US-12624449-B2 - Methods and systems for inhibiting precursor interactions during radical-enhanced atomic layer deposition

Abstract

This disclosure relates to methods and systems for inhibiting precursor interactions during radical-enhanced atomic layer deposition. A substrate may be completely exposed to a precursor gas. Meanwhile, a gaseous radical species is directed through a shroud towards the substrate. The gaseous radical species flows through the shroud under sufficient flow and pressure conditions to substantially prevent the precursor gas from flowing into the shroud. The shroud can be alternately positioned over selected regions of the substrate to thereby alternately expose the selected regions of the substrate to the radical species and the precursor gas multiple times. A thin film of reaction product is formed in the selected regions of the substrate and not on undesired surfaces.

Inventors

• Eric Dickey

Assignees

• LOTUS APPLIED TECHNOLOGY, LLC

Dates

Publication Date

20260512

Application Date

20230828

Claims (19)

1. 1 . A system for depositing a thin film on a substrate, the system comprising: a reaction chamber, including an inlet for introducing a precursor gas into the reaction chamber; a shroud located within the reaction chamber, the shroud positioned such that the inlet is located outside of the shroud to introduce the precursor gas outside of the shroud, the shroud operably coupled to a secondary gas supply system configured to flow a secondary gas into the shroud, the shroud configured to direct the secondary gas towards a substrate, when the substrate is present in the reaction chamber and positioned proximal to a perimeter of the shroud, and so that the secondary gas exits the shroud along the perimeter and into the reaction chamber where the secondary gas mixes with the precursor gas; a radical generator operably coupled to the shroud, the radical generator configured to generate a gaseous radical species from the secondary gas and to introduce the gaseous radical species inside of the shroud, when the secondary gas is present and flowing; and a positioning system configured to alternately position the shroud over selected regions of the substrate, when the substrate is present in the reaction chamber, to thereby alternately expose the selected regions of the substrate to the gaseous radical species and the precursor gas multiple times, each exposure of to the precursor gas resulting in some of the precursor gas adsorbing on the selected regions of the substrate as an adsorbed precursor, and each subsequent exposure of the selected regions of the substrate to the gaseous radical species resulting in some of the radicals converting at least a portion of the adsorbed precursor to a product in the selected regions, whereby a thin film is formed in the selected regions of the substrate; and wherein the shroud further comprises a radical deactivation device including a deactivating surface extending outwardly from the perimeter of the shroud and facing an exposed surface of the substrate, when the substrate is present in the reaction chamber and positioned proximal to the perimeter, to create a gap, between the deactivating surface and the exposed surface of the substrate, through which the gaseous radical species flows as the secondary gas exits the shroud, the deactivating surface sized to allow time for substantial recombination or other deactivation of radicals present in the gaseous radical species as the gaseous radical species flows through the gap, prior to the secondary gas exiting the shroud, to thereby prevent the gaseous radical species from interacting with the precursor gas in the reaction chamber outside of the shroud.
2. 2 . The system of claim 1 , wherein the radical generator is located within an interior of the shroud for generating radicals in-situ from the secondary gas.
3. 3 . The system of claim 2 , wherein the radical generator comprises a plasma generator.
4. 4 . The system of claim 1 , wherein a substrate proximal surface of the radical generator is configured to be in close proximity to the substrate and the shroud comprises a housing sized and configured to surround the radical generator on all sides other than the substrate proximal surface, such that when the secondary gas is present and flowing within the shroud, the shroud directs the secondary gas between the substrate proximal surface of the radical generator and the exposed surface of the substrate.
5. 5 . The system of claim 1 , wherein the reaction chamber includes a printhead within the reaction chamber.
6. 6 . The system of claim 2 , wherein the radical generator comprises a UV light source.
7. 7 . The system of claim 1 , wherein the radical generator is located in a flow path of the secondary gas upstream of an interior volume of the shroud within which the gaseous radical species is introduced, when the secondary gas is flowing.
8. 8 . The system of claim 1 , wherein the deactivating surface is configured to generate laminar flow of the gaseous radical species between the deactivating surface and the exposed surface of the substrate.
9. 9 . The system of claim 1 , wherein the radical deactivation device includes a getter, a catalyst, a charged electrode, or combinations thereof.
10. 10 . The system of claim 1 , further comprising a pump for pumping a continuous flow of the secondary gas into the shroud at sufficient flow and pressure conditions to substantially prevent the precursor gas from flowing into the shroud, during operation.
11. 11 . The system of claim 1 , wherein the positioning system moves the substrate relative to the shroud.
12. 12 . The system of claim 1 , wherein the positioning system moves the substrate in an x-y plane proximal the shroud.
13. 13 . The system of claim 1 , further comprising a carriage configured to rotate axially a cylindrical substrate, rotate radially a circular substrate, advance linearly a rectangular substrate, or advance roll-to-roll a thin film substrate.
14. 14 . The system of claim 13 , wherein the positioning system is configured to move transverse to a direction the carriage is configured to move.
15. 15 . The system of claim 1 , further comprising: additional shrouds located within the reaction chamber, the additional shrouds operably coupled to the secondary gas supply system, the additional shrouds configured to direct the secondary gas towards the substrate, when the substrate is present in the reaction chamber; each of the additional shrouds operably coupled to an additional radical generator, each additional radical generator configured to generate the gaseous radical species from the secondary gas and to introduce the gaseous radical species inside of the additional shroud, when the secondary gas is present and flowing.
16. 16 . The system of claim 15 , wherein some of the additional shrouds are oriented to coat a backside of a substrate opposite the exposed surface of the substrate, when the substrate is present in the reaction chamber.
17. 17 . The system of claim 1 , wherein the deactivating surface is configured to induce turbulent flow of the gaseous radical species in the gap between the deactivating surface and the exposed surface of the substrate.
18. 18 . The system of claim 1 , wherein the positioning system moves the shroud relative to the substrate and the reaction chamber.
19. 19 . The system of claim 1 , wherein the deactivating surface extends from the perimeter of the shroud a distance that is not uniform around the perimeter.

Description

COPYRIGHT NOTICE © 2023 Lotus Applied Technology, LLC. A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 37 CFR § 1.71 (d). CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/500,521 filed May 5, 2023, titled “METHODS AND SYSTEMS FOR INHIBITING PRECURSOR INTERACTIONS DURING RADICAL-ENHANCED ATOMIC LAYER DEPOSITION,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD This disclosure relates generally to manufacturing processes and in particular to methods and systems for inhibiting precursor interactions during radical-enhanced atomic layer deposition. BACKGROUND An overview of conventional ALD processes is provided in Atomic Layer Epitaxy (T. Suntola and M. Simpson, eds., Blackie and Son Ltd., Glasgow, 1990), which is incorporated herein by reference. Numerous patents and publications describe the use of radicals in connection with thin film deposition techniques, including atomic layer deposition (ALD) and sequential chemical vapor deposition. Many chemistries for radical-enhanced ALD (REALD) have been proposed, and many more are expected to be developed in view of the need for efficient production of high-quality thin films in semiconductor manufacturing and other industries. Radicals (also sometimes called “free radicals”) are unstable atomic or molecular species having an unpaired electron. For example, hydrogen gas exists principally in diatomic molecular form, but molecular hydrogen may be split into atomic hydrogen radicals each having an unpaired electron. Many other radical species are known. In embodiments described herein, the radicals produced and used in the thin film deposition process may include highly-reactive radical gas species formed of a single element such as hydrogen, nitrogen, oxygen (e.g. ozone), or chlorine, as well as compound radicals such as hydroxide (OH). U.S. Pat. No. 8,187,679, titled “Radical-Enhanced Atomic Layer Deposition System and Method,” incorporated herein by reference, described systems and methods for ALD in which oscillating, reciprocating, or circular movement of a substrate can be employed to accomplish ALD processes using precursor radicals that are continuously introduced into a reaction space by a steady-state radical source. The gaseous radical species is maintained in a radicals zone within the reaction chamber while a precursor gas is introduced into a precursor zone. The precursor zone is spaced apart from the radicals zone to define a radical deactivation zone therebetween. A need exists for REALD methods and systems that allow precursor gas to be present throughout a reaction chamber. BRIEF DESCRIPTION OF THE DRAWINGS The embodiments disclosed herein will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. The drawings depict primarily generalized embodiments (and are not necessarily to scale), which embodiments will be described with additional specificity and detail in connection with the drawings in which: FIG. 1 illustrates a cross-sectional view of one embodiment of an exemplary system for inhibiting precursor interactions during radical-enhanced atomic layer deposition. FIG. 2A illustrates a cross-sectional view of one embodiment of an exemplary shroud according to the methods and systems disclosed herein. FIG. 2B illustrates a plan view of the shroud of FIG. 2A. FIG. 3A illustrates a cross-sectional view of one embodiment of an exemplary shroud according to the methods and systems disclosed herein. FIG. 3B illustrates a plan view of the shroud of FIG. 3A. FIG. 4A illustrates a cross-sectional view of one embodiment of an exemplary shroud according to the methods and systems disclosed herein. FIG. 4B illustrates a plan view of the shroud of FIG. 4A. FIG. 5A illustrates a cross-sectional view of one embodiment of an exemplary shroud according to the methods and systems disclosed herein. FIG. 5B illustrates a plan view of the shroud of FIG. 5A. FIG. 6A illustrates a cross-sectional view of one embodiment of an exemplary shroud according to the methods and systems disclosed herein. FIG. 6B illustrates a plan view of the shroud of FIG. 6A. FIG. 7 illustrates a cross-sectional view of one embodiment of an exemplary shroud according to the methods and systems disclosed herein. FIG. 8 illustrates a cross-sectional view of one embodiment of an exemplary shroud and electrode according to the methods and systems disclosed herein. FIG. 9 illustrates a cross-sectional view of one embodiment of an exemplary shroud and electrode according to the methods and systems