EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Mechanical properties of materials in small dimensions have become an important area of fundamental research, including the development and introduction of new techniques for micro- and nanomechanical testing. A miniaturised micro double-cantilever beam test (micro-DCB) setup was designed and integrated into a laboratory transmission X-ray microscopy (TXM) tool to study the fracture behaviour in skeleton materials, composites and nanopatterned structures in microchips [1]. In-situ mechanical studies in a nano X-ray computed tomography (nano-XCT) system allow a 3D visualization of the micro-crack evolution in materials or in microchips with a spatial resolution of about 100 nm. During the micro-DCB experiment, the load is applied perpendicular to the optical axis of the X-ray microscope while images are collected. A force sensor allows to determine the mechanical load at certain stages of crack propagation. The local energy release rate can be determined quantitatively. The in-situ micro-DCB technique offers several benefits over existing methods and is applicable across a range of disciplines, including materials science (e.g. composites, porous materials), microelectronics (e.g. interconnect stacks), and life sciences (e.g. tissue, bones). High-resolution 3D image sequences based on nano-XCT are used to visualize crack opening and propagation in fully integrated multilevel on-chip interconnect structures of integrated circuits. The nondestructive study of the propagation of microcracks during the in-situ micro-DCB test allows to image cohesive failures in organosilicate glass (so-called low-k materials) or adhesive failure, i.e. delamination along Cu/dielectrics interfaces. Weakest layers and interfaces in the interconnect stack can be identified.
[1] K. Kutukova, S. Niese, J. Gelb, R. Dauskardt, E. Zschech, „A Novel Micro-Double Cantilever Beam (micro-DCB) Test in an X-ray Microscope to Study Crack Propagation in Materials and Structures“, Mater. Today Comm. 16, 293–299 (2018)