AN SIO2 FILM DEPOSITION TECHNOLOGY USING TETRAETHYLORTHOSILICATE AND OZONE FOR INTERLAYER METAL DIELECTRICS

A void-free SiO2 interlayer dielectric film formation technology has b een developed. This technology utilizes tetraethylorthosilicate [TEOS, Si(OC2H5)(4)]/ozone (O-3) atmospheric pressure chemical vapor deposit ion (APCVD) SiO2 film gap-filling, and the TEOS-based dual frequency p lasma enhanced vapor deposition (PECVD) SiO2 film as an underlayer of TEOS/O-3 APCVD SiO2 film. This technology enables the formation of voi d-free SiO2 interlayer dielectric films without any pretreatment for t he underlayer between aluminum wirings line and Space of 600 and 600 n m, respectively. Single-frequency PECVD SiO2 films are also applied as an underlayer of TEOS/O-3 APCVD SiO2 gap-filling. However, void-free gap-filling cannot be achieved, even using the single frequency PECVD SiO2 underlayer. To clarify the mechanism of the void-free gap-filling , the underlayer PECVD SiO2 film properties are investigated. The SiO2 film density at the Al wiring pattern's sidewall of the dual-frequenc y PECVD SiO2 films is equal to that at the pattern's bottom, while the density at the pattern's sidewall formed using single-frequency PECVD SiO2 films is lower than that at the pattern's bottom. The carbon con centration for the dual-frequency PECVD SiO2 films is lower than that for the single-frequency PECVD SiO2 films. The H2O and acetaldehyde (C H3CHO) detected from the dual-frequency PECVD SiO2 films due to the ox idation of the ethoxy group, is much more than that from the single-fr equency PECVD SiO2 films. Based on the experimental results, the mecha nism of void-free gap-filling of TEOS/O-3 APCVD SiO2 films is consider ed to consist of three steps; (i) involving R ions (R, alkyl group) in to the PECVD SiO2 films during film deposition, (ii) Si-OR bonds forma tion at the PECVD SiO2 films' surface, and (iii) oligomers flow at TEO S/O-3 APCVD SiO2 film deposition. It is considered that the oligomers flow is promoted by the Si-OR bonds, resulting in the void-free gap-fi lling. The dual-frequency PECVD SiO2 films can improve the gap-filling of TEOS/O-3 APCVD SiO2 films.