Impact of reductive N{sub 2}/H{sub 2} plasma on porous low-dielectric constant SiCOH thin films

Journal Article · Wed Jun 01 04:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1926392· OSTI ID:20711702

Hao, Cui; Carter, Richard J; Moore, Darren L; Peng, Hua-Gen; Gidley, David W; Burke, Peter A ^[1]

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1. LSI Logic Corporation, 23400 NE Glisan Street, Gresham, Oregon 97030 (United States)

Porous low-dielectric constant (low-{kappa}) SiCOH thin films deposited using a plasma-enhanced chemical-vapor deposition have been comprehensively characterized before and after exposure to a reactive-ion-etch-type plasma of N{sub 2} and H{sub 2} chemistry. The low-{kappa} film studied in this work is a carbon-doped silicon oxide film with a dielectric constant ({kappa}) of 2.5. Studies show that a top dense layer is formed as a result of significant surface film densification after exposure to N{sub 2}/H{sub 2} plasma while the underlying bulk layer remains largely unchanged. The top dense layer is found to seal the porous bulk SiCOH film. SiCOH films experienced significant thickness reduction, {kappa} increase, and leakage current degradation after plasma exposure, accompanied by density increase, pore collapse, carbon depletion, and moisture content increase in the top dense layer. Both film densification and removal processes during N{sub 2}/H{sub 2} plasma treatment were found to play important roles in the thickness reduction and {kappa} increase of this porous low-{kappa} SiCOH film. A model based upon mutually limiting film densification and removal processes is proposed for the continuous thickness reduction during plasma exposure. A combination of surface film densification, thickness ratio increase of top dense layer to bulk layer, and moisture content increase results in the increase in {kappa} value of this SiCOH film.

• OSTI ID: 20711702
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON
CHEMICAL VAPOR DEPOSITION
DIELECTRIC MATERIALS
DOPED MATERIALS
ETCHING
HYDROGEN
LAYERS
LEAKAGE CURRENT
MOISTURE
PERMITTIVITY
PLASMA
POROUS MATERIALS
SEMICONDUCTOR MATERIALS
SILICON OXIDES
SPUTTERING
SURFACES
THICKNESS
THIN FILMS