Dielectric-on-Dielectric Achieved on SiO₂ in Preference to W by Water-free Chemical Vapor Depositions with Aniline Passivation

Abstract

Selective and smooth dielectric-on-dielectric was achieved by water-free single-precursor chemical vapor deposition (CVD) processes with the help of aniline passivation. Aniline selective passivation was demonstrated on W surfaces in preference to SiO 2 at 250, 300, and 330 °C. After aniline passivation, selective HfO 2 , Al 2 O 3 , and TiO 2 were deposited only on the HF-cleaned SiO 2 surface by water-free single-precursor CVD using hafnium tert-butoxide Hf(O t Bu) 4 , aluminum-tri-sec-butoxide (ATSB), and titanium isopropoxide Ti(O i Pr) 4 as the precursor reactants, respectively. Hf(O t Bu) 4 and Ti(O i Pr) 4 single-precursor CVD was carried out at 300 °C, while the ATSB CVD process was conducted at 330 °C. HfO 2 and Al 2 O 3 nanoselectivity tests were performed on W/ SiO 2 patterned samples. Transmission electron microscopy images of the W/SiO 2 patterned samples after deposition demonstrated nanoselectivity and low surface roughness of HfO 2 and Al 2 O 3 deposition on the SiO 2 regions only.

Low-k SiOx/AlOx Nanolaminate Dielectric on Dielectric Achieved by Hybrid Pulsed Chemical Vapor Deposition

“…In previous studies on water-free selective oxide deposition, water-free pulsed CVD has been shown to exhibit faster growth on metal surfaces compared to SiO 2 . 8 This phenomenon is particularly evident on W metal surfaces, which tend to undergo oxidation. Because of this facile oxidation, W has a propensity to favor the formation of hydroxyl groups and oxide layers.…”

“…Because of this facile oxidation, W has a propensity to favor the formation of hydroxyl groups and oxide layers. 8 To inhibit oxide growth on metals and allow growth on dielectrics, aniline passivation is required. The passivation ability of aniline was tested on HFcleaned SiO 2 , degreased Si 3 N 4 , and degreased W substrates with the pulsed AlO x (ATSB) CVD.…”

“…7 There are previous reports of 5 nm selective deposition of AlO 2 , TiO 2 , and HfO 2 on SiO 2 in preference to W with 300 °C aniline passivation. 8 These AlO 2 , TiO 2 , and HfO 2 DOD depositions were achieved by water-free pulsed CVD using tris(2-butoxy)aluminum (ATSB), hafnium tert-butoxide, and titanium isopropoxide, respectively. 9−11 In the present study, a "water-free process" denotes the absence of water as a coreactant; however, a minute quantity of water might be formed by dehydration reactions of the alkoxy precursor With a dielectric constant of 3.9, SiO 2 has an acceptable lowk value widely used in the semiconductor industry.…”

“…In a previous study, pulsed CVD AlO x DOD was successfully deposited on SiO 2 and not on the W surface. 8 By utilizing aniline passivation, ATSB alone proved capable of depositing up to 4 nm of selective DOD on SiO 2 surface at 330 °C. 8 This present report documents the benefits of merging the area-selective ATSB process with the low-k catalytic-based SiO 2 /Al 2 O 3 nanolaminate process.…”

“…8 By utilizing aniline passivation, ATSB alone proved capable of depositing up to 4 nm of selective DOD on SiO 2 surface at 330 °C. 8 This present report documents the benefits of merging the area-selective ATSB process with the low-k catalytic-based SiO 2 /Al 2 O 3 nanolaminate process. Through this combination, a selective low-k dielectric on dielectric can be achieved by using the novel hybrid two-temperature pulsed CVD leveraging the advantages of both techniques.…”