Measurement of the Mode Mix Dependent Interfacial Fracture Toughness for a Ti/Si Interface Using a Modified Decohesion Test

2003 ◽  
Author(s):  
Mitul B. Modi ◽  
Suresh K. Sitaraman
Keyword(s):  
Fracture Toughness ◽  
Crack Surface ◽  
Unit Area ◽  
Interfacial Fracture ◽  
Analytical Models ◽  
Interfacial Fracture Toughness ◽  
Testing Methods ◽  
Available Energy ◽  
Test Parameters ◽  
Toughness Testing

The Modified Decohesion Test (MDT), developed by the authors, eliminates shortcomings of current interfacial fracture toughness testing methods. In this approach, a highly stressed super layer is used to drive delamination and create any mode mix at the crack tip. MDT uses the change in crack surface area to vary the available energy per unit area for crack growth and thus to bound the interfacial fracture toughness. Therefore, this technique uses a single sample to measure the interfacial fracture toughness, as opposed to the decohesion test that uses several samples to be able to bound the interfacial fracture toughness. Since the deformations remain elastic, a mechanics-based solution can be used to correlate test parameters to the energy release rate. Common IC fabrication techniques are used to prepare the sample and execute the test, thereby making the test compatible with current microelectronic or MEMS facilities. In this paper, the mechanics based solution used in the MDT to correlate test parameters to the fracture metrics is discussed and compared against other analytical models. Interfacial fracture toughness results are provided for a Ti/Si interface at several mode mixes.

Interfacial Fracture Toughness Measurement of a Ti/Si Interface

2004 ◽  
Vol 126 (3) ◽  
pp. 301-307 ◽  
Author(s):  
Mitul Modi ◽  
Suresh K. Sitaraman
Keyword(s):  
Fracture Toughness ◽  
Interfacial Fracture ◽  
Interfacial Fracture Toughness ◽  
Thermally Induced ◽  
Adhesive Layers ◽  
Available Energy ◽  
Fracture Toughness Measurement ◽  
Test Parameters ◽  
Metal Layers ◽  
Toughness Measurement

Titanium adhesive layers are commonly used in microelectronic and MEMS applications to help improve the adhesion of other metal layers to a silicon substrate. Such Ti/Si interfaces could potentially delaminate under externally applied mechanical loads, thermally induced stresses, or process-induced intrinsic stresses or a combination of these different loads. In order to design against delamination, knowledge of the interfacial fracture toughness of the Ti/Si interface is necessary. However, interfacial fracture toughness data for such interfaces is not widely available in the open literature, in part due to the difficulty in measuring the strength of thin film interfaces. The Modified Decohesion Test (MDT), a new test developed by the authors, has been used to characterize the mode mix dependent interfacial fracture toughness of a Ti/Si interface. In this approach, a highly stressed super layer is used to drive delamination and generate any mode mix at the crack tip. MDT uses the change in crack surface area to vary the available energy per unit area for crack growth and thus to bound the interfacial fracture toughness. Therefore, this technique uses a single sample to measure the interfacial fracture toughness. Since the deformations remain elastic, a mechanics-based solution can be used to correlate test parameters to the energy release rate. Common IC fabrication techniques are used to prepare the sample and execute the test, thereby making the test compatible with current microelectronic or MEMS facilities. Using the MDT, interfacial fracture toughness (Γ) bounds were found for a Ti/Si interface at three mode mixes. At a mode mix of 19.5 deg, 5.97J/m2⩽Γ⩽7.87J/m2, at a mode mix of 23 deg, 9.32J/m2⩽Γ⩽10.42J/m2, and at a mode mix of 30 deg, 12.70J/m2⩽Γ⩽17.02J/m2.

Interfacial Fracture Toughness of a Plasma Sprayed Hydroxyapatite Coating Used for Orthopedic Implants

1998 ◽  
Vol 550 ◽  
Author(s):  
Y. Sugimura ◽  
M. Spector
Keyword(s):  
Fracture Toughness ◽  
Elastic Modulus ◽  
Adhesion Strength ◽  
Unit Area ◽  
Interfacial Fracture ◽  
Orthopedic Implants ◽  
New Method ◽  
Aqueous Environment ◽  
Interfacial Fracture Toughness ◽  
Plasma Sprayed

AbstractThis study introduces a new method for evaluating the adhesion strength of a coating on a substrate. The interfacial fracture toughness, Γi is used to assess the work per unit area required to separate an interface. Γi is measured for the as-received specimens of hydroxyapatite plasma sprayed on Ti-6A1-4V substrate. Calculation of the interfacial fracture toughness requires that the elastic modulus of the coating to be known. The Young's modulus of the plasma sprayed hydroxyapatite is assessed using a bend test. The effect of aqueous environment on the interfacial fracture toughness is also investigated.

Modified Decohesion Test (MDT) for Interfacial Fracture Toughness Measurement in Microelectronic/MEMS Applications

2002 ◽  
Author(s):  
Mitul B. Modi ◽  
Suresh K. Sitaraman
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Fracture Toughness ◽  
Energy Release ◽  
Physical Vapor Deposition ◽  
Interfacial Fracture ◽  
Interfacial Fracture Toughness ◽  
Testing Methods ◽  
Structural Variations ◽  
Metal Thin Film

Delamination of intrinsically or residually stressed thin films is commonly encountered in microelectronics and MEMS systems. Thin films typically accrue stresses through micro structural variations caused by physical vapor deposition, thermally induced stresses imposed due to thermal mismatch, and/or extrinsically introduced forces. These stresses can reach upwards of 1 GPa and can easily exceed the strength of the metal thin film interface. Knowledge of the interfacial fracture toughness (Γ) is necessary to predict if delamination will occur. However, measuring Γ is a challenge for thin film interfaces. Typical testing methods such as bimaterial cantilever, microscratch, peel, bulge, or edge lift-off are limited to organic films, cause complex stress fields, can only measure a single mode mix, or cannot achieve the large energy release rates typical of metal thin film interfaces. A new approach based on the decohesion test, called the modified decohesion test (MDT), eliminates these shortcomings of current testing methods. In this approach, a highly stressed super layer is used to drive delamination and “tune-in” the mode mix at the crack tip. Since the deformations remain elastic, a mechanics-based solution can be used to correlate test parameters to the energy release rate. Common IC fabrication techniques are used to prepare the sample and execute the test, thereby making the test compatible with current microelectronic or MEMS facilities. Varying the crack surface area rather than the energy in the super layer allows the ability to bound Γ using a single test wafer providing a 90% savings in resources and 95% savings in time. Other modifications allow application of the method to highly chemically reactive metals and decrease the sample preparation time. Design, preparation, and execution of the MDT are presented. Results of finite element models are used to validate the approach. Results are shown for a Ti/Al2O3 interface.

scholarly journals Evaluation of the Interfacial Fracture Toughness of Anodic Bonds

2007 ◽  
Vol 73 (735) ◽  
pp. 1266-1272 ◽  
Author(s):  
Yoshiaki NOMURA ◽  
Masaki NAGAI ◽  
Toru IKEDA ◽  
Noriyuki MIYAZAKI
Keyword(s):  
Fracture Toughness ◽  
Interfacial Fracture ◽  
Interfacial Fracture Toughness

scholarly journals Evaluation of Interfacial Fracture Toughness and Interfacial Shear Strength of Typha Spp. Fiber/Polymer Composite by Double Shear Test Method

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2225 ◽  
Author(s):  
Ikramullah ◽  
Samsul Rizal ◽  
Yoshikazu Nakai ◽  
Daiki Shiozawa ◽  
H.P.S. Abdul Khalil ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Shear Strength ◽  
Interfacial Shear Strength ◽  
Epoxy Composite ◽  
Interfacial Fracture ◽  
Interfacial Shear ◽  
Composite Model ◽  
Interfacial Fracture Toughness ◽  
Double Shear ◽  
The Matrix

The aim of this paper is to evaluate the Mode II interfacial fracture toughness and interfacial shear strength of Typha spp. fiber/PLLA and Typha spp. fiber/epoxy composite by using a double shear stress method with 3 fibers model composite. The surface condition of the fiber and crack propagation at the interface between the fiber and the matrix are observed by scanning electron microscope (SEM). Alkali treatment on Typha spp. fiber can make the fiber surface coarser, thus increasing the value of interfacial fracture toughness and interfacial shear strength. Typha spp. fiber/epoxy has a higher interfacial fracture value than that of Typha spp. fiber/PLLA. Interfacial fracture toughness on Typha spp. fiber/PLLA and Typha spp. fiber/epoxy composite model specimens were influenced by the matrix length, fiber spacing, fiber diameter and bonding area. Furthermore, the interfacial fracture toughness and the interfacial fracture shear stress of the composite model increased with the increasing duration of the surface treatment.

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