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.

Effects of Confinement on Plastic Deformation in Passivated AL Films

1993 ◽  
Vol 308 ◽  
Author(s):  
S.G.H. Anderson ◽  
I.-S. Yeo ◽  
P.S. Ho ◽  
S. Ramaswami ◽  
R. Cheung
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Thermal Cycling ◽  
Temperature Behavior ◽  
Weighted Sum ◽  
Wafer Curvature ◽  
Tension And Compression ◽  
Curvature Measurements

ABSTRACTWafer curvature measurements of a trilayer (SiO2 / AlSiCu / Si) structure are compared to that predicted by a weighted sum of individual measurements of SiO2 and AlSiCu films on Si, and significant differences are found to exist for temperatures above 200°C. A straightforward analysis of the stresses in each layer has been modeled using an extension of a model by Feng et al. which assumes uniform plastic deformation throughout the Al. The modeling results suggest a straightforeward method for determining stresses in deformable thin films that are confined by elastic overlayers. A comparison of the stress-temperature behavior for unpassivated and passivated AlSiCu films reveals that the confined films exhibit less plastic deformation and both higher tension and compression during thermal cycling.

Effects of Confinement on Plastic Deformation in Passivated Al Films

1993 ◽  
Vol 309 ◽  
Author(s):  
S.G.H. Anderson ◽  
I.-S. Yeo ◽  
P.S. Ho ◽  
S. Ramaswami ◽  
R. Cheung
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Thermal Cycling ◽  
Temperature Behavior ◽  
Weighted Sum ◽  
Wafer Curvature ◽  
Tension And Compression ◽  
Curvature Measurements

AbstractWafer curvature measurements of a trilayer (SiO2 / AlSiCu / Si) structure are compared to that predicted by a weighted sum of individual measurements of SiO2 and AISiCu films on Si, and significant differences are found to exist for temperatures above 200°C. A straightforward analysis of the stresses in each layer has been modeled using an extension of a model by Feng et al. which assumes uniform plastic deformation throughout the Al. The modeling results suggest a straightforeward method for determining stresses in deformable thin films that are confined by elastic overlayers. A comparison of the stress-temperature behavior for unpassivated and passivated AISiCu films reveals that the confined films exhibit less plastic deformation and both higher tension and compression during thermal cycling.

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.

Thermomechanical Behavior and Properties of Passivated Pvd and Ecd Cu Thin Films

2005 ◽  
Vol 875 ◽  
Author(s):  
M. Gregoire ◽  
S. Kordic ◽  
P. Gergaud ◽  
O. Thomas ◽  
M. Ignat
Keyword(s):  
Thin Films ◽  
Thermal Cycling ◽  
Grain Growth ◽  
Impurity Content ◽  
Thermomechanical Behavior ◽  
Temperature Curve ◽  
Cu Films ◽  
Texture Change ◽  
Cu Film ◽  
Electrochemically Deposited

AbstractThe thermomechanical behavior is investigated of SiCN-encapsulated blanket Physical Vapor Deposited (PVD) and Electrochemically Deposited (ECD) Cu films. At lower ECD Cu film thicknesses an anomalous shape and a tail of the stress-temperature curve are observed, which are not caused by impurities at the interfaces, but are correlated to highly textured microstructure. Repeated thermal cycling of up to 400 °C does not markedly change the texture of the films, but a significant texture change takes place with increasing ECD Cu thickness. Thermal cycling induces grain growth for thicker films only. Impurity content and distribution in the PVD films do not change due to cycling.

Direct measurement of mechanical properties of (Pb,La)TiO3 ferroelectric thin films using nanoindentation techniques

2001 ◽  
Vol 16 (4) ◽  
pp. 993-1002 ◽  
Author(s):  
M. Algueró ◽  
A. J. Bushby ◽  
M. J. Reece
Keyword(s):  
Thin Films ◽  
Plastic Deformation ◽  
Lead Titanate ◽  
Mechanical Response ◽  
High Spatial Resolution ◽  
Ferroelectric Thin Films ◽  
Intergranular Porosity ◽  
Major Mechanism ◽  
Wall Movement ◽  
Film Substrate

A procedure using nanoindentation with spherical tipped indenters is presented that allows separation of elastic, anelastic, and plastic contributions to the deformation of thin films. The procedure was demonstrated on a range of lanthanum-modified lead titanate (Pb,La)TiO3 (PTL) ferroelectric thin films. Indentation stiffness coefficients ranging from 110 to 147 GPa have been obtained depending on the microstructure and orientation of the PTL films. This coefficient was equivalent to (and so, can be directly compared with) Young's modulus of a nontextured, unpoled ceramic when films do not present preferred orientation. The trends of the anelastic contribution with the thickness, structure, microstructure, and stress level at the film/substrate interface of the films were consistent with it being produced by ferroelastic domain wall movement. Pore compaction was a major mechanism of plastic deformation for the PTL films. Grain size also affected plastic deformation, probably as a consequence of its correlation with intergranular porosity. The technique has a high spatial resolution (contact area < 10 μm2 for the results presented here), which allowed the mechanical homogeneity of the films to be studied and inhomogeneities to be identified from their mechanical response (elastic, anelastic, and plastic).

In Situ Measurement of Stress. Included During Annealing, in A1-2%Cu Thin Films

1985 ◽  
Vol 47 ◽  
Author(s):  
P. H. Townsend ◽  
H. A. Vander Plas
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Plastic Deformation ◽  
Stress Relaxation ◽  
Thermal Cycling ◽  
Compressive Stress ◽  
Stress Measurement ◽  
Metal Films ◽  
Si Substrates

ABSTRACTStress measurement in thin film systems is discussed and applied to Al-2%Cu filns on SiO2/Si substrates during thermal cycling. Plastic deformation obscrved during compressive stress relaxation is correlated with the formation of hillocks on the metal films. The effect of secondary layers of 10%Ti-90%W on the thermo-mcchanical response of Al films is examined.

A new method to study cyclic deformation of thin films in tension and compression

1999 ◽  
Vol 14 (6) ◽  
pp. 2373-2376 ◽  
Author(s):  
M. Hommel ◽  
O. Kraft ◽  
E. Arzt
Keyword(s):  
New Method ◽  
Film Stress ◽  
X Ray Diffraction ◽  
Cu Films ◽  
Compliant Substrates ◽  
Compressive Stresses ◽  
First Results ◽  
Tension And Compression ◽  
Film Substrate ◽  
Cyclic Plastic Deformation

In this paper, a new method to study cyclic plastic deformation in thin metal films is presented. Cu films were deposited onto compliant substrates allowing the film to be subjected to tensile and compressive stresses on loading and unloading of the film/substrate composite. The film stress was measured in situ by x-ray diffraction. First results lend to characteristic stress-strain hysteresis curves, indicative of fatigue processes in small dimensions.

Energy Storage And Recovery In Thin Metal Films On Substrates

1997 ◽  
Vol 505 ◽  
Author(s):  
Shefford P Baker ◽  
Rose-Marie Keller ◽  
Eduard Arzt
Keyword(s):  
Plastic Deformation ◽  
Strain Energy ◽  
Dislocation Line ◽  
Line Length ◽  
Metal Films ◽  
Silicon Substrates ◽  
Cu Films ◽  
Compressive Flow ◽  
Film Substrate ◽  
Increasing Temperature

ABSTRACTDislocation segments which extend through the thickness of a film can move through the film only if dislocation line length is deposited or removed at the film/substrate and film/passivation (if any) interfaces. The dislocation density and, therefore, the energy stored in the film increase during plastic deformation. The reverse process, that is, the reduction of strain energy in the film by the reduction of dislocation line length, is here suggested to be the origin of a number of unexplained features of experimentally obtained stress-temperature curves, including very low (or even “negative”) yield stresses in compression, tensile-compressive flow stress asymmetries, increasing strength with increasing temperature upon heating, and a very strong Bauschinger-like effect which has been seen in thin Cu films. The results of stress-temperature measurements of passivated Cu thin films on silicon substrates are presented.

Stress Relaxation in Al–Cu and Al–Si–Cu Thin Films

1999 ◽  
Vol 14 (4) ◽  
pp. 1246-1254 ◽  
Author(s):  
A. Witvrouw ◽  
J. Proost ◽  
Ph. Roussel ◽  
P. Cosemans ◽  
K. Maex
Keyword(s):  
Stress Relaxation ◽  
Thermal Cycling ◽  
Thermal Cycle ◽  
Room Temperature ◽  
Relaxation Data ◽  
Cu Films ◽  
Dislocation Glide ◽  
Transmission Electron ◽  
Stress Changes ◽  
Curvature Measurements

Substrate curvature measurements were used to study stress changes during thermal cycling and isothermal tensile stress relaxation in 800 nm Al–0.5 wt% Cu and Al–1 wt% Si–0.5 wt% Cu films. For both compositions dislocation glide can describe the relaxation data well for temperatures up to 120 °C for Al–Si–Cu and up to 100 °C for Al–Cu. The average activation energy for Al–Si–Cu and Al–Cu is 1.7 ± 0.2 eV and 3.0 ± 0.3 eV, respectively. The athermal flow stress is the same for both and equal to 600 ± 200 MPa. This result is consistent with the obstacles for glide being Al2Cu precipitates, which, in the case of Al–Si–Cu, are fine and can be cut by the dislocations, and, in the case of Al–Cu, are strong and provide Orowan strengthening. Also, the stress changes during thermal cycling in the Al–Cu films are different from those in the Al–Si–Cu films. For Al–Cu films, the room temperature stress decreases after each thermal cycle, while for Al–Si–Cu stress changes during thermal cycling are stable from the second cycle on. These observations are supported by thorough transmission electron microscopy (TEM) studies.

Influence of Film/Substrate Interface Structure on Plasticity in Metal Thin Films

2001 ◽  
Vol 673 ◽  
Author(s):  
G. Dehm ◽  
B.J. Inkson ◽  
T.J. Balk ◽  
T. Wagner ◽  
E. Arzt
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Dislocation Motion ◽  
Metal Thin Films ◽  
Cu Films ◽  
Substrate Interface ◽  
Transmission Electron ◽  
Curvature Measurements ◽  
Film Substrate

ABSTRACTIn-situ transmission electron microscopy studies of metal thin films on substrates indicate that dislocation motion is influenced by the structure of the film/substrate interface. For Cu films grown on silicon substrates coated with an amorphous SiNx diffusion barrier, the transmission electron microscopy studies reveal that dislocations are pulled towards the interface, where their contrast finally disappears. However, in epitaxial Al films deposited on single-crystalline α- Al2O3 substrates, threading dislocations advance through the layer and deposit dislocation segments adjacent to the interface. In this latter case, the interface is between two crystalline lattices. Stresses in epitaxial Al films and polycrystalline Cu films were determined by substrate- curvature measurements. It was found that, unlike the polycrystalline Cu films, the flow stresses in the epitaxial Al films are in agreement with a dislocation-based model.

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