Nitrogen-doped fluorinated-silicate-glass (N-FSG) films were prepared by adding N-2 gas to the SiH4/SiF4/O-2/Ar gas mixtures using high-density-plasma (HDP) chemical vapor deposition method. When N-2 is increasingly added, the fluorine concentration of the films increases and the dielectric constant decreases from 3.8 to 3.4. In addition, better gap-filling ability is obtained by adding N-2 due to a lowered deposition/(sputtering+etching) (D/S+E) ratio. Moreover, these films were stabilized by a decreased change in dielectric constant after thermal treatment; indicating a significant improvement in the thermal resistivity of the films. It is proposed that the improvement of stability is correlated with the reduction of unstable fluorine bonds in the N-FSG films. Furthermore, the thermal stability of the N-FSG films was also identified by Al wiring delamination check. After annealing, the blister was observed only in non-N-2 FSG film with 5.5% Si-F concentration, while no blisters or delamination were observed when N-2 is introduced into the FSG process. Therefore, the N-FSG film, deposited by HDP-chemical vapor deposition, was a good candidate for the interconnect dielectric application. (c) 2008 American Vacuum Society.
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JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A Volume: 26 Issue: 3 Pages: 481-484
