集成电路互联金属的电迁移效应研究

电迁移效应是因传导电子动量对金属的轰击作用造成金属互连线原子迁移、堆积、断裂的现象，是集成电路损坏的重要原因。本课题用离子束溅射，在介质层上沉积Al，Al—Cu和Cu薄膜，然后对三种薄膜材料进行光刻，得到所需的线条。对经光刻后的各种材质线条通以不同的电流密度，观察电迁移发生的极限电流密度，实验测得Al的极限电流密度为2．706×10^5A／cm^2，含10％Cu的Al—Cu合金的极限电流密度为1．331×10^6A／cm^2，通以Al线条45倍电流密度下，Cu没有观察到电迁移现象。由此可以得出结论，Cu有着很好的抗电迁移性能，在Al中掺入10％左右的Cu可以有效的提高其抗电迁移的能力。

An Investigation of Metal Electromigration in Integrated Circuit Interconnect

Electro--migration is an atomic transport process which results from momentum transfer to the constituent metal atoms due to collisions with the current conduction electrons. As atoms electro--migrate, there is a depletion of material ＂upstream＂ and an accumulation ＂downstream＂ at sites of flux divergence. Electro--migration is the main reliability issue in modern integrated circuits. This study uses ion beam sputtering to deposit Al, Al--Cu and Cu film on medium layers. The method of lithography to get the required lines of the three film materials was used. Different current density was applied to the three lines to observe the limit current density when the electro--migration occurs. The limit current density of AI is 2. 706 × 10^5 A/cm^2 , Al-- Cu was 1. 331 × 10^6 A/cm^2. As to Cu, The electro-- migration effect was mot observed until the current density was more than 45 times of Al limit current density. Conclusively, Cu has the best anti--electro--migration ability, the Al--Cu alloy containing 10% of Cu could better anti -- electro-- migration effect.