scholarly journals Micro-fluidic applications of telephone cord delamination blisters

2004 ◽  
Vol 855 ◽  
Author(s):  
Alex A. Volinsky ◽  
Patrick Waters ◽  
Gregory Wright
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Argon Pressure ◽  
Inexpensive Method ◽  
Directional Growth ◽  
Interfacial Toughness ◽  
Micro Fluidics ◽  
Buckling Delamination ◽  
Sputter Deposited ◽  
Stored Elastic Energy

ABSTRACTArgon pressure significantly affects the residual stress in sputter deposited thin films and coatings. In case of W thin films, high residual stresses on the order of 1–2 GPa are quite common. With the rest of sputtering parameters being equal, argon pressure determines the sign and the value of residual stress.When the amount of stored elastic energy in the film due to the residual stress exceeds the interfacial toughness, fracture normally occurs. Telephone cord buckling delamination blisters are commonly observed in compressed thin films. These mechanically active features form by a loss of adhesion between the film and the substrate due to residual stress relief, and exhibit directional growth under certain conditions. This paper considers telephone cord delamination channels for micro-fluidics applications, as this could to be a valuable, reliable, and inexpensive method of forming open channels.

scholarly journals Nanoindentation of Au and Pt/Cu thin films at elevated temperatures

2004 ◽  
Vol 19 (9) ◽  
pp. 2650-2657 ◽  
Author(s):  
Alex A. Volinsky ◽  
Neville R. Moody ◽  
William W. Gerberich
Keyword(s):  
Thin Films ◽  
Elastic Modulus ◽  
Yield Stress ◽  
Elevated Temperatures ◽  
Nanocrystalline Structure ◽  
Cu Films ◽  
Interfacial Toughness ◽  
Film Hardness ◽  
Cu Film ◽  
Sputter Deposited

This paper describes the nanoindentation technique for measuring sputter-deposited Au and Cu thin films’ mechanical properties at elevated temperatures up to 130 °C. A thin, 5-nm Pt layer was deposited onto the Cu film to prevent its oxidation during testing. Nanoindentation was then used to measure elastic modulus and hardness as a function of temperature. These tests showed that elastic modulus and hardness decreased as the test temperature increased from 20 to 130 °C. Cu films exhibited higher hardness values compared to Au, a finding that is explained by the nanocrystalline structure of the film. Hardness was converted to the yield stress using both the Tabor relationship and the inverse method (based on the Johnson cavity model). The thermal component of the yield-stress dependence followed a second-order polynomial in the temperature range tested for Au and Pt/Cu films. The decrease in yield stress at elevated temperatures accounts for the increased interfacial toughness of Cu thin films.

scholarly journals Fracture patterns in thin films and multilayers

2003 ◽  
Vol 795 ◽  
Author(s):  
Alex A. Volinsky ◽  
Dirk C. Meyer ◽  
Tilmann Leisegang ◽  
Peter Paufler
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Residual Stress ◽  
Stress Relief ◽  
Fracture Pattern ◽  
External Stress ◽  
Final Fracture ◽  
Fracture Patterns ◽  
Buckling Delamination ◽  
Applied Stresses

ABSTRACTWhile there are many stress relief mechanisms observed in thin films, excessive residual and externally applied stresses cause film fracture. In the case of tensile stress a network of through-thickness cracks forms in the film. In the case of compressive stress thin film buckling is observed in the form of blisters. Thin film delamination is an inseparable phenomenon of buckling. The buckling delamination blisters can be either circular, straight, or form periodic buckling patterns commonly known as telephone cord delamination morphology.While excessive biaxial residual stress is the key for causing thin film fracture, either in tension, or compression, it is the influence of the external stress that can control the final fracture pattern. In this paper we consider phone cord buckling delamination observed in compressed W/Si and TiWN/GaAs thin film systems, as well as spiral and sinusoidal though-thickness cracks observed in Mo/Si multilayers under 3-point high-temperature bending in tension.

Finite Element Modelling of Stress-Induced Fracture in Ti-Si-N Films

2014 ◽  
Vol 553 ◽  
pp. 10-15
Author(s):  
E.A. Flores-Johnson ◽  
Lu Ming Shen ◽  
R.K. Annabattula ◽  
P.R. Onck ◽  
Yao Gen Shen ◽  
...  
Keyword(s):  
Thin Films ◽  
Residual Stresses ◽  
Finite Element Modelling ◽  
Nanocomposite Coating ◽  
Industrial Applications ◽  
Coating Films ◽  
Element Modelling ◽  
Mechanical And Physical Properties ◽  
Buckling Delamination ◽  
Sputter Deposited

Nanocomposite coating films have been increasingly used in industrial applications because of their unique mechanical and physical properties. Residual stresses generated during the growth of sputter-deposited thin films due to a strain mismatch between the film and the substrate may lead to significant failure problems. Large residual stresses may generate buckling, delamination and film fracture. Although buckles with cracks in thin films have been experimentally observed, their origins are still not well understood.

Influence of deposition parameters on the stress of magnetron sputter-deposited AlN thin films on Si(100) substrates

2003 ◽  
Vol 18 (2) ◽  
pp. 423-432 ◽  
Author(s):  
G.F. Iriarte ◽  
F. Engelmark ◽  
M. Ottosson ◽  
I.V. Katardjiev
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Substrate Temperature ◽  
Diffraction Method ◽  
Radius Of Curvature ◽  
X Ray Diffraction ◽  
Polycrystalline Aluminum ◽  
Deposition Parameters ◽  
Curvature Measurements ◽  
Sputter Deposited

In this work, a systematic study of the influence of five deposition parameters, i.e., process pressure, substrate temperature, target power, and substrate bias, as well as gas composition on the residual stress in fully textured polycrystalline aluminum nitride thin films deposited on Si(100) wafers using the reactive sputtering method was performed. Post-growth residual stress measurements were obtained indirectly from radius of curvature measurements of the wafer prior to and after deposition. Two different techniques were used to determine the curvature: an optically levered laser beam and an x-ray diffraction method. Stresses in both cases were then evaluated using the Stoney formulation [G.G. Stoney, Proc. R. Soc. (London)A82,172 (1909)]. Both methods give similar results, with slight quantitative differences. The existence of a transition region between tensile and compressive stress previously reported in the literature is also confirmed. The transition is shown to be strongly dependent on the process parameters. Optimal films regarding stress were grown at 2 mtorr, 900 W at the target, a 20/45 Ar/N2gas mixture, and floating potential at the substrate. The substrate temperature did not influence the measured internal stress in the films.

Residual Stress Reduction in Sputter Deposited Thin Films by Density Modulation

2009 ◽  
Vol 1224 ◽  
Author(s):  
Arif Sinan Alagoz ◽  
Jan-Dirk Kamminga ◽  
Sergey Yu Grachev ◽  
Toh-Ming Lu ◽  
Tansel Karabacak
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Residual Stress ◽  
Stress Reduction ◽  
Mechanical Stability ◽  
Film Stress ◽  
Radius Of Curvature ◽  
Thin Film Stress ◽  
Order Of Magnitude ◽  
Sputter Deposited

AbstractControl of residual stress in thin films is critical in obtaining high mechanical quality coatings without cracking, buckling, or delamination. In this work, we present a simple and effective method of residual stress reduction in sputter deposited thin films by stacking low and high material density layers of the same material. This multilayer density modulated film is formed by successively changing working gas pressure between high and low values, which results in columnar nanostructured and dense continuous layers, respectively. In order to investigate the evolution of residual stress in density modulated thin films, we deposited ruthenium (Ru) films using a DC magnetron sputtering system at alternating argon (Ar) pressures of 20 and 2 mTorr. Wafer’s radius of curvature was measured to calculate the intrinsic thin film stress of multilayer Ru coatings as a function of total film thickness by changing the number of high density and low density layers. By engineering the film density, we were able to reduce film stress more than one order of magnitude compared to the conventional dense films produced at low working gas pressures. Due to their low stress and enhanced mechanical stability, we were able to grow these density modulated films to much higher thicknesses without suffering from buckling. Morphology and crystal structure of the thin films were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). A previously proposed model for stress reduction by means of relatively rough and compliant sublayers was used to explain the unusually low stress in the specimens investigated.

Characterization of reactive phase formation in sputter-deposited Ni/Al multilayer thin films using TEM

1996 ◽  
Vol 54 ◽  
pp. 1000-1001
Author(s):  
G. Lucadamo ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Dark Field ◽  
Nickel Layer ◽  
Multilayer Thin Films ◽  
Cross Sectional ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Constant Heating

The subject of reactive phase formation in multilayer thin films of varying periodicity has stimulated much research over the past few years. Recent studies have sought to understand the reactions that occur during the annealing of Ni/Al multilayers. Dark field imaging from transmission electron microscopy (TEM) studies in conjunction with in situ x-ray diffraction measurements, and calorimetry experiments (isothermal and constant heating rate), have yielded new insights into the sequence of phases that occur during annealing and the evolution of their microstructure.In this paper we report on reactive phase formation in sputter-deposited lNi:3Al multilayer thin films with a periodicity A (the combined thickness of an aluminum and nickel layer) from 2.5 to 320 nm. A cross-sectional TEM micrograph of an as-deposited film with a periodicity of 10 nm is shown in figure 1. This image shows diffraction contrast from the Ni grains and occasionally from the Al grains in their respective layers.

TEM studies of solid-state reactions in sputter-deposited Nb/Al multilayer thin films

1996 ◽  
Vol 54 ◽  
pp. 1020-1021
Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Stoichiometric Composition ◽  
Analytical Electron Microscopy ◽  
Grain Structure ◽  
Solid State Reactions ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputter Deposited

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.

Transformation and Deformation Behavior in Sputter-Deposited Ti-Ni-Cu Thin Films

1995 ◽  
Vol 05 (C8) ◽  
pp. C8-689-C8-694 ◽  
Author(s):  
T. Hashinaga ◽  
S. Miyazaki ◽  
T. Ueki ◽  
H. Horikawa
Keyword(s):  
Thin Films ◽  
Deformation Behavior ◽  
Sputter Deposited
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