Dresden 2017 – wissenschaftliches Programm
MM 18: Topical session: Interface-Controlled Microstructures: Mechanical Properties and Mechano-Chemical Coupling - Experimental Characterization
MM 18.4: Vortrag
Montag, 20. März 2017, 18:30–18:45, BAR 205
Experimental determination of interface strength and toughness in multi-layered thin films — Ruth Konetschnik1, Darjan Kozic2, Ronald Schöngrundner2, Hans-Peter Gänser2, Roland Brunner2, and •Daniel Kiener1 — 1Department Materials Physics, Montanuniversität Leoben, Austria — 2Material Center Leoben Forschungs GmbH, Austria
In recent years, ongoing miniaturization has led to increasingly complex thin film combinations and geometries. As macroscale tests are not applicable, miniaturized tests are suggested to study the materials response in state of the art and future devices at small length scales. Here, we concentrate on the local determination of interface strength and toughness in layered thin films also taking into account the residual stresses. The materials investigated are sputter deposited Cu-W-Cu and W-Cu-W trilayer systems, with an individual layer thickness of 500 nm, on a Si substrate. Samples with different geometries such as notched bending beams, double cantilever beams, and miniaturized shear specimens are fabricated via cross section polishing and focused ion beam (FIB) milling to quantitatively test individual interfaces. Subsequently, miniaturized fracture experiments parallel and perpendicular to the interfaces are performed in-situ in the SEM to obtain comprehensive knowledge of the fracture and interface toughness. We emphasize the importance of elastic and plastic incompatibilities and residual stresses when addressing fracture mechanical quantities of multi-layered thin film systems and discuss challenges and benefits of our different approaches.