Peter Wai-Man Lee

Dielectric Constant and Stability of Fluorine‐Doped Plasma Enhanced Chemical Vapor Deposited SiO2 Thin Films

As device geometry shrinks to 0.35 μm and below, the parasitic capacitance between closely spaced metal lines becomes important in terms of resistance-capacitance time delay in device switching. In this study, we investigated the use of fluorine doped plasma enhanced chemical vapor deposition grown silicon oxide thin film as a low dielectric constant intermetal dielectric material. We evaluated C 2 F 6 and an organometallic liquid source triethoxyfluorosilane as the F dopant. It was found that the dielectric constant generally decreased as the F concentration increased. However, we also found that above a certain F concentration, the F-doped oxide film would become unstable and absorb moisture from the ambient. At similar F concentrations, the films deposited with the liquid source are always more stable than those deposited with C 2 F 6 . This, in addition to the different stress vs. low frequency radio frequency power behavior between the two types of film, suggests that the already present Si-F bond in the liquid precursor results in a denser and more stable film compared to the C 2 F 6 doped film where interstitial F may be present.

Dielectric constant and stability of fluorine doped PECVD silicon oxide thin films

Abstract As device geometry shrinks to 0.35 mm and below, the parasitic capacitance between closely spaced metal lines becomes important in terms of RC time delay in device switching. In this study, we investigated the use of fluorine doped plasma enhanced chemical vapour deposition (PECVD) grown silicon oxide thin film as a low dielectric constant inter-metal dielectric (IMD) material. We evaluated C2F6 and an organometallic liquid source as the F dopant. It was found that the dielectric constant generally decreased as the F concentration increased. However, we also found that above certain F concentration, the F-doped oxide film would become unstable and absorb moisture from ambient. At similar F concentrations, the films deposited with the liquid source are always more stable than those deposited with C2F6. This, in addition to the different stress versus low frequency rf power behaviour between the two types of film, suggests that the already present SiF bond in the liquid precursor results in a denser and more stable film comparing to the C2F6 doped film where interstitial F may be present.

Improved gap-filling capability of fluorine-doped PECVD silicon oxide thin films

Abstract Fluorine-doped plasma-enhanced chemical vapour deposition (PECVD) tetraethylorthosilicate (TEOS) SiO 2 thin film was investigated for improvement in gap-filling capability as an inter-metal dielectric. Both C 2 F 6 and triethoxyfluorosilicate (TEFS) were evaluated as fluorine (F) dopants. Both kinds of F-doped films provided significantly better gap-filling capability than undoped films. This was attributed to the good bottom-step coverage and preferential sidewall etching due to the presence of F. However, there was a markedly different relationship between gap-filling capability and F concentration for the two dopant precursors. Finally, it was shown that either C 2 F 6 or TEFS doping can extend the gap-filling capability of SiO 2 down to 0.35 μm metal spacing with an aspect ratio of 2.0:1.

Multi-generation CVD low /spl kappa/ films for 0.13 /spl mu/m and beyond

After several delays in the implementation of /spl kappa/<3.0 inter metal dielectric, the semiconductor industry has finally begun to use these low /spl kappa/ materials in manufacturing in 2001. After several years of intense industry wide evaluation and assessment, the most critical requirements for these materials were identified to be high mechanical strength, low cost, high productivity and extendibility to at least another generation. CVD low /spl kappa/ films, IMD film black diamond (BD) and barrier/etch stop film BLO/spl kappa/, have become the materials of choice for 0.13 /spl mu/m an below generation IMD because of their silicon oxide like materials properties, proven manufacturability using time-tested familiar PECVD tool sets, and the recently proven extendibility to /spl kappa/<2.5. This paper focuses on the characteristics and performance of these materials both in Cu damascene integration and in production environment.

Effects of PE-TEOS process on O3-TEOS characteristics and device reliability

This work studies the effect of PE-TEOS underlayer on O3-TEOS based intermetal dielectric (IMD) in terms of gap filling, moisture resistance, and device reliability. PE-TEOS films investigated here were formed by mixed-frequency plasma process and were differed by their reaction oxidizers and/or plasma powers. It is found that the bottom and sidewall step coverages of PE-TEOS vary with processing conditions, with both degrading as nitrogen content or film stress increases. By optimizing the underlayer thickness voidless gap fill has been achieved by O3-TEOS for 0.5 micrometers generation. To eliminate moisture absorption the deposited O3-TEOS was then integrated with SOG etchback for planarization. The integrated IMD has been evaluated by hot carrier stressing, which suggests that increasing PE-TEOS stress helps improve device reliability. For a fixed stress, the increased amount of oxygen or nitrogen also help inhibit hot carrier aging. To obtain best device reliability, a tradeoff exists between the moisture resistance and gap filling capability of PE-TEOS underlayer.