thus, a three dimensional quantitative system that allows low resolution virtual reconstruction of the mammary gland from serial sections, followed by high resolution cell-level reconstruction and quantitative analysis of the ductal epithelium emerges as an essential tool in studying the disease. We present here a distributed microscopic imaging system which allows acquiring and registering low magnification (1 pixel = 5 μm) conventional (bright field or fluorescence) images of entire tissue sections; then it allows tracing (in 3D) the ducts of the mammary gland from adjacent sections, to create a 3D virtual reconstruction of the gland; finally it allows revisiting areas of interest for high resolution (1 pixel = 0.5 μm) imaging and automatic analysis. We illustrate the use of the system for the reconstruction of a small volume of breast tissue.

The second generation of computer-controlled scanning electron microscopes (SEMs), i.e. instruments directed by software executing on conventional personal computers (PC-SEMs), has become the industry standard. Although limited automation has been incorporated by most manufacturers, these features do not significantly alleviate the requirement for operator expertise to attain optimal performance from the microscope. Our approach to the expertise deficit has been to pursue a knowledge-based approach to microscope control, encapsulating human knowledge in software to achieve expert performance. The task of SEM operation was decomposed into five phases - Specimen Preparation, SEM Preparation, SEM Initialisation, SEM Optimisation and External Analysis - and the central three phases were modelled in detail. A stand-alone prototype system (XpertEze) was developed to utilise this model for the LEO 400 series. A web-based version was implemented to support intelligent remote microscopy.

A stand-alone knowledge-based system has several disadvantages: its user interface competes for screen space with the conventional control software, its speed of execution is reduced as its instructions must be transferred via application programming interfaces to the microscope, and the operator must learn and manage two sets of software. Our ongoing work has been to remove these problems by incorporating the XpertEze system directly within the control system.