@phdthesis{Kutukova2023, author = {Kutukova, Kristina}, title = {In-situ study of crack propagation in patterned structures of microchips using X-ray microscopy}, doi = {10.26127/BTUOpen-6256}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-62567}, school = {BTU Cottbus - Senftenberg}, year = {2023}, abstract = {The motivation of this thesis was to control crack steering into regions of engineered 3D-nanopatterned structures with high fracture toughness and to determine the local critical energy release rate for crack propagation in 3D-nanopatterned systems. On-chip copper interconnect structures of advanced microchips, insulated by organosilicate glasses, were chosen as an example system to study fracture on small scale, since this is a well-defined 3D- nanopatterned system and since a high mechanical robustness is requested for microchips. An experiment for in-situ high-resolution 3D imaging of the fracture behavior of 3D-nanopatterned structures and of the kinetics of microcrack propagation in solids was designed and applied, combining a miniaturized micromechanical test and high-resolution X-ray imaging. Particularly, a miniaturized piezo-driven double cantilever beam test set-up (micro- DCB) was integrated in a laboratory X-ray microscope, and nano X-ray computed tomography was applied for high-resolution 3D imaging of the microcrack evolution in the on-chip interconnect stack of microchips manufactured in the 14 nm technology node. The measured geometry of the microcrack at several loading steps during the micro-DCB test and the subsequent data analysis based on linear elastic fracture mechanics and the Euler-Bernoulli beam model were the basis for the development and application of a new methodology to determine the critical energy release rate for crack propagation in sub- 100 nm regions of a processed wafer quantitatively. It was experimentally proven that specially designed metallic guard ring structures at the rim of the microchips dissipate energy in such a way that the microcrack propagation is efficiently slowed down and eventually stopped, i.e. they are effective to prevent mechanical damage of microchips. It was demonstrated that it is possible to steer the microcrack in a controlled way by tuning the fracture mode mixity locally at the crack tip. The established concept for a controlled crack propagation provides the basis for further fundamental studies of the fracture behavior of nanoscale materials and structures. The results have significant effects for the understanding of fracture mechanics at small scales, e.g. in microchips, but also in other nanopatterned materials, e.g. in bio-inspired, hierarchically structured engineered materials. The experimental results gathered at realistic microelectronic products provide valuable information to control the crack path in on-chip interconnect stacks for design-for-reliability in semiconductor industry and to manufacture mechanically robust microchips in leading-edge technology nodes. The experimental study of controlled microcrack steering into regions with high fracture toughness provides knowledge for the design of guard ring structures in microchips to stop the propagation of microcracks, e.g. generated during the wafer dicing process.}, subject = {R{\"o}ntgenmikroskopie; In-situ-Rissausbreitung; On-Chip-Interconnect-Stacks; Bruchmechanik; Schutzringstrukturen; X-ray microscopy; In-situ crack propagation; On-chip interconnect stacks; Fracture mechanics; Guard ring structures; Rissausbreitung; Mikroriss; Bruchverhalten; Bruchmechanik; Nanostrukturiertes Material; Chip; R{\"o}ntgenmikroskopie}, language = {en} }