Based On Nanoindentation Experiments Micronanoelectronic Mechanical Properties Characterization Techniques

With the scaling down of device feature size in integrated circuits (IC), it becomes apparent that the mechanical properties of micro-nanoelectronics materials exert increasingly important impact on the reliability of devices, even to that of the entire circuit. Therefore, an effective method of evaluation is needed to characterize the mechanical properties of those materials on nanometer scale. In this thesis, the method of nanoindentation experiment is adopted to conduct research on silicon dioxide thin films and silicon nitride thin films, which are commonly used in IC process, and on Cu/Ta/SiO₂/Si structured multi-layer thin films, which are widely used in copper interconnect. Nanohardness tester is adopted to measure the hardness and elastic modulus of those three kinds of samples respectively. The relationship of hardness and elastic modulus over indentation depth/load is analyzed. The relationship between material performance and nano-mechanical behaviors during the process of indentation is discussed. Furthermore, FIB is adopted to fabricate a cross-section sample of residual indent from the Cu/Ta/SiO₂/Si multi-layer thin film sample. With follow-up TEM observation and EDX spectrum analysis, delamination caused by load exerted is found at Ta/SiO₂ interface. Possible reasons leading to that phenomenon are discussed.Through the research on silicon dioxide thin films, silicon nitride thin films and Cu/Ta/SiO₂/Si multi-layer thin films, nanoindentation method is evaluated concerning the feasibility as an online monitoring method in the process of IC manufacture, the reliability of the test results under the conditions of hard-film-hard-substrate and soft-film-hard-substrate (very common in IC structure), and existing problems and the probability of improvement.