An Approach for the Characterization of the Adhesion Strength Degradation of Semiconductor's Thin Film Metallizations
Internally funded project
Start date : 01.09.2021
End date : 30.09.2023
Project details
Short description
The research project is being worked on as part of a PhD project in collaboration with the Fraunhofer Institute for Integrated Systems and Device Technology (IISB).
In this project a method to characterize the adhesion strength of thin film metallization on semiconductors is developed first. Furthermore, the degradation behavior of the adhesion strength of thin film metallization is investigated and characterized for the first time.
Scientific Abstract
The thin film metallization, as a key structure of the semiconductor devices, realizes the bond-ability of the chips on circuit carriers and directly influences the electrical and mechanical reliability of the interconnection. One of the reliability issues of thin film metallization is delamination due to its adhesion strength degradation in operation. To investigate the degradation behavior of the thin film metallization, its adhesion strength needs to be quantitatively characterized.
In a previous study, a recently developed method, cross-sectional nanoindentations (CSN), has been utilized to characterize the adhesion strength of the brittle thin film quantitatively. With the help of elastic plate theory, the strain energy release rate of the thin film which is the required specific elastic strain energy to result in delamination can be calculated. However, due to the high ductility of the metal, the current technology is not suitable for thin film metallization.
In this project, a combined experimental and numerical approach is developed. In the experiment, the thin film is tested by CSN and its delamination behavior is statistically analyzed. In the finite-element model, the plastic dissipation of the thin film is separately considered during the delamination. By using the CSN-induced crack profiles from the experiment, the parameters of the cohesive zone model in simulation which can describe the thin film adhesion strength can be inversely identified. Finally, with this approach, the adhesion strength degradation behavior of a standard thin film system in temperature cycling test (TCT) is investigated and characterized.
