Formation of SiOF Films by Plasma-Enhanced Chemical Vapor Deposition Using (C₂H₅O)₃SiF

Abstract

A new Plasma-Enhanced Chemical Vapor Deposition (PECVD) method using (C2H5O)3SiF: tri-ethoxy-fluoro-silane as an interlayer dielectric film is proposed based on considerations of gas chemistry. RF power dependence of the film characteristics is investigated, and it is clarified that fluorine stability is improved with increasing RF power. The relative dielectric constant of the films deposited at the power of more than 700 W is about 3.5. Moisture absorption of the film formed from TEFS at 900 W is smaller than that of the SiOF film formed from C2F6 added TEOS.

Dielectric behavior of triethoxyfluorosilane aerogels

“…The peaks at about 930 and 980 cm À1 are Si-F and Si-O, respectively [17]. The overall normalized difference in the peak height change from r ¼ 2 to 6 is about 0.02 Si-O-Si rocking for the peak at 980 cm À1 and is about 0.04 for the peak at about 930 cm À1 for the acid-catalyzed samples.…”

“…This group will appear in the FTIR spectra in the same regions as the siloxane bonding and therefore can easily be masked [17]. Unreacted alkoxy groups can have peaks appear at about 1100-1020, 810-800, and 500-405 cm À1 , all of which would be masked by the Si-O-Si peaks [17]. The peaks in the above mentioned regions are broad in the FTIR spectra indicating more than one species could be present.…”

“…The peak assignments are tabulated in Table 1 [7,8,[15][16][17][18][19]. The Si-O-Si peak due to asymmetrical stretching is present at about 1085 cm À1 .…”

“…It is proposed that the peak at about 980 cm À1 is due to Si-O stretching. Long chain siloxane polymers have been reported to have two maxima at about 1085 and 1025 cm À1 [17]. An increase in water will affect the disorder of the microstructure.…”

“…It should be noted that not all of the alkoxy groups of the precursor will have been reacted with water when r ¼ 2, resulting in incomplete hydrolysis and condensation. This group will appear in the FTIR spectra in the same regions as the siloxane bonding and therefore can easily be masked [17]. Unreacted alkoxy groups can have peaks appear at about 1100-1020, 810-800, and 500-405 cm À1 , all of which would be masked by the Si-O-Si peaks [17].…”