材化毕业论文.doc

摘　　要 与传统的金属互连材料Al相比Cu具有更低的电阻率，更好的抗电迁徙性能和更高的热传导系数采用Cu作为互连线材料可大大提高电路的运算速度与可靠性，铜已经取代了铝成为新一代的互连材料。但Cu在Si和Si的氧化物中扩散相当快且Cu一旦进入其中即形成深能级杂质对器件中的载流子具有很强的陷阱效应使器件性能退化甚至失效。而要解决Cu扩散问题同时增强Cu与介质的附着力必须在Cu与Si或SiO2之间增加一个扩散阻挡层。Ta-Si-NTa-Si-N的电阻率大于600μΩ.cm不能很好地满足未来电路高速运行的特点。 本文设计了一种新型的Ta-Si-N/Zr阻挡层旨在降低阻挡层与Cu膜和Si间的接触电阻，提高电路的运行速度。首先通过射频磁控溅射Si基片上沉积Ta-Si-N/Zr薄膜，然后在阻挡层上沉积Cu膜。为了研究Cu/Ta-Si-N/Zr/Si体系的热稳定性，本文将在高纯N2环境下对试样退火1小时，退火温度从600℃到800℃。最后使用XRD、AES、SEM、XPS以及FPP等方法对试样进行热稳定性评价。 实验结果表明Ta-Si-N/Zr薄膜在750℃时仍能有效的阻挡Cu的扩散。通过750℃退火处理后，体系中生成的ZrSi2明显降低阻挡层与Si基片之间的电阻。 关键词:Ta-Si-N/Zr；扩散阻挡层；Cu互连Abstract To reduce the interconnection delay, Cu metallization is taking the plaee of traditional Al intereonnection due to its lower resistivity and superior resistanec to electromigration. However, adhesion of Cu to Si substrate is poor. In addition, Cu atoms are quite mobile and can diffuse into Si easily, which leads to formation of Cu-Si Compounds. Cu atoms act as deep level impurities, affecting the reliability of devices.Therefore, it is necessary to add diffusion batrier between Si and Cu. This paper will introduce a barrier layer of Ta-Si-N/ Zr which may reduce the contact resistance between Cu and Si. The Ta-Si-N/Zr bilayer film was grown on n-type (100) silicon wafer by RF magnetron sputtering, followed by insitu deposition of Cu. The Cu/Ta-Si-N/Zr/Si samples were subsequently annealed at different temperatures ranging from 600 to 750℃ in N2 gas for 1h. In order to investigate the thermal stability of the barrier structure, X-ray diffraction (XRD), Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and 4-point probe technique (FPP) were performed respectively. The results revealed that Ta-Si-N/Zr film can serve as effective diffusion barriers up to 750℃. After annealing at 750℃, the production of ZrSi2 layer can effectively decrease contact resistance between barrier and Si. Keywords: Ta-Si-N/Zr; Diffusion barrier; Cu interconnection; RF magnetron sputtering 目　　录 第1章　绪论 1 1.1　集成电路金属互连材料的