Effects of Ag Addition on the Resistivity, Texture and Surface Morphology of Cu Metallization
Effects of Ag Addition on the Resistivity, Texture and Surface Morphology of Cu Metallization
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DOI：
10.1143/jjap.44.l1278
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发表时间：
2005-09
影响因子：
1.5
通讯作者：
Bin Zhao;Hoon Kim;Y. Shimogaki
中科院分区：
文献类型：
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作者：
Bin Zhao;Hoon Kim;Y. Shimogaki
在铜中掺杂某些元素已被证明是提高铜互连线可靠性的一种很有前途的方法。本文选择银作为合金元素，因为它的体电阻率低，在铜中的溶解度低。采用真空分层蒸发和沉积后退火的方法制备了铜银合金薄膜。薄膜的电阻率随退火温度的升高而降低。在400℃下热处理后，由于Cu-Ag系统具有负的偏析能，大部分Ag原子偏聚到薄膜表面。通过比较纯铜薄膜和铜-银薄膜在退火过程中的织构演化，发现Ag的加入通常会延缓合金薄膜的织构发展。真空退火使铜银薄膜表面变得更加粗糙。研究了合金化对铜在TaN基片上团聚的影响，结果表明，Ag的加入可能会破坏铜在TaN基片上的润湿性。提出了改善铜合金表面形貌的可能方法。
Doping Cu with some elements has been proved to be a promising method to improve the reliability of Cu interconnects. In this paper, Ag was chosen as the alloying element because of its low bulk resistivity and low solubility in Cu. Cu–Ag alloy film was prepared by layered evaporation and postdeposition annealing in vacuum. The resistivity of the films decreased with annealing temperature. After annealing at 400°C, most of the Ag atoms were segregated to the film surface because Cu–Ag system had a negative segregation energy. By comparing the texture evolution of pure Cu film and Cu–Ag films during annealing, it was found that Ag addition usually retarded the texture development of the alloy film. Vacuum annealing resulted in a rougher surface for the Cu–Ag films. The investigation of alloying effect on Cu agglomeration on TaN substrate suggested that Ag addition might impair the Cu wettability on TaN substrate. Possible methods for improving the surface morphology of Cu alloy were also proposed.