Grain Boundary Chemistry in Al-Cu Metallizations as Determined by Analytical Electron Microscopy

1991 ◽  
Vol 229 ◽  
Author(s):  
J. R. Michael ◽  
A. D. Romig ◽  
D. R. Frear
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Grain Boundary ◽  
Analytical Electron Microscopy ◽  
Second Phase ◽  
Collector Plate ◽  
Analytical Electron ◽  
Cu Thin Film ◽  
Boundary Chemistry ◽  
Interconnect Lines

AbstractAl with additions of Cu is commonly used as the conductor metallizations for integrated circuits (ICs). As the packing density of ICs increases, interconnect lines are required to carry ever higher current densities. Consequently, reliability due to electromigration failure becomes an increasing concern. Cu has been found to increase the lifetimes of these conductors, but the mechanism by which electromigration is improved is not yet fully understood. In order to evaluate certain theories of electromigration it is necessary to have a detailed description of the Cu distribution in the Al microstructure, with emphasis on the distribution of Cu at the grain boundaries. In this study analytical electron microscopy (AEM) has been used to characterize grain boundary regions in an Al-2 wt.% Cu thin film metallization on Si after a variety of thermal treatments. The results of this study indicate that the Cu distribution is dependent on the thermal annealing conditions. At temperatures near the θ phase (CuAl2) solvus, the Cu distribution may be modelled by the collector plate mechanism, in which the grain boundary is depleted in Cu relative to the matrix. At lower temperatures, Cu enrichment of the boundaries occurs, perhaps as a precursor to second phase formation. Natural cooling from the single phase field produces only grain boundary depletion of Cu consistent with the collector-plate mechanism. The kinetic details of the elemental segregation behavior derived from this study can be used to describe microstructural evolution in actual interconnect alloys.

Analytical electron microscopy of grain boundaries in Al-Cu metallizations

1992 ◽  
Vol 50 (2) ◽  
pp. 1684-1685
Author(s):  
J. R. Michael ◽  
A. D. Romig ◽  
D. R. Frear
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Failure Mode ◽  
Current Density ◽  
Thermal History ◽  
Analytical Electron Microscopy ◽  
Cu Metallization ◽  
Analytical Electron ◽  
Interconnect Lines

Al with additions of Cu is commonly used as the conductor metallizations for integrated circuits, the Cu being added since it improves resistance to electromigration failure. As linewidths decrease to submicrometer dimensions, the current density carried by the interconnect increases dramatically and the probability of electromigration failure increases. To increase the robustness of the interconnect lines to this failure mode, an understanding of the mechanism by which Cu improves resistance to electromigration is needed. A number of theories have been proposed to account for role of Cu on electromigration behavior and many of the theories are dependent of the elemental Cu distribution in the interconnect line. However, there is an incomplete understanding of the distribution of Cu within the Al interconnect as a function of thermal history. In order to understand the role of Cu in reducing electromigration failures better, it is important to characterize the Cu distribution within the microstructure of the Al-Cu metallization.

Analytical Electron Microscopy of Surface-Modified Ceramics

1985 ◽  
Vol 43 ◽  
pp. 276-279
Author(s):  
P. S. Sklad
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Theoretical Models ◽  
Ceramic Materials ◽  
Solute Concentration ◽  
Second Phase ◽  
Analytical Electron ◽  
Implantation Techniques ◽  
Lattice Damage ◽  
Surface Modified

Over the past several years, it has become increasingly evident that materials for proposed advanced energy systems will be required to operate at high temperatures and in aggressive environments. These constraints make structural ceramics attractive materials for these systems. However it is well known that the condition of the specimen surface of ceramic materials is often critical in controlling properties such as fracture toughness, oxidation resistance, and wear resistance. Ion implantation techniques offer the potential of overcoming some of the surface related limitations.While the effects of implantation on surface sensitive properties may be measured indpendently, it is important to understand the microstructural evolution leading to these changes. Analytical electron microscopy provides a useful tool for characterizing the microstructures produced in terms of solute concentration profiles, second phase formation, lattice damage, crystallinity of the implanted layer, and annealing behavior. Such analyses allow correlations to be made with theoretical models, property measurements, and results of complimentary techniques.

Characterization of Intergranular Phases in Doped Zirconia Polycrystals

1999 ◽  
Vol 589 ◽  
Author(s):  
N. D. Evans ◽  
P. H. Imamura ◽  
J. Bentley ◽  
M. L. Mecartney
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Analytical Electron Microscopy ◽  
Tetragonal Zirconia ◽  
Barium Ions ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Triple Points ◽  
Boundary Chemistry

AbstractAnalytical electron microscopy at high spatial resolution in a scanning-transmission mode has been used to investigate the effects of glassy or crystalline material additions on grain boundary chemistry in yttria-stabilized zirconia polycrystals. Powders of additive phase were mixed into 3-mol% yttria-stabilized tetragonal zirconia polycrystals (‘3Y-TZP’) or 8-mol% yttria-stabilized cubic zirconia polycrystals (‘8Y-CSZ’). Zirconias processed without additive phases were also examinedWithout additives, grain boundaries were depleted in zirconium and enriched in yttrium. In 3Y-TZP with I wt% borosilicate glass, silicon was observed only at triple points, but not in grain boundaries. In 3Y-TZP with 1 wt% barium silicate glass, barium was observed both along grain boundaries and at triple points, whereas silicon was detected only within the triple points. This suggests either the composition of the additive phase at the grain boundary is different from that at the triple points, or that barium ions segregate to grain boundaries during processing. In 8Y-CSZ with I wt% silica, silicon was observed in grain boundaries by an EDS spatial differencing technique. In 8Y-CSZ with 10 wt% alumina, EDS revealed aluminum at all grain boundaries examined

Analytical Electron Microscopy Studies of Bi-Substituted Garnet Films

1991 ◽  
Vol 232 ◽  
Author(s):  
P. A. Crozier ◽  
P. A. Labun ◽  
T Suzuki
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Second Phase ◽  
Processing Conditions ◽  
Transformation Kinetics ◽  
Heating Rates ◽  
Garnet Films ◽  
Analytical Electron ◽  
In Situ Heating

ABSTRACTIn-situ heating in an electron microscope, together with EDX and EELS analysis, was used to characterize as-deposited amorphous and transformed garnet films. It was found that upon initial crystallization, a non-uniform precipitation of a second phase occurred, altering the local chemistry and microstructure of the transformed film. In addition, to study the transformation kinetics in more detail some experiments were conducted at slower heating rates and lower temperatures. It is hoped that the data obtained can be correlated to magnetic property measurements and contribute to the development of improved processing conditions.

Phase Identification in TiB2-Ni Composites by Analytical Electron Microscopy

1981 ◽  
Vol 39 ◽  
pp. 138-139
Author(s):  
P. S. Sklad ◽  
J. Bentley ◽  
A. T. Fisher ◽  
G. L. Lehman
Keyword(s):  
Electron Microscopy ◽  
Cutting Tools ◽  
Analytical Electron Microscopy ◽  
High Hardness ◽  
Phase Identification ◽  
Second Phase ◽  
Binder Phase ◽  
Ion Milling ◽  
X Ray ◽  
Analytical Electron

The transition metal diboride TiB2 is characterized by high hardness and high melting point (3253 K) . These properties make this material attractive for applications such as valve components in coal liquefaction plants and cutting tools. Liquid phase hot pressing using nickel as the fluidizing medium allows densification at lower temperatures than when using TiB2 powders alone, but the nickel and TiB2 react to form a complex multiphase microstructure. The purpose of this investigation was to identify the nickel-rich binder phase. The material examined was taken from a cylindrical compact hot pressed at ∼1720 K. During pressing most of the original 15 mol % Ni exuded from the initial mixtures. Specimens 3 mm dia were prepared for analytical electron microscopy (AEM) examination by mechanical lapping followed by ion milling.A typical microstructure of the TiB2-Ni composite examined at 120 kv by conventional transmission electron microscopy (TEM) is shown in Fig. 1. The microstructure is characterized by TiB2 grains bonded by a second phase which was observed at multiple grain intersections. X-ray energy dispersive spectroscopy (EDS) measurements were made using a Philips EM400T/FEG. probe sizes of ∼10 nm dia and probe currents of ∼5 nA were used so that measurements could be made in thin regions of the binder phase, where beam broadening was small. Typical x-ray spectra from an intergranular region and an adjacent TiB2 grain are shown in Fig. 2. The results of standardless quantitative analyses of binder phase spectra indicated a composition (for Z > 11) of at least 95% Ni.

Measurement of compositional changes accompanying solid-state transformations at grain boundaries in metals

1987 ◽  
Vol 45 ◽  
pp. 296-299
Author(s):  
Ernest L. Hall ◽  
Clyde L. Briant
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Precipitation Process ◽  
Second Phase ◽  
Slow Cooling ◽  
Collector Plate ◽  
Compositional Changes ◽  
Property Changes ◽  
Boundary Chemistry

In many multicomponent metallic systems, solid-state precipitation processes can occur upon slow cooling or isothermal aging of solutionized material. Frequently, the precipitates form at grain boundaries, which are preferred sites for the nucleation and growth of the second phase. The precipitates generally grow through a combination of matrix and grain boundary diffusion, in which the grain boundary acts as a collector plate for the delivery of the solute to the growing precipitate. The precipitation process is thus accompanied by significant changes in the chemistry of the grain boundary and matrix regions near the grain boundary. These grain boundary chemistry changes can have a profound effect on the macroscopic properties of the material, including corrosion resistance, strength, and ductility. In order to understand the mechanism associated with these property changes, it is necessary to obtain a complete and precise description of the magnitude and extent of the compositional changes which have occurred at the grain boundaries.

Second Phase Formation in Aluminum annealed after Ion Implantation with Molybdenum.

1983 ◽  
Vol 27 ◽  
Author(s):  
J. Bentley ◽  
L. D. Stephenson ◽  
R. B. Benson ◽  
P. A. Parrish ◽  
J. K. Hirvonen
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Phase Transformations ◽  
Phase Formation ◽  
Analytical Electron Microscopy ◽  
Second Phase ◽  
Continuous Film ◽  
Video Recordings ◽  
Analytical Electron ◽  
Annealing Experiments

ABSTRACTThe microstructure of aluminum annealed after implantation to peak concentrations of approximately 4.4 and 11 at. % Mo was investigated by analytical electron microscopy. Al12Mo precipitates formed with pseudo-lamellar and continuous film microstructures. Video recordings of insitu annealing experiments revealed the details of the phase transformations.

Sign in / Sign up

Export Citation Format

Share Document