Selective Dielectric on Dielectric (DOD) achieved on SiO2 in Preference to Wby 300°C Aniline Passivation and Water-free Chemical Vapor Deposition

A water-free non-plasma process is needed for selective deposition of oxide on oxide for interconnect fabrication to avoid compromising the performance of middle and back end of line (MEOL and BEOL) circuits by edge placement error. A water-free, plasma-free process is most desirable to avoid conductor oxidation and avoid damage to low k hydrophobic dielectrics (SiCOH) as well as to ensure conformality. In the present research, selective HfO
2
and Al2O3 depositions were achieved on SiO
2
in preference to vapor phase aniline passivated W. HfO
2
and Al2O3 were deposited by a single precursor pulsed CVD process with Hf (OtBu)4 at 300°C and aluminum tri-sec butoxide (ATSB) at 330°C respectively. These selective processes were tested on a 50 nm pitch size W/SiO
2
patterned sample. The pulsed CVD process with initial aniline passivation showed around 5 nm of selective oxide deposition on SiO
2
region of the patterned sample.