磁控溅射沉积Cu-W薄膜的特征及热处理的影响

采用磁控共溅射法制备含钨1.51%~14.20%(原子分数,下同)的Cu-W合金薄膜,并用EDX、XRD、SEM、显微硬度仪和电阻仪研究了其成分、结构及性能。结果表明,添加W可显著细化Cu-W薄膜基体相晶粒,晶粒尺寸随W含量的增加而减小,Cu-W薄膜呈纳米晶结构。Cu-W薄膜中存在W在Cu中形成的fcc Cu(W)非平衡亚稳过饱和固溶体,固溶度随W含量的增加而提高,最大值为10.65%。与纯Cu膜对比发现,薄膜的显微硬度和电阻率总体上随W含量的增加而显著增大。经200℃、400℃及650℃热处理1h后,Cu-W薄膜基体相晶粒长大,EDX分析显示晶界处出现富W第二相;薄膜显微硬度降低,电阻率下降,降幅与退火温度呈正相关。添加W引起的晶粒细化效应以及退火中基体相晶粒度增大分别是Cu-W薄膜微观结构和性能形成及演变的主要原因。

Characteristics of Cu-W Thin Films Deposited by Magnetron Sputtering and Effect of Heat-treatment

Cu-W alloy thin films with W content of 1.51%～14.20% were deposited by magnetron co-sputtering.The composition,structure,properties of Cu-W thin films were investigated by EDX,XRD,SEM,microhardness instrument and resistivity meter.The results show that W addition leads to grain refinement significantly,and the grain size reduces with the W content increasing.Cu-W thin films possess fcc Cu(W) non-equilibrium metastable supersaturated solid solution,the W solubility increases with the incremental W concentration,and the maximum W solubility is 10.65%.Comparison with pure Cu films,it can be found that the microhardness and electrical resistivity of Cu-W thin films increase with the adding of W concentration in the films generally.After heat treatment at 200℃,400℃ and 650℃ for 1h,the grain sizes of the matrix phases of Cu-W films grow up,and the submicron W-rich se-cond-phase is observed at the grain boundary of Cu-W films.Both of the microhardness and electrical resistivity of Cu-W thin films decrease,and the reduction extent has positive correlation with annealing temperature.It is considered that the formation and evolution of the microstructure and the properties of Cu-W thin films can be mainly attributed to the grain refining effect of W addition as well as the growth of matrix grain sizes in annealing process,respectively.