Showing papers on "Focused ion beam published in 2000"

Atom probe tomography

Abstract: Atom probe tomography is a powerful tool for the characterization of the size, morphology and composition of ultrafine features in a variety of materials. With the development of new forms of specimen preparation especially with focused ion beam milling systems, atom probe tomography should be extended to a wider variety of applications in nanotechnology.

Three-dimensional nanostructure fabrication by focused-ion-beam chemical vapor deposition

Abstract: Three-dimensional nanostructure fabrication has been demonstrated by 30 keV Ga+ focused ion beam assisted deposition using a aromatic hydrocarbon precursor. The characterization of deposited film on a silicon substrate was performed by a transmission microscope and Raman spectra. This result indicates that the deposition film is a diamondlike amorphous carbon. Production of three-dimensional nanostructure is discussed. Microcoil, drill, and bellows with 0.1 μm dimension were fabricated as parts of the microsystem. Furthermore, microstructure plastic arts is advocated as a new field using microbeam technology, presenting one example of a microwine glass with 2.75 μm external diameter and 12 μm height.

On the red-blue set cover problem

Abstract: Both the increased complexity of integrated circuits, resulting in six or more levels of integration, and the increasing use of flip-chip packaging have driven the development of integrated circuit (IC) failure analysis tools that can be applied to the backside of the chip. Among these new approaches are focused ion beam (FIB) tools and processes for performing chip edits/repairs from the die backside. This paper describes the use of backside FIB for a failure analysis application rather than for chip repair. Specifically, we used FIB technology to prepare an IC for inspection of voided metal interconnects (''lines'') and vias. Conventional FIB milling was combined with a super-enhanced gas assisted milling process that uses XeF{sub 2} for rapid removal of large volumes of bulk silicon. This combined approach allowed removal of the TiW underlayer from a large number of Ml lines simultaneously, enabling rapid localization and plan view imaging of voids in lines and vias with backscattered electron (BSE) imaging in a scanning electron microscope (SEM). Sequential cross sections of individual voided vias enabled us to develop a 3-d reconstruction of these voids. This information clarified how the voids were formed, helping us identify the IC process steps that needed tomore » be changed.« less

Electron beam ion source with integral low-temperature vaporizer

Abstract: An ion source for ion implantation system and a method of ion implantation employs a controlled broad, directional electron beam to ionize process gas or vapor, such as decaborane, within an ionization volume by primary electron impact, in CMOS manufacturing and the like. Isolation of the electron gun for producing the energetic electron beam and of the beam dump to which the energetic beam is directed, as well as use of the thermally conductive members for cooling the ionization chamber and the vaporizer, enable use with large molecular species such as decaborane, and other materials which are unstable with temperature. Electron optics systems, facilitate focusing of electrons from an emitting surface to effectively ionize a desired volume of the gas or vapor that is located adjacent the extraction aperture. The components enable retrofit into ion implanters that have used other types of ion sources. Demountable vaporizers, and numerous other important features, realize economies in construction and operation. Achievement of production-worthy operation in respect of very shallow implants is realized.

Ion beam scanner system and operating method

Abstract: The invention relates to an ion beam scanner system with ion sourcing equipment, an ion accelerator system and ion beam guide, containing an outlet aperture for a converging, centred ion beam and a mechanical alignment system for the target volume which is to be scanned. For this purpose, the ion accelerator system can be set to the acceleration required for maximum penetration depth of the ions. In addition, the scanning system has an energy absorption element, which is mounted in the path of the beam crosswise to the centre of the beam, between the target volume and the ion beam outlet aperture. The energy absorption element can be displaced crossways to the centre of the ion beam to vary the beam's energy, so that modulation of the ion beam depth which is effected by a linear motor and transversal displacement of the energy absorption element can be carried out in rapid succession by depthwise graduated scanning on volumetric elements of the target volume. The invention also relates to a method for ion-beam scanning and to a method for operating an ion-beam scanner system using a gantry system.

Nanoscale patterning of self-assembled monolayers with electrons

Abstract: We show the fabrication of gold nanostructures using self-assembled monolayers of aliphatic and aromatic thiols as positive and negative electron beam resists. We applied a simple and versatile proximity printing technique using focused ion beam structured stencil masks and low energy (300 eV) electrons. We also used conventional e-beam lithography with a beam energy of 2.5 keV and doses from 3500 to 80 000 μC/cm2. Gold patterns were generated by wet etching in KCN/KOH and characterized by atomic force microscopy and scanning electron microscopy. The width of the finest lines is ∼20 nm; their edge definition is limited by the isotropic etching process in the polycrystalline gold.

Near-infrared Yablonovite-like photonic crystals by focused-ion-beam etching of macroporous silicon

Abstract: We report on the fabrication of three-dimensional (3D) Yablonovite-like photonic crystals by focused-ion-beam (FIB) etching of macroporous silicon. Crystals containing up to 25×25×5 lattice cells are fabricated with a submicronic period of ∼0.75 μm. Photonic band gaps at wavelengths close to 3 μm are demonstrated from reflection measurements and confirmed by numerical calculations. The combination of plasma or chemical etching with FIB micromachining appears to be promising for the fabrication of a large variety of multiple-period 3D photonic crystals at optical wavelengths.

Microgrooving and microthreading tools for fabricating curvilinear features

Abstract: This paper presents techniques for fabricating microscopic, curvilinear features in a variety of workpiece materials. Micro-grooving and micro-threading tools having cutting widths as small as 13 {micro}m are made by focused ion beam sputtering and used for ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide to create a number of critically aligned facets. Sputtering produces rake facets of desired angle and cutting edges having radii of curvature equal to 0.4 {micro}m. Clearance for minimizing frictional drag of a tool results from a particular ion beam/target geometry that accounts for the sputter yield dependence on incidence angle. It is believed that geometrically specific cutting tools of this dimension have not been made previously. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close match between tool width and feature size. Microtools are used to machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061 Al cylindrical workplaces. Micro-grooving tools are also used to fabricate sinusoidal cross-section features in planar metal samples.

Focused ion beam induced deposition: fabrication of three-dimensional microstructures and Young's modulus of the deposited material

Abstract: In this work, some of the possibilities of focused ion beams for applications in microsystem technology are explored. Unlike most previous studies, the emphasis is on `additive' techniques, i.e. localized maskless deposition of metals and insulators. More precisely, we will show the possibility of fabricating small three-dimensional structures, using focused ion beam deposition of silicon oxide. Deposition examples will show that the technique is most promising for small post-processing steps or prototyping, because of its high degree of flexibility. Furthermore, an investigation into the mechanical properties of the deposited material is presented. More specifically, the Young's modulus of the deposited silicon oxide is determined.

Perforated tips for high-resolution in-plane magnetic force microscopy

Abstract: We describe a technique to modify batch-fabricated magnetic force microscopy (MFM) tips to allow high resolution imaging of the in-plane components of stray field. A hole with a diameter as small as 20 nm was milled through the magnetic layer at the apex of each tip using a focused ion beam. The tips were magnetized in the direction parallel to the sample plane. The hole at the apex forms a small pole gap, and the MFM signal arises from interaction of the stray field leakage from this gap with magnetic charge distribution of the sample. Data tracks written in recording media have been used to characterize tip performance.

Selective high-resolution electrodeposition on semiconductor defect patterns.

Abstract: We report a new principle and technique that allows one to electrodeposit material patterns of arbitrary shape down to the submicrometer scale. We demonstrate that an electrochemical metal deposition reaction can be initiated selectively at surface defects created in a p-type Si(100) substrate by Si (++) focused ion beam bombardment. The key principle is that, for cathodic electrochemical polarization of p-type material in the dark, breakdown of the blocking Schottky barrier at the semiconductor/electrolyte interface occurs at significantly lower voltages at implanted locations than for an unimplanted surface. This difference in the threshold voltages is exploited to achieve selective electrochemical deposition.

Progress in extreme ultraviolet mask repair using a focused ion beam

Abstract: The key challenge in extreme ultraviolet (EUV) mask defect repair is to avoid or limit the damage to the sensitive reflective multilayer (ML) stacks on the mask substrate and repair <55 nm mask defects. Our EUV mask design employs an oxide buffer layer between the ML and the absorber to protect the ML during repair. We have developed both opaque and clear EUV mask defect repair processes using focus ion beam (FIB) based gas-assisted etching (GAE) and ion-induced deposition. The process has been successfully demonstrated on our TiN baseline mask by 10× EUV print tests of 100 nm resist lines/spaces. More importantly we have assessed the current FIB tool performance capability and compared it with the general requirements for repairing the EUV mask for the 70 nm lithography node. The characterization includes minimum “effective” beam size, etch selectivity, and edge placement precision. We discussed the required improvements and future directions in repair tool research and development in order for the mask ...

Method and apparatus for enhancing yield of secondary ions

Abstract: The sensitivity of a secondary ion mass spectrometer (SIMS) is increased by using water vapor to enhance the yield of positive secondary ions sputtered by a primary focused ion beam. Water vapor is injected through a needle that is positioned close to the sample and electrically biased to reduce interference with secondary ion collection field. The sensitivity is enhanced for metals in particular, which tend to be sputtered as positive ions.

Junction profiling using a scanning voltage micrograph

Abstract: A method is provided for obtaining an accurate image of a two-dimensional junction profile of a semiconductor device. Embodiments include sectioning a sample to be analyzed through the active transistor, either at a 90° angle to the planar surface or at a desired angle, as by a focused ion beam (FIB) apparatus. The sectioned transistor can be analyzed directly on the exposed silicon, or the exposed silicon of the cross-section can be passivated with a thin film material such as silicon dioxide, or with an undoped semiconductor material such as silicon or germanium. The electrodes (i.e., source, gate, drain and substrate electrodes) of the sample active transistor are then connected so they can be individually electrically biased. A direct current (DC) potential is imposed on an active region of the prepared sample, and a small alternating current (AC) potential is imposed on the DC potential. The active region is then scanned using a conventional atomic force micrograph (AFM) or scanning capacitance micrograph (SCM) tip as an AC signal detector to generate an accurate image of the active region.

Influence of the Redeposition effect for Focused Ion Beam 3D Micromachining in Silicon

Abstract: The influence of the redeposition effect on the focused ion beam 3D micromachining process of silicon is discussed. Milling of some typical patterns in which redeposition is serious has been carried out. Experimental results are analysed in combination with a theoretical model. It can be seen from the analysis that the order of recycle-milling is very important for 3D microfabrication owing to redeposition during the process. In addition, the parameters of beam current, ion beam spot size, etc. are also key factors in the process. A groove and dome shape will be formed at the root of the sidewall and the bottom of the pattern, respectively, because of the ion sputtering yield variation and sidewall redeposition. Finally, avoidance methods are suggested as a result of the analysis.

Performance of multicusp plasma ion source for focused ion beam applications

Abstract: The multicusp plasma ion source has found many uses such as in ion implanters, ion projection lithography, and injectors for particle accelerators. This source is favorable for such applications because of its low ion temperature, small energy spread, and good stability. These properties also offer the tantalizing possibility of utilizing such a source to create a noncontaminating focused ion beam (FIB) system for semiconductor fabrication line use and advanced photomask repair applications. We have made measurements of the brightness of this ion source and have done some preliminary applications work with a Kr+-enabled FIB system for mask repair and ion milling. A specially designed multicusp plasma ion source has been used to measure focused beam spot size versus current relationships for several inert gas ion species. From these data the axial brightness of the ion source was ascertained. For the extraction of Kr+ from the source we find an angular intensity of 12 μA/sr and a virtual source size of 16....

Diffractive optical elements with continuous relief fabricated by focused ion beam for monomode fiber coupling

Abstract: The design, microfabrication and testing of diffractive optical elements (DOE's) with continuous relief used for fiber coupling are discussed in detail. DOE's with diameters as small as 50 mm are fabricated by means of focused ion beam (FIB) technology. A focused Ga+ ion beam is used to mill a continuous relief microstructure at a 50 kV acceleration voltage. The optical performance of DOE's made in this way was compared with that of DOE's fabricated by other methods. The focusing performance of DOE's fabricated with three and six annulus by FIB milling was investigated. Testing of the system which has a coupling efficiency of -1.25 dB (75%) shows that the design meets the application's requirement for fiber coupling, and that DOE's manufactured by our FIB technology are practicable. Compared with a conventional fiber coupling system that uses a plano - convex lens, our system has the advantages of simplicity, short focal length, low cost for the lens and high coupling efficiency.

Use of an SF5+ polyatomic primary ion beam for ultrashallow depth profiling on an ion microscope secondary ion mass spectroscopy instrument

Abstract: A magnetic sector secondary ion mass spectrometry (SIMS) instrument has been fitted with a modified hot filament duoplasmatron ion source for generation of SF5+ primary ion beams for SIMS depth profiling applications. The SF5+ primary ion beam has been evaluated by depth profiling of several low energy boron ion implants, boron delta-doped structures and a Ni/Cr metal multilayer depth profiling standard reference material. Using 3.0 keV impact SF5+ bombardment at a 52° impact angle with oxygen flooding gives a trailing edge decay length (1/e) for the boron implants and delta-doped layers of 1.3 nm. Under the same conditions, O2+ bombardment gives a trailing edge decay length (1/e) of 2.3 nm. The use of the SF5+ beam without oxygen flooding gives a substantial increase in decay length that is related to the formation of ripples as determined by atomic force microscopy. In the case of the Ni/Cr reference material, a significant reduction in sputter-induced topography is observed with SF5+ bombardment.

Metal vapor vacuum arc ion source development at GSI

Abstract: The status of experimental research, ongoing development, and upgrade of the high current metal vapor vacuum arc ion source is presented. By applying a magnetic field in the cathode region of the vacuum arc ion source it is possible to shift the charge state distribution to higher mean charge state. The combination of a magnetic field and small metal meshes in the plasma drift region is used to decrease the beam noise and to improve the ion beam stability. The results of experiments on the beam stability with different magnetic fields, cathode materials, and mesh are presented and discussed.

Maskless fabrication of field-emitter array by focused ion and electron beam

Abstract: Niobium-gated field-emitter arrays with Pt tips were fabricated using focused ion and electron beams. A promising approach, based on a two-step etch process in a Nb/SiO2/Si structure, has been implemented for the suppression of beam-induced damage and contamination in the processed area during the production of the gate openings. Only the top Nb layer was removed for gate openings by physical sputtering using the focused ion beam. The underlying SiO2 was subsequently removed by wet etching. Deposition of Pt pillars into these gate openings using electron-beam-induced chemical reaction resulted in field emission at an applied gate bias of 50 V even without any thermal annealing process.

Integrated micro-cylindrical lens with laser diode for single-mode fiber coupling

Abstract: The integration of a laser diode with a microlens on its emitting surface is introduced in this letter. Calculated results are based on integration of micro-cylindrical lens to laser diode. The lens is directly microfabricated on the emitting surface of the laser diode with operating wavelength 635 nm by focused ion beam (FIB) SiO/sub 2/ deposition function. The controlled SiO/sub 2/ deposition process is realized by programming our FIB machine. Using single-mode fiber with core diameter of 10 /spl mu/m as testing prototype, coupling efficiency of the compact and miniaturized system reaches as high as 80.1%. Measured far field angle (full angle) is 2.1 and 31/spl deg/ with and without the lens, respectively.

Modeling of focused ion beam induced surface chemistry

Abstract: A new macroscopic model for focused ion beam induced surface chemistry is presented. The model consists of two parts. The first part is based on previous work by several authors and assumes a uniform current distribution for the ion beam. In this case an analytical solution for the reaction yield can be obtained. Compared to previous work, the new model shows an improved agreement with experimental data and delivers physically meaningful parameter values. In an extended model a Gaussian beam shape has been used to account for the spatial and temporal variations in the current distribution, which are present in a real focused ion beam system. In this case the analytical solution for the yield dependence has to be solved using a spatially depended ion flux and integrated over the whole area of the pixel, which was done numerically. This model shows very good agreement with experimental data and delivers a consistent set of parameters values. In addition, experimental changes in parameter values such as beam size (defocusing) and pixel step size are accurately reflected in the simulation.

Method for repairing pattern defect, photo mask using the method, and semiconductor device manufacturing method employing the photo mask

Abstract: A new method for repairing pattern defect on a photo mask is provided. The method includes the steps of: (a) determining the irradiation area of the focused ion beam (FIB) directed towards a defect, by narrowing the irradiation area by a predetermined distance inwardly from the edge of the defect; (b) focusing the FIB onto its irradiation area to remove a part of the pattern film material of the defect from its top surface and thus leave a thin layer on a mask substrate; and (c) removing the thin layer by using a laser beam. The defect may be an isolated pattern or a pattern extended continuously from an edge of the normal pattern. Further, the photo mask repaired by the method, and a manufacturing method of semiconductor devices employing the repaired photo mask are proposed. The photo mask may include a phase shift mask.

Method and apparatus for a coaxial optical microscope with focused ion beam

Abstract: An optical microscope has an optical axis that coincides with a focused ion beam. The optical microscope can be used to locate target features on a specimen for subsequent operations by the ion beam, thereby eliminating the need for complex and potentially inaccurate registration procedures. The optical microscope can use infrared light so that features on a silicon flip chip are observable through the silicon from the backside. The ion beam can then machine the chip to expose the features for subsequent operations.

Method of making a patterned magnetic recording head

Abstract: A thin film magnetic recording head (5) utilizing a timing based servo pattern is fabricated using a focused ion beam (FIB). The recording head is fabricated by sputtering a magnetically permeable thin film (16) onto a substrate (12, 14). A gap pattern, preferably a timing based pattern, is defined on the thin film and the FIB cuts a gap (30) through the thin film based on that pattern. Once completed, the recording head is used to write a servo track onto magnetic tape. The timing based servo track then allows for the precise alignment of data read heads based on the positional information obtained by a servo read head which scans the continuously variable servo track.

Processing/observing instrument

Abstract: A processing/observing instrument which allows for obtaining a SIM image of a processed cross section of a specimen without changing an angle of the specimen. This processing/observing instrument includes a processing ion beam irradiation system which processes the surface of a specimen with an irradiation of a focused ion beam, an observing ion beam irradiation system which, with an exposure of a focused ion beam, detects secondary ions emitted from the specimen to detect the surface condition of the specimen, a specimen holder which holds the surface of the specimen at a point of intersection of a processing ion beam exposure axis and an observing ion beam exposure axis, and a display which displays the surface condition of the specimen.