A Novel Approach for Enhancing Critical FIB Imaging for Failure Analysis and Circuit Edit Applications

2004 ◽  
Author(s):  
Joseph Myers ◽  
Marsha Abramo ◽  
Michael Anderson ◽  
Michael W. Phaneuf
Keyword(s):  
Aspect Ratio ◽  
Failure Analysis ◽  
Secondary Electron ◽  
Semiconductor Device ◽  
Ion Beam ◽  
Sample Surface ◽  
Beam Current ◽  
Shielding Effect ◽  
Endpoint Detection ◽  
Novel Approach

Abstract As semiconductor device features continue to decrease in size from merely sub micron to below 100 nanometers it becomes necessary to mill smaller and higher aspect ratio FIB vias with reduced ion beam current. This significantly reduces the number of secondary electrons and ions available for endpoint detection and imaging. In addition FIB gas assisted etching introduces a gas delivery nozzle composed of conductive material. This component is grounded to prevent charge build up during ion beam imaging or milling. The proximity of the nozzle to the sample surface creates a shielding effect which reduces the secondary electron detection level as well [1]. The ability to enhance secondary electron imaging for end point detection is required for successful FIB circuit edit and failure analysis applications on advanced technologies. This paper reviews the results obtained using FIB Assist, an image and signal enhancement product for the FEI / Micrion platform, for critical FIB endpoint determination. Examples of FIB fabricated probe points with 30 x 30 nm FIB vias and circuit edit applications endpointing on metal 1 with high aspect ratio holes are presented.

Novel Approach of Improving Secondary Electron Detector in FIB System

2018 ◽  
Author(s):  
Steve Wang ◽  
Jim McGinn ◽  
Peter Tvarozek ◽  
Amir Weiss
Keyword(s):  
Integrated Circuit ◽  
Secondary Electron ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Vital Role ◽  
Electron Detector ◽  
System A ◽  
Novel Approach

Abstract Secondary electron detector (SED) plays a vital role in a focused ion beam (FIB) system. A successful circuit edit requires a good effective detector. Novel approach is presented in this paper to improve the performance of such a detector, making circuit altering for the most advanced integrated circuit (IC) possible.

Alloy surface composition resulting from fabrication, as determined by s.i.m.s. (secondary ion mass spectrometry)

1980 ◽  
Vol 295 (1413) ◽  
pp. 134-135
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Surface Composition ◽  
Ion Beam ◽  
Sample Surface ◽  
Beam Current ◽  
Ion Source ◽  
Beam Current Density ◽  
Dynamic Mode ◽  
Static Mode ◽  
Subsequent Performance

In s.i.m.s. the sample surface is ion bombarded and the emitted secondary ions are mass analysed. When used in the static mode with very low primary ion beam current densities (10 -11 A/mm 2 ), the technique analyses the outermost atomic layers with the following advantages (Benninghoven 1973, I975): the structural—chemical nature of the surface may be deduced from the masses of the ejected ionized clusters of atoms; detection of hydrogen and its compounds is possible; sensitivity is extremely high (10 -6 monolayer) for a number of elements. Composition profiles are obtained by increasing the primary beam current density (dynamic mode) or by combining the technique in the static mode with ion beam machining with a separate, more powerful ion source. The application of static s.i.m.s. in metallurgy has been explored by analysing a variety of alloy surfaces after fabrication procedures in relation to surface quality and subsequent performance. In a copper—silver eutectic alloy braze it was found that the composition of the solid surface depended markedly on its pretreatment. Generally there was a surface enrichment of copper relative to silver in melting processes while sawing and polishing enriched the surface in silver

scholarly journals Localizing Heat-Generating Defects Using Fluorescent Microthermal Imaging

1996 ◽  
Author(s):  
P. Tangyunyong ◽  
A.Y. Liang ◽  
A.W. Righter ◽  
D.L. Barton ◽  
J.M. Soden
Keyword(s):  
Failure Analysis ◽  
Focused Ion Beam ◽  
Uv Light ◽  
Ion Beam ◽  
Sample Surface ◽  
Analysis Tool ◽  
Temperature Dependent ◽  
Root Cause ◽  
Ideal Situation ◽  
Sem Imaging

Abstract Fluorescent microthermal imaging (FMI) involves coating a sample surface with a thin fluorescent film that, upon exposure to UV light source, emits temperature-dependent fluorescence [1-7]. The principle behind FMI was thoroughly reviewed at the ISTFA in 1994 [8, 9]. In two recent publications [10,11], we identified several factors in film preparation and data processing that dramatically improved the thermal resolution and sensitivity of FMI. These factors include signal averaging, the use of base mixture films, film stabilization and film curing. These findings significantly enhance the capability of FMI as a failure analysis tool. In this paper, we show several examples that use FMI to quickly localize heat-generating defects ("hot spots"). When used with other failure analysis techniques such as focused ion beam (FIB) cross sectioning and scanning electron microscope (SEM) imaging, we demonstrate that FMI is a powerful tool to efficiently identify the root cause of failures in complex ICs. In addition to defect localization, we use a failing IC to determine the sensitivity of FMI (i.e., the lowest power that can be detected) in an ideal situation where the defects are very localized and near the surface.

High Aspect Ratio via Milling Endpoint Phenomena in Focused Ion Beam Modification of Integrated Circuits

2004 ◽  
Author(s):  
Valery Ray
Keyword(s):  
Aspect Ratio ◽  
Integrated Circuits ◽  
High Aspect Ratio ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Endpoint Detection ◽  
Metal Line ◽  
Ion Beam Modification ◽  
Electron Collection ◽  
Current Monitoring

Abstract Precision detection of endpoint after the milling has reached targeted conductor during circuit modification by focused ion beam system is important. While the sensitivity of the endpoint detection can be enhanced by improved secondary electron collection and sample absorbed current monitoring, a detailed understanding of the endpoint signal distribution within a high aspect ratio (HAR) via is of great interest. This article presents an alternative model of HAR via milling endpointing mechanism in which a phenomenon of spatial distribution of the endpoint information within the HAR via is explained based on sputtering of the material from the targeted metal line and redeposition of the spattered material on the via sidewalls. Increased emission of the secondary electrons, resulting from the subsequent bombardment of this conductive re-deposition by the primary ion beam, is detected as the endpoint. A methodology for the future experimental verification of the proposed model is also described.

Andradite grain boundary secondary electron image generated by high-intensity electron beam in an electron microprobe

1991 ◽  
Vol 49 ◽  
pp. 998-999
Author(s):  
D. R. Liu
Keyword(s):  
Grain Boundaries ◽  
Electron Microprobe ◽  
Secondary Electron ◽  
Surface Defects ◽  
Wave Length ◽  
Sample Surface ◽  
Beam Current ◽  
Interesting Phenomenon ◽  
Voltage Range ◽  
Probe Current

The calcium iron silicate Ca3Fe2Si3O12, which is also called andradite, is commonly used for simultaneous verification of wave-length spectrometers in the CAMECA SX-50 electron microprobe. However, an interesting phenomenon was observed that the grain boundaries, which would not show up under normal secondary electron (SE) imaging conditions, would delineate themselves at high beam current.The SX-50 microprobe was operated in the voltage range of 10 to 20 kV. The probe current was varied from a few nA to a few hundred nA. The surface of the andradite sample was polished and carbon coated. When the beam current was only a few nA, the SE image showed only surface scratches and other surface defects such as pits (Fig. 1). However, if the current was increased to above 100 nA, the grain boundaries, which were hidden under the sample surface and thus invisible at low probe current, would then show up clearly (Figs. 2 and 3).

Improvements of Secondary Electron Imaging and Endpoint Detection in Focused Ion Beam Circuit Modification

2003 ◽  
Author(s):  
Valery Ray ◽  
Nicholas Antoniou ◽  
Alex Krechmer ◽  
Andrew Saxonis
Keyword(s):  
Integrated Circuit ◽  
Secondary Electron ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Copper Sample ◽  
Shielding Effect ◽  
Secondary Electrons ◽  
Aspect Ratios ◽  
Scanning Area ◽  
Beam Currents

Abstract Secondary electron signal is widely used in Focused Ion Beam (FIB) systems for imaging and endpointing. In the application of integrated circuit modification, technology has progressed towards smaller dimensions and higher aspect ratios. Therefore, FIB based circuit modification processes require the use of primary ion beam currents below 10 pA and Gas Assisted Etching (GAE). At low beam currents, short pixel dwell times and high aspect ratios, the level of available secondary electrons for detection has declined significantly. FIB GAE and deposition requires delivery and release of a gaseous agent near the beam scanning area, and involves insertion of a gas delivery nozzle made of conductive material and grounded for charge prevention purposes. The proximity of a grounded gas delivery nozzle to the area being milled and/or imaged creates a “shielding” effect, further lowering secondary electron signal level. The application of a small positive bias to the gas delivery nozzle provides an effective way of reducing the “shielding” effect. Depending on the geometrical arrangement of the gas delivery system and other conductive objects in the chamber, an optimized nozzle bias potential can create conditions favorable for enhanced extraction and collection of secondary electrons. The level of the secondary electron image signal, collected in an FEI Vectra 986+ system, from a grounded copper sample with the nozzle extended and biased can be enhanced as much as six times as compared to the grounded nozzle. Secondary electron intensity endpoint is improved on backside samples, however shielding of the nozzle field by the bulk silicon substrate limits the electron extraction effect from within a via. For front side edits the improvement of endpoint signal level can be dramatic. Lateral image offset induced by the electrostatic field of a biased nozzle, can be removed by software position compensation.

scholarly journals Angular Dependence of the Ion-Induced Secondary Electron Emission for He+ and Ga+ Beams

2011 ◽  
Vol 17 (4) ◽  
pp. 624-636 ◽  
Author(s):  
Vincenzo Castaldo ◽  
Josephus Withagen ◽  
Cornelius Hagen ◽  
Pieter Kruit ◽  
Emile van Veldhoven
Keyword(s):  
Secondary Electron ◽  
Focused Ion Beam ◽  
Incidence Angle ◽  
Ion Beam ◽  
Secondary Electron Emission ◽  
Surface Characteristics ◽  
Sample Surface ◽  
Secondary Electron Yield ◽  
Flat Surfaces ◽  
Electron Yield

AbstractIn recent years, novel ion sources have been designed and developed that have enabled focused ion beam machines to go beyond their use as nano-fabrication tools. Secondary electrons are usually taken to form images, for their yield is high and strongly dependent on the surface characteristics, in terms of chemical composition and topography. In particular, the secondary electron yield varies characteristically with the angle formed by the beam and the direction normal to the sample surface in the point of impact. Knowledge of this dependence, for different ion/atom pairs, is thus the first step toward a complete understanding of the contrast mechanism in scanning ion microscopy. In this article, experimentally obtained ion-induced secondary electron yields as a function of the incidence angle of the beam on flat surfaces of Al and Cr are reported, for usual conditions in Ga+ and He+ microscopes. The curves have been compared with models and simulations, showing a good agreement for most of the angle range; deviations from the expected behavior are addressed and explanations are suggested. It appears that the maximum value of the ion-induced secondary electron yield is very similar in all the studied cases; the yield range, however, is consistently larger for helium than for gallium, which partially explains the enhanced topographical contrast of helium microscopes over the gallium focused ion beams.

Effects of Ion Beam Milling on Surface Topography

1973 ◽  
Vol 31 ◽  
pp. 84-85
Author(s):  
P.G. Pawar ◽  
P. Duhamel ◽  
G.W. Monk
Keyword(s):  
Surface Topography ◽  
Ion Beam ◽  
Solid Material ◽  
Beam Current ◽  
Atomic Mass ◽  
Micro Milling ◽  
Ion Milling ◽  
Controlled Atmospheres ◽  
Milling Operations ◽  
Sufficient Energy

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.

SEM analysis of DC magnetron sputtered beryllium films

1988 ◽  
Vol 46 ◽  
pp. 960-961
Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh
Keyword(s):  
Fine Structure ◽  
Electron Emission ◽  
Secondary Electron ◽  
Low Voltage ◽  
Ion Beam ◽  
Secondary Electron Emission ◽  
Sem Analysis ◽  
Fused Silica ◽  
Grain Structure ◽  
Silica Substrate

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.

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