Thermal stability of barrierless Cu–Ni–Sn films
Thermal stability of barrierless Cu–Ni–Sn films
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DOI：
10.1016/j.apsusc.2014.01.084
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发表时间：
2014-04
影响因子：
6.7
通讯作者：
X. Li;Minhuan Wang;L. Zhao;C. Bao;J. Chu;C. Dong
中科院分区：
文献类型：
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作者：
X. Li;Minhuan Wang;L. Zhao;C. Bao;J. Chu;C. Dong
为了提高Cu-Ni-Sn种子层在界面反应中的热稳定性，本文研究了基于团簇+胶原子模型组成的Cu-Ni-Sn种子层。在该模型中，Sn通过Ni溶解在Cu中，Ni与Cu和Sn均可溶解，稳定的固溶体为[Sn - ni12]Cux，其中以Sn为中心的[Sn - ni12]八面体簇嵌在FCC Cu原子基体中。采用磁控溅射技术在Si（1 0 0）衬底上沉积了不同Ni/Sn比的Cu-Ni-Sn薄膜，并对其微观结构和电阻率进行了表征。（Sn1.1/13.1Ni12/13.1）0.3Cu99.7（at.%）薄膜的Ni/Sn组成比接近模型理想的12/1值，在500℃/1 h退火条件下，其电阻率最小为2.7 μΩ cm。在400°C/40 h退火后，电阻率仍保持在2.8 μΩ cm以下。XRD和TEM均未观察到硅化铜，但有微量的Cu - sn化合物析出。Sn在固溶体中以Ni为中间体，具有较好的扩散抑制作用。
To increase the thermal stability against interface reaction, barrierless Cu–Ni–Sn seed layers, with compositions formulated according to the cluster-plus-glue-atom model for stable solid solutions, was investigated in this paper. In this model, Sn is dissolved in Cu via Ni which is soluble both with Cu and with Sn, and the stable solid solution is formulated as [Sn–Ni12]Cux, where the Sn-centered [Sn–Ni12] octahedral clusters are embedded in an FCC Cu matrix ofxatoms. Cu–Ni–Sn films with various Ni/Sn ratios were deposited onto the Si(1 0 0) substrate by magnetron sputtering and were characterized for microstructure and for electrical resistivity. The (Sn1.1/13.1Ni12/13.1)0.3Cu99.7(at.%) film, with its Ni/Sn composition ratio being close to the ideal 12/1 value of the model, showed the minimum electrical resistivity of 2.7 μΩ cm on 500 °C/1 h annealing among all the samples. The resistivity maintained as low as 2.8 μΩ cm even after 400 °C/40 h annealing. No Cu silicide was observed by XRD and TEM in this sample, though a minute amount of fine Cu–Sn compound precipitates was present. The superior diffusion inhibiting effect was attributed to Sn in solid solution via intermediate of Ni.