Cyclic etching of tin-doped indium oxide using hydrogen-induced modified layer

Abstract

The rate of etching of tin-doped indium oxide (ITO) and the effects of a hydrogen-induced modified layer on cyclic, multistep thin-layer etching were investigated. It was found that ITO cyclic etching is possible by precisely controlling the hydrogen-induced modified layer. Highly selective etching of ITO/SiO 2 was also investigated, and it was suggested that cyclic etching by selective surface adsorption of Si can precisely control the etch rates of ITO and SiO 2 , resulting in an almost infinite selectivity for ITO over SiO 2 and in improved profile controllability.

One-Step Etching Characteristics of ITO/Ag/ITO Multilayered Electrode in High-Density and High-Electron-Temperature Plasma

“…The plasma chemistry of HCl has similar properties to that of Cl 2 + H 2 ; however, it also produces chlorine and hydrogen ions at a ratio of 1:1 during dissociation, which makes its use a more efficient approach than breaking high-energy bonding hydrogen molecules. Higher H ion bombardment helps to break the oxygen bonds on the ITO surface, and the consequential chemical reactions produce volatile etch products, such as OH [ 28 , 29 , 30 ]. In addition, this process makes the film more accessible, and makes the surface more reactive to the reactive species of chlorine.…”

Damage recovery and low‐damage etching of ITO in H2/CO plasma: Effects of hydrogen or oxygen

“…As the exposure time increased, the hydrogen penetration depth increased. The dominant ion species in H 2 /Ar plasma is known to be H 3 + and the penetration depth of H 3 + is less than 20 nm, as estimated by the SRIM (Stopping and Range of Ions in Matter; http://www.srim.org/) simulations . The V pp of the bottom electrode during H 2 /Ar plasma exposure was about 960 V. The IED is well‐known to be affected by the RF modulation of the sheath voltage and sheath thickness.…”

“…A dual frequency capacitively‐coupled plasma reactor was used for the damage generation and recovery process . The reactor was commercially available, and a wafer with a diameter of 200 mm can be placed on an electrostatic chuck during processing.…”

“…However, the mechanism of etching by hydrogen‐containing plasma still needs to be understood. We have previously proposed ITO etching using H 2 /Ar plasma . For highly selective etching over a dielectric hard mask, CH 4/ H 2 /Ar plasma was also proposed by some researchers .…”

Utilizing surface modification in plasma‐enhanced cyclic etching of tantalum nitride to surpass lithographic limits

“…Sub‐surface modification of films such as Si 3 N 4 and indium‐doped tin oxide (ITO) by low atomic weight ions such as H + has been discussed in literature . This modification typically occurs in the absence of pronounced physical sputtering and drastically affects subsequent etch behavior of the film by chemical or physical processes.…”