Study On Failure Determination Method Of Metal Electromigration In Deep Submicron Copper Interconnect Process

With the continuous evolution of semiconductor technology,the continuous reduction of critical dimensions in the process,and the substitution of new materials,there will be fundamental changes in the generation mechanism of leakage current,grain growth method and so on,leading to the challenge on failure judgment method in reliability testing.In the metal electromigration test,it was found that the determination method of “a certain percentage change in resistance value as a criterion for electromigration failure” cannot meet the requirements of advanced technology anymore.However,there are no corresponding latest standards in the world.The goal of this article is to define the failure determination method for a failure-type reliability test project for an unconventional failure mode.The research consists the root cause and failure model of occurring multiple trip points in the metal electro-migration(EM)test of the destructive reliability test project,and the time-to-failure judgment method is defined accordingly.It tries to find a reasonable theoretical model and accurately define of the failure reliability test items,such as the determination of the failure time of metal electro-migration(EM)tests.This article presents the basic knowledge of metal electromigration as a reliability project from the reliability principle,the basic concept of metal electromigration,the current status of metal electromigration failure determination methods,and the metal electromigration life model.Then by studying the EM resistance degradation curves under different processes,we find different feature points on the degradation curve,calculate the failure time for these feature points,compare the failure time distribution characteristics of different feature points,and design the experiment at the feature point of the degradation curve to conduct failure analysis.Combining with the international literature,the first jump is considered as a new failure criterion for metal electromigration,which is more in line with the failure mechanism.In the process of analysis,the abnormal electromigration failure can be found,which is more conducive to the accurate evaluation of electromigration life.