Focused ion beam observation of grain structure and precipitates in aluminum thin films

Author(s):  
D. L. Barr
1999 ◽  
Vol 594 ◽  
Author(s):  
R. Spolenak ◽  
C. A. Volkert ◽  
K. Takahashi ◽  
S. Fiorillo ◽  
J. Miner ◽  
...  

AbstractIt is well known that the mechanical properties of thin films depend critically on film thickness However, the contributions from film thickness and grain size are difficult to separate, because they typically scale with each other. In one study by Venkatraman and Bravman, Al films, which were thinned using anodic oxidation to reduce film thickness without changing grain size, showed a clear increase in yield stress with decreasing film thickness.We have performed a similar study on both electroplated and sputtered Cu films by using chemical-mechanical polishing (CMP) to reduce the film thickness without changing the grain size. Stress-temperature curves were measured for both the electroplated and sputtered Cu films with thicknesses between 0.1 and 1.8 microns using a laser scanning wafer curvature technique. The yield stress at room temperature was found to increase with decreasing film thickness for both sets of samples. The sputtered films, however, showed higher yield stresses in comparison to the electroplated films. Most of these differences can be attributed to the different microstructures of the films, which were determined by focused ion beam (FIB) microscopy and x-ray diffraction.


2006 ◽  
Vol 960 ◽  
Author(s):  
Koji Sato ◽  
Chiemi Ishiyama ◽  
Masato Sone ◽  
Yakichi Higo

ABSTRACTWe studied the effects of phosphorus (P) on Ni nanocrystalline morphology formed by focused ion beam (FIB) irradiation for Ni-P amorphous alloy thin films. The P content in the amorphous alloy was varied from 8 to 12 wt.%. The nanocrystals induced by the FIB irradiation for Ni-11.8, 8.9, 7.9 wt.% amorphous alloy had an f.c.c. structure and showed unique crystallographic orientation relationships to the geometry of the focused ion beam, that is, {111}f.c.c. parallel to the irradiated plane and <110>f.c.c. parallel to the projected ion beam direction, respectively. The Ni nanocrystals precipitated like aggregates with decreasing of the P content. These results represent that the P content does not affect crystallographic orientation relationships, while influences the precipitation distribution of Ni nanocrystals generated by the FIB irradiation.


2012 ◽  
Vol 717-720 ◽  
pp. 889-892 ◽  
Author(s):  
Hamidreza Zamani ◽  
Seung Wan Lee ◽  
Amir Avishai ◽  
Christian A. Zorman ◽  
R. Mohan Sankaran ◽  
...  

We report on experimental explorations of using focused ion beam (FIB) nanomachining of different types of silicon carbide (SiC) thin membranes, for making robust, high-quality stencil masks for new emerging options of nanoscale patterning. Using thin films and membranes in polycrystalline SiC (poly-SiC), 3C-SiC, and amorphous SiC (a-SiC) with thicknesses in the range of t~250nm−1.6μm, we have prototyped a series of stencil masks, with nanoscale features routinely down to ~100nm.


1997 ◽  
Vol 505 ◽  
Author(s):  
Joost J. Vlassak ◽  
T. Y. Tsui ◽  
W. D. Nix

ABSTRACTWe have developed a new technique for visualizing displacement fields of indentations in thin films. In this technique, the indented film consists of alternating layers of two different materials. One of the materials serves as a marker for visualizing the plastic flow induced by the indentation. Focused Ion Beam (FIB) milling is used to cross-section the indentation, revealing the deformed layers. This technique can be used to study how the presence of the substrate affects the plastic displacement field around the indentation. The technique is applied to a multilayered film of aluminum and titanium nitride on a silicon substrate. The titanium nitride layers are much thinner than the aluminum layers and serve the function of marker. Pile-up of the film material around the indenter and the effect of the hard substrate are easily revealed and a mechanism for pile-up is suggested. The technique also shows that the grain structure in the deformed zone around the indentation is altered profoundly.


2012 ◽  
Vol 520 (6) ◽  
pp. 2073-2076 ◽  
Author(s):  
Xu Song ◽  
Kong Boon Yeap ◽  
Jing Zhu ◽  
Jonathan Belnoue ◽  
Marco Sebastiani ◽  
...  

1999 ◽  
Vol 564 ◽  
Author(s):  
L. M. Gignac ◽  
K. P. Rodbel ◽  
C. Cabral ◽  
P. C. Andricacos ◽  
P. M. Rice ◽  
...  

AbstractElectroplated Cu was found to have a fine as-plated microstructure, 0.05 ± 0.03 μm, with multiple grains through the film thickness and evidence of twins and dislocations within grains. Over time at room temperature, the grains grew to greater than 1 μm in size. Studied as a function of annealing temperature, the recrystallized grains were shown to be 1.6 ± 1.0 μm in size, columnar and highly twinned. The grain growth was directly related to the time dependent decrease in sheet resistance. The initial grain structure was characterized using scanning transmission electron microscopy (STEM) from a cross-section sample prepared by a novel focused ion beam (FIB) and lift-out technique. The recrystallized grain structures were imaged using FIB secondary electron imaging. From these micrographs, the grain boundary structures were traced, and an image analysis program was used to measure the grain areas. A Gaussian fit of the log-normal distribution of grain areas was used to calculate the mean area and standard deviation. These values were converted to grain size diameters by assuming a circular grain geometry.


2021 ◽  
Author(s):  
Qasim Imtiaz ◽  
Andac Armutlulu ◽  
Felix Donat ◽  
Muhammad Awais Naeem ◽  
Christoph Müller

Chemical looping combustion (CLC) is a promising alternative to the conventional combustion-based, fossil fuel conversion processes. In CLC, a solid oxygen carrier is used to transfer oxygen from air to a carbonaceous fuel. This indirect combustion route allows for effective CO<sub>2</sub> capture since a sequestrable stream of CO<sub>2 </sub>is inherently produced without any need for energy-intensive CO<sub>2</sub> separation. From a thermodynamic point of view, CuO is arguably one of the most promising oxygen carrier candidates for CLC. However, the main challenge associated with the use of CuO for CLC is its structural instability at the typical operating temperatures of chemical looping processes, leading to severe thermal sintering and agglomeration. To minimize irreversible microstructural changes during CLC operation, CuO is commonly stabilized by a high Tammann temperature ceramic, e.g., Al<sub>2</sub>O<sub>3</sub>, MgAl<sub>2</sub>O<sub>4</sub>, etc. However, it has been observed that a high Tammann temperature support does not always provide a high resistance to agglomeration. This work aims at identifying descriptors that can be used to characterize accurately the agglomeration tendency of CuO-based oxygen carriers. CuO-based oxygen carriers supported on different metal oxides were synthesized using a Pechini method. The cyclic redox stability and agglomeration tendency of the synthesized materials was evaluated using both a thermo-gravimetric analyser and a lab-scale fluidized bed reactor at 900 °C using 10 vol. % H<sub>2</sub> in N<sub>2</sub> as the fuel and air for re-oxidation. In order to study the diffusion of Cu(O) during redox reactions, well-defined model surfaces comprising thin films of Cu/CuO and two different supports, viz. ZrO<sub>2</sub> or MgO, were prepared via magnetron sputtering. Energy dispersive X-ray (EDX) spectroscopy on focused ion beam (FIB)-cut cross-sections of the thin films revealed that Cu atoms have a tendency to diffuse outward through most of the films of the support material under redox conditions. The support that inhibits the outward movement of Cu(O), i.e. avoiding the presence of low melting Cu on the oxygen carrier surface, is found to provide the highest agglomeration resistance. The support MgO was found to possesses such diffusion characteristics.


2005 ◽  
Vol 42 (4) ◽  
pp. 172-187 ◽  
Author(s):  
Michael Rogers ◽  
Gerald Kothleitner ◽  
Antje Berendes ◽  
Wolfgang Bock ◽  
Bernd O. Kolbesen

1998 ◽  
Author(s):  
S.B. Herschbein ◽  
L.S. Fischer ◽  
T.L. Kane ◽  
M.P. Tenney ◽  
A.D. Shore

Abstract Copper will probably replace aluminum alloys as the interconnect metallurgy of choice for high performance semiconductor devices. This transition will challenge the suitability of established practices in focused ion beam (FIB) chip repair. A fundamental rethink in methodology, techniques, and process gases will be required to deal with the new metal films. This paper discusses the results of recent experiments in the areas of FIB exposure, cuts and connections to buried copper lines. While copper tends to mill faster than aluminum, etch rate variations due to grain structure tend to make reliable isolation cuts more difficult. The films also have been shown to suffer regrowth and surface reactions during long term storage following FIB exposure. Attempts at halogen gas assisted etch (GAE) mills result in undesirable removal characteristics, and in the case of bromine, the spontaneous destruction of all exposed copper in the immediate area. Resistance measurements and reliability of deposited tungsten connections to copper lines are also presented. In addition, the latest techniques developed for aluminum wiring isolation and device characterization are shown. These include 'cleanup' methods for achieving good circuit isolation without the extensive use of local oxide deposition, and the latest multilevel version of the FIB ‘wagon wheel’ for SRAM cell characterization. Also included is preliminary data from a custom built FIB chamber four manipulator prober module.


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