Mechanical behavior of thin Cu films studied by a four-point bending technique

2001 ◽  
Vol 673 ◽  
Author(s):  
Volker Weihnacht ◽  
Winfried Brückner
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
High Vacuum ◽  
Misfit Dislocations ◽  
Plastic Strains ◽  
Yield Behavior ◽  
Cu Films ◽  
Si Substrates ◽  
Four Point Bending ◽  
Tension And Compression

ABSTRACTFour-point bending experiments in combination with thermal cycling of thin films on substrates were performed in a dedicated apparatus. Strains up to ±0.8% could be imposed into Cu films of 0.2, 0.5, and 1.0 μm thickness on Si substrates by bending the substrates at various temperatures in high vacuum. After relief of the bending, the residual stress was measured by the wafer-curvature method. At temperatures below 250°C, the yield behavior is asymmetric in tension and compression. The amount of plastic strain introduced by external bending increases with film thickness, but the absolute values of the introduced plastic strains are very low throughout. At higher temperatures, there is no clear thickness dependence and no asymmetry in tension and compression. The results are discussed in connection with the formation of misfit dislocations during plastic deformation of thin films.

scholarly journals Effect of Annealing on Microstructure and Mechanical Properties of Magnetron Sputtered Cu Thin Films

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shiwen Du ◽  
Yongtang Li
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Strain Energy ◽  
Texture Coefficient ◽  
Elastic Strain Energy ◽  
Interface Energy ◽  
Cu Films ◽  
Si Substrates

Cu thin films were deposited on Si substrates using direct current (DC) magnetron sputtering. Microstructure evolution and mechanical properties of Cu thin films with different annealing temperatures were investigated by atomic force microscopy (AFM), X-ray diffraction (XRD), and nanoindentation. The surface morphology, roughness, and grain size of the Cu films were characterized by AFM. The minimization of energy including surface energy, interface energy, and strain energy (elastic strain energy and plastic strain energy) controlled the microstructural evolution. A classical Hall-Petch relationship was exhibited between the yield stress and grain size. The residual stress depended on crystal orientation. The residual stress as-deposited was of tension and decreased with decreasing of (111) orientation. The ratio of texture coefficient of (111)/(220) can be used as a merit for the state of residual stress.

Plasticity in Copper Thin Films

1999 ◽  
Vol 594 ◽  
Author(s):  
V. Weihnacht ◽  
W. Brückner
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Thermal Cycling ◽  
Thermal Cycle ◽  
Cu Films ◽  
Strain Behavior ◽  
Four Point Bending ◽  
Dislocation Arrangement ◽  
Tension And Compression ◽  
Film Substrate

AbstractPlastic deformation in thin Cu films was studied by stress measurements with the wafercurvature technique during thermal cycling and in combination with four-point bending. The results from 0.5 ¼m and 1 ¼m thick Cu films are compared. In thermal cycling experiments, strengthening during cooling and a Bauschinger-like effect during reheating were observed. The stress-strain behavior investigated by four-point bending showed to be asymmetric regarding tension and compression at lower temperatures. These phenomenons are explained by a dislocation arrangement at the film-substrate interface which has formed during a previous thermal cycle.

Observation of GaAs/Si Epitaxial Interfaces by Atomic Resolution Electron Microscopy

1986 ◽  
Vol 67 ◽  
Author(s):  
N. Otsuka ◽  
C. Choi ◽  
Y. Nakamura ◽  
S. Nagakura ◽  
R. Fischer ◽  
...  
Keyword(s):  
Substrate Surface ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Si Substrates ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Gaas Films ◽  
Substrate Surfaces

ABSTRACTRecent studies have shown that high quality GaAs films can be grown by MBE on Si substrates whose surfaces are slightly tilted from the (100) plane. In order to investigate the effect of the tilting of substrate surfaces on the formation of threading dislocations, the GaAs/Si epitaxial interfaces have been observed with a 1 MB ultra-high vacuum, high voltage electron microscope. Two types of misfit dislocations, one with Burgers vectors parallel to the interface and the other with Burgers vectors inclined from the interface, were found in these epitaxial interfaces. The observation of crosssectional samples perpendicular to each other has shown that the tilting of the substrate surface directly influences the generation of these two types of misfit dislocations. The mechanism of the reduction of threading dislocations by the tilting of the substrate surface is discussed based on these observations.

Structure and Magnetic Properties of Fe-N Thin Films Grown by ECR Deposition

1999 ◽  
Vol 562 ◽  
Author(s):  
Š émeth ◽  
H. Akinaga ◽  
H. Boeve ◽  
H. Bender ◽  
J. de Boeck ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Nitrogen Concentration ◽  
High Vacuum ◽  
Plasma Source ◽  
Columnar Structure ◽  
Ultra High Vacuum ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTThe growth of FexNy thin films on GaAs, In0.2Ga0.8As, and SiO2/Si substrates using an ultra high-vacuum (UHV) deposition chamber equipped with electron cyclotron resonance (ECR) microwave plasma source is presented. The structural properties of the deposited films have been measured using various techniques as x-ray diffraction (XRD), Auger electron spectroscopy (AES), and transmission electron microscopy (TEM). The results of XRD measurements show that the films consist of a combination of α-Fe, α'-Fe, y-Fe4N, and α”- Fe16N2 phases. The depth profiles, calculated from the Auger peak intensities, show a uniform nitrogen concentration through the films. The TEM reveals a columnar structure of these films. The properties of the different Fe-N layers have been exploited in the fabrication of Fe(N) / FexNy / Fe trilayer structures, where Fe(N) means a slightly nitrogen doped Fe film. The magneto-transport properties of this trilayer structure grown on In0.2Ga0.8As substrates are presented.

scholarly journals Residual Stress and Microstructure of Electroplated Cu Film on Different Barrier Layers

2001 ◽  
Vol 695 ◽  
Author(s):  
Alex A. Volinsky ◽  
Meike Hauschildt ◽  
Joseph B. Vella ◽  
N.V. Edwards ◽  
Rich Gregory ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Vacuum ◽  
Temperature Cycling ◽  
Copper Films ◽  
Stress Distributions ◽  
Cu Films ◽  
Barrier Layers ◽  
Cu Film ◽  
Processing Step ◽  
Stress Mapping

ABSTRACTCopper films of different thicknesses between 0.2 and 2 microns were electroplated on adhesion-promoting TiW and Ta barrier layers on <100> single crystal 6-inch silicon wafers. The residual stress was measured after each processing step using a wafer curvature technique employing Stoney's equation. Large gradients in the stress distributions were found across each wafer. Controlled Cu grain growth was achieved by annealing films at 350 C for 3 minutes in high vacuum. Annealing increased the average tensile residual stress by about 200 MPa for all the films, which is in agreement with stress-temperature cycling measurements.After aging for 1 year wafer stress mapping showed that the stress gradients in the copper films were alleviated. No stress discrepancies between the copper on Ta and TiW barrier layers could be found. However, X-ray pole figure analysis showed broad and shifted (111) texture in films on a TiW underlayer, whereas the (111) texture in Cu films on Ta is sharp and centered.

An Anodic Process for the Determination of Grain Boundary and Film Thickness Strengthening Effects in Aluminum Films on Oxidized Silicon.

1991 ◽  
Vol 239 ◽  
Author(s):  
Ramnath Venkatraman ◽  
John C. Bravman
Keyword(s):  
Grain Size ◽  
Film Thickness ◽  
Anodic Oxide ◽  
Film Stress ◽  
Anodic Process ◽  
Aluminum Films ◽  
Cu Films ◽  
Si Substrates ◽  
Tension And Compression ◽  
Stress Variations

ABSTRACTWe have measured stress variations with temperature as a function of film thickness and a given grain size in pure Al and AI-0.5%Cu films on Si substrates. The variation in thickness for a given grain size is brought about by using the same film and the repeated controlled growth and dissolution of a barrier anodic oxide which can be grown uniformly on the film. Stress measurements were made as a function of temperature by measuring wafer curvature after successively removing each 0. Iμm of Al film. The components of strengthening due to the film thickness and the presence of grain boundaries were separated by assuming that the flow stress of the film is simply the sum of these two components. The observations are consistent with results obtained using lascr-rcflowed films in an earlier work. The variations of these two components with temperature, and under tension and compression is discussed.

Influence of stress on structural and dielectric anomaly of Bi2(Zn1/3Ta2/3)207 thin films

2005 ◽  
Vol 875 ◽  
Author(s):  
Jun Hong Noh ◽  
Hee Bum Hong ◽  
Kug Sun Hong
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Interfacial Layer ◽  
Monoclinic Phase ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Dielectric Anomaly ◽  
Laser Deposition ◽  
Cubic Phase ◽  
Si Substrates

AbstractBi2(Zn1/3Ta2/3)2O7 (BZT) thin films were grown on the (111) oriented Pt/TiOx/SiO2/Si substrates using a pulsed laser deposition (PLD) technique. BZT thin films deposited at an oxygen partial pressure of 400 mTorr have the non-stoichiometric anomalous cubic phase despite the BZT target was the monoclinic phase. Compositions, the lattice mismatch, the interfacial layer and the residual stress in the film were investigated as the factors which may affect the formation of the anomalous cubic phase. Among them, the coherent interfacial layer which formed at high oxygen pressures resulted in the formation of the cubic phase by reducing the internal stress.

Measuring the elastic modulus and residual stress of freestanding thin films using nanoindentation techniques

2009 ◽  
Vol 24 (9) ◽  
pp. 2974-2985 ◽  
Author(s):  
Erik G. Herbert ◽  
Warren C. Oliver ◽  
Maarten P. de Boer ◽  
George M. Pharr
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Dimensional Analysis ◽  
Experimental Verification ◽  
Cu Films ◽  
Proposed Model ◽  
The Difference

A new method is proposed to determine the elastic modulus and residual stress of freestanding thin films based on nanoindentation techniques. The experimentally measured stiffness-displacement response is applied to a simple membrane model that assumes the film deformation is dominated by stretching as opposed to bending. Dimensional analysis is used to identify appropriate limitations of the proposed model. Experimental verification of the method is demonstrated for Al/0.5 wt% Cu films nominally 22 µm wide, 0.55 µm thick, and 150, 300, and 500 µm long. The estimated modulus for the four freestanding films match the value measured by electrostatic techniques to within 2%, and the residual stress to within 19.1%. The difference in residual stress can be completely accounted for by thermal expansion and a modest change in temperature of 3 °C. Numerous experimental pitfalls are identified and discussed. Collectively, these data and the technique used to generate them should help future investigators make more accurate and precise measurements of the mechanical properties of freestanding thin films using nanoindentation.

Early yielding and stress recovery in (111) and (100) texture components in Cu thin films determined using synchrotron x-ray diffraction

2003 ◽  
Vol 795 ◽  
Author(s):  
D. E. Nowak ◽  
S. P. Baker
Keyword(s):  
Thin Films ◽  
Thermomechanical Behavior ◽  
Stress Recovery ◽  
X Ray Diffraction ◽  
Thermal Cycles ◽  
Yield Behavior ◽  
X Ray ◽  
Barrier Layers ◽  
Si Substrates ◽  
Plane Film

ABSTRACTSynchrotron x-ray diffraction experiments were used to study the thermomechanical behavior of individual texture components in passivated Cu thin films. Films were deposited to a thickness of 500 nm on SiNx barrier layers on Si substrates and then passivated with SiNx. The films were highly textured with grains having (111) or (100) planes parallel to the plane of the film. In-plane film stresses were determined separately in the two texture components as a function of temperature during thermal cycles and also during isothermal holds at 140°C. The results are compared to models of yield behavior and anelastic recovery.

Separation of film thickness and grain boundary strengthening effects in Al thin films on Si

1992 ◽  
Vol 7 (8) ◽  
pp. 2040-2048 ◽  
Author(s):  
Ramnath Venkatraman ◽  
John C. Bravman
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Film Thickness ◽  
Grain Boundaries ◽  
Anodic Oxide ◽  
Film Stress ◽  
Cu Films ◽  
Si Substrates ◽  
Tension And Compression ◽  
Stress Variations

We have measured stress variations with temperature as a function of film thickness and a given grain size in pure Al and Al–0.5% Cu films on Si substrates. The variation in thickness for a given grain size is brought about by using the same film and the repeated controlled growth and dissolution of a barrier anodic oxide which can be grown uniformly on the film. Stress measurements were made as a function of temperature by measuring wafer curvature after successively removing each 0.1 μm of Al film. The components of strengthening due to the film thickness and the presence of grain boundaries were separated by assuming that the flow stress of the film is simply the sum of these two components. It is found that strengthening due to film thickness varies inversely with the thickness, which is consistent with results obtained by us using laser-reflowed films in an earlier work. The Hall–Petch coefficients calculated from the strengthening due to the grain boundaries are slightly higher than those reported for bulk Al. However, it is also recognized that the variation of the flow stress as g−1, where g is the grain size, is more plausible than that predicted by the Hall–Petch relation (i.e., as g−1/2). The variations of these two components with temperature, and under tension and compression, are discussed.

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