Reliability Analysis And Modeling Of Thermo-optical Devices Using Physics-of-Failure Approach

Due to the unique physical properties of thermo-optical effect, new photoelectron devices have been developed continuously and played a very important role in the optical communication industry. However, the manufacturing technology of thermo-optical devices is difference from that of traditional devices. And the integration of devices is becoming higher and higher because of the harsh market demands. Thus, there is a severe challenge to the reliability of thermo-optical devices. In fact, traditional reliability model developing based on the statistical method is time-consuming and costly. And beside the difficulty of finding failure mechanism, it is almost impossible to reveal the relationship between failure mechanism and reliability of new thermo-optical effect devices.In order to meet the demand for the improvement of reliability of thermo-optical devices, the failure modes were investigated. The fundamental cause of device failure and relationship between the failure and reliability were researched using physics-of-failure approach. Based on these research, the general reliability mathematical model and simulation model were established respectively.Firstly, the deeply study on the failure behavior of heating interconnection was carried out based on the working principle and fabrication process of thermo-optical variable optical attenuator. The possible failure reasons were deduced through the theoretical and experimental research. According to the results of environmental simulation test, the effects of multi-physics fields, including electromigration, mass diffusion etc, would cause the failure of interconnection.Secondly, a mathematical model under complex conditions of multi-physics was established based on classical theoretical model. This model would reveal the relationship between lifetime and multi-physics. The finite element model of interconnection was built by ANSYS, to conduct thermoelectric and thermomechanical analysis. The relationships among the failure regularities, temperature and stress gradient of interconnection were studied. In order to predict lifetime of interconnection, the method of element birth and death was used to discover the failure course of interconnection.Finally, through the reliability lifetime test, the rationality of mathematical model and simulation model was proved. Based on the research of this thesis, some valuable ideas were proposed to improve the reliability of devices. The technical support and theoretical base for processing optimization were also offered.