Interconnect Failure Analysis And Reliability Modeling Of The Thermo-optic Effect VOA

The continuous development of micro-fabrication technique has promptednumerous production of optoelectronic products which represented by thermo-opticaleffect devices. However, due to the rapid development of the manufacturingtechnology, the device reliability has faced the great challenge at the same time, whichinclude the higher processing density, shorter interconnection lines and the increasingpower density. Nowadays, the reliability models based on the statistical method aremainly used for traditional optical products. It is hard to reveal the relation between thefailure mechanisms and reliability of the new thermo-optic effect of optoelectronicdevices.This dissertation focuses on the highly integrated modern optoelectronic deviceswith short interconnections. The fundamental cause of device failure and relationshipbetween the failure and reliability are researched based on the failure physics theory.The reliability model of the fault mechanism analysis was established by this theory.And the failure modes of the thermo-optic VOA devices were found through thesimulation and test.Firstly, the deeply study on the microscopic behavior of the device failure wascarried out based on the working principle and processing characteristics of thethermo-optic VOA device. The effect of current and temperature on the interconnectionlines was revealed by theoretical and experimental research. According to the results ofreliability test, it is discovered that the damage of heating interconnection line was theorigin of failure and interconnect electromigration was the main failure mechanism.Then, a reliability model was established under complex conditions of multi-physicalquantities.Secondly, the finite element model of heating interconnects among thethermo-optic VOA devices was built by ANSYS according to the theoretical researchresults, to conduct electric coupling simulation. The relationships among the failureregularities, current density and temperature gradient of thermo-optic VOA heatinginterconnects were studied. The results of simulation validated the correctness of theconclusion above.Finally, through the reliability lifetime test, the electromigration failuremechanism of the interconnection lines was researched. The test samples which wasdesigned to simulate the thermo-optic VOA was manufactured. Based on the results ofreliability test, valuable ideas were proposed to alleviate the influence ofelectromigration and optimize the interconnection structures of the thermo-optic VOAdevices.