TEM Specimen Preparation Research Articles

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.

Microstructural Characterization of Automated Specimen Preparation for TEM Analysis

Abstract Automated specimen preparation for transmission electron microscopy has the obvious advantage of saving personnel time. While some people may perform labor intensive specimen preparation techniques quickly, automated specimen preparation performed in a timely and reproducible fashion can significantly improve the throughput of specimens in an industrial laboratory. The advent of focused ion beam workstations for the preparation of electron transparent membranes has revolutionized TEM specimen preparation. The FIB lift-out technique is a powerful specimen preparation method. However, there are instances where the “traditional” FIB method of specimen preparation may be more suitable. The traditional FIB method requires that specimens must be prepared so that the area of interest is as thin as possible (preferably less than 50 μm) prior to FIB milling. Automating the initial specimen preparation for brittle materials (e.g., Si wafers) may be performed using the combination of cleaving and sawing techniques as described below.

Implications of specimen preparation and of surface contamination for the measurement of the grain boundary carbon concentration of steels using x-ray microanalysis in an UHV FESTEM

The purpose of the present investigation was to gain an understanding of the nature of the carbon contamination on the surface of standard steel transmission electron spectroscopy (TEM) specimens, the effect of exposure of a clean specimen to normal laboratory air, and the efficacy of plasma-cleaning treatments. This knowledge is a necessary prerequisite to the development of appropriate specimen preparation and/or specimen cleaning methods. X-ray photoelectron spectroscopy in combination with argon ion beam profiling was used to characterize the specimen surfaces of X65 steel and 316 stainless steel. The only clean carbon-free surface obtained was that during argon etching of the sample in the surface analysis chamber. Any exposure of a previously cleaned sample to laboratory air resulted in a rapid carbon (hydrocarbon) contamination of the sample surface and the development of surface oxidation, Plasma cleaning with subsequent exposure of the specimen to the laboratory air also resulted in a carbon-contaminated surface. This suggests that procedures of preparation of TEM specimens of steels outside an ultrahigh vacuum chamber are unlikely to result in the lowering of contamination rates on specimens to levels where measurements for carbon in the grain boundaries are possible. What is needed is a cleaning system as an integral part of the specimen insertion system into the field-emission scanning transmission electron microscope. This cleaning could be carried out by argon ion etching. Copyright (C) 2000 John Wiley & Sons, Ltd.

Precision FIB TEM Specimen Preparation ‘at a Distance’

There is a trend in electron microscopy towards centralization of the more sophisticated EM systems. The rationale is that the techniques associated with such instrumentation are more efficiently practiced and developed by dedicated specialists in a regional or national centre surrounded by an extensive infrastructure. A similar argument can be used for the preparation of TEM specimens, especially as the demand grows for more precise location of the thin area to be examined. A new trio of techniques - tripod polishing, ultramicrotomy, and focused ion beam (FIB) thinning - can locate the thin area to within a micron or less. In the first two, a linear feature first located via light or scanning electron microscopy can be cross-sectioned by controlled material removal via mechanical polishing or diamond knife sectioning, respectively. With FIB, feature location and material removal are carried out in-situ, first imaging with a low intensity beam, then milling trenches on either side of the feature with a high intensity beam that is decreased as the feature is approached.

Reactive Ion Beam Etching (RIBE) Technique and Instrumentation for SEM Specimen Preparation of Semiconductors

Argon ion beam etching has established itself as an alternative technique to “wet chemical” etching for the preparation of cross sectional SEM specimens of semiconductors [1]. Complementing this technique, we are reporting the results of an iodine RIBE method for improved etching/cleaning capabilities with a measurable increase in etching rates as compared to argon ion beam etching. RIBE systems have been used for decades in the semiconductor research/industry for wafer processing, patterning and surface cleaning. This same technique has also been used for high quality TEM specimen preparation of certain semiconductor materials [2,3]. The beneficial aspects of the iodide RIBE technique for surface etching for a variety of semiconductor structures along with the related instrumentation will be discussed. The semiconductor specimens include traditional ICs and more advanced copper technology devices.The design and construction of the original system used in this work has already been reported [4].

Characterization of Thin Films on Oxide Using a Unique Tem Specimen Preparation Process

Transmission Electron Microscopy technique is a powerful tool to examine microstructures. However, the specimen preparation process usually requires tedious and careful cutting and lapping. In this paper, we present a TEM specimen preparation process which is simple, requires about one hour, and allows specific areas of patterned films deposited on silicon dioxide to be examined. The sample consisted of three thin film layers deposited on a Corning 1737 glass substrate. The top layer was 1000 A thick, low temperature oxide; the middle layer, 1000 A thick; amorphous silicon; the bottom layer, 1000 A thick, low temperature oxide. The top oxide layer was patterned to contain a square array of 10 × l0um openings, with a 100 um center to center spacing. A thin nickel layer was the evaporated, and the specimen was heated to form nickel silicide in the 10 × 10 um areas where Ni and Si were in contact.

TEM FIB Lift-Out of Mount Saint Helens Volcanic Ash

Focused Ion Beam (FIB) specimen preparation for both scanning and transmission electron microscopy (SEM and TEM respectively) has seen an increase in usage over the past few years. The advantage to the FIB is that site specific cross sections (or plan view sections) may be fabricated quickly and reproducibly from numerous types of materials using a finely focused beam of Ga+ ions [1,2]. It was demonstrated by Prenitzer et al. that TEM specimens may be acquired from individual Zn powder particles by employing the FIB LO specimen preparation technique [3]. In this paper, we use the FIB LO technique to prepare TEM specimens from Mount Saint Helens volcanic ash.Volcanic ash from Mount Saint Helens was obtained at the Microscopy and Microanalysis 1998 meeting in Atlanta. TEM analysis of the ash was performed using the FIB lift out technique [1]. Ash powders were dusted onto an SEM sample stud that had been coated with silver paint.

Optimization of TEm specimen preparation by double-sided ion beam thinning under low angles

We have developed special specimen holders for double-sided low angle ion beam thinning and have systematically studied possible improvements of the resulting TEM specimens with respect to surface roughness, radiation-induced damage and contamination. The specimen holders are entirely made from graphite and were built for two different ion beam thinners. The design makes it possible to work at angles of incidence of 6° and lower and to precisely position the centre of rotation. The resulting specimen geometry was characterized with respect to a number of critical parameters. The surface topography was measured with atomic force microscopy, defect-induced localized strain was revealed by HRTEM and the thicknesses of contamination layers, carbon coating and amorphous oxide layers were quantitatively determined by electron spectroscopic imaging in an energy filtering TEM. It was found that the surface roughness not only decreases with decreasing angle of incidence, but also when the ion energy is lowered. In the lowangle regime, the thinning mechanism is based on the formation and propagation of ledges. Simultaneous ion bombardment from both sides has been found to be one of the most critical parameters.

Tutorial: Tem Specimen Preparation in the Physical Sciencestripod Polishing and Ion Milling

Over the past few decades, the demands of modern analytical electron microscopy have increased the need for TEM specimen preparation techniques with a minimum of misleading artifacts in terms of chemical microanalysis. At the same time, the demands of modern industrial materials, be they semiconductor, polymeric or composite in nature, call for speed, flexibility and high spatial resolution as well. The response from the electron microscopy community, especially that portion in the private sector, have been to devise (or advocate) radically different forms of TEM thin specimen preparation from that of classic replication, electropolishing and ion thinning.This tutorial sets forth the goals of TEM specimen preparation, and the requirements for a "good" TEM specimen. The strategic choices governing which technique to use for preparing a wide variety of specimens will be covered. A TEM Specimen Preparation Flow Chart will be used to plot a course that makes optimum use of the preparation techniques available as a function of the type of specimen to be prepared.

A New Method for Pin Point Failure Analysis Using Fib Combined Analytical Tem

Abstract Recently, we developed the dedicated FIB system(FB-2000A) for the TEM specimen preparation. The system has ion optics with the maximum ion beam current density of 15 A/cm2 and the minimum ion probe size of l0nm. In the system, the side entry type specimen stage originally designed for high resolution TEM was employed, and the drift rate of the stage during FIB milling is less than lnm/min. The FIB-TEM compatible specimen holder has been developed it made milling of specimen in FIB system and observation of milled specimen in TEM without remounting the specimen possible.. The holder was designed to rotate the specimen around the axis of specimen holder so that both side of milled surfaces can be faced to incident electron beam in TEM. To improve positional resolution in pin point TEM specimen preparation, it is important to know the inside structure of specimen before starting the milling.

Tem Specimen Preparation for Display Materials of Vacuum Fluorescent Displays

Further development of Vacuum Fluorescent Displays (Fig.l) for low cost production and high yield requires investigation of all the components on a submicron scale at various processing stages.A variety of specimen preparation methods have been used for making different types of high quality cross-sectional and plan-view TEM specimens from:1.Initial phosphor materials - ZnCdS powders admixed with conducting powder of ln2O3;2.In2O3 mixed ZnCdS phosphor layers of ready-made working VFD;3.W - filament cathodes coated with (Ba,Sr,Ca) oxides.Rapid sharing of results.Group 1 specimens were made both by direct dispersion of phosphor powder particles on the carbon coated copper grid from acetone diluted powder suspension, and by preparation of cured bulk material from the powder using Gatan G-l epoxy, followed by cutting, grinding-dimpling and final ion milling in Gatan DuoMill 600 (Fig.2).

Comparison of Focused Ion Beam and Conventional Techniques on Tem Specimen Preparation of Metal-Ceramic Interfaces

Abstract The results of TEM analyses of materials are critically dependent on the quality of the sample prepared. Although numerous techniques have been developed in the last two decades, differential thinning of inhomogeneous materials remains a serious problem. Recently, focused ion beam (FIB) technique has been introduced for cross-sectional sample preparation for TEM and SEM. A novel system for depositing a fine-grain (∼ 200 nm) ceramic coating on a metal surface via a patent pending Small-Particle Plasma Spray (SPPS) technique has been developed at the Basic Industry Research Laboratory of Northwestern University. To understand the properties of the coated surface, the ceramic/metal interface and the microstructure of the ceramic coating must be investigated. This paper presents a comparison of the microstructure of an A12O3 coating on a mild steel substrate prepared using conventional and FEB techniques.

Applications of the FIB lift-out technique for TEM specimen preparation.

A site-specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented. A focused ion beam was used to slice an electron transparent membrane from a specific area of interest within a bulk sample. Micromanipulation lift-out procedures were then used to transport the electron-transparent specimen to a carbon-coated copper grid for subsequent TEM analysis. The FIB (focused ion beam) lift-out technique is a fast method for the preparation of site-specific TEM specimens. The versatility of this technique is demonstrated by presenting cross-sectioned TEM specimens from several types of materials systems, including a multi-layered integrated circuit on a Si substrate, a galvanized steel, a polycrystalline SiC ceramic fiber, and a ZnSe optical ceramic. These specimens have both complex surface geometry and interfaces with complex chemistry. FIB milling was performed sequentially through different layers of cross-sectioned materials so that preferential sputtering was not a factor in preparing TEM specimens. The FIB lift-out method for TEM analysis is a useful technique for the study of complex materials systems for TEM analysis.

透過電子顕微鏡による接合界面の観察 接合界面のＴＥＭ試料作製の方法

透過電子顕微鏡による接合界面の観察 接合界面のＴＥＭ試料作製の方法

Influence of material properties on TEM specimen preparation of thin films

Influence of material properties on TEM specimen preparation of thin films

Focused Ion Beam Sample Preparation of Non-Semiconductor Materials

AbstractFocused Ion Beam (FIB) systems have been steadily gaining acceptance as specimen preparation tools in the semiconductor industry. This is largely due to the fact that such instruments are relatively commonplace as failure analysis tools in semiconductor houses, and are commonly used in the preparation of cross-sections for imaging under the ion beam or using an electron beam in an SEM. Additionally, the ease with which cross-sectional TEM specimens of semiconductor devices can be prepared using FIB systems has been well demonstrated. However, this technology is largely unknown outside the semiconductor industry. Relatively few references exist in the literature on the preparation of cross-sectional TEM specimens of non-semiconductor materials by FIB. This paper discusses a specific use of FIB technology in the preparation of cross-sectional TEM specimens of non-semiconductor samples that are difficult to prepare by conventional means. One example of such materials is commercial galvannealed steel sheet that is used to form corrosion resistant auto-bodies for the automobile industry. Cross-sectional TEM specimens of this material have proved difficult and time-intensive to prepare by standard polishing and ion milling techniques due to galvanneal's inherent flaking and powdering difficulties, as well as the different sputtering rates of the various Fe-Zn intermetallic phases present in the galvannealed coatings. TEM results from cross-sectional samples of commercial galvannealed steel coatings prepared by conventional ion milling and FIB techniques are compared to assess image quality, the size of the electron-transparent thin regions that can be readily prepared and the quality of samples produced by both techniques. Specimen preparation times for both techniques are reported.

Evaluation of a New Strategy for Transverse Tem Specimen Preparation by Focused-Ion-Beam Thinning

AbstractIn this paper, different variations of a recently developed focused ion beam (FIB)-based TEM specimen preparation technique are studied conceptually and experimentally, compared, and evaluated. This procedure mainly consists of formation, removal, transport, and mounting of an electron transparent transverse membrane on a support grid for TEM study. Based on the experimental results obtained from this evaluation, some modifications have been conceived and implemented. These details as well as other critical information have been presented and discussed.

Preparation of Cross-Section Tem Specimens of Semiconductors Containing Tungsten Interconnects Using Chemical Mechanical Polishing and Chemically Assisted ion Beam Milling, and Use of Afm to Evaluate the Success of These Procedures

AbstractTEM of semiconductors containing tungsten interconnects is hampered by the problem of tungsten being intrinsically opaque to the electron beam, and at the same time typically being much thicker than the rest of the specimen. This work describes a technique which can predictably and reproducibly thin tungsten to electron transparency using chemical mechanical polishing (CMP). Chemically-assisted ion beam etching (CAIBE) techniques were also investigated, but found to be of little benefit. The key to development and evaluation of these methods was the AFM.

Focused Ion Beam Milling and Micromanipulation Lift-Out for Site Specific Cross-Section Tem Specimen Preparation

AbstractA site specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented. Focused ion beams are used to slice an electron transparent sliver of the specimen from a specific area of interest. Micromanipulation lift-out procedures are then used to transport the electron transparent specimen to a carbon coated copper grid for subsequent TEM analysis. The experimental procedures are described in detail and an example of the lift-out technique is presented.

An Updated Ion Polishing System for Tem Specimen Preparation of Materials

AbstractThe construction and performance of an improved ion milling instrument are described. The updated instrument is based upon an earlier version fixed low angle ion milling system. The updated system employs two improved guns having the ability of independent variable milling angle adjustment, while operating at high voltage in the vacuum system. The milling rate of these ion guns is typically ≈ 90μm/hr/gun pair for copper at 5keV and 10°. Designed to compliment the variable angle ion gun is a new specimen holder which permits low angle double sided milling. The combination of these two features offers numerous single or double sided milling conditions to facilitate the production of higher quality TEM specimens in less time. The range of ion gun angles encompassed is 0° to 10° for single-sided milling and 0° to ± 10° for double-sided milling. The instrument also incorporates an electronic mechanism to generate directional sector milling which benefits primarily the production of cross sectional TEM specimens and heat sensitive materials since the ion guns are turned off for a portion of time during each revolution. Another new feature of the instrument is chemical ion milling which facilitates the preparation of certain compound semiconductors. The ability of this improved ion milling instrument for rapid ion polishing and improved specimen quality is demonstrated by a number of TEM images of metals, ceramics and semiconductors.