departmental bulletin paper

Departmental Bulletin Paper

Text

Transactions of JWRI. 2014, 43(2), p. 37-43

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

English

Text

2014-12

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.

10.18910/51359

51359

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

大阪大学接合科学研究所

English

2014-12

Transactions of JWRI

43

2

37

43

https://hdl.handle.net/11094/51359

10.18910/51359

https://doi.org/10.18910/51359