Area selective deposition of TiO2 by intercalation of plasma etching cycles in PEALD process: A bottom up approach for the simplification of 3D integration scheme

Abstract

A selective deposition process for bottom-up approach was developed in a modified plasma enhanced atomic layer deposition (PEALD) sequence. As a case study, a very standard PEALD TiO2 using organo-amine precursor and O2 plasma is chosen. The metal oxide selectivity is obtained on TiN versus Si-based surfaces by adding one etching/passivation plasma step of fluorine every n cycles in a PEALD-TiO2 process. Fluorine gas NF3 allows (1) to etch the TiO2 layer on Si, SiO2, or SiN surface while keeping few nanometers of TiO2 on the TiN substrate and (2) to increase the incubation time on the Si-based surface. Quasi-in situ XPS measurements were used to study the incubation time between Si/SiO2 substrates versus TiN substrate. Results show that Si–F bonds are formed on Si and lock the surface reactions. The effectiveness of this atomic layer selective deposition method was successfully tested on a 3D patterned substrate with the metal oxide deposited only at the edge of metal lines.