AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP10
Physical Characterization of the Etching of Low-k Hydrogen SilsesQuioxanes (HSQ) Dielectrics under Medium and High Density Plasma Conditions

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: C.H. Low, Chartered Semiconductor Manufacturing Limited, Singapore
Authors: C.H. Low, Chartered Semiconductor Manufacturing Limited, Singapore
H. Cong, Chartered Semiconductor Manufacturing Limited, Singapore
P. Yelehanka, Chartered Semiconductor Manufacturing Limited, Singapore
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The interconnect technology ventures into the development of low-k inter-metal dielectrics integration, arising from the need to reduce interconnect delay.@footnote 1@ The evolution of new low-k dielectric materials posts challenges to the conventional oxide etching processes.@footnote 2@ Hydrogen SilsesQuioxanes (HSQ)-based Flowable-Oxide (FOx), similar in composition as conventional oxide while offering low k values of 2.9 - 3.0, is used as the low-k IMD materials in our studies. The direct-on-metal (DOM) approach is employed for the integration of FOx as IMD layer for sub-0.25 micron application.@footnote 3,4@ The FOx layer is further capped with a thick PETEOS film, preventing it from degradation when subjected to subsequent high temperature processing steps. The etching of FOx integrated IMD stack is carried out using both TEL 85 DRM medium density plasma etcher and LAM TCP 9100 high density plasma etcher with different fluorocarbon etch chemistry. The physical characterization of the etching of FOx IMD stack under both conditions is demonstrated. In both cases, the FOx IMD vias are successfully opened with reasonably straight profiles. While high density plasma etching posesses in-situ PR strip capability for process simplification, it is also shown to induce more Si-H loss in the FOx layer. On the other hand, less damage is introduced to the FOx layer when etching under medium density plasma condition. Etch rate studies of FOx film cured at different temperature and duration as well as the film properties changes upon etching are also investigated. This is for better understanding of the etch process capability when subjected to different film curing conditions. @FootnoteText@ @footnote 1@L. Peters, Semicon. Int'l, p.64, Sep. 1998. @footnote 2@T.E.F.M. Standaert et.al., Mat. Res. Soc. Symp. Proc., p.265, vol.511, 1998. @footnote 3@B.T. Ahlburn et.al., Conf. Proc. ULSI XI, p.67, 1996. @footnote 4@Technical notes from Dow Corning Corp..