Synthesis Using Cu(Ti) Alloy Films for Self-Forming Functionality in Electronic Devices

• Kohama Kazuyuki

• Ito Kazuhiro

抄録

Cu interconnects have been used extensively in ULSI devices. However, large resistance-capacitance delay and poor device reliability have been critical issues as the device feature size has reduced to nanometer scale. In order to achieve low resistance and high reliability of Cu interconnects, we have proposed a process forming a thin Ti-based self-formed barrier (SFB) after annealing a Cu(Ti) alloy film deposited on dielectrics at elevated temperatures. Identification of Ti-based SFB was conducted using the electron diffraction, X-ray photoelectron spectroscopy, and the Rutherford backscattering spectrometry techniques. Those indicate that the Ti-based SFB consists of mainly amorphous Ti oxides for any kinds of dielectrics. Small amount of cystalline Ti compounds such as TiC, TiN, TiSi was dependent on a kind of dielectrics. The Ti-based SFB growth was concluded to be controlled by a thermally activated process. The activation enery and the pre-exponential factor values decreased with decreasing C concentration in dielectrics, suggesting that the growth is controlled by a chemical reactions of Ti atoms with dielectrics. The process was applied to 45 nm-node dual damascene interconnects and evaluated its performance. The microstructure analysis by transmission electron microscope and energy dispersive X-ray fluorescence spectrometer showed the 2 nm-thick Ti-based SFB at the interface between a Cu wire and low-k dielectrics. The line resistance and via resistance significantly decreased compared with those when using the conventional Ta/TaN barrier. The stress migration performance was also drastically improved using the SFB process. A performance of time dependent dielectric breakdown revealed superior endurance. These results suggest that the Ti-based SFB process is one of the most promising candidates for advanced Cu interconnects. This process using Ti as an alloy element can be applied for Cu-interconnect formation in electronic devices such as TFT-LCDs.

収録刊行物

• Transactions of JWRI

  Transactions of JWRI 43 (2), 37-43, 2014-12

  大阪大学接合科学研究所

キーワード

• Cu(Ti) alloy films
• Cu interconnects
• Resistivity
• Diffusion barrier
• Adhesion

詳細情報

• CRID: 1390575727755591296
• NII論文ID: 120005588197
• NII書誌ID: AA00867058
• DOI: 10.18910/51359
• HANDLE: 11094/51359
• ISSN: 03874508
• 本文言語コード: en
• データソース種別:
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  • IRDB
  • CiNii Articles