Mechanical Characterization of Sub-Micron Polytetrafluoroethylene (PTFE) Thin Films

1997 ◽  
Vol 505 ◽  
Author(s):  
B. N. Lucas ◽  
C. T. Rosenmayer ◽  
W. C. Oliver
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Film Thickness ◽  
Excitation Frequency ◽  
Tensile Modulus ◽  
Depth Sensing ◽  
Free Standing ◽  
Reliability Modeling ◽  
Interlayer Dielectric ◽  
Constrained Deformation

ABSTRACTThis study reports the results of an investigation of the mechanical properties of polytetrafluoroethylene (PTFE) thin films on silicon substrates in the 0.5 to 15 μm thickness regime using frequency specific depth-sensing indentation. All measurements were conducted at an excitation frequency of 45 Hz using a constant (1/P dP/dt) load ramp of 0.1 s−1. The modulus of the PTFE at a depth of 5% of the film thickness was measured to be approximately 1 GPa (v = 0.46) independent of film thickness. These values are somewhat higher than the values obtained from free-standing 15 μm film measurements of 0.4 GPa for the tensile modulus and 0.49 GPa for the storage modulus @ 1.1 Hz. The film hardness at these depths was observed to range between 30 and 55 MPa with no correlation observed between the hardness and respective film thickness. While reliability modeling for interconnects currently uses interlayer dielectric mechanical properties data determined from free-standing films with thicknesses of several microns, these insitu results should more closely mimic the constrained deformation that occurs during service and perhaps lead to a better understanding of the electromigration resistance of PTFE.

Mechanical Properties of Electroplated Copper Thin Films

1999 ◽  
Vol 594 ◽  
Author(s):  
R. Spolenak ◽  
C. A. Volkert ◽  
K. Takahashi ◽  
S. Fiorillo ◽  
J. Miner ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Grain Size ◽  
Film Thickness ◽  
Yield Stress ◽  
Laser Scanning ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Cu Films ◽  
Electroplated Copper

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.

scholarly journals Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hendrik Wulfmeier ◽  
Dhyan Kohlmann ◽  
Thomas Defferriere ◽  
Carsten Steiner ◽  
Ralf Moos ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
Film Thickness ◽  
Solid Solutions ◽  
Low Voltage ◽  
Excitation Frequency ◽  
Dimensional Change ◽  
Potential Core ◽  
Chemical Expansion

Abstract The chemical expansion of Pr0.1Ce0.9O2–δ (PCO) and CeO2–δ thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.

scholarly journals Effect of Cellulose Nanofibrils and TEMPO-mediated Oxidized Cellulose Nanofibrils on the Physical and Mechanical Properties of Poly(vinylidene fluoride)/Cellulose Nanofibril Composites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1091 ◽  
Author(s):  
Eftihia Barnes ◽  
Jennifer A. Jefcoat ◽  
Erik M. Alberts ◽  
Mason A. McKechnie ◽  
Hannah R. Peel ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinylidene Fluoride ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Weight Ratio ◽  
Tensile Modulus ◽  
Physical And Mechanical Properties ◽  
Free Standing ◽  
Composite Surface ◽  
Poly Vinylidene Fluoride

Cellulose nanofibrils (CNFs) are high aspect ratio, natural nanomaterials with high mechanical strength-to-weight ratio and promising reinforcing dopants in polymer nanocomposites. In this study, we used CNFs and oxidized CNFs (TOCNFs), prepared by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation process, as reinforcing agents in poly(vinylidene fluoride) (PVDF). Using high-shear mixing and doctor blade casting, we prepared free-standing composite films loaded with up to 5 wt % cellulose nanofibrils. For our processing conditions, all CNF/PVDF and TOCNF/PVDF films remain in the same crystalline phase as neat PVDF. In the as-prepared composites, the addition of CNFs on average increases crystallinity, whereas TOCNFs reduces it. Further, addition of CNFs and TOCNFs influences properties such as surface wettability, as well as thermal and mechanical behaviors of the composites. When compared to neat PVDF, the thermal stability of the composites is reduced. With regards to bulk mechanical properties, addition of CNFs or TOCNFs, generally reduces the tensile properties of the composites. However, a small increase (~18%) in the tensile modulus was observed for the 1 wt % TOCNF/PVDF composite. Surface mechanical properties, obtained from nanoindentation, show that the composites have enhanced performance. For the 5 wt % CNF/PVDF composite, the reduced modulus and hardness increased by ~52% and ~22%, whereas for the 3 wt % TOCNF/PVDF sample, the increase was ~23% and ~25% respectively.

Film Thickness Effect on Tensile Properties and Microstructures of Submicron Aluminum Thin Films on Polyimide

1996 ◽  
Vol 436 ◽  
Author(s):  
Y. S. Kang ◽  
P. S. Ho ◽  
R. Knipe ◽  
J. Tregilgas
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Film Thickness ◽  
Metal Film ◽  
Tensile Force ◽  
Thickness Effect ◽  
Published Data ◽  
Free Standing ◽  
Aluminum Films ◽  
Flexible Polymer

AbstractThe mechanical behavior of the metal film on a polymer substrate becomes an important issue in microelectronics metallization. The metal/polymer structure is also useful to investigate the deformation behavior of very thin free-standing metal film since the flexible polymer serves as a deformable substrate. The tensile force-elongation curves have been measured using a microtensile tester for aluminum thin films, deposited on a PMDA-ODA polyimide film, in the thickness range from 60 rum to 480 nm. The stress-strain curves for aluminum films were constructed by subtracting these curves with polyimide curves measured separately. Tensile strength increases linearly with decreasing film thickness from 196 MPa to 408 MPa within the film thickness range studied. This is in good agreement with the published data for free-standing aluminum films in the same thickness range. The measured Young's modulus is lower than the bulk modulus and exhibits no systematic dependence on the film thickness. The microstructures of aluminum films have been examined using a transmission electron microscope (TEM). These films posses the (111)-textured columnar grain structures. Grain sizes exhibit log-normal distributions and the mean grain size increases monotonically with the film thickness. An attempt is made to evaluate the effect of film thickness and grain size on the strength of aluminum thin film and the result is discussed.

The Analysis of Depth-Sensing Indentation Data: Review of the Special Discussion Session

1993 ◽  
Vol 308 ◽  
Author(s):  
Shefford P. Baker ◽  
T.P. Weihs
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
State Of The Art ◽  
The State ◽  
Discussion Session ◽  
Depth Sensing ◽  
Recent Advances

In light of recent advances in the analysis of depth-sensing indentation data and of the importance of this technique in the study of the mechanical properties of thin films, a special discussion session was held in order to explore the state of the art and to provide an informal forum for discussion. This is a brief review of that discussion. The discussion was focused by the four main sources of deviation from model behavior described in the previous paper.

Depth sensing indentation of nanoscale graphene platelets in nanocomposite thin films

2011 ◽  
Vol 1312 ◽  
Author(s):  
Ardavan Zandiatashbar ◽  
Catalin R. Picu ◽  
Nikhil Koratkar
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Characteristic Length ◽  
Matrix Interface ◽  
Depth Sensing ◽  
Epoxy Nanocomposites ◽  
Dramatic Decrease ◽  
Graphene Platelet ◽  
Nanocomposite Thin Films

ABSTRACTSignificant improvement of mechanical properties was observed recently in graphene platelet-epoxy nanocomposites relative to unfilled epoxy, such as an increase of the fracture toughness by 50% and dramatic decrease of fatigue crack growth rate. In this work, thin films of 0.1 wt.% of graphene platelet (GPL) – epoxy nanocomposites were fabricated and the nanoscale mechanical properties of the nanocomposite were investigated by nanoindentation. This provides information about the presence of characteristic length scales induced by the microstructure and the strength of the filler-matrix interface.

Mechanical properties of interference thin films on colored stainless steel evaluated by depth-sensing nanoindentation

2006 ◽  
Vol 201 (6) ◽  
pp. 2431-2437 ◽  
Author(s):  
Rosa M.R. Junqueira ◽  
Margareth S. Andrade ◽  
Célia R.O. Loureiro ◽  
Vicente T.L. Buono
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Stainless Steel ◽  
Depth Sensing

scholarly journals A Direct Comparison of Three Buckling-Based Methods to Measure the Elastic Modulus of Nanobiocomposite Thin Films

2020 ◽  
Author(s):  
Taylor C. Stimpson ◽  
Daniel A. Osorio ◽  
Emily D. Cranston ◽  
Jose Moran-Mirabal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Elastic Moduli ◽  
Input Parameter ◽  
Layer By Layer ◽  
Free Standing ◽  
Film Composition ◽  
Parameter Values

<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>

scholarly journals The Effect of Film Thickness on the Structural Properties of Vacuum Evaporated Poly(3-methylthiophene) Thin Films

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sandip V. Kamat ◽  
Vijaya Puri ◽  
R. K. Puri
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Surface Roughness ◽  
Surface Morphology ◽  
Film Thickness ◽  
Structural Properties ◽  
Vacuum Evaporation ◽  
Intrinsic Stress ◽  
Glass Substrates ◽  
Structure Surface

This paper reports on the structural properties of poly(3-methylthiophene) P3MeT thin films prepared by vacuum evaporation on the glass substrates. The structural and surface morphology, wettability, adhesion, and intrinsic stress of these thin films were studied for three different thicknesses. The variation of the film thickness affects the structure, surface, and mechanical properties of P3MeT thin films. Vapor chopping also strongly influences the surface morphology, surface roughness, and wettability of the thin films. It was found that there is a decrease in the intrinsic stress and (RMS) roughness, while the adhesion increases with increase in film thickness.

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