ISSN:
1572-8978
Keywords:
hexamethyldisiloxane
;
tetrafluoroethylene
;
octafluorocyclobutane
;
plasma
;
chemical vapor deposition
;
low dielectric constant
;
intermetal dielectric
;
in situ Fourier transform infrared spectroscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Technology
Notes:
Abstract Plasma copolymerization of hexamethyldisiloxane (HMDSO,(CH3)3-Si-O-Si-(CH3)3) and C4F8 was performed using an RF plasma enhanced chemical vapor deposition method for application to low dielectric constant intermetal dielectrics. Structure of the films was investigated by X-ray photoelectron spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. The film composition was controlled gradually from fluorinated carbon to organic siloxane by changing the mixing ratio of HMDSO/Ar. Dielectric constant of the films ranged from 2–3.3. Thermal stability of the films, which was characterized by intensity loss of IR absorbance peak around 1000–1500 cm−1 corresponding to C-F n , Si-O-Si and Si-(CH2)n-Si bonds, was inferior to that from C2F4/HMDSO/Ar. In situ gasphase FT-IR spectroscopy revealed that there was a marked difference between the gas phase of C4F8/HMDSO/Ar and that of C2F4/HMDSO/Ar discharges. The IR spectrum of the former combination plasma contained a peak at 1250 cm−1 with full width at half maximum as large as 150 cm−1, which suggests that fluorocarbon particles and/or dusts are formed in the plasma. This suggests also that deposition precursors are not only CF n (n = 1, 2, and 3) but also larger precursors such as C x F y (x 〉 1, y 〈 2x + 2) in C4F8/HMDSO/Ar discharges, which is presumably the cause of difference in thermal stability of the films prepared from C4F8/HMDSO/Ar and C2F4/HMDSO/Ar mixtures.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1021803615715
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