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 TiO 2 using organo-amine precursor and O 2 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-TiO 2 process. Fluorine gas NF 3 allows (1) to etch the TiO 2 layer on Si, SiO 2 , or SiN surface while keeping few nanometers of TiO 2 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/SiO 2 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.

Atmospheric Pressure Plasma Deposition of TiO2: A Review

“…In a previous PEALD study, a typical cycle was used to deposit TiO 2 thin films, while Al-doped TiO 2 thin films were deposited in a supercycle, which was made up of a number of cycles of Ti precursor followed by one cycle of Al precursor [ 68 ]. Recently, a supercycle process was used to selectively deposit TiO 2 on defined regions over substrates by intercalation of plasma etching cycles in PEALD [ 69 ]. In this approach, three steps were performed as is presented in Figure 3 .…”

“…Schematic of an atomic layer selective deposition process as an alternative method for three-dimensional patterning. The supercycle consists of three steps, in which (1) nucleation times on two substrates (A and B) differ due to different surface chemistries on each surface; (2) a precise and selective plasma etching process is used to remove undesired growth on substrate B; and (3) chemical passivation is used to prevent material growth on substrate B. Reprinted with permission from[69]. Copyright (2019), American Vacuum Society.…”

Plasma deposition—Impact of ions in plasma enhanced chemical vapor deposition, plasma enhanced atomic layer deposition, and applications to area selective deposition

“…Finally, one can also want different properties for a unique material (resistivity, transparency), or varying chemical and/or structural composition (crystallinity, density, roughness, doping level) as a function of a surface or a space direction. Selective deposition by ALD can be obtained using: inherent selectivity of the process [66][67][68][69][70] , surface activation 71 , surface deactivation [72][73][74][75][76][77][78][79][80] , and super-cycles ABC type 81 or with alternate deposition and etching steps 58,[82][83][84][85] . As in PECVD and PEALD processes, ions from the plasma can be used in any of these steps and therefore help to promote a selective deposition.…”

“…One last approach for selective deposition is to exploit ions from the plasma for an in situ etching step during the PEALD process, so-called ASD by deposition/etching or supercycles (see some examples here 58,[82][83][84][85] ). The sidewall deposition illustrated in Figure 16 can be easily obtained without modifying the nature of the deposited film if an anisotropic etching cycle is added to the PEALD cycles, as shown Figure 19.…”

Atomic layer deposition and selective etching of ruthenium for area-selective deposition: Temperature dependence and supercycle design

“…17 To obtain a sufficiently high selectivity, it is necessary to employ methods that involve an intermittent correction or cleaning step to remove material from the non-growth area during the deposition process. 10,[18][19][20][21] Interestingly, the use of "cleaning steps" has already been reported several decades ago for area-selective epitaxy of Si. 22,23 By adding an etchant gas such as HCl to the Si source gas, unwanted Si nuclei on SiO 2 or Si 3 N 4 are removed, resulting in area-selective CVD of Si on Si growth areas.…”