scholarly journals Comparison of Tensile and Fatigue Properties of Copper Thin Film Depending on Process Method

2020 ◽  
Vol 10 (1) ◽  
pp. 388
Author(s):  
Hyeon-Gyu Min ◽  
Dong-Joong Kang ◽  
Jun-Hyub Park

In this study, tensile and fatigue tests were performed and analyzed to evaluate an influence of fabrication method on mechanical characteristics of copper thin film which widely used in flexible printed circuit board (FPCB). In general, manufacturing methods are known to affect the mechanical properties of materials, especially for thin films. The copper thin film is manufactured by a rolling process or an electrodeposition process. Therefore, specimen for tensile and fatigue tests were fabricated using by etching process with the rolled and electrodeposited thin films. First, the tensile tests were performed to obtain the elastic modulus, 0.2% offset yield stress, and tensile strength of the rolled copper and the electrodeposited copper thin film. Second, the copper thin films in FPCB is most often subjected to mechanical or/and thermal cyclic loading. The fatigue tests were performed to compare the fatigue characteristics and to evaluate an influence of fabrication method. Tensile test results showed that the elastic modulus was similar for each process, but the 0.2% yield strength and ultimate tensile strength were greater in the rolling process. In addition, the fatigue test results show that the copper thin films by the rolling process are better than by the electrodeposition process in fatigue life in all region.

2015 ◽  
Vol 60 (4) ◽  
pp. 2821-2826 ◽  
Author(s):  
A. Wierzba ◽  
S. Mróz ◽  
P. Szota ◽  
A. Stefanik ◽  
R. Mola

The paper presents the results of the experimental study of the three-layer Al-Mg-Al sheets rolling process by the ARB method. The tests carried out were limited to single-pass symmetric and asymmetric rolling processes. An Al-Mg-Al package with an initial thickness of 4 mm (1-2-1 mm) was subjected to the process of rolling with a relative reduction of 50%. To activate the shear band in the strip being deformed, an asymmetry factor of av=2 was applied. From the test results, an increase in the tensile strength of the multi-layer Al-Mg-Al sheets obtained from the asymmetric process was observed. Microhardness tests did not show any significant differences in aluminium layer between respective layers of sheets obtained from the symmetric and the asymmetric process. By contrast, for the magnesium layer, an increase in microhardness from 72 HV to 79 HV could be observed for the asymmetric rolling. The analysis of the produced Al-Mg-Al sheets shows that the good bond between individual layers and grain refinement in the magnesium layer contributed to the obtaining of higher mechanical properties in the multi-layer sheets produced in the asymmetric process compared to the sheets obtained from the symmetric process.


2011 ◽  
Vol 495 ◽  
pp. 108-111 ◽  
Author(s):  
Vasiliki P. Tsikourkitoudi ◽  
Elias P. Koumoulos ◽  
Nikolaos Papadopoulos ◽  
Costas A. Charitidis

The adhesion and mechanical stability of thin film coatings on substrates is increasingly becoming a key issue in device reliability as magnetic and storage technology driven products demand smaller, thinner and more complex functional coatings. In the present study, chemical vapor deposited Co and Co3O4thin films on SiO2and Si substrates are produced, respectively. Chemical vapor deposition is the most widely used deposition technique which produces thin films well adherent to the substrate. Co and Co3O4thin films can be used in innovative applications such as magnetic sensors, data storage devices and protective layers. The produced thin films are characterized using nanoindentation technique and their nanomechanical properties (hardness and elastic modulus) are obtained. Finally, an evaluation of the reliability of each thin film (wear analysis) is performed using the hardness to elastic modulus ratio in correlation to the ratio of irreversible work to total work for a complete loading-unloading procedure.


Author(s):  
Pornvitoo Rittinon ◽  
Ken Suzuki ◽  
Hideo Miura

Copper thin films are indispensable for the interconnections in the advanced electronic products, such as TSV (Trough Silicon Via), fine bumps, and thin-film interconnections in various devices and interposers. However, it has been reported that both electrical and mechanical properties of the films vary drastically comparing with those of conventional bulk copper. The main reason for the variation can be attributed to the fluctuation of the crystallinity of grain boundaries in the films. Porous or sparse grain boundaries show very high resistivity and brittle fracture characteristic in the films. Thus, the thermal conductivity of the electroplated copper thin films should be varied drastically depending on their micro texture based on the Wiedemann-Franz’s law. Since the copper interconnections are used not only for the electrical conduction but also for the thermal conduction, it is very important to quantitatively evaluate the crystallinity of the polycrystalline thin-film materials and clarify the relationship between the crystallinity and thermal properties of the films. The crystallinity of the interconnections were quantitatively evaluated using an electron back-scatter diffraction method. It was found that the porous grain boundaries which contain a significant amount of vacancies increase the local electrical resistance in the interconnections, and thus, cause the local high Joule heating. Such porous grain boundaries can be eliminated by control the crystallinity of the seed layer material on which the electroplated copper thin film is electroplated.


2010 ◽  
Vol 25 (4) ◽  
pp. 728-734 ◽  
Author(s):  
Han Li ◽  
Nicholas X. Randall ◽  
Joost J. Vlassak

Indentation experiments on thin films are analyzed by using a rigorous solution to model elastic substrate effects. Two cases are discussed: elastic indentations where film and substrate are anisotropic and elastoplastic indentations where significant material pileup occurs. We demonstrate that the elastic modulus of a thin film can be accurately measured in both cases, even if there is significant elastic mismatch between film and substrate.


Author(s):  
Jiatong Liu ◽  
Ken Suzuki ◽  
Hideo Miura

In a three-dimensional (3D) packaging systems, the interconnections which penetrate stacked silicon chips have been employed. Such interconnection structure is called TSV (Through Silicon Via) structure, and the via is recently filled by electroplated copper thin film. The electroplated copper thin films often consist of fine columnar grains and porous grain boundaries with high density of defects which don’t appear in conventional bulk material. This unique micro texture has been found to cause the wide variation of physical and chemical properties of this material. In the TSV structure, the shrinkage of the copper thin film caused by thermal deformation and recrystallization of the unique texture during high-temperature annealing is strictly constrained by surrounding rigid Si and thus, high tensile residual stress remains in the thin film after thermal annealing. High residual stress should give rise to mechanical fracture of the interconnections and the shift of electronic function of thin film devices formed in Si. Therefore, the residual stress in the interconnections should be minimized by controlling the appearance of the porous boundaries during electroplating for assuring the longterm reliability of the interconnections. As the lattice mismatch between Cu and its barrier film (Ta) is as larger as 18%, which is the main reason for the fine columnar structures and porous grain boundaries, it is necessary to control the underlayer crystallinity to improve the crystallinity of electroplated copper thin films. In this study, the effective method for controlling the crystallinity of the underlayer was investigated by improving the atomic configuration in the electroplated copper thin film. The result showed that by controlling the crystallinity of underlayer, crystallinity of electroplated copper thin films can be improved, the mechanical properties of thin films was improved and thus, stability and lifetime of electroplated copper interconnections can be improved.


2020 ◽  
Author(s):  
Taylor C. Stimpson ◽  
Daniel A. Osorio ◽  
Emily D. Cranston ◽  
Jose Moran-Mirabal

<p>To engineer tunable thin film materials, accurate measurement of their mechanical properties is crucial. However, characterizing the elastic modulus with current methods is particularly challenging for sub-micrometer thick films and hygroscopic materials because they are highly sensitive to environmental conditions and most methods require free-standing films which are difficult to prepare. In this work, we directly compared three buckling-based methods to determine the elastic moduli of supported thin films: 1) biaxial thermal shrinking, 2) uniaxial thermal shrinking, and 3) the mechanically compressed, strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) method. Nanobiocomposite model films composed of cellulose nanocrystals (CNCs) and polyethyleneimine (PEI) were assembled using layer-by-layer deposition to control composition and thickness. The three buckling-based methods yielded the same trends and comparable values for the elastic moduli of each CNC-PEI film composition (ranging from 15 – 44 GPa, depending on film composition). This suggests that the methods are similarly effective for the quantification of thin film mechanical properties. Increasing the CNC content in the films statistically increased the modulus, however, increasing the PEI content did not lead to significant changes. The standard deviation of elastic moduli determined from SIEBIMM was 2-4 times larger than for thermal shrinking, likely due to extensive cracking and partial film delamination. In light of these results, biaxial thermal shrinking is recommended as the method of choice because it affords the simplest implementation and analysis and is the least sensitive to small deviations in the input parameter values, such as film thickness or substrate modulus.</p>


2016 ◽  
Vol 8 (2) ◽  
pp. 1
Author(s):  
Kasem K. Kasem ◽  
Christopher Santuzzi ◽  
Nick Daanen ◽  
Kortany Baker

<p>Photoactive (IOI) inorganic/organic interface assemblies were prepared using an occlusion electrodeposition method. Poly-2,2′:5′,2′′-Terthiophene (PTTh) were the organic thin films that occluded each of CdS, TiO<sub>2</sub>, and Zn-doped WO<sub>3</sub> nanoparticles.<strong> </strong>The energy band gap structures were investigated using spectroscopic and electrochemical techniques.<strong> </strong>The obtained assemblies were investigated in aqueous solutions under both dark and illuminated conditions. The results were compared with the behavior of PTTh thin film. Oxygen played an important role in minimizing electron/hole recombination as was evident by observed very low photocurrent when oxygen was removed by nitrogen purge. Results show that PTTh/CdS gave the greatest photocurrent, followed by PTTh/Zn-WO<sub>3</sub> and PTTh/TiO<sub>2</sub>.</p>


2018 ◽  
Vol 64 (No. 4) ◽  
pp. 202-208
Author(s):  
Margus Arak ◽  
Kaarel Soots ◽  
Marge Starast ◽  
Jüri Olt

In order to model and optimise the structural parameters of the working parts of agricultural machines, including harvesting machines, the mechanical properties of the culture harvested must be known. The purpose of this article is to determine the mechanical properties of the blueberry plant’s stem; more precisely the tensile strength and consequent elastic modulus E. In order to achieve this goal, the measuring instrument Instron 5969L2610 was used and accompanying software BlueHill 3 was used for analysing the test results. The tested blueberry plant’s stems were collected from the blueberry plantation of the Farm Marjasoo. The diameters of the stems were measured, test units were prepared, tensile tests were performed, tensile strength was determined and the elastic modulus was obtained. Average value of the elastic modulus of the blueberry (Northblue) plant’s stem remained in the range of 1268.27–1297.73 MPa.


2002 ◽  
Vol 738 ◽  
Author(s):  
Lucas Pérez ◽  
Oscar de Abril ◽  
Claudio Aroca ◽  
Pedro Sánchez ◽  
Eloísa López ◽  
...  

ABSTRACTThin films and arrays of lines of magnetic CoNiFe alloy have been produced by electrodeposition. A magnetic field was applied during the electrodeposition process in order to induce a magnetic anisotropy in the sample. The dependence of the magnetic properties and the magnetic domain structures on the thickness of the films is reported. In addition to this, the magnetic properties and the domain structure of a thin film and an array of lines, with the same thickness and deposited in the same conditions, have been compared. An increase in the coercivity of the array of lines has been shown.


2007 ◽  
Vol 561-565 ◽  
pp. 2005-2008
Author(s):  
X.Y. Zhou ◽  
Hai Rong Wang ◽  
Zhuang De Jiang ◽  
Rui Xia Yu

A simple method to extract the intrinsic mechanical properties of the soft metallic thin films on hard substrates by nanoindenation is presented. Utilizing the geometry relationship of residual impressions obtained by the SEM image and the cross-sectional profile, the pile up error in elastic modulus determination of soft thin films by the Oliver and Pharr analysis is first corrected. Knowledge of the ‘true’ elastic modulus, the ‘true’ hardness of thin film is then extracted from the measured contact stiffness data for an elastically homogeneous film-substrate system. The present method is applied for a 504 nm Au thin film sputter deposited on the glass substrate and the results show that the ‘true’ elastic modulus and hardness of Au film are 80 GPa and 1.3 GPa, which are in agreement well with the literatures.


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