金属互连线电迁移的影响因素
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摘要
应用有限元分析软件ABAQUS,对金属互连线的电迁移过程进行了电热耦合仿真分析,比较了不同互连线材料、不同温度、不同层间介质等因素对互连线电迁移失效的影响.结果表明,与铝硅合金互连线相比,在同样电流密度条件下,无论是电势梯度最大值还是热通量最大值,铜互连线的均高于铝互连线的,从而将加速互连线的电迁移;在一定的温度范围内,电流密度是影响互连线电迁移寿命的主要因素,而温度的变化对其影响较小;与SiO_2相比,SiN作为层间介质能够防止互连线中的热聚集,有利于互连线热量的散发,从而对于缓解电迁移具有积极的作用.
The electric-thermal coupling simulation analysis was performed for the electromigration process of metal interconnects based on the ABAQUS software. The influences of the different factors,including interconnects material,temperature and dielectric layer,on the electromigration failure of interconnects were compared. The results indicated that,comparison with the Al-Si alloy interconnects,the maximum value of both potential gradient and heat flux of Cu interconnects are higher for the same current density,which will accelerate the electromigration of interconnects. Comparison with temperature,current density is the major factor for influencing the electromigration lifetime of interconnects in a certain temperature range. As the insulating layer,SiN favors the heat dissipation of interconnects comparison with SiO_2,which can relieve the electromigration failure of interconnects.
The electric-thermal coupling simulation analysis was performed for the electromigration process of metal interconnects based on the ABAQUS software. The influences of the different factors,including interconnects material,temperature and dielectric layer,on the electromigration failure of interconnects were compared. The results indicated that,comparison with the Al-Si alloy interconnects,the maximum value of both potential gradient and heat flux of Cu interconnects are higher for the same current density,which will accelerate the electromigration of interconnects. Comparison with temperature,current density is the major factor for influencing the electromigration lifetime of interconnects in a certain temperature range. As the insulating layer,SiN favors the heat dissipation of interconnects comparison with SiO_2,which can relieve the electromigration failure of interconnects.
引文
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[2]Yang T L,Yu J J,Li C C,et al.Dominant effects of Sn orientation on serrated cathode dissolution and resulting failure in actual solder joints under electromigration[J].Journal of Alloys and Compounds,2015,627(5):281-286.
[3]卢曦,徐艳.典型表面工艺强化对材料强度特性的影响[J].上海理工大学学报,2013,35(2):183-186.Lu Xi,Xu Yan.Investigation on the strength characteristics of material after typical surface strengthen[J].Journal of University of Shanghai for Science and Technology,2013,35(2):183-186.
[4]Cheng Y L,Chang Y M,Leu J,et al.Effect of layout on electromigration characteristics in copper dual damascene interconnects[J].Microelectronic Engineering,2014,128(5):19-23.
[5]Lu Y B,Tohmyoh H,Masumi S.Comparison of stress migration and electromigration in the fabrication of thin Al wires[J].Thin Solid Films,2012,52(9):3448-3452.
[6]Ceric H,Selberherr S.Electromigration in submicron interconnect features of integrated circuits[J].Materials Science and Engineering,2011,71(5-6):53-86.
[7]崔海坡,邓登.铝硅合金互连线电迁移失效试验[J].焊接学报,2015,36(4):21-24.Cui Haipo,Deng Deng.Research on electromigration failure experiment of Al-Si interconnects[J].Transactions of the China Welding Institution,2015,36(4):21-24.
[8]Cher M T,Kelvin N,Chong Y.A reliability statistics perspective on the pitfalls of standard wafer-level electromigration accelerated test(SWEAT)[J].Journal of Electronic Testing Theory and Applications,2001,17:63-68.
[9]Kao C L,Chen T C,Lai Y S,et al.Investigation of electromigration reliability of redistribution lines in wafer-level chip-scale packages[J].Microelectronics Reliability,2014,54(11):2471-2478.
[10]Dandu P,Fan X J,Liu Y,et al.Finite element modeling on electromigration of solder joints in wafer level packages[J].Microelectronics Reliability,2010,50(4):547-555.
[11]Li W,Tan C M.Enhanced finite element modelling of Cu electromigration using ANSYS and matlab[J].Microelectronics Reliability,2007,47(9-11):1497-1501.
[12]Joint Electron Device Engineering Council.JESD63 Standard method for calculating electro-migration model parameters for current density and temperature[S].USA,JEDEC Solid State Technology Association,2007.
[13]梁利华,张元祥,刘勇,等.金属互连结构的电迁移失效分析新算法[J].固体力学学报,2010,31(2):164-172.Liang Lihua,Zhang Yuanxiang,Liu Yong,et al.A new algorithm for electromigration failure analysis of metal interconnects[J].Chinese Journal of Solid Mechanics,2010,31(2):164-172.
[14]Dalleau D.3D time-depending simulation of void formation in metallization structures[D].Hannover:Hannover University,2003.
[15]王家兵,孙凤莲,刘洋.微量元素对无铅焊点电迁移性能的改善[J].焊接学报,2012,33(2):29-32.Wang Jiabing,Sun Fenglian,Liu Yang.Improvement electromigration resistance of Pb-free solder joints with element addition[J].Transactions of the China Welding Institution,2012,33(2):29-32.