Effect of Cu3Sn coatings on electromigration lifetime improvement of Cu dual-damascene interconnects
Effect of Cu3Sn coatings on electromigration lifetime improvement of Cu dual-damascene interconnects
复制标题
DOI：
10.1063/1.2132536
复制
发表时间：
2005-11
影响因子：
4
通讯作者：
M. Yan;J. Suh;F. Ren;K. Tu;A. V. Vairagar;S. Mhaisalkar;A. Krishnamoorthy
中科院分区：
文献类型：
--
作者：
M. Yan;J. Suh;F. Ren;K. Tu;A. V. Vairagar;S. Mhaisalkar;A. Krishnamoorthy
在Cu互连表面上覆盖一层20 nm厚的Cu3Sn金属间化合物可以有效地阻断主要的表面扩散路径，从而使电迁移寿命提高了近一个数量级。这种改进可以解释为基于梯田-壁架-扭结模型，在该模型中，铜表面台阶上的扭结上的原子解离导致的铜原子的供应被更强的Sn原子与扭结位点的化学结合所阻碍。电迁移失效的模式似乎已经从阴极表面经角扩散引起的孔洞形成转变为互连线上界面和晶界扩散引起的孔洞形成。
A 20 nm thick Cu3Sn intermetallic compound overlayer on Cu interconnect surfaces was found to effectively block dominant surface diffusion paths, thus resulting in close to one order of magnitude improvement in electromigration lifetimes. This improvement may be explained on the basis of the terrace-ledge-kink model in which the supply of Cu adatoms by the dissociation of atoms from the kinks on the Cu surface steps is hindered by a stronger chemical binding of Sn atoms to the kink sites. The mode of electromigration failures seem to have changed from surface diffusion-induced void formation at the cathode via corner to interfacial and grain-boundary diffusion-induced void formation in the interconnect line.