The Mechanical Properties of Electroplated Cu Thin Films Measured by means of the Bulge Test Technique

2001 ◽  
Vol 695 ◽  
Author(s):  
Yong Xiang ◽  
Xi Chen ◽  
Joost J. Vlassak

ABSTRACTThe mechanical properties of freestanding electroplated Cu films were determined by measuring the deflection of Si-framed, pressurized membranes. The films were deformed under plane-strain conditions. The pressure-deflection data are converted into stress-strain curves by means of simple analytical formulae. The microstructure of the Cu films was characterized using scanning electron microscopy and x-ray diffraction. The yield stress, Young's modulus, and residual stress were determined as a function of film thickness and microstructure. Both yield stress and Young's modulus increase with decreasing film thickness and correlate well with changes in the microstructure and texture of the films.

2003 ◽  
Vol 795 ◽  
Author(s):  
Yong Xiang ◽  
Joost J. Vlassak ◽  
Maria T. Perez-Prado ◽  
Ting Y. Tsui ◽  
Andrew J. McKerrow

ABSTRACTThe goal of this paper is to investigate the effects of film thickness and the presence of a passivation layer on the mechanical behavior of electroplated Cu thin films. In order to study the effect of passivating layers, freestanding Cu membranes were prepared using standard silicon micromachining techniques. Some of these Cu membranes were passivated by sputter depositing thin Ti films with thicknesses ranging from 20 nm to 50 nm on both sides of the membrane. The effect of film thickness was evaluated by preparing freestanding films with varying thickness but constant microstructure. To that effect, coatings of a given thickness were first vacuum annealed at elevated temperature to stabilize the microstructure. The annealed films were subsequently thinned to various thicknesses by means of chemical mechanical planarization (CMP) and freestanding membranes were prepared both with and without Ti passivation. The stress-strain curves of the freestanding Cu films were evaluated using the bulge test technique. The residual stress and elastic modulus of the film are not affected significantly by the passivation layer. The elastic modulus does not change with film thickness if the microstructure keeps constant. The yield stress increases if the film is passivated. For passivated films, yield stress is proportional to the inverse of the film thickness, which is consistent with the formation of a boundary layer of high dislocation density near the interfaces.


2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.


2008 ◽  
Vol 33-37 ◽  
pp. 969-974 ◽  
Author(s):  
Bong Bu Jung ◽  
Seong Hyun Ko ◽  
Hun Kee Lee ◽  
Hyun Chul Park

This paper will discuss two different techniques to measure mechanical properties of thin film, bulge test and nano-indentation test. In the bulge test, uniform pressure applies to one side of thin film. Measurement of the membrane deflection as a function of the applied pressure allows one to determine the mechanical properties such as the elastic modulus and the residual stress. Nano-indentation measurements are accomplished by pushing the indenter tip into a sample and then withdrawing it, recording the force required as a function of position. . In this study, modified King’s model can be used to estimate the mechanical properties of the thin film in order to avoid the effect of substrates. Both techniques can be used to determine Young’s modulus or Poisson’s ratio, but in both cases knowledge of the other variables is needed. However, the mathematical relationship between the modulus and Poisson's ratio is different for the two experimental techniques. Hence, achieving agreement between the techniques means that the modulus and Poisson’s ratio and Young’s modulus of thin films can be determined with no a priori knowledge of either.


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.


1996 ◽  
Vol 438 ◽  
Author(s):  
J. A. Knapp ◽  
D. M. Follstaedt ◽  
J. C. Barbour ◽  
S. M. Myers ◽  
J. W. Ager ◽  
...  

AbstractWe present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.


2021 ◽  
Author(s):  
Hui Cao ◽  
Wenke Chen ◽  
Zhiyuan Rui ◽  
Changfeng Yan

Abstract Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the <110>{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the <111> Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the <110> Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.


2012 ◽  
Vol 27 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Michela Gioffrè ◽  
Paola Torricelli ◽  
Silvia Panzavolta ◽  
Katia Rubini ◽  
Adriana Bigi

The effect of the film-forming solution pH on the triple-helix content, thermal stability, and mechanical properties of gelatin films was investigated. The films were prepared from solutions at different pHs of type A pigskin gelatin, and their mechanical characteristics were determined. At pHs higher than 9 and lower than 5, Young’s modulus, E, and the stress at break, σb, of the films decreased significantly. Cross-linking with genipin reduced deformation at break, ϵb, and increased Young’s modulus. The intensity of the 1.1-nm X-ray diffraction reflection and the denaturation enthalpy decreased at these pHs, indicating that the triple helix reduced. Preliminary in vitro tests on the cross-linked samples indicated good cell proliferation and viability.


2005 ◽  
Vol 297-300 ◽  
pp. 574-580 ◽  
Author(s):  
Takahiro Namazu ◽  
Shozo Inoue ◽  
Daisuke Ano ◽  
Keiji Koterazawa

This paper focuses on investigating mechanical properties of micron-thick polycrystalline titanium nitride (TiN) films. We propose a new technique that can directly measure lateral strain of microscale crystalline specimen by X-ray diffraction (XRD) during tensile test. The XRD tensile test can provide not only Young’s modulus but also Poisson’s ratio of TiN films. Micron-thick TiN films were deposited onto both surfaces of single crystal silicon (Si) specimen by r.f. reactive magnetron sputtering. Young’s modulus and Poisson’s ratio of Si specimen obtained by XRD tensile tests were in good agreement with analytical values. TiN films deposited at Ar partial pressure of 0.7Pa had the average values of 290GPa and 0.36 for Young’s modulus and Poisson’s ratio. The elastic mechanical properties of TiN films gradually decreased down to 220GPa and 0.29 with increasing Ar partial pressure up to 1.0Pa, regardless of film thickness. The change in the film properties with Ar partial pressure would be attributed to the change in the film density.


Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 801 ◽  
Author(s):  
Jaweb Ben Messaoud ◽  
Jean-François Michaud ◽  
Dominique Certon ◽  
Massimo Camarda ◽  
Nicolò Piluso ◽  
...  

The stress state is a crucial parameter for the design of innovative microelectromechanical systems based on silicon carbide (SiC) material. Hence, mechanical properties of such structures highly depend on the fabrication process. Despite significant progresses in thin-film growth and fabrication process, monitoring the strain of the suspended SiC thin-films is still challenging. However, 3C-SiC membranes on silicon (Si) substrates have been demonstrated, but due to the low quality of the SiC/Si heteroepitaxy, high levels of residual strains were always observed. In order to achieve promising self-standing films with low residual stress, an alternative micromachining technique based on electrochemical etching of high quality homoepitaxy 4H-SiC layers was evaluated. This work is dedicated to the determination of their mechanical properties and more specifically, to the characterization of a 4H-SiC freestanding film with a circular shape. An inverse problem method was implemented, where experimental results obtained from bulge test are fitted with theoretical static load-deflection curves of the stressed membrane. To assess data validity, the dynamic behavior of the membrane was also investigated: Experimentally, by means of laser Doppler vibrometry (LDV) and theoretically, by means of finite element computations. The two methods provided very similar results since one obtained a Young’s modulus of 410 GPa and a residual stress value of 41 MPa from bulge test against 400 GPa and 30 MPa for the LDV analysis. The determined Young’s modulus is in good agreement with literature values. Moreover, residual stress values demonstrate that the fabrication of low-stressed SiC films is achievable thanks to the micromachining process developed.


2018 ◽  
Vol 913 ◽  
pp. 564-570 ◽  
Author(s):  
Wei Wang ◽  
Wei Wang ◽  
Dong Lv ◽  
Jing Shen Wu

The matrix/filler interface plays a vital role in mechanical properties of polypropylene (PP)/rigid nanoparticles composites. In general, the use of spherical stearic acid modified CaCO3 (SA-CaCO3) can induce a weak interfacewhich facilitatesparticle debonding from the matrix under loading and reduces plastic resistance, enhancing the toughness of nanocomposites, while the use of polymer-grafted nanoparticles (PGS) can improve the Young’s modulus and yield stress because of strong interfacial binding between particle and matrix. With the objective to simultaneously improve the modulus, yield stress and toughness, the ternary nanocomposites, PP/PGS/CaCO3 (PPSC), were prepared and the morphology, crystallization, and mechanical behavior were investigated and compared to their binary nanocomposites. The results show that Young’s modulus is enhanced as the particle loading, and the yield stress is balanced by two interactions, i.e. the decreasing effect of the weak interface and the enhancement effect of the strong interface. The impact strength of the ternary nanocomposites shows insignificant improvement compared with neat PP, which is attributed to the brittle effect of the weak interface in the particle cluster of SA-CaCO3 and PGS.


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