Evaluation of the modified edge lift-off test for adhesion characterization in microelectronic multifilm applications

2001 ◽  
Vol 16 (2) ◽  
pp. 385-393 ◽  
Author(s):  
Jack C. Hay ◽  
Eric G. Liniger ◽  
Xiao Hu Liu
Keyword(s):  
Steady State ◽  
Film Thickness ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Release Rate ◽  
Crack Problem ◽  
Young’S Moduli ◽  
Lift Off ◽  
Unexpected Outcomes

The modified edge lift-off test (MELT) has gained enough acceptance in the community for evaluating interfacial adhesion that there is now commercial equipment for automating the test. However, there are several experimental and mechanics assumptions of the test that may provide unexpected outcomes. Experimental data suggested that for crack lengths greater than 5% of the film thickness the energy release rate was independent of crack length, contradicting the rule of thumb suggesting that the crack length should be greater than 10–20 times the film thickness to obtain a steady-state energy release rate in the edge crack problem. Finite element simulations not only corroborated the experimental observation but seemed to indicate that the crack length required for steady-state conditions was a function of the relative Young's moduli for the film and substrate. It was also shown via an analytical model that plate bending (commonly neglected) can significantly affect the energy release rate in the MELT and lead to incorrect conclusions regarding the reliability of an interface.

Calculating Energy Release Rate as a Function of Crack Length Using a Multiple-Step Crack Closure Technique in Tire Finite Element Models

2018 ◽  
Vol 46 (3) ◽  
pp. 130-152
Author(s):  
Dennis S. Kelliher
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Crack Closure ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Three Dimensions ◽  
Quantitative Prediction ◽  
Closure Technique

ABSTRACT When performing predictive durability analyses on tires using finite element methods, it is generally recognized that energy release rate (ERR) is the best measure by which to characterize the fatigue behavior of rubber. By addressing actual cracks in a simulation geometry, ERR provides a more appropriate durability criterion than the strain energy density (SED) of geometries without cracks. If determined as a function of crack length and loading history, and augmented with material crack growth properties, ERR allows for a quantitative prediction of fatigue life. Complications arise, however, from extra steps required to implement the calculation of ERR within the analysis process. This article presents an overview and some details of a method to perform such analyses. The method involves a preprocessing step that automates the creation of a ribbon crack within an axisymmetric-geometry finite element model at a predetermined location. After inflating and expanding to three dimensions to fully load the tire against a surface, full ribbon sections of the crack are then incrementally closed through multiple solution steps, finally achieving complete closure. A postprocessing step is developed to determine ERR as a function of crack length from this enforced crack closure technique. This includes an innovative approach to calculating ERR as the crack length approaches zero.

Modified Edge Lift-Off Test: Experimental Modifications for Multifilm Systems

1999 ◽  
Vol 594 ◽  
Author(s):  
J. C. Hay ◽  
E. G. Liniger ◽  
X-H Liu
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Plate Bending ◽  
Adhesion Test ◽  
Testing Method ◽  
Rate Calculation ◽  
Lift Off ◽  
Microelectronics Fabrication

AbstractIn developing an adhesion test for a microelectronics fabrication facility there are many criteria which must be met. Some of these include (i) sample prep must be simple, (ii) deformations should be elastic so the problem can be easily modeled, (iii) mechanics are ideally analytical, and (iv) the test end-point must be unambiguous and easy to obtain. A testing method in the literature which meets many of these criteria is the modified edge liftoff test (MELT). Delamination is induced through the release of strain energy stored in an elastic superlayer which results from a large mismatch in CTE between the film and substrate. In this work we consider details of the energy release rate calculation, effects of plate bending, and initial flaw size.

scholarly journals Experimental Investigation of the Size Effect of the Mode I Static Fracture Toughness of Limestone

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Sheng Zhang ◽  
Longfei Wang ◽  
Mingzhong Gao
Keyword(s):  
Fracture Toughness ◽  
Size Effect ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Release Rate ◽  
Construction Materials ◽  
Reference Method ◽  
Dimensionless Energy ◽  
Static Fracture

To study the size effect of the fracture toughness of notched semicircular bend (NSCB) specimens, the dimensionless energy release rate equation of the NSCB specimen was deduced on the basis of the Bažant energy release rate. The influence of the crack length and the specimen size on the fracture toughness was analyzed. The Bažant scale equation was obtained using the International Union of Laboratories and Experts in Construction Materials, Systems, and Structures (RILEM) method. Finally, the Bažant equation was used to analyze the fracture toughness of an NSCB specimen with a radius of 75 mm, and the degree of variation was predicted. The results show that a longer fracture is correlated with a lower fracture toughness value for the same sample size and that a larger specimen radius is correlated with a higher fracture toughness value for the same crack length. The obtained Bažant equation correctly reflects the scale law of the fracture toughness of the NSCB specimen and provides highly accurate predictions of the fracture toughness of large specimens, with an error of not more than 3%. The results obtained in this study provide a new reference method and theoretical basis for the future testing work.

On The Response Of Dynamic Cracks To Increasing Overload

1995 ◽  
Vol 409 ◽  
Author(s):  
P. Gumbsch
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Mechanical Energy ◽  
Terminal Velocity ◽  
Brittle Crack ◽  
Dislocation Generation ◽  
Stable Crack Propagation

AbstractOne of the most interesting questions in the dynamics of brittle fracture is how a running brittle crack responds to an overload, i.e. to a mechanical energy release rate larger than that due to the increase in surface energy of the two cleavage surfaces. To address this question, dynamically running cracks in different crystal lattices are modelled atomistically under the condition of constant energy release rate. Stable crack propagation as well as the onset of crack tip instabilities are studied.It will be shown that small overloads lead to stable crack propagation with steady state velocities which quickly reach the terminal velocity of about 0.4 of the Rayleigh wave speed upon increasing the overload. Further increasing the overload does not change the steady state velocity but significantly changes the energy dissipation process towards shock wave emission at the breaking of every single atomic bond. Eventually the perfectly brittle crack becomes unstable, which then leads to dislocation generation and to the production of cleavage steps. The onset of the instability as well as the terminal velocity are related to the non-linearity of the interatomic interaction.

The Mixed Mode I and II Interface Crack in Piezoelectromagneto–Elastic Anisotropic Bimaterials

2006 ◽  
Vol 74 (4) ◽  
pp. 614-627 ◽  
Author(s):  
R. Li ◽  
G. A. Kardomateas
Keyword(s):  
Magnetic Field ◽  
Energy Release Rate ◽  
Energy Release ◽  
Interface Crack ◽  
Release Rate ◽  
Plane Deformation ◽  
Crack Problem ◽  
Crack Tip ◽  
Electro Magnetic ◽  
Anisotropic Bimaterials

Taking the electric–magnetic field inside the interface crack into account, the interface crack problem of dissimilar piezoelectromagneto (PEMO)–elastic anisotropic bimaterials under in-plane deformation is investigated. The conditions to decouple the in-plane and anti-plane deformation is presented for PEMO–elastic biaterials with a symmetry plane. Using the extended Stroh’s dislocation theory of two-dimensional space and the analytic continuition principle of complex analysis, the interface crack problem is turned into a nonhomogeneous Hilbert equation in matrix notation. Four possible eigenvalues as well as four eigenvectors for the fundamental solution to the corresponding homogeneous Hilbert equation are found, so are four modes of singularities for the fields around the interface crack tip. These singularities are shown to have forms of r−(1∕2)±iϵ1 and r−(1∕2)±iϵ2, in which the bimaterial constants ϵ1 and ϵ2 are proven to be real numbers for practical dissimilar PEMO–elastic bimaterials. Compared with the solution for the interface crack of dissimilar elastic bimaterials without electro–magnetic properties, two new additional singularities are discovered for the interface crack in the PEMO–elastic bimaterial media. The electric–magnetic field inside the crack is solved by employing the “energy method,” which is based on finding the stationary point of the saddle surface of the energy release rate with respect to the electro–magnetic field inside the crack. Closed form expressions for the extended crack tip stress fields and crack open displacements are formulated, so are some other fracture characteristic parameters, such as the extended stress intensity factors and energy release rate (G) for dissimilar PEMO–elastic bimaterial solids. Finally, fundamental results and some conclusions are presented, which could have applications in the failure of piezoelectro/magneto–elastic devices.

Evaluation of Transverse Shear Effect on Film Delamination in Blister Test

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Wei Wang ◽  
Yong Huang ◽  
Nicole Coutris ◽  
Hongseok Noh ◽  
Peter J. Hesketh
Keyword(s):  
Film Thickness ◽  
Energy Release Rate ◽  
Energy Release ◽  
Phase Angle ◽  
Release Rate ◽  
Transverse Shear ◽  
Shear Force ◽  
Shear Effect ◽  
Blister Test ◽  
Elastic Mismatch

The transverse shear effect has been frequently ignored in determining the debonding-related energy release rate and the phase angle in the blister test, resulting in underestimated values. This study aims to study the effect of shear force on the energy release rate and phase angle prediction in the blister test. A generalized approach is proposed to predict them under the effect of shear force. The predictions show that when the ratio of the film thickness to the debonded film window radius is large (such as 0.05), the transverse shear effect cannot be ignored in determining the energy release rate and the phase angle. The study also further illustrates the importance of including the shear force contribution in estimation and how this importance depends on the film thickness to debonded radius ratio, as well as the elastic mismatch.

The Dynamic Energy Release Rate for a Steadily Propagating Mode I Crack in an Infinite, Linearly Viscoelastic Body

1990 ◽  
Vol 57 (2) ◽  
pp. 343-353 ◽  
Author(s):  
J. R. Walton
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Viscoelastic Body ◽  
Mode I ◽  
Mode I Crack ◽  
Failure Zone ◽  
Special Cases

An analysis is presented for the dynamic, steady-state propagation of a semi-infinite, mode I crack in an infinite, linearly viscoelastic body. For mathematical convenience, the material is assumed to have a constant Poisson’s ratio, but the shear modulus is only assumed to be decreasing and convex. An expression for the Stress Intensity Factor (SIF) is derived for very general tractions on the crack faces and the Energy Release Rate (ERR) is constructed assuming that a fully developed Barenblatt type failure zone with nonsingular stresses exists at the crack tip and the loadings have a simple exponential form. For comparative purposes, expressions for the ERR are derived for the special cases of dynamic steady-state crack propagation in elastic material and quasi-static crack propagation in viscoelastic material, both with and without a failure zone. Sample calculations are included for power-law material and a standard linear solid in order to illustrate the combined influence of inertial effects, material viscoelasticity, and a failure zone upon the ERR.

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