Short-ranged structural rearrangement and enhancement of mechanical properties of organosilicate glasses induced by ultraviolet radiation

Journal Article · Wed Mar 01 00:00:00 EST 2006 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2178393· OSTI ID:20787927

Iacopi, F; Travaly, Y; Eyckens, B; Waldfried, C; Abell, T; Guyer, E P; Gage, D M; Dauskardt, R H; Sajavaara, T; Houthoofd, K; Grobet, P; Jacobs, P; Maex, K ^[1]

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1. IMEC, Kapeldreef 75, B-3001 Leuven (Belgium)

The short-ranged bonding structure of organosilicate glasses can vary to a great extent and is directly linked to the mechanical properties of the thin film material. The combined action of ultraviolet (UV) radiation and thermal activation is shown to generate a pronounced rearrangement in the bonding structure of thin organosilicate glass films involving no significant compositional change or film densification. Nuclear magnetic resonance spectroscopy indicates loss of -OH groups and an increase of the degree of cross-linking of the organosilicate matrix for UV-treated films. Fourier transform infrared spectroscopy shows a pronounced enhancement of the Si-O-Si network bond structure, indicating the formation of more energetically stable silica bonds. Investigation with x-ray reflectivity and ellipsometric porosimetry indicated only minor film densification. As a consequence, the mechanical properties of microporous organosilicate dielectric films are substantially enhanced while preserving the organosilicate nature and pristine porosity of the films. UV-treated films show an increase in elastic modulus and hardness of more than 40%, and a similar improvement in fracture energy compared to untreated films. A minor increase in material dielectric constant from 3.0 to 3.15 was observed after UV treatment. This mechanism is of high relevance for the application of organosilicate glasses as dielectric materials for microelectronics interconnects, for which a high mechanical stability and a low dielectric constant are both essential film requirements.

• OSTI ID: 20787927
• Journal Information: Journal of Applied Physics, Vol. 99, Issue 5; Other Information: DOI: 10.1063/1.2178393; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
CHEMICAL BONDS
CROSS-LINKING
DIELECTRIC MATERIALS
ELLIPSOMETRY
FOURIER TRANSFORM SPECTROMETERS
FRACTURES
GLASS
HARDNESS
INFRARED SPECTRA
MICROELECTRONICS
NUCLEAR MAGNETIC RESONANCE
PERMITTIVITY
POROUS MATERIALS
REFLECTIVITY
SILICA
SPECTROSCOPY
THIN FILMS
ULTRAVIOLET RADIATION
X RADIATION